Note: Descriptions are shown in the official language in which they were submitted.
CA 02550804 2008-07-31
WO 2005/070679 PCT/AU2004/000070
PRINTHEAD ASSEMBLY AND PRINTIIEAD MODULE FOR SAME
FIELD OF THE INVENTTON
The present invention relates to a printhead unit for use in a printing
system. More particularly, the
present invention relates to a printhead assembly which is mountable to and
demountable from a printing unit,
a printhead module of the printhead assembly and a method of assembling. such,
and various components of
the printhead assembly, including a print circuit boarcL
15
BACKGROUND OF THE INVENTION
Pagewidth printheads, for use in printing systems, are known. Such printheads
typically span the
width of the print media on which information is to be printed, and as such
the dimensions and configuration
of the printheads vary depending upon the application of the printing system
and the dimensions of the print
media. In this regard, due to the large variation in the required dimensions
of such printheads, it is difficult to
manufacture such printheads in a manner which caters for this variability.
Accordingly, the applicant has proposed the use of a pagewidth printhead made
up of a plurality of
replaceable printhead tiles arranged in an end-to-end manner. Each of the
tiles mount an integrated circuit
incorporating printing nozzles which eject printing fluid, e.g., ink, onto the
print media in a known fashion.
Such an arrangement has made it easier to manufacture printheads of variable
dimensions and has also enabled
the ability to remove and replace any defective tile in a pagewidth printhead
without having to scrap the entire
printhead.
However, apart from the ability to remove and replace any defective tiles, the
previously proposed
printhead is generally formed as an integral unit, with each component of the
printhead fixedly attached to
other components. Such an arrangement complicates the assembly process and
does not provide for easy
disassembly should the need to replace components other than just the
defective tiles be necessary.
Accordingly, a printhead unit which is easier to assemble and disassemble and
which is made up of a number
of separable individual parts to form a printhead unit of variable dimensions
is required.
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SUMMARY OF THE INVENTION
In one embodiment of the present invention, there is provided a printhead
module for a printhead
assembly, comprising a unitary arrangement of a support member, at least two
printhead integrated circuits,
each of which has nozzles formed therein for delivering printing fluid onto
the surface of print media, at least
one fluid distribution member mounting the at least two printhead integrated
circuits to the support member,
and an electrical connector for connecting electrical signals to the at least
two printhead integrated circuits,
wherein the support member has at least one longitudinally extending channel
for carrying the
printing fluid for the printhead integrated circuits and includes a plurality
of apertures extending through a
wall of the support member arranged so as to direct the printing fluid from
the at least one channel to
associated nozzles in both, or if more than two, all of the printhead
integrated circuits by way of respective
ones of the fluid distribution members.
The unitary arrangement of the printhead module allows it to be removably
mounted to the printhead
assembly.
The support member may be formed with a plurality of the channels, each of
which is arranged to
carry a different printing fluid for direction to associated groups of the
nozzles in the both, or if more than two,
all of the printhead integrated circuits by way of respective ones of the
fluid distribution members. A further
channel for delivering air to the printhead integrated circuits for
maintaining the nozzles of the printhead
integrated circuits substantially free from impurities may be provided.
The use of separate fluid distribution members supporting individual ones of
the printhead integrated
circuits provides printhead tiles. Each of these tiles/fluid distribution
members may be formed as a laminated
stack of at least three layers comprising an upper layer upon which the
associated printhead integrated circuit
is mounted, a middle layer and a lower layer which is attached to an upper
surface of the support member.
The lower layer includes first distribution apertures arranged to align with
respective ones of the
apertures in the support member and first distribution channels in an upper
surface thereof associated with
respective ones of the first distribution apertures, the first distribution
apertures having substantially the same
diameter as the apertures in the support member.
The middle layer includes second distribution apertures arranged to align with
the first distribution
channels of the lower layer, the second distribution apertures having a
smaller diameter than the first
distribution apertures.
The upper layer includes second distribution channels in a lower surface
thereof arranged to align
with the second distribution apertures of the middle layer and third
distribution apertures associated with the
second distribution channels, the third distribution apertures having a
smaller diameter than the second
distribution apertures.
The associated printhead integrated circuit include nozzle supply apertures
arranged to align with the
third distribution apertures of the upper layer and to direct fluid to
respective ones of the nozzles, the nozzle
supply apertures having substantially the same diameter as the third
distribution apertures, with the apertures
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of the support member having a diameter of the order of millimetres and the
nozzle supply apertures of the at
least two printhead integrated circuits having a diameter of the order of
micrometres.
For attaching the fluid distribution member(s) to the support member, a lower
surface of the fluid
distribution member(s) may be attached to the upper surface of the support
member by an adhesive material.
This adhesive material may be used to form a seal between the respective
apertures by being deposited to
surround each of the apertures of the support member and each of corresponding
apertures formed in the lower
surface of the fluid distribution member(s).
In an arrangement having the apertures of the support member formed in a row
extending across the
support member with respect to the longitudinally extending direction of the
support member, two deposits of
the adhesive material may be deposited on either side of the row of apertures
to provide stability for the
mounting arrangement. The adhesive material may be a curable resin.
In another embodiment of the present invention, there is provided a printhead
module for a printhead
assembly, comprising at least two printhead integrated circuits, each of which
has nozzles formed therein for
delivering printing fluid onto the surface of print media, and a support
member supporting the printhead
integrated circuits,
wherein the support member has a plurality of longitudinally extending
channels for carrying
different printing fluids for the printhead integrated circuits, and
the support member is selectable to meet specific requirements as to the
number of said printing
fluids to be employed for printing.
In another embodiment of the present invention, there is provided a printhead
module for a printhead
assembly, comprising at least two printhead integrated circuits, each of which
has nozzles formed therein for
delivering printing fluid onto the surface of print media, a support member
supporting the printhead integrated
circuits and at least two fluid distribution members individually mounting a
respective one of the at least two
printhead integrated circuits to the support member,
wherein the support member has at least one longitudinally extending channel
for carrying the
printing fluid for the printhead integrated circuits and includes a plurality
of apertures extending from the at
least one channel through a wall of the support member, and
each of the fluid distribution members is formed as a laminated stack of
layers for directing the
printing fluid from the apertures of the support member to the nozzles of the
associated printhead integrated
circuit.
In another embodiment of the present invention, there is provided a printhead
module for a printhead
assembly, comprising at least one printhead integrated circuit having nozzles
formed therein for delivering
printing fluid onto the surface of print media, a support member supporting
and carrying printing fluid for the
at least one printhead integrated circuit, and at least one fluid distribution
member mounting the at least one
printhead integrated circuit to the support member and distributing the
printing fluid from the support member
to the printhead integrated circuit,
wherein a lower surface of the at least one fluid distribution member is
attached to an upper surface
of the support member by an adhesive material.
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In another embodiment of the present invention, there is provided a method of
assembling a printhead
module for a printhead assembly, the method comprising the steps of:
mounting at least two printhead integrated circuits to an upper surface of at
least one fluid
distribution member, the at least two printhead integrated circuits each
having nozzles formed therein for
printing fluid onto the surface of print media; and
fixedly attaching with an adhesive material a lower surface of the at least
one fluid distribution
member onto an upper surface of a support member having fluid delivery
channels for the nozzles of the at
least two printhead integrated circuits, so as to form a unitary arrangement
of the support member, the at least
two printhead integrated circuits and the at least one fluid distribution
member.
The method may further comprise the step of adhering an electrical connector
to a section of the
upper surface of the fluid distribution member for connecting electrical
signals to the printhead integrated
circuits. The adhesive material used may be a curable resin, in which case,
the attaching step of the method
fiu-ther includes the step of curing the curable resin so as to fix the fluid
distribution member to the support
member. Further, the attaching step may include the step of depositing the
curable resin about apertures on
the upper surface of the support member which extend to the fluid delivery
channels. Further still, the
attaching step may include the step of curing the curable resin so as to form
sealing gaskets about the apertures
of the support member and associated apertures of the fluid distribution
member.
In another embodiment of the present invention, there is provided a printhead
assembly, comprising:
at least one printhead module comprising a unitary arrangement of a support
member, at least two
printhead integrated circuits, each of which has nozzles formed therein for
delivering printing fluid onto the
surface of print media, at least one fluid distribution member mounting the at
least two printhead integrated
circuits to the support member, and an electrical connector for connecting
electrical signals to the at least two
printhead integrated circuits; and
a casing in which the at least one printhead module is removably mounted,
wherein the support member has at least one longitudinally extending channel
for carrying the
printing fluid for the printhead integrated circuits and includes a plurality
of apertures extending through a
wall of the support member arranged so as to direct the printing fluid from
the at least one channel to
associated nozzles in both, or if more than two, all of the printhead
integrated circuits by way of respective
ones of the fluid distribution members.
Where the printhead assembly comprises a single printhead module having a
plurality of printhead
integrated circuits, the length of the printhead module is predetermined to
provide for selected pagewidth
printing.
Where the printhead assembly comprises at least two printhead modules, these
are mounted in
linearly aligned relationship with the assembly having an aggregate length and
a number of printhead
integrated circuits predetermined to provide for selected pagewidth printing.
In such a case, each of the
printhead modules may be provided with end portions which permit
interconnection of the linearly aligned
printhead modules and provide for fluid connection of the channels thereof,
these end portions being
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complementary female and male end portions. A sealing adhesive, such as an
epoxy, may be provided at the
interface of the interconnected printhead modules to assist sealing of the
fluid connections.
The printhead module(s) is mounted to the casing in a manner to constrain
movement of the printhead
module(s) relative to the casing in at least the direction of printing fluid
delivery from the nozzles to the print
media. To assist this, the support member may be formed such that a first side
thereof is slidably received in a
longitudinally extending groove of the casing and a second side thereof is
clamped to the casing by a clamping
arrangement. The clamping arrangement being employed to constrain the movement
of the printhead
module(s).
The casing may comprise a longitudinally extending channel portion within
which the printhead
module(s) is mounted, with the channel comprising first and second side walls
joined by a lower wall. The
first side wall includes the longitudinally extending groove and the
longitudinally extending groove being
formed between upper and lower longitudinally extending tabs, and the second
side wall has a longitudinally
extending upper surface upon which the second side of the at least one
printhead module is mounted, the
longitudinally extending upper surface having a height from the lower surface
of the channel portion
substantially equal to a height of the lower longitudinally extending
protrusion of the first side wall.
This channel portion of the casing is incorporated in a support frame with
which the clainping
arrangement engages. A cover portion for covering the support frame is also
comprised in the casing.
In order to cap or seal the a terminal end of the support member of the
printhead module, a capping
member may be provided. Where the support member has complementary female and
male end portions, this
capping member is arranged to cap each of the female and male end portions.
Further, a sealing adhesive,
such as an epoxy, may be used at the interface of the interconnected capping
member and printhead module.
In order to connect printing fluid delivery hose(s) from a printing fluid
supply to the channel(s) of the
printhead module(s), at least one fluid connector may be arranged at at least
one longitudinal end of the
printhead module. Where the support member has complementary female and male
end portions, the fluid
connector(s) is arranged to interconnect with either the female or male end
portion. Further, a sealing
adhesive, such as an epoxy, may be used at the interface of the interconnected
fluid connector(s) and printhead
module(s).
For connecting with the fluid delivery hose(s), the fluid connector(s) has at
least one tubular portion
arranged to be in (linear) fluid connection with the channel(s) of the
printhead module(s). Where two fluid
connectors are provided, one is connected at each longitudinal end of the
printhead module(s), for providing
fluid supply from both ends of the channel(s).
Wiiere the support member is formed with a plurality of the channels, the
channels may be arranged
to carry different printing fluids for direction to associated groups of the
nozzles in the both, or if more than
two, all of the printhead integrated circuits by way of respective ones of the
fluid distribution members. A
further channel for delivering air to the printhead integrated circuits for
maintaining the nozzles of the
printhead integrated circuits substantially free from impurities may be
provided.
The use of separate fluid distribution members supporting individual ones of
the printhead integrated
circuits provides printhead tiles. Each of these tiles/fluid distribution
members may be formed as a laminated
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stack of at least three layers comprising an upper layer upon which the
associated printhead integrated circuit
is mounted, a middle layer and a lower layer which is attached to an upper
surface of the support member.
The lower layer includes first distribution apertures arranged to align with
respective ones of the
apertures in the support member and first distribution channels in an upper
surface thereof associated with
respective ones of the first distribution apertures, the first distribution
apertures having substantially the same
diameter as the apertures in the support member.
The middle layer includes second distribution apertures arranged to align with
the first distribution
channels of the lower layer, the second distribution apertures having a
smaller diameter than the first
distribution apertures.
The upper layer includes second distribution channels in a lower surface
thereof arranged to align
with the second distribution apertures of the middle layer and third
distribution apertures associated with the
second distribution channels, the third distribution apertures having a
smaller diameter than the second
distribution apertures.
The associated printhead integrated circuit include nozzle supply apertures
arranged to align with the
third distribution apertures of the upper layer and to direct fluid to
respective ones of the nozzles, the nozzle
supply apertures having substantially the same diameter as the third
distribution apertures, with the apertures
of the support member having a diameter of the order of millimetres and the
nozzle supply apertures of the at
least two printhead integrated circuits having a diameter of the order of
micrometres.
For attaching the fluid distribution member(s) to the support member, a lower
surface of the fluid
distribution member(s) may be attached to the upper surface of the support
member by an adhesive material.
This adhesive material may be used to form a seal between the respective
apertures by being deposited to
surround each of the apertures of the support member and each of corresponding
apertures formed in the lower
surface of the fluid distribution member(s).
In an arrangement having the apertures of the support member formed in a row
extending across the
support member with respect to the longitudinally extending direction of the
support member, two deposits of
the adhesive material may be deposited on either side of the row of apertures
to provide stability for the
mounting arrangement. The adhesive material may be a curable resin.
The printhead module(s) is supported by a support frame of the casing. A cover
portion for covering
the support frame is also comprised in the casing. The support frame also
supports drive electronics provided
for driving the printhead integrated circuits via the electrical connector.
The printhead assembly may also comprise a print media guide mounted to the
casing. This print
media guid4 is arranged to guide print media past the print surface formed by
the printhead module mounted
to the casing, such that the print media is precluded from impinging on the
nozzles of each of the printhead
integrated circuits. This is achieved by arranging the print media guide to
form a gap between the nozzles of
the printhead integrated circuits and the passing print media.
The drive electronics is able to control the printing operation of the
printhead integrated circuits by
incorporating at least one controller which is connected to at least one of
the at least two printhead integrated
circuits via the electrical connector. The drive electronics is provided on at
least one printed circuit board
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which is in turn supported by the support frame of the casing. In order to
connect the drive electronics with
the electrical connector, the printed circuit board carries at least one
connection port, which is aligned with the
electrical connector. Each printhead integrated circuit may be connected with
an individual electrical
connector, such that the at least one controller is arranged to control the
printing operation of a selectable
number of the printhead integrated circuits.
Where the printhead module(s) comprises one or more groups of two printhead
integrated circuits, a
single controller may be selected for controlling each group of two printhead
integrated circuits via the
electrical connector. Where the printhead module(s) comprises one or more
groups of four printhead
integrated circuits, a single controller may be selected for controlling each
group of four printhead integrated
circuits via the electrical connector. Where the printhead module(s) comprises
one or more groups of eight
printhead integrated circuits, a single controller may be selected for
controlling each group of eight printhead
integrated circuits via the electrical connector. Where the printhead
module(s) comprises one or more groups
of sixteen printhead integrated circuits, a single controller may be selected
for controlling each group of
sixteen printhead integrated circuits via the electrical connector.
The printed circuit board for the controller is supported on the support frame
of the casing via at least
one mounting element, which incorporates a clamping arrangement for clamping
the printhead module to the
casing. Further, the printed circuit board may have connection strips provided
at opposite edge regions
thereof, the connection strips adjacent one end of the support frame being
connectable to a data input, and the
connection strips adjacent the other end of the support frame being terminated
in a manner so as to prevent
data signal reflections.
In order to deliver power from a power supply to the drive electronics, the
printhead assembly
comprises a plurality of longitudinally extending electrical conductors,
located within the casing. The power
from the electrical conductors is delivered to the drive electronics via the
electrical connector. Further, the
power from the electrical conductors is also delivered to the printhead
integrated circuits via the electrical
connector.
To ensure electrical connection of the various components, a loading plate is
provided for loading
conductor portions of the electrical connector against respective ones of the
plurality of electrical conductors.
The loading plate includes a non-conductive portion, fonned of a resilient
material, for example, which urges
the electrical connector against the electrical conductors.
The plurality of electrical conductors may be arranged to be connected to the
power supply at one
end of the printhead assembly. Alternatively, the plurality of electrical
conductors may be arranged as two
groups of eicctrical conductors respectively connected to the power supply at
respective ends of the printhead
assembly, with respective ones of electrical conductors of the two groups of
electrical conductors being
connected together at abutting regions intermediate the ends of the printhead
assembly. To facilitate this, the
abutting regions of the individual electrical conductors are arranged in
overlapping relationship.
The plurality of electrical conductors are conveniently carried by the
mounting element which is
mounted to the support frame of the casing. This is facilitated by he mounting
element having a plurality of
recessed channels for receiving individual ones of the plurality of electrical
conductors formed therein.
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The printhead assembly may comprise at least two of the mounting elements
arranged in abutting
relationship along a longitudinal direction of the casing, each being arranged
to support an individual printed
circuit board. In this arrangement, the individual printed circuit boards are
interconnected by an electrical
connecting member located between (each of) the abutting mounting elements.
The electrical connecting
member(s) is placed in a recess formed by side regions of the mounting
elements which have raised and
recessed portions arranged so that the recessed portions of abutting mounting
elements form the recess. The
electrical connecting member(s) comprises a non-conductive material which is
clad with conductive strips,
where the electrical connecting member(s) is positioned to overlay a series of
spaced connection strips at the
edge regions of each of the individual printed circuit boards.
To ensure reliable connection, each connection strip of the printed circuit
board engages with at least
one of two adjacent conductive strips of the electrical connecting member(s),
there being twice as many
conductive strips of the electrical connecting member(s) as there are
connection strips of the printed circuit
boards.
The mounting element(s) may incorporate the clamping arrangement for clamping
the printhead
module(s) to the support frame. This is achieved by the mounting element(s)
comprising at least one
extending arm portion arranged so as to clamp the longitudinally extending tab
of the support member to the
upper surface of the second side wall of the support frame. Further, the
longitudinally extending tabs of the
support member include a plurality of lugs arranged along the lengths thereof,
which are spaced so as to
correspond to the mounted positions of the printhead integrated circuits. The
extending arm portion(s)
includes a recessed section arranged to engage with one of the plurality of
lugs on the longitudinally extending
tab clamped thereby.
The (first) printed circuit board carrying the drive electronics supported by
support frame of the
casing may be engaged at one end of the support frame by a second printed
circuit board which connects the
drive electronics to power and data supplies. To this end, the second printed
circuit board may comprise a
power terminal for connecting the electrical connector to a power supply via
the longitudinally extending
electrical conductors, a data terminal for connecting the drive electronics to
a data input via the first printed
circuit board, and a fluid delivery port for connecting the at least one
channel of the support member to a fluid
supply via fluid delivery tubes.
Further, the first printed circuit board may be engaged at the other end of
the support frame by a third
printed circuit board which is arranged to spring load the first printed
circuit board in the direction of the
second printed circuit board. The third printed circuit may comprise
termination connections for terminating a
data signal _caversing the first printed circuit board from the second printed
circuit board.
In another embodiment of the present invention, there is provided a printhead
assembly, comprising:
at least one printhead module comprising a unitary arrangement of at least two
printhead integrated
circuits, each of which has nozzles formed therein for delivering printing
fluid onto the surface of print media,
and a support member supporting and carrying the printing fluid for the at
least two printhead integrated
circuits; and
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a casing in which the at least one printhead module is removably mounted so as
to constrain
movement of the at least one printhead module relative to the casing in at
least the direction of printing fluid
delivery from the nozzles to the print media.
In another embodiment of the present invention, there is provided a printhead
assembly, comprising:
at least one printhead module comprising at least two printhead integrated
circuits, each of which has
nozzles formed therein for delivering printing fluid onto the surface of print
media, and a support member
supporting and carrying the printing fluid for the at least two printhead
integrated circuits; and
a casing in which the at least one printhead module is removably mounted by
having a first side
thereof slidably received in a longitudinally extending groove of the casing
and a second side thereof clamped
to the casing by a clamping arrangement.
In another embodiment of the present invention, there is provided a printhead
assembly, comprising:
at least two printhead modules each comprising at least two printhead
integrated circuits, each of
which has nozzles formed therein for delivering printing fluid onto the
surface of print media, and a support
member supporting and carrying the printing fluid for the at least two
printhead integrated circuits; and
a casing in which the at least two printhead modules are arranged so as to be
removably mounted in
linearly aligned relationship,
wherein the assembly has an aggregate length and a number of printhead
integrated circuits
predetermined to provide for selected pagewidth printing.
In another embodiment of the present invention, there is provided a printhead
assembly, comprising:
at least two printhead modules, each comprising at least two printhead
integrated circuits, each of
which has nozzles formed therein for delivering printing fluid onto the
surface of print media, and a support
member supporting the at least two printhead integrated circuits; and
a casing in which the at least two printhead modules are arranged so as to be
removably mounted in
linearly aligned relationship,
wherein the support member has at least one longitudinally extending channel
for carrying the
printing fluid for the printhead integrated circuits, and
each printhead module has end portions which permit interconnection of the
linearly aligned
printhead modules and provide for fluid connection of the channels of the
support members thereof.
In another embodiment of the present invention, there is provided a printhead
assembly, comprising:
at least one printhead module comprising at least two printhead integrated
circuits, each of which has
nozzles formed therein for delivering printing fluid onto the surface of print
media, and a support member
supporting.ad carrying the printing fluid for the at least two printhead
integrated circuits;
a casing in which the at least one printhead module is removably mounted; and
a capping member capping a terminal end of the support member of the at least
one printhead
module.
In another embodiment of the present invention, there is provided a printhead
assembly, comprising:
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at least one printhead module comprising at least two printhead integrated
circuits, each of which has
nozzles formed therein for delivering printing fluid onto the surface of print
media, and a support member
supporting the at least two printhead integrated circuits; and
a casing in which the at least one printhead module is removably mounted,
wherein the support member has at least one longitudinally extending channel
for carrying the
printing fluid for the printhead integrated circuits, and
at least one fluid connector is provided to connect at least one printing
fluid delivery hose from a
printing fluid supply to the at least one channel at at least one longitudinal
end of the at least one printhead
module.
In another embodiment of the present invention, there is provided a printhead
assembly, comprising:
at least one printhead module comprising at least two printhead integrated
circuits, each of which has
nozzles formed therein for delivering printing fluid onto the surface of print
media, and a support member
supporting the at least two printhead integrated circuits; and
a casing in which the at least one printhead module is removably mounted,
wherein the support member has at least one longitudinally extending channel
for carrying the
printing fluid for the printhead integrated circuits, and
two fluid connectors are provided to each connect with a longitudinal end of
the at least one
printhead module, each of the fluid connectors being arranged to connect at
least one fluid delivery hose from
a fluid supply to the at least one channel at the corresponding longitudinal
end of the at least one printhead
module.
In another embodiment of the present invention, there is provided a printhead
assembly, comprising:
at least one printhead module comprising at least two printhead integrated
circuits, each of which has
nozzles formed therein for delivering printing fluid onto the surface of print
media, and a support member
supporting and carrying the printing fluid for the at least two printhead
integrated circuits;, and
a casing comprising a support frame for supporting the at least one printhead
module and a cover
portion which is removably attached to the support frame.
In another embodiment of the present invention, there is provided a printhead
assembly, comprising:
at least one printhead module comprising at least two printhead integrated
circuits, each of which has
nozzles formed therein for delivering printing fluid onto the surface of print
media, and a support member
supporting and carrying the printing fluid for the at least two printhead
integrated circuits;
a casing in which the at least one printhead module is removably mounted; and
a,; :nt media guide mounted to the casing, arranged to guide print media past
the print surface
formed by the at least one printhead module mounted to the casing.
In another embodiment of the present invention, there is provided a printhead
assembly, comprising:
at least one printhead module comprising at least two printhead integrated
circuits, each of which has
nozzles formed therein for delivering printing fluid onto the surface of print
media, a support member for
supporting and carrying the printing fluid for the at least two printhead
integrated circuits, and an electrical
connector for connecting electrical signals to the at least two printhead
integrated circuits;
CA 02550804 2006-06-21
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drive electronics incorporating at least one controller which is connected to
at least one of the at least
two printhead integrated circuits via the electrical connector for controlling
the printing operation of at least
one of the at least two printhead integrated circuits; and
a casing in which the at least one printhead module and the drive electronics
are removably mounted.
In another embodiment of the present invention, there is provided a printhead
assembly, comprising:
at least one printhead module comprising at least two printhead integrated
circuits, each of which has
nozzles formed therein for delivering printing fluid onto the surface of print
media, a support member
supporting the at least two printhead integrated circuits, and an electrical
connector for connecting electrical
signals to the at least two printhead integrated circuits;
drive electronics incorporating at least one controller arranged to control
the printing operation of a
selectable number of the at least two printhead integrated circuits via the
electrical connector; and
a casing in which the at least one printhead module and the drive electronics
are removably mounted.
In another embodiment of the present invention, there is provided a printhead
assembly, comprising:
at least one printhead module comprising at least two printhead integrated
circuits, a support member
for supporting and carrying the printing fluid for the at least two printhead
integrated circuits, and an electrical
connector for connecting electrical signals to the at least two printhead
integrated circuits;
drive electronics incorporating at least one controller which is connected to
at least one of the at least
two printhead integrated circuits via the electrical connector for controlling
the printing operation of at least
one of the at least two printhead integrated circuits; and
a casing in which the at least one printhead module and the drive electronics
are removably mounted,
wherein the drive electronics is provided on a printed circuit board which is
supported by a support
frame of the casing via at least one mounting element.
In another embodiment of the present invention, there is provided a printhead
assembly, comprising:
at least one printhead module comprising at least two printhead integrated
circuits, each of which has
nozzles formed therein for delivering printing fluid onto the surface of print
media, a support member
supporting and carrying the printing fluid for the at least two printhead
integrated circuits, and at least two
flexible printed circuit boards for connecting electrical signals to the at
least two printhead integrated circuits;
drive electronics incorporating at least one controller which is connected to
at least one of the at least
two printhead integrated circuits via the respective flexible printed circuit
board for controlling the printing
operation of at least one of the at least two printhead integrated circuits;
and
a casing in which the at least one printhead module and the drive electronics
are removably mounted,
wi -ein the drive electronics is provided on a printed circuit board carrying
respective connection
ports for connecting with the flexible circuit boards which are directly
aligned with the respective flexible
printed circuit boards and printhead integrated circuits.
In another embodiment of the present invention, there is provided a printhead
assembly, comprising:
at least one printhead module comprising at least two printhead integrated
circuits, each of which has
nozzles formed therein for delivering printing fluid onto the surface of print
media, a support member
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supporting and canying the printing fluid for the at least two printhead
integrated circuits, and an electrical
connector for connecting electrical signals to the at least two printhead
integrated circuits;
drive electronics incorporating at least one controller which is connected to
at least one of the at least
two printhead integrated circuits via the electrical connector for controlling
the printing operation of at least
one of the at least two printhead integrated circuits; and
a casing for removably holding at least one mounting element which mounts the
drive electronics and
incorporates a clamping arrangement for clamping the at least one printhead
module to the casing.
In another embodiment of the present invention, there is provided a printhead
assembly, comprising:
at least one printhead module comprising at least two printhead integrated
circuits, each of which has
nozzles formed therein for delivering printing fluid onto the surface of print
media, a support member
supporting and carrying the printing fluid for the at least two printhead
integrated circuits, and an electrical
connector for connecting electrical signals to the at least two printhead
integrated circuits;
drive electronics incorporating at least one controller for controlling the
printing operation of at least
one of the at least two printhead integrated circuits;
a plurality of longitudinally extending electrical conductors arranged to
provide power from a power
supply to the drive electronics and the at least two printhead integrated
circuits; and
a casing in which the at least one printhead module, the drive electronics and
the plurality of
electrical conductors are removably mounted."
In another embodiment of the present invention, there is provided a printhead
system, comprising:
at least one printhead module comprising at least two printhead integrated
circuits, each of which has
nozzles formed therein for delivering printing fluid onto the surface of print
media, a support member
supporting and carrying the printing fluid for the at least two printhead
integrated circuits, and at least two
electrical connectors for connecting electrical signals to the respective ones
of the at least two printhead
integrated circuits;
drive electronics incorporating at least one controller for controlling the
printing operation of at least
one of the at least two printhead integrated circuits; and
a casing in which the at least one printhead module and the drive electronics
are removably mounted,
wherein each of the at least two electrical connectors is arranged to direct
control signals from the at
least one controller to the corresponding printhead integrated circuit and to
direct power from a power supply
to the corresponding printhead integrated circuit and the drive electronics.
In another embodiment of the present invention, there is provided a printhead
assembly, comprising:
at, ast one printhead module comprising at least two printhead integrated
circuits, each of which has
nozzles formed therein for delivering printing fluid onto the surface of print
media, a support member
supporting and carrying the printing fluid for the at least two printhead
integrated circuits, and an electrical
connector for connecting electrical signals to the at least two printhead
integrated circuits;
drive electronics incorporating at least one controller for controlling the
printing operation of at least
one of the at least two printhead integrated circuits;
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a plurality of longitudinally extending electrical conductors arranged to
provide power from a power
supply to the drive electronics and the at least two printhead integrated
circuits; and
a loading plate for loading conductor portions of the electrical connector
against respective ones of
the plurality of electrical conductors.
In another embodiment of the present invention, there is provided a printhead
assembly, comprising:
at least one printhead module comprising at least two printhead integrated
circuits, each of which has
nozzles formed therein for delivering printing fluid onto the surface of print
media, a support member
supporting and carrying the printing fluid for the at least two printhead
integrated circuits, and an electrical
connector for connecting electrical signals to the at least two printhead
integrated circuits; and
a plurality of longitudinally extending electrical conductors for providing
power from a power supply
to the at least two printhead integrated circuits, being arranged as two
groups of electrical conductors
respectively connected to the power supply at respective ends of the printhead
assembly, respective ones of
electrical conductors of the two groups of electrical conductors being
connected together at abutting regions
intermediate the ends of the printhead assembly.
In another embodiment of the present invention, there is provided a printhead
assembly, comprising:
at least one printhead module comprising at least two printhead integrated
circuits, each of which has
nozzles formed therein for delivering printing fluid onto the surface of print
media, a support member
supporting and carrying the printing fluid for the at least two printhead
integrated circuits, and an electrical
connector for connecting electrical signals to the at least two printhead
integrated circuits;
a plurality of longitudinally extending electrical conductors arranged to
provide power from a power
supply to the at least two printhead integrated circuits via the electrical
connector; and
a casing comprising a support frame on which the at least one printhead module
and a mounting
element are removably held, the mounting element having formed therein a
plurality of recessed channels for
receiving and removably mounting individual ones of the plurality of
electrical conductors.
In another embodiment of the present invention, there is provided a printhead
assembly, comprising:
at least one printhead module comprising at least two printhead integrated
circuits, each of which has
nozzles formed therein for delivering printing fluid onto the surface of print
media, a support member
supporting and carrying the printing fluid for the at least two printhead
integrated circuits, and an electrical
connector for connecting electrical signals to the at least two printhead
integrated circuits;
drive electronics incorporating at least two controllers for controlling the
printing operation of at least
one of the at least two printhead integrated circuits via the electrical
connector, the at least two controllers
being inter mected; and
a casing in which the at least one printhead module and the drive electronics
are removably mounted.
In another embodiment of the present invention, there is provided a printhead
assembly, comprising:
at least one printhead module comprising at least two printhead integrated
circuits, each of which has
nozzles formed therein for delivering printing fluid onto the surface of print
media, a support member
supporting and carrying the printing fluid for the at least two printhead
integrated circuits, and an electrical
connector for connecting electrical signals to the at least two printhead
integrated circuits;
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drive electronics incorporating at least two controllers each arranged on a
printed circuit board so as
to control the printing operation of at least one of the at least two
printhead integrated circuits via the electrical
connector;
a casing comprising a support frame supporting the at least one printhead
module and at least two
mounting elements arranged in abutting relationship along a longitudinal
direction of the casing, each of the
printed circuit boards being removably supported by at least one of the two or
more mounting elements; and
an electrical connecting member comprising a non-conductive material clad with
conductive strips
arranged between the abutting mounting elements so that the conductive strips
are positioned to overlay a
series of spaced connection strips at the edge regions of each of the
individual printed circuit boards.
In another embodiment of the present invention, there is provided a printhead
assembly, comprising:
at least one printhead module comprising at least two printhead integrated
circuits, each of which has
nozzles formed therein for delivering printing fluid onto the surface of print
media, a support member
supporting and carrying the printing fluid to the at least two printhead
integrated circuits, and an electrical
connector for connecting electrical signals to the at least two printhead
integrated circuits;
drive electronics arranged to control the printing operation of at least one
of the at least two printhead
integrated circuits via the electrical connector;
a plurality of longitudinally extending electrical conductors for providing
power from a power supply
to the drive electronics and the at least two printhead integrated circuits;
a casing comprising a support frame supporting the at least one printhead
module; and
at least one mounting element held by the support frame, the at least one
mounting element mounting
the drive electronics and electrical conductors and incorporating a clamping
arrangement for clamping the at
least one printhead module to the support frame.
In another embodiment of the present invention, there is provided a printhead
assembly, comprising:
at least one printhead module comprising at least two printhead integrated
circuits, each of which has
nozzles formed therein for delivering printing fluid onto the surface of print
media, a support member
supporting and carrying the printing fluid for the at least two printhead
integrated circuits, and an electrical
connector for connecting electrical signals to the at least two printhead
integrated circuits;
drive electronics arranged to control the printing operation of at least one
of the at least two printhead
integrated circuits via the electrical connector;
a casing comprising a support frame on which the at least one printhead module
and a plurality of
mounting ele-nents mounting the drive electronics are removably arranged;
a ~ connector arrangement at one end of the support frame connecting the drive
electronics and the
printhead integrated circuits to a power supply and a data input; and
a second connector arrangement at the other end of the support frame spring
loading the plurality of
mounting elements in the direction of the first connector arrangement.
In another embodiment of the present invention, there is provided a printhead
assembly, comprising:
at least one printhead module comprising at least two printhead integrated
circuits, each of which has
nozzles formed therein for delivering printing fluid onto the surface of print
media, a support member
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supporting and carrying the printing fluid for the at least two printhead
integrated circuits, and an electrical
connector for connecting electrical signals to the at least two printhead
integrated circuits from both ends of
the printhead assembly; and
a casing in which the at least one printhead module is removably mounted.
In another embodiment of the present invention, there is provided a printhead
assembly, comprising:
at least one printhead module comprising at least two printhead integrated
circuits, each of which has
nozzles formed therein for delivering printing fluid onto the surface of print
media, a support member
supporting the at least two printhead integrated circuits and having at least
one longitudinally extending
channel for carrying the printing fluid, and an electrical connector for
connecting electrical signals to the
printhead integrated circuits;
a casing comprising a support frame removably mounting the at least one
printhead module and drive
electronics arranged to control the printing operation of at least one of the
at least two printhead integrated
circuits via the electrical connector; and
at least one connector arrangement mounted to at least one longitudinal end of
the support frame and
carrying at least one power terminal for connecting the electrical connector
to a power supply, at least one data
terminal for connecting the drive electronics to a data input, and at least
one fluid delivery port for connecting
the at least one channel of the support member to a fluid supply via fluid
delivery tubes.
In another embodiment of the present invention, there is provided a printhead
assembly, comprising:
at least one printhead module comprising at least two printhead integrated
circuits, each of which has
nozzles formed therein for delivering printing fluid onto the surface of print
media, a support member
supporting and carrying the printing fluid for the at least two printhead
integrated circuits; and
a casing comprising a support frame removably mounting the at least one
printhead module and at
least one clamping arrangement clamping the at least one printhead module to
the support frame,
wherein the clamped printhead module and the at least one clamping arrangement
are substantially
positionally independent of the casing.
In yet another embodiment of the present invention, there is provided a
printed circuit board
comprising an integrally formed spring portion.
The integrally formed spring portion of the printed circuit board may be
formed by removing a
section of the printed circuit board.
In yet another embodiment of the present invention, there is provided a
circuit assembly, comprising:
a phrality of first printed circuit boards arranged in a linearly aligned
manner;
a ond printed circuit board arranged at one end of the linearly aligned first
printed circuit boards
for connecting electronics supported by the plurality of first printed circuit
boards to power and data supplied;
and
a third printed circuit board arranged at the other end of the linearly
aligned first printed circuit
boards, the third printed circuit board comprising an integrally formed spring
portion.
In yet another embodiment of the present invention, there is provided a
printhead assembly,
comprising:
CA 02550804 2006-06-21
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at least one printhead module comprising at least two printhead integrated
circuits, each of which has
nozzles formed therein for delivering printing fluid onto the surface of print
media, a support member
supporting and carrying the printing fluid for the at least two printhead
integrated circuits, and an electrical
connector for connecting electrical signals to the at least two printhead
integrated circuits;
the above-described circuit assembly which is electrically connected to the at
least two printhead
integrated circuits via the electrical connector; and
a casing comprising a support frame on which the at least one printhead module
and the circuit
assembly are removably mounted.
The printhead assembly may be arranged such that the plurality of first
printed circuit boards of the
circuit assembly are mounted to the support frame so as to be linearly aligned
in the longitudinal direction
thereof, the second and third printed circuit boards of the circuit assembly
being arranged at the respective
longitudinal ends of the support frame, and drive electronics are arranged on
the plurality of first printed
circuit boards for controlling the printing operation of at least one of the
at least two printhead integrated
circuits via the electrical connector.
The third printed circuit board, being that which comprises the spring
portion, may farther comprise
termination connections on the spring portion for terminating a data signal
traversing the at least one first
printed circuit board from the second printed circuit board.
In the printhead assembly, the printhead module may be forme'd as a unitary
arrangement of the at
least two printhead integrated circuits, the,support member, the electrical
connector, and at least one fluid
distribution member mounting the at least two printhead integrated circuits to
the support member. In this
arrangement, the support member has at least one longitudinally extending
channel for carrying the printing
fluid for the printhead integrated circuits and includes a plurality of
apertures extending through a wall of the
support member arranged so as to direct the printing fluid from the at least
one channel to associated nozzles
in both, or if more than two, all of the printhead integrated circuits by way
of respective ones of the fluid
distribution members.
These and other embodiments and advantages of the present invention are now
described by way of
example with reference to the accompanying drawings.
BRIEF DESC ;'..,.PTION OF THE DRAWINGS
Is, drawings:
Fig. 1 shows a perspective view of a printhead assembly in accordance with an
embodiment of the
present invention;
Fig. 2 shows the opposite side of the printhead assembly of Fig. 1;
Fig. 3 shows a sectional view of the printhead assembly of Fig. 1;
Fig. 4A illustrates a portion of a printhead module that is incorporated in
the printhead assembly of
Fig. 1;
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Fig. 4B illustrates a lid portion of the printhead module of Fig. 4A;
Fig. 5A shows a top view of a printhead tile that forms a portion of the
printhead module of Fig. 4A;
Fig. 5B shows a bottom view of the printhead tile of Fig. 5A;
Fig. 6 illustrates electrical connectors for printhead integrated circuits
that are mounted to the
printhead tiles as shown in Fig. 5A;
Fig. 7 illustrates a connection that is made between the printhead module of
Fig. 4A and the
underside of the printhead tile of Figs. 5A and 5B;
Fig. 8 illustrates a "female" end portion of the printhead module of Fig. 4A;
Fig. 9 illustrates a "male" end portion of the printhead module of Fig. 4A;
Fig. 10 illustrates a fluid delivery connector for the male end portion of
Fig. 9;
Fig. 11 illustrates a fluid delivery connector for the female end portion of
Fig. 8;
Fig. 12 illustrates the fluid delivery connector of Figs. 10 or 11 connected
to fluid delivery tubes;
Fig. 13 illustrates a tubular portion arrangement of the fluid delivery
connectors of Figs. 10 and 11;
Fig. 14A illustrates a capping member for the female and male end portions of
Figs. 8 and 9;
Fig. 14B illustrates the capping member of Fig. 14A applied to the printhead
module of Fig. 4A;
Fig. 15A shows a sectional (skeletal) view of a support frame of a casing of
the printhead assembly of
Fig. 1;
Figs. 15B and 15C show perspective views of the support frame of Fig. 15A in
upward and
downward orientations, respectively;
Fig. 16 illustrates a printed circuit board (PCB) support that forms a portion
of the printhead
assembly of Fig. 1;
Figs. 17A, 17B and 17C show side and rear perspective views of the PCB support
of Fig. 16;
Fig. 18A illustrates circuit components carried by a PCB supported by the PCB
support of Fig. 16;
Fig. 18B shows an opposite side perspective view of the PCB and the circuit
components of
Fig. 18A;
Fig. 19A shows a side view illustrating further components attached to the PCB
support of Fig. 16;
Fig. 19B shows a rear side view of a pressure plate that forms a portion of
the printhead assembly of
Fig. 1;
Fig. 20 shows a front view illustrating the fiu-ther components of Fig. 19;
Fig. 21 shows a perspective view illustrating the further components of Fig.
19;
Fig. "_ shows a front view of the PCB support of Fig. 16;
F 2A shows a side sectional view taken along the line I-I in Fig. 22;
Fig. 22B shows an enlarged view of the section A of Fig. 22A;
Fig. 22C shows a side sectional view taken along the line II-II in Fig. 22;
Fig. 22D shows an enlarged view of the section B of Fig. 22C;
Fig. 22E shows an enlarged view of the section C of Fig. 22C;
Fig. 23 shows a side view of a cover portion of the casing of the printhead
assembly of Fig. 1;
Fig. 24 illustrates a plurality of the PCB supports of Fig. 16 in a modular
assembly;
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Fig. 25 illustrates a connecting member that is carried by two adjacent PCB
supports of Fig. 24 and
which is used for interconnecting PCBs that are carried by the PCB supports;
Fig. 26 illustrates the connecting member of Fig. 25 interconnecting two PCBs;
Fig. 27 illustrates the interconnection between two PCBs by the connecting
member of Fig. 25;
Fig. 28 illustrates a connecting region of busbars that are located in the
printhead assembly of Fig. 1;
Fig. 29 shows a perspective view of an end portion of a printhead assembly in
accordance with an
embodiment of the present invention;
Fig. 30 illustrates a connector arrangement that is located in the end portion
of the printhead
assembly as shown in Fig. 29;
Fig. 31 illustrates the connector arrangement of Fig. 30 housed in an end
housing and plate assembly
which forms a portion of the printhead assembly;
Figs. 32A and 32B show opposite side views of the connector arrangement of
Fig. 30;
Fig. 32C illustrates a fluid delivery connection portion of the connector
arrangement of Fig. 30;
Fig. 33A illustrates a support member that is located in a printhead assembly
in accordance with an
embodiment of the present invention;
Fig. 33B shows a sectional view of the printhead assembly with the support
member of Fig. 33A
located therein;
Fig. 33C illustrates a part of the printhead assembly of Fig. 33B in more
detail;
Fig. 34 illustrates the connector arrangement of Fig. 30 housed in the end
housing and plate assembly
of Fig. 31 attached to the casing of the printhead assembly;
Fig. 35A shows an exploded perspective view of the end housing and plate
assembly of Fig. 31;
Fig. 35B shows an exploded perspective view of an end housing and plate
assembly which forms a
portion of the printhead assembly of Fig. 1;
Fig. 36 shows a perspective view of the printhead assembly when in a form
which uses both of the
end housing and plate assemblies of Figs. 35A and 35B;
Fig. 37 illustrates a connector arrangement housed in the end housing and
plate assembly of Fig. 35B;
Figs. 38A and 38B shows opposite side views of the connector arrangement of
Fig. 37;
Fig. 39 illustrates an end plate when attached to the printhead assembly of
Fig. 29;
Fig. 40 illustrates data flow and functions performed by a print engine
controller integrated circuit
that forms one of the circuit components shown in Fig. 18A;
Fig. 41 illustrates the print engine controller integrated circuit of Fig. 40
in the context of an overall
printing system architecture;
Fig. 42 illustrates the architecture of the print engine controller integrated
circuit of Fig. 41;
Fig. 43 shows an exploded view of a fluid distribution stack of elements that
form the printhead tile
of Fig. 5A;
Fig. 44 shows a perspective view (partly in section) of a portion of a nozzle
system of a printhead
integrated circuit that is incorporated in the printhead module of the
printhead assembly of Fig. 1;
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Fig. 45 shows a vertical sectional view of a single nozzle (of the nozzle
system shown in Fig. 44) in a
quiescent state;
Fig. 46 shows a vertical sectional view of the nozzle of Fig. 45 at an initial
actuation state;
Fig. 47 shows a vertical sectional view of the nozzle of Fig. 46 at a later
actuation state;
Fig. 48 shows in perspective a partial vertical sectional view of the nozzle
of Fig. 45, at the actuation
state shown in Fig. 46;
Fig. 49 shows in perspective a vertical section of the nozzle of Fig. 45, with
ink omitted;
Fig. 50 shows a vertical sectional view of the nozzle of Fig. 49;
Fig. 51 shows in perspective a partial vertical sectional view of the nozzle
of Fig. 45, at the actuation
state shown in Fig. 46;
Fig. 52 shows a plan view of the nozzle of Fig. 45; and
Fig. 53 shows a plan view of the nozzle of Fig. 45 with lever arm and movable
nozzle portions
omitted.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
The exemplary embodiments of the present invention are described in relation
to a printhead
assembly and a printhead module that is incorporated in the printhead assembly
along with a method of
assembling the printhead module. A printed circuit board for the printhead
assembly is also described.
General Overview
The printhead assembly 10 as shown in Figs. 1 and 2 is intended for use as a
pagewidth printhead in a
printing system. That is, a printhead which extends across the width or along
the length of a page of print
media, e.g., paper, for printing. During printing, the printhead assembly
ejects ink onto the print media as it
progresses past, thereby forming printed information thereon, with the
printhead assembly being maintained in
a stationary position as the print media is progressed past. That is, the
printhead assembly is not scanned
across the page in the manner of a conventional printhead.
As can be seen from Figs. 1 and 2, the printhead assembly 10 includes a casing
20 and a printhead
module 30. The casing 20 houses the dedicated (or drive) electronics for the
printhead assembly together with
power and data inputs, and provides a structure for mounting the printhead
assembly to a printer unit. The
printhead module 30, which is received within a channel 21 of the casing 20 so
as to be removable therefrom,
includes a fluid channel member 40 which carries printhead tiles 50 having
printhead integrated circuits 51
incorporating printing nozzles thereon. The printhead assembly 10 further
includes an end housing 120 and
plate 110 assembly and an end plate 111 which are attached to longitudinal
ends of the assembled casing 20
and printhead module 30.
The printhead module 30 and its associated components will now be described
with reference to
Figs. 1 to 14B.
As shown in Fig. 3, the printhead module 30 includes the fluid channel member
40 and the printhead
tiles 50 mounted on the upper surface of the member 40.
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As illustrated in Figs. 1 and 2, sixteen printhead tiles 50 are provided in
the printhead module 30.
However, as wfll be understood from the following description, the number of
printhead tiles and printhead
integrated circuits mounted thereon may be varied to meet specific
applications of the present invention.
As illustrated in Figs. 1 and 2, each of the printhead tiles 50 has a stepped
end region so that, when
adjacent printhead tiles 50 are butted together end-to-end, the printhead
integrated circuits 51 mounted thereon
overlap in this region. Further, the printhead integrated circuits 51 extend
at an angle relative to the
longitudinal direction of the printhead tiles 50 to facilitate overlapping
between the printhead integrated
circuits 51. This overlapping of adjacent printhead integrated circuits 51
provides for a constant pitch
between the printing nozzles (described later) incorporated in the printhead
integrated circuits 51 and this
arrangement obviated discontinuities in information printed across or along
the print media (not shown)
passing the printhead assembly 10. This overlapping arrangement of the
printhead integrated circuits is
described in the Applicant's issued U.S. Patent No. 6,623,106.
Fig. 4 shows the fluid channel member 40 of the printhead module 30 which
serves as a support
member for the printhead tiles 50. The fluid channel member 40 is configured
so as to fit within the channel
21 of the casing 20 and is used to deliver printing ink and other fluids to
the printhead tiles 50. To achieve
this, the fluid channel member 40 includes channel-shaped ducts 41 which
extend throughout its length from
each end of the fluid channel member 40. The channel-shaped ducts 41 are used
to transport printing ink and
other fluids from a fluid supply unit (of a printing system to'which the
printhead assembly 10 is mounted) to
the printhead tiles 50 via a plurality of outlet ports 42.
The fluid channel member 40 is formed by injection moulding a suitable
material. Suitable materials
are those which have a low coefficient of linear thermal expansion (CTE), so
that the nozzles of the printhead
integrated circuits are accurately maintained under operational condition
(described in more detail later), and
have chemical inertness to the inks and other fluids channelled through the
fluid channel member 40. One
example of a suitable material is a liquid crystal polymer (LCP). The
injection moulding process is employed
to form a body portion 44a having open channels or grooves therein and a lid
portion 44b which is shaped
with elongate ridge portions 44c to be received in the open channels. The body
and lid portions 44a and 44b
are then adhered together with an epoxy to form the channel-shaped ducts 41 as
shown in Figs. 3 and 4A.
However, alternative moulding techniques may be employed to form the fluid
channel member 40 in one piece
with the channel-shaped ducts 41 therein.
The plurality of ducts 41, provided in communication with the corresponding
outlet ports 42 for each
printhead tile 50, are used to transport different coloured or types of inks
and the other fluids. The different
inks can have different colour pigments, for example, black, cyan, magenta and
yellow, etc., and/or be selected
for different printing applications, for example, as visually opaque inks,
infrared opaque inks, etc. Further, the
other fluids which can be used are, for example, air for maintaining the
printhead integrated circuits 51 free
from dust and other impurities and/or for preventing the print media from
coming into direct contact with the
printing nozzles provided on the printhead integrated circuits 51, and
fixative for fixing the ink substantially
immediately after being printed onto the print media, particularly in the case
of high-speed printing
applications.
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In the assembly shown in Fig. 4, seven ducts 41 are shown for transporting
black, cyan, magenta and
yellow coloured ink, each in one duct, infrared ink in one duct, air in one
duct and fixative in one duct. Even
though seven ducts are shown, a greater or lesser number may be provided to
meet specific applications. For
example, additional ducts might be provided for transporting black ink due to
the generally higher percentage
of black and white or greyscale printing applications.
The fluid channel member 40 further includes a pair of longitudinally
extending tabs 43 along the
sides thereof for securing the printhead module 30 to the channel 21 of the
casing 20 (described in more detail
later). It is to be understood however that a series of individual tabs could
alternatively be used for this
purpose.
As shown in Fig. 5A, each of the printhead tiles 50 of the printhead module 30
carries one of the
printhead integrated circuits 51; the latter being electrically connected to a
printed circuit board (PCB) 52
using appropriate contact methods such as wire bonding, with the connections
being protectively encapsulated
in an epoxy encapsulant 53. The PCB 52 extends to an edge of the printhead
tile 50, in the direction away
from where the printhead integrated circuits 51 are placed, where the PCB 52
is directly connected to a
flexible printed circuit board (flex PCB) 80 for providing power and data to
the printhead integrated circuit 51
(described in more detail later). This is shown in Fig. 6 with individual flex
PCBs 80 extending or "hanging"
from the edge of each of the printhead tiles 50. The flex PCBs 80 provide
electrical connection between the
printhead integrated circuits 51, a power supply 70 and a PCB 90 (see Fig. 3)
with drive electronics 100 (see
Fig. 18A) housed within the casing 20 (described in more detail later).
Fig. 5B shows the underside of one of the printhead tiles 50. A plurality of
inlet ports 54 is provided
and the inlet ports 54 are arranged to communicate with corresponding ones of
the plurality of outlet ports 42
of the ducts 41 of the fluid channel member 40 when the printhead tiles 50 are
mounted thereon. That is, as
illustrated, seven inlet ports 54 are provided for the outlet ports 42 of the
seven ducts 41. Specifically, both
the inlet and outlet ports are orientated in an inclined disposition with
respect to the longitudinal direction of
the printhead module so that the correct fluid, i.e., the fluid being
channelled by a specific duct, is delivered to
the correct nozzles (typically a group of nozzles is used for each type of ink
or fluid) of the printhead
integrated circuits.
On a typical printhead integrated circuit 51 as employed in realisation of the
present invention, more
than 7000 (e.g., 7680) individual printing nozzles may be provided, which are
spaced so as to effect printing
with a resolution of 1600 dots per inch (dpi). This is achieved by having a
nozzle density of 391 nozzles/mmZ
across a print surface width of 20 mm (0.8 in), with each nozzle capable of
delivering a drop volume of 1 p1.
Accordingly, the nozzles are micro-sized (i.e., of the order of 10-6 metres)
and as such are not capable
of receiving a macro-sized (i.e., millimetric) flows of ink and other fluid as
presented by the inlet ports 54 on
the underside of the printhead tile 50. Each printhead tile 50, therefore, is
formed as a fluid distribution stack
500 (see Fig. 43), which includes a plurality of laminated layers, with the
printhead integrated circuit 51, the
PCB 52, and the epoxy 53 provided thereon.
The stack 500 carries the ink and other fluids from the ducts 41 of the fluid
channel member 40 to the
individual nozzles of the printhead integrated circuit 51 by reducing the
macro-sized flow diameter at the inlet
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ports 54 to a micro-sized flow diameter at the nozzles of the printhead
integrated circuits 51. An exemplary
structure of the stack which provides this reduction is described in more
detail later.
Nozzle systems which are applicable to the printhead assembly of the present
invention may comprise
any type of ink jet nozzle arrangement which can be integrated on a printhead
integrated circuit. That is,
systems such as a continuous ink system, an electrostatic system and a drop-on-
demand system, including
thermal and piezoelectric types, may be used.
There are various types of known thermal drop-on-demand system which may be
employed which
typically include ink reservoirs adjacent the nozzles and heater elements in
thermal contact therewith. The
heater elements heat the ink and create gas bubbles which generate pressures
in the ink to cause droplets to be
ejected through the nozzles onto the print media. The amount of ink ejected
onto the print media and the
timing of ejection by each nozzle are controlled by drive electronics. Such
thermal systems impose limitations
on the type of ink that can be used however, since the ink must be resistant
to heat.
There are various types of known piezoelectric drop-on-demand system which may
be employed
which typically use piezo-crystals (located adjacent the ink reservoirs) which
are caused to flex when an
electric current flows therethrough. This flexing causes droplets of ink to be
ejected from the nozzles in a
similar manner to the thermal systems described above. In such piezoelectric
systems the ink does not have to
be heated and cooled between cycles, thus providing for a greater range of
available ink types. Piezoelectric
systems are difficult to integrate into drive integrated circuits and
typically require a large number of
connections between the drivers and the nozzle actuators.
As an alternative, a micro-electromechanical system (MEMS) of nozzles may be
used, such a system
including thermo-actuators which cause the nozzles to eject ink droplets. An
exemplary MEMS nozzle system
applicable to the printhead assembly of the present invention is described in
more detail later.
Returning to the assembly of the fluid channel member 40 and printhead tiles
50, each printhead tile
50 is attached to the fluid channel member 40 such that the individual outlet
ports 42 and their corresponding
inlet ports 54 are aligned to allow effective transfer of fluid therebetween.
An adhesive, such as a curable
resin (e.g., an epoxy resin), is used for attaching the printhead tiles 50 to
the fluid channel member 40 with the
upper surface of the fluid channel member 40 being prepared in the manner
shown in Fig. 7.
That is, a curable resin is provided around each of the outlet ports 42 to
form a gasket member 60
upon curing. This gasket member 60 provides an adhesive seal between the fluid
channel member 40 and
printhead tile 50 whilst also providing a seal around each of the
communicating outlet ports 42 and inlet ports
54. This sealing arrangement facilitates the flow and containment of fluid
between the ports. Further, two
curable resin deposits 61 are provided on either side of the gasket member 60
in a symmetrical manner.
The symmetrically placed deposits 61 act as locators for positioning the
printhead tiles 50 on the
fluid channel member 40 and for preventing twisting of the printhead tiles 50
in relation to the fluid channel
member 40. In order to provide additional bonding strength, particularly prior
to and during curing of the
gasket members 60 and locators 61, adhesive drops 62 are provided in free
areas of the upper surface of the
fluid channel member 40. A fast acting adhesive, such as cyanoacrylate or the
like, is deposited to form the
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locators 61 and prevents any movement of the printhead tiles 50 with respect
to the fluid channel member 40
during curing of the curable resin.
With this arrangement, if a printhead tile is to be replaced, should one or a
number of nozzles of the
associated printhead integrated circuit fail, the individual printhead tiles
may easily be removed. Thus, the
surfaces of the fluid channel member and the printhead tiles are treated in a
manner to ensure that the epoxy
remains attached to the printhead tile, and not the fluid channel member
surface, if a printhead tile is removed
from the surface of the fluid channel member by levering. Consequently, a
clean surface is left behind by the
removed printhead tile, so that new epoxy can readily be provided on the fluid
channel member surface for
secure placement of a new printhead tile.
The above-described printhead module of the present invention is capable of
being constructed in
various lengths, accommodating varying numbers of printhead tiles attached to
the fluid channel member,
depending upon the specific application for which the printhead assembly is to
be employed. For example, in
order to provide a printhead assembly for A3-sized pagewidth printing in
landscape orientation, the printhead
assembly may require 16 individual printhead tiles. This may be achieved by
providing, for example, four
printhead modules each having four printhead tiles, or two printhead modules
each having eight printhead
tiles, or one printhead module having 16 printhead tiles (as in Figs. 1 and 2)
or any other suitable combination.
Basically, a selected number of standard printhead modules may be combined in
order to achieve the
necessary width required for a specific printing application.
In order to provide this modularity in an easy and efficient manner, plural
fluid channel members of
each of the printhead modules are formed so as to be modular and are
configured to permit the connection of a
number of fluid channel members in an end-to-end manner. Advantageously, an
easy and convenient means of
connection can be provided by configuring each of the fluid channel members to
have complementary end
portions. In one embodiment of the present invention each fluid channel member
40 has a "female" end
portion 45, as shown in Fig. 8, and a complementary "male" end portion 46, as
shown in Fig. 9.
The end portions 45 and 46 are configured so that on bringing the male end
portion 46 of one
printhead module 30 into contact with the female end portion 45 of a second
printhead module 30, the two
printhead modules 30 are connected with the corresponding ducts 41 thereof in
fluid communication. This
allows fluid to flow between the connected printhead modules 30 without
interruption, so that fluid such as
ink, is correctly and effectively delivered to the printhead integrated
circuits 51 of each of the printhead
modules 30.
In order to ensure that the mating of the female and male end portions 45 and
46 provides an
effective seal between the individual printhead modules 30 a sealing adhesive,
such as epoxy, is applied
between the mated end portions.
It is clear that, by providing such a configuration, any number of printhead
modules can suitably be
connected in such an end-to-end fashion to provide the desired scale-up of the
total printhead length. Those
skilled in the art can appreciate that other configurations and methods for
connecting the printhead assembly
modules together so as to be in fluid communication are within the scope of
the present invention.
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Further, this exemplary configuration of the end portions 45 and 46 of the
fluid channel member 40
of the printhead modules 30 also enables easy connection to the fluid supply
of the printing system to which
the printhead assembly is mounted. That is, in one embodiment of the present
invention, fluid delivery
connectors 47 and 48 are provided, as shown in Figs. 10 and 11, wbich act as
an interface for fluid flow
between the ducts 41 of the printhead modules 30 and (internal) fluid delivery
tubes 6, as shown in Fig. 12.
The fluid delivery tubes 6 are referred to as being internal since, as
described in more detail later, these tubes 6
are housed in the printhead assembly 10 for connection to external fluid
delivery tubes of the fluid supply of
the printing system. However, such an arrangement is clearly only one of the
possible ways in which the inks
and other fluids can be supplied to the printhead assembly of the present
invention.
As shown in Fig. 10, the fluid delivery connector 47 has a female connecting
portion 47a which can
mate with the male end portion 46 of the printhead module 30. Alternatively,
or additionally, as shown in
Fig. 11, the fluid delivery connector 48 has a male connecting portion 48a
which can mate with the female end
portion 45 of the printhead module 30. Further, the fluid delivery connectors
47 and 48 include tubular
portions 47b and 48b, respectively, which can mate with the internal fluid
delivery tubes 6. The particular
manner in which the tubular portions 47b and 48b are configured so as to be in
fluid communication with a
corresponding duct 41 is shown in Fig'. 12.
As shown in Figs. 10 to 13, seven tubular portions 47b and 48b are provided to
correspond to the
seven ducts 41 provided in accordance with the above-described exemplary
embodiment of the present
invention. Accordingly, seven internal fluid delivery tubes 6 are used each
for delivering one of the seven
aforementioned fluids of black, cyan, magenta and yellow ink, IR ink, fixative
and air. However, as
previously stated, those skilled in the art clearly understand that more or
less fluids may be used in different
applications, and consequently more or less fluid delivery tubes, tubular
portions of the fluid delivery
connectors and ducts may be provided.
Further, this exemplary configuration of the end portions of the fluid channel
member 40 of the
printhead modules 30 also enables easy sealing of the ducts 41. To this end,
in one embodiment of the present
invention, a sealing member 49 is provided as shown in Fig. 14A, which can
seal or cap both of the end
portions of the printhead module 30. That is, the sealing member 49 includes a
female connecting section 49a
and a male connecting section 49b which can respectively mate with the male
end portion 46 and the female
end portion 45 of the printhead modules 30. Thus, a single sealing member is
advantageously provided
despite the differently configured end portions of a printhead module. Fig.
14B illustrates an exemplary
arrangement of the sealing member 49 sealing the ducts 41 of the fluid channel
member 40. Sealing of the
sealing member 49 and the fluid channel member 40 interface is further
facilitated by applying a sealing
adhesive, such as an epoxy, as described above.
In operation of a single printhead module 30 for an A4-sized pagewidth
printing application, for
example, a combination of one of the fluid delivery connectors 47 and 48
connected to one corresponding end
portion 45 and 46 and a sealing member 49 connected to the other of the
corresponding end portions 45 and
46 is used so as to deliver fluid to the printhead integrated circuits 51. On
the other hand, in applications
where the printhead assembly is particularly long, being comprised of a
plurality of printhead modules 30
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WO 2005/070679 PCT/AU2004/000070
connected together (e.g., in wide format printing), it may be necessary to
provide fluid from both ends of the
printhead assembly. Accordingly, one each of the fluid delivery connectors 47
and 48 may be connected to
the corresponding end portions 45 and 46 of the end printhead modules 30.
The above-described exemplary configuration of the end portions of the
printhead module of the
present invention provides, in part, for the modularity of the printhead
modules. This modularity makes it
possible to manufacture the fluid channel members of the printhead modules in
a standard length relating to
the minimum length application of the printhead assembly. The printhead
assembly length can then be scaled-
up by combining a number of printhead modules to form a printhead assembly of
a desired length. For
example, a standard length printhead module could be manufactured to contain
eight printhead tiles, which
may be the minimum requirement for A4-sized printing applications. Thus, for a
printing application
requiring a wider printhead having a length equivalent to 32 printhead tiles,
four of these standard length
printhead modules could be used. On the other hand, a number of different
standard length printhead modules
might be manufactured, which can be used in combination for applications
requiring variable length
printheads.
However, these are merely examples of how the modularity of the printhead
assembly of the present
invention functions, and other combinations and standard lengths could be
employed and fall within the scope
of the present invention.
The casing 20 and its associated components will now be described with
reference to Figs. 1 to 3 and
15A to 28.
In one embodiment of the present invention, the casing 20 is formed as a two-
piece outer housing
which houses the various components of the printhead assembly and provides
structure for the printhead
assembly which enables the entire unit to be readily mounted in a printing
system. As shown in Fig. 3, the
outer housing is composed of a support frame 22 and a cover portion 23. Each
of these portions 22 and 23 are
made from a suitable material which is lightweight and durable, and which can
easily be extruded to form
various lengths. Accordingly, in one embodiment of the present invention, the
portions 22 and 23 are formed
from a metal such as aluminium.
As shown in Figs. 15A to 15C, the support frame 22 of the casing 20 has an
outer frame wa1124 and
an inner frame wa1125 (with respect to the outward and inward directions of
the printhead assembly 10), with
these two walls being separated by an internal cavity 26. The channel 21 (also
see Fig. 3) is formed as an
extension of an upper wa1127 of the support frame 22 and an arm portion 28 is
formed on a lower region of
the support frame 22, extending from the inner frame wa1125 in a direction
away from the outer frame wal124.
The channel 21 extends along the length of the support frame 22 and is
configured to receive the printhead
module 30. The printhead module 30 is received in the channel 21 with the
printhead integrated circuits 51
facing in an upward direction, as shown in Figs. 1 to 3, and this upper
printhead integrated circuit surface
defnes the printing surface of the printhead assembly 10.
As depicted in Fig. 15A, the channel 21 is formed by the upper wa1127 and two,
generally parallel
side walls 24a and 29 of the support frame 22, which are arranged as outer and
inner side walls (with respect
to the outward and inward directions of the printhead assembly 10) extending
along the length of the support
CA 02550804 2006-06-21
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frame 22. The two side walls 24a and 29 have different heights with the
taller, outer side wall 24a being
defned as the upper portion of the outer frame wall 24 which extends above the
upper wa1127 of the support
frame 22, and the shorter, inner side wall 29 being provided as an upward
extension of the upper wall 27
substantially parallel to the inner frame wall 25. The outer side wall 24a
includes a recess (groove) 24b
formed along the length thereof. A bottom surface 24c of the recess 24b is
positioned so as to be at the same
height as a top surface 29a of the inner side wal129 with respect to the upper
wall 27 of the channe121. The
recess 24b further has an upper surface 24d which is formed as a ridge which
runs along the length of the outer
side wall 24a (see Fig. 15B).
In this arrangement, one of the longitudinally extending tabs 43 of the fluid
channel member 40 of the
printhead module 30 is received within the recess 24b of the outer side
wa1124a so as to be held between the
lower and upper surfaces 24c and 24d thereof. Further, the other
longitudinally extending tab 43 provided on
the opposite side of the fluid channel member 40, is positioned on the top
surface 29a of the inner side wall
29. In this manner, the assembled printhead module 30 may be secured in place
on the casing 20, as will be
described in more detail later.
Further, the outer side wall 24a also includes a slanted portion 24e along the
top margin thereof, the
slanted portion 24e being provided for fixing a print media guide 5 to the
printhead assembly 10, as shown in
Fig. 3. This print media guide is fixed following assembly of the printhead
assembly and is configured to
assist in guiding print media, such as paper, across the printhead integrated
circuits for printing without
making direct contact with the nozzles of the printhead integrated circuits.
As shown in Fig. 15A, the upper wall 27 of the support frame 22 and the arm
portion 28 include lugs
27a and 28a, respectively, which extend along the length of the support frame
22 (see Figs. 15B and 15C).
The lugs 27a and 28a are positioned substantially to oppose each other with
respect to the inner frame wall 25
of the support frame 22 and are used to secure a PCB support 91 (described
below) to the support frame 22.
Figs. 15B and 15C illustrate the manner in which the outer and inner frame
walls 24 and 25 extend
for the length of the casing 20, as do the channel 21, the upper wall 27, and
its lug 27a, the outer and inner
side walls 24a and 29, the recess 24b and its bottom and upper surfaces 24c
and 24d, the slanted portion 24e,
the top surface 29a of the inner side wall 29, and the arm portion 28, and its
lugs 28a and 28b and recessed
and curved end portions 28c and 28d (described in more detail later).
The PCB support 91 will now be described with reference to Figs. 3 and 16 to
22E. In Fig. 3, the
support 91 is shown in its secured position extending along the inner frame
wal125 of the support frame 22
from the upper wall 27 to the arm portion 28. The support 91 is used to carry
the PCB 90 which mounts the
drive electronics 100 (as described in more detail later).
As can be seen particularly in Figs. 17A to 17C, the support 91 includes lugs
92 on upper and lower
surfaces thereof which communicate with the lugs 27a and 28a for securing the
support 91 against the inner
frame wa1125 of the support frame 22. A base portion 93 of the support 91, is
arranged to extend along the
arm portion 28 of the support frame 22, and is seated on the top surfaces of
the lugs 28a and 28b of the arm
portion 28 (see Fig. 15B) when mounted on the support frame 22.
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The support 91 is formed so as to locate within the casing 20 and against the
inner frame wal125 of
the support frame 22. This can be achieved by moulding the support 91 from a
plastics material having
inherent resilient properties to engage with the inner frame wal125. This also
provides the support 91 with the
necessary insulating properties for carrying the PCB 90. For example,
polybutylene terephthalate (PBT) or
polycarbonate may be used for the support 91.
The base portion 93 further includes recessed portions 93a and corresponding
locating lugs 93b,
which are used to secure the PCB 90 to the support 91 (as described in more
detail later). Further, the upper
portion of the support 91 includes upwardly extending arm portions 94, which
are arranged and shaped so as
to fit over the inner side wall 29 of the channel 21 and the longitudinally
extending tab 43 of the printhead
module 30 (which is positioned on the top surface 29a of the inner side wall
29) once the fluid channel
member 40 of the printhead module 30 has been inserted into the channe121.
This arrangement provides for
securement of the printhead module 30 within the channel 21 of the casing 20,
as is shown more clearly in
Fig. 3.
In one embodiment of the present invention, the extending arm portions 94
of'the support 91 are
configured so as to perform a "clipping" or "clamping" action over and along
one edge of the printhead
module 30, which aids in preventing the printhead module 30 from being
dislodged or displaced from the fully
assembled printhead assembly 10. This is because the clipping action acts upon
the fluid channel member 40
of the printhead module 30 in a manner which substantially constrains the
printhead module 30 from moving
upwards from the printhead assembly 10 (i.e., in the z-axis direction as
depicted in Fig. 3) due to both
longitudinally extending tabs 43 of the fluid channel member 40 being held
firmly in place (in a manner which
will be described in more detail below), and from moving across the
longitudinal direction of the printhead
module 30 (i.e., in the y-axis direction as depicted in Fig. 3), which will be
also described in more detail
below.
In this regard, the fluid channel member 40 of the printhead module 30 is
exposed to a force exerted
by the support 91 directed along the y-axis in a direction from the inner side
wall 29 to the outer side wall 24a.
This force causes the longitudinally extending tab 43 of the fluid channel
member 40 on the outer side wall
24a side of the support frame 22 to be held between the lower and upper
surfaces 24c and 24d of the recess
24b. This force, in combination with the other longitudinally extending tab 43
of the fluid channel member 40
being held between the top surface 29a of the inner side wall 29 and the
extending arm portions 94 of the
support 91, acts to inhibit movement of the printhead module 30 in the z-axis
direction (as described in more
detail later).
However, the printhead module 30 is still able to accommodate movement in the
x-axis direction
(i.e., along the longitudinal direction of the printhead module 30), which is
desirable in the event that the
casing 20 undergoes thermal expansion and contraction, during operation of the
printing system. As the
casing is typically made from an extruded metal, such as aluminium, it may
undergo dimensional changes due
to such materials being susceptible to thermal expansion and contraction in a
thermally variable environment,
such as is present in a printing unit.
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That is, in order to ensure the integrity and reliability of the printhead
assembly, the fluid channel
member 40 of the printhead module 30 is firstly formed of material (such as
LCP or the like) which will not
experience substantial dimensional changes due to environmental changes
thereby retaining the positional
relationship between the individual printhead tiles, and the printhead module
30 is arranged to be substantially
independent positionally with respect to the casing 20 (i.e., the printhead
module "floats" in the longitudinal
direction of the channe121 of the casing 20) in which the printhead module 30
is removably mounted.
Therefore, as the printhead module is not constrained in the x-axis direction,
any thermal expansion
forces from the casing in this direction will not be transferred to the
printhead module. Further, as the
constraint in the z-axis and y-axis directions is resilient, there is some
tolerance for movement in these
directions. Consequently, the delicate printhead integrated circuits of the
printhead modules are protected
from these forces and the reliability of the printhead assembly is maintained.
Furthermore, the clipping arrangement also allows for easy assembly and
disassembly of the
printhead assembly by the mere "unclipping" of the PCB support(s) from the
casing. In the exemplary
embodiment shown in Fig. 16, a pair of extending arm portions 94 is provided;
however those skilled in the art
will understand that a greater or lesser number is within the scope of the
present invention.
Referring again to Figs. 16 to 17C, the support 91 further includes a channel
portion 95 in the upper
portion thereof. In the exemplary embodiment illustrated, the channel portion
95 includes three channelled
recesses 95a, 95b and 95c. The channelled recesses 95a, 95b and 95c are
provided so as to accommodate
three longitudinally extending electrical conductors or busbars 71, 72 and 73
(see Fig. 2) which form the
power supply 70 (see Fig. 3) and which extend along the length of the
printhead assembly 10. The busbars 71,
72 and 73 are conductors which carry the power required to operate the
printhead integrated circuits 51 and
the drive electronics 100 located on the PCB 90 (shown in Fig. 18A and
described in more detail later), and
may be formed of copper with gold plating, for example.
In one embodiment of the present invention, three busbars are used in order to
provide for voltages of
Vcc (e.g., via the busbar 71), ground (Gnd) (e.g., via the busbar 72) and V+
(e.g., via the busbar 73).
Specifically, the voltages of Vcc and Gnd are applied to the drive electronics
100 and associated circuitry of
the PCB 90, and the voltages of Vcc, Gnd and V+ are applied to the printhead
integrated circuits 51 of the
printhead tiles 50. It will be understood by those skilled in the art that a
greater or lesser number of busbars,
and therefore channelled recesses in the PCB support can be used depending on
the power requirements of the
specific printing applications.
The support 91 of the present invention further includes (lower) retaining
clips 96 positioned below
the channel portion 95. In the exemplary embodiment illustrated in Fig. 16, a
pair of the retaining clips 96 is
provided. The retaining clips 96 include a notch portion 96a on a bottom
surface thereof which serves to
assist in securely mounting the PCB 90 on the support 91. To this end, as
shown in the exemplary
embodiment of Fig. 18A, the PCB 90 includes a pair of slots 97 in a topmost
side thereof (with respect to the
mounting direction of the PCB 90), which align with the notch portions 96a
when mounted so as to facilitate
engagement with the retaining clips 96.
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As shown in Fig. 3, the PCB 90 is snugly mounted between the notch portions
96a of the retaining
clips 96 and the afore-mentioned recessed portions 93a and locating lugs 93b
of the base portion 93 of the
support 91. This arrangement securely holds the PCB 90 in position so as to
enable reliable connection
between the drive electronics 100 of the PCB 90 and the printhead integrated
circuits 51 of the printhead
module 30.
Referring again to Fig. 18A, an exemplary circuit arrangement of the PCB 90
will now be described.
The circuitry includes the drive electronics 100 in the form of a print engine
controller (PEC) integrated
circuit. The PEC integrated circuit 100 is used to drive the printhead
integrated circuits 51 of the printhead
module 30 in order to print information on the print media passing the
printhead assembly 10 when mounted
to a printing unit. The functions and structure of the PEC integrated circuit
100 are discussed in more detail
later.
The exemplary circuitry of the PCB 90 also includes four connectors 98 in the
upper portion thereof
(see Fig. 18B) which receive lower connecting portions 81 of the flex PCBs 80
that extend from each of the
printhead tiles 50 (see Fig. 6). Specifically, the corresponding ends of four
of the flex PCBs 80 are connected
between the PCBs 52 of four printhead tiles 50 and the four connectors 98 of
the PCB 90. In turn, the
connectors 98 are connected to the PEC integrated circuit 100 so that data
communication can take place
between the PEC integrated circuit 100 and the printhead integrated circuits
51 of the four printhead tiles 50.
In the above-described embodiment, one PEC integrated circuit is chosen to
control four printhead
tiles in order to satisfy the necessary printing speed requirements of the
printhead assembly. In this manner,
for a printhead assembly having 16 printhead tiles, as described above with
respect to Figs. 1 and 2, four PEC
integrated circuits are required and therefore four PCB supports 91 are used.
However, it will be understood
by those skilled in the art that the number of PEC integrated circuits used to
control a number of printhead
tiles may be varied, and as such many different combinations of the number of
printhead tiles, PEC integrated
circuits, PCBs and PCB supports that may be employed depending on the specific
application of the printhead
assembly of the present invention. Further, a single PEC integrated circuit
100 could be provided to drive a
single printhead integrated circuit 51. Furthermore, more than one PEC
integrated circuit 100 may be placed
on a PCB 90, such that differently configured PCBs 90 and supports 91 may be
used.
It is to be noted that the modular approach of employing a number of PCBs
holding separate PEC
integrated circuits for controlling separate areas of the printhead
advantageously assists in the easy
determination, removal and replacement of defective circuitry in the printhead
assembly.
The above-mentioned power supply to the circuitry of the PCB 90 and the
printhead integrated
circuits 51 mounted to the printhead tiles 50 is provided by the flex PCBs 80.
Specifically, the flex PCBs 80
are used for the two functions of providing data connection between the PEC
integrated circuit(s) 100 and the
printhead integrated circuits 51 and providing power connection between the
busbars 71, 72 and 73 and the
PCB 90 and the printhead integrated circuits 51. In order to provide the
necessary electrical connections, the
flex PCBs 80 are arranged to extend from the printhead tiles 50 to the PCB 90.
This may be achieved by
employing the arrangement shown in Fig. 3, in which a resilient pressure plate
74 is provided to urge the flex
PCBs 80 against the busbars 71, 72 and 73. In this arrangement, suitably
arranged electrical connections are
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WO 2005/070679 PCT/AU2004/000070
provided on the flex PCBs 80 which route power from the busbars 71 and 72
(i.e., Vcc and Gnd) to the
connectors 98 of the PCB 90 and power from all of the busbars 71, 72 and 73
(i.e., Vcc, Gnd and V+) to the
PCB 52 of the printhead tiles 50.
The pressure plate 74 is shown in more detail in Figs. 19A to 21. The pressure
plate 74 includes a
raised portion (pressure elastomer) 75 which is positioned on a rear surface
of the pressure plate 74 (with
respect to the mounting direction on the support 91), as shown in Fig. 19B, so
as to be aligned with the
busbars 71, 72 and 73, with the flex PCBs 801ying therebetween when the
pressure plate 74 is mounted on the
support 91. The pressure plate 74 is mounted to the support 91 by engaging
holes 74a with corresponding
ones of (upper) retaining clips 99 of the support 91 which project from the
extending arm portions 94 (see
Fig. 15A) and holes 74b with the corresponding ones of the (lower) retaining
clips 96, via tab portions 74c
thereof (see Fig. 20). The pressure plate 74 is formed so as to have a spring-
like resilience which urges the
flex PCBs 80 into electrical contact with the busbars 71, 72 and 73 with the
raised portion 75 providing
insulation between the pressure plate 74 and the flex PCBs 80.
As shown most clearly in Fig. 21, the pressure plate 74 further includes a
curved lower portion 74d
which serves as a means of assisting the demounting of the pressure plate 74
from the support 91.
The specific manner in which the pressure plate 74 is retained on the support
91 so as to urge the flex
PCBs 80 against the busbars 71, 72 and 73, and the manner in which the
extending arm portions 94 of the
support 91 enable the above-mentioned clipping action will now be fully
described with reference to Figs. 22
and 22A to 22E.
Fig. 22 illustrates a front schematic view of the support 91 in accordance
with a exemplary
embodiment of the present invention. Fig. 22A is a side sectional view taken
along the line I-I in Fig. 22 with
the hatched sections illustrating the components of the support 91 situated on
the line M.
Fig. 22A particularly shows one of the upper retaini.ng clips 99. An enlarged
view of this retaining
clip 99 is shown in Fig. 22B. The retaining clip 99 is configured so that an
upper surface of one of the holes
74a of the pressure plate 74 can be retained against an upper surface 99a and
a retaining portion 99b of the
retaining clip 99 (see Fig. 21). Due to the spring-like resilience of the
pressure plate 74, the upper surface 99a
exerts a slight upwardly and outwardly directed force on the pressure plate 74
when the pressure plate 74 is
mounted thereon so as to cause the upper part of the pressure plate 74 to abut
against the retaining portion
99b.
Referring now to Fig. 22C, which is a side sectional view taken along the line
II-II in Fig. 22, one of
the lower retaini.ug clips 96 is illustrated. An enlarged view of this
retaining clip 96 is shown in Fig. 22D.
The retaining clip 96 is configured so that a tab portion 74c of one of the
holes 74b of the pressure plate 74
can be retained against an inner surface 96c of the retaining clip 96 (see
Fig. 20). Accordingly, due to the
above-described slight force exerted by the retaining clip 99 on the upper
part of the pressure plate 74 in a
direction away from the support 91, the lower part of the pressure plate 74 is
loaded towards the opposite
direction, e.g., in an inward direction with respect to the support frame 22.
Consequently, the pressure plate
74 is urged towards the busbars 71, 72 and 73, which in turn serves to urge
the flex PCBs 80 in the same
direction via the raised portion 75, so as to effect reliable contact with the
busbars 71, 72 and 73.
CA 02550804 2006-06-21
WO 2005/070679 PCT/AU2004/000070
Returning to Fig. 22C, in which one of the extending arm portions 94 is
illustrated. An enlarged
view of this extending arm portion 94 is shown in Fig. 22E. The extending arm
portion 94 is configured so as
to be substantially L-shaped, with the foot section of the L-shape located so
as to fit over the inner side wal129
of the channel 21 and the longitudinally extending tab 43 of the fluid channel
member 40 of the printhead
module 30 arranged thereon. As shown in Fig. 22E, the end of the foot section
of the L-shape has an arced
surface. This surface corresponds to the edge of a recessed portion 94a
provided in each the extending arm
portions 94, the centre of which is positioned substantially at the line II-II
in Fig. 22 (see Figs. 16 and 17C).
The recessed portions 94a are arranged so as to engage with angular lugs 43a
regularly spaced along the length
of the longitudinally extending tabs 43 of the fluid channel member 40 (Fig.
4A), so as to correspond with the
placement of the printhead tiles 50, when the extending arm portions 94 are
clipped over the fluid channel
member 40.
In this position, the arced edge of the recessed portion 94a is contacted with
the angled surface of the
angular lugs 43a (see Fig. 4A), with this being the only point of contact of
the extending arm portion 94 with
the longitudinally extending tab 43. Although not shown in Fig. 4A, the
longitudinally extending tab 43 on the
other side of the fluid channel member 40 has similarly angled lugs 43a, where
the angled surface comes into
contact with the upper surface 24d of the recess 24b on the support frame 22.
As alluded to previously, due to this specific arrangement, at these contact
points a downwardly and
inwardly directed force is exerted on the fluid channel member 40 by the
extending arm portion 94. The
downwardly directed force assists to constrain the printhead module 30 in the
channel 21 in the z-axis
direction as described earlier. The inwardly directed force also assists in
constraining the printhead module 30
in the channe121 by urging the angular lugs 43a on the opposing longitudinally
extending tab 43 of the fluid
channel member 40 into the recess 24b of the support frame 20, where the upper
surface 24d of the recess 24b
also applies an opposing downwardly and inwardly directed force on the fluid
channel member. In this regard
the opposing forces act to constrain the range of movement of the fluid
channel member 40 in the y-axis
direction. It is to be understood that the two angular lugs 43a shown in Fig.
4A for each of the recessed
portions 94a are merely an exemplary arrangement of the angular lugs 43a.
Further, the angular lugs 43a are positioned so as to correspond to the
placement of the printhead tiles
50 on the upper surface of the fluid channel member 40 so that, when mounted,
the lower connecting portions
81 of each of the flex PCBs 80 are aligned with the corresponding connectors
98 of the PCBs 90 (see Figs. 6
and 18B). This is facilitated by the flex PCBs 80 having a hole 82 therein
(Fig. 6) which is received by the
lower retaining clip 96 of the support 91. Consequently, the flex PCBs 80 are
correctly positioned under the
pressure plate 74 retained by the retaining clip 96 as described above.
Further still, as also shown in Figs. 22C and 22E, the (upper) lug 92 of the
support 91 has an inner
surface 92a which is also slightly angled from the normal of the plane of the
support 91 in a direction away
from the support 91. As shown in Figs. 17B and 17C, the upper lugs 92 are
formed as resilient members
which are able to hinge with respect to the support 91 with a spring-like
action. Consequently, when mounted
to the casing 20, a slight force is exerted against the lug 27a of the
uppermost face 27 of the support frame 22
which assists in securing the support 91 to the support frame 22 of the casing
20 by biasing the (lower) lug 92
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into the recess formed between the lower part of the inner surface 25 and the
lug 28a of the arm portion 28 of
the support frame 22.
The manner in which the structure of the casing 20 is completed in accordance
with an exemplary
embodiment of the present invention will now be described with reference to
Figs. 1, 2, 15A and 23.
As shown in Figs. 1 and 2, the casing 20 includes the aforementioned cover
portion 23 which is
positioned adjacent the support frame 22. Thus, together the support frame 22
and the cover portion 23 define
the two-piece outer housing of the printhead assembly 10. The profile of the
cover portion 23 is as shown in
Fig. 23.
The cover portion 23 is configured so as to be placed over the exposed PCB 90
mounted to the PCB
support 91 which in turn is mounted to the support frame 22 of the casing 20,
with the channel 21 thereof
holding the printhead module 30. As a result, the cover portion 23 encloses
the printhead module 30 within
the casing 20.
The cover portion 23 includes a longitudinally extending tab 23a on a bottom
surface thereof (with
respect to the orientation of the printhead assembly 10) which is received in
the recessed portion 28c formed
between the lug 28b and the curved end portion 28d of the arm portion 28 of
the support frame 22 (see
Fig. 15A). This arrangement locates and holds the cover portion 23 in the
casing 20 with respect to the
support frame 22. The cover portion 23 is further held in place by affixing
the end plate 111 or the end
housing 120 via the end plate 110 on the longitudinal side thereof using
screws through threaded portions 23b
(see Figs. 23, 29 and 39). The end plates 110 and/or 111 are also affixed to
the support frame 22 on either
longitudinal side thereof using screws through threaded portions 22a and 22b
provided in the internal cavity
26 (see Figs. 15A, 29 and 39). Further, the cover portion 23 has the profile
as shown in Fig. 23, in which a
cavity portion 23c is arranged at the inner surface of the cover portion 23
(with respect to the inward direction
on the printhead assembly 10) for accommodating the pressure plate(s) 74
mounted to the PCB support(s) 91.
Further, the cover portion may also include fin portions 23d (see also Fig. 3)
which are provided for
dissipating heat generated by the PEC integrated circuits 100 during operation
thereof. To facilitate this the
inner surface of the cover portion 23 may also be provided with a heat
coupling material portion (not shown)
which physically contacts the PEC integrated circuits 100 when the cover
portion 23 is attached to the support
frame 22. Further still, the cover portion 23 may also function to inhibit
electromagnetic interference (EMI)
which can interfere with the operation of the dedicated electronics of the
printhead assembly 10.
The manner in which a plurality of the PCB supports 91 are assembled in the
support frame 22 to
provide a sufficient number of PEC integrated circuits 100 per printhead
module 30 in accordance with one
embodiment of the present invention will now be described with reference to
Figs. 16 and 24 to 27.
As described earlier, in one embodiment of the present invention, each of the
supports 91 is arranged
to hold one of the PEC integrated circuits 100 which in turn drives four
printhead integrated circuits 51.
Accordingly, in a printhead module 30 having 16 printhead tiles, for example,
four PEC integrated circuits
100, and therefore four supports 91 are required. For this purpose, the
supports 91 are assembled in an end-to-
end manner, as shown in Fig. 24, so as to extend the length of the casing 20,
with each of the supports 91
being mounted and clipped to the support frame 22 and printhead module 30 as
previously described. In such
32
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WO 2005/070679 PCT/AU2004/000070
a way, the single printhead module 30 of sixteen printhead tiles 50 is
securely held to the casing 20 along the
length thereof.
As shown more clearly in Fig. 16, the supports 91 further include raised
portions 91a and recessed
portions 91b at each end thereof. That is, each edge region of the end walls
of the supports 91 include a raised
portion 91a with a recessed portion 91b formed along the outer edge thereof.
This configuration produces the
abutting arrangement between the adjacent supports 91 shown in Fig. 24.
This arrangement of two abutting recessed portions 91b with one raised portion
91a at either side
thereof forms a cavity which is able to receive a suitable electrical
connecting member 102 therein, as shown
in cross-section in Fig. 25. Such an arrangement enables adjacent PCBs 90,
carried on the supports 91 to be
electrically connected together so that data signals which are input from
either or both ends of the plurality of
assembled supports 91, i.e., via data connectors (described later) provided at
the ends of the casing 20, are
routed to the desired PEC integrated circuits 100, and therefore to the
desired printhead integrated circuits 51.
To this end, the connecting members 102 provide electrical connection between
a plurality of pads
provided at edge contacting regions on the underside of each of the PCBs 90
(with respect to the mounting
direction on the supports 91). Each of these pads is connected to different
regions of the circuitry of the PCB
90. Fig. 26 illustrates the pads of the PCBs as positioned over the connecting
member 102. Specifically, as
shown in Fig. 26, the plurality of pads are provided as a series of connection
strips 90a and 90b in a
substantially central region of each edge of the underside of the PCBs 90.
As mentioned above, the connecting members 102 are placed in the cavity formed
by the abutting
recessed portions 91b of adjacent supports 91 (see Fig. 25), such that when
the PCBs 90 are mounted on the
supports 91, the connection strips 90a of one PCB 90 and the connection strips
90b of the adjacent PCB 90
come into contact with the same connecting member 102 so as to provide
electrical connection therebetween.
To achieve this, the connecting members 102 may each be formed as shown in
Fig. 27 to be a
rectangular block having a series of conducting strips 104 provided on each
surface thereof. Alternatively, the
conducting strips 104 may be formed on only one surface of the connecting
members 102 as depicted in Figs.
25 and 26. Such a connecting member may typically be formed of a strip of
silicone rubber printed to provide
sequentially spaced conductive and non-conductive material strips. A shown in
Fig. 27, these conducting
strips 104 are provided in a 2:1 relationship with the connecting strips 90a
and 90b of the PCBs 90. That is,
twice as many of the conducting strips 104 are provided than the connecting
strips 90a and 90b, with the width
of the conducting strips 104 being less than half the width of the connecting
strips 90a and 90b. Accordingly,
any one connecting strip 90a or 90b may come into contact with one or both of
two corresponding conducting
strips 104, thus minimising alignment requirements between the connecting
members 104 and the contacting
regions of the PCBs 90.
In one embodiment of the present invention, the connecting strips 90a and 90b
are about 0.4 mm
wide with a 0.4 mm spacing therebetween, so that two thinner conducting strips
104 can reliably make contact
with only one each of the connecting strips 90a and 90b whilst having a
sufficient space therebetween to
prevent short circuiting. The connecting strips 90a and 90b and the conducting
strips 104 may be gold plated
so as to provide reliable contact. However, those skilled in the art will
understand that use of the connecting
33
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WO 2005/070679 PCT/AU2004/000070
members and suitably configured PCB supports is only one exemplary way of
connecting the PCBs 90, and
other types of connections are within the scope of the present invention.
Additionally, the circuitry of the PCBs 90 is arranged so that a PEC
integrated circuit 100 of one of
the PCB 90 of an assembled support 91 can be used to drive not only the
printhead integrated circuits 51
connected directly to that PCB 90, but also those of the adjacent PCB(s) 90,
and further of any non-adjacent
PCB(s) 90. Such an arrangement advantageously provides the printhead assembly
10 with the capability of
continuous operation despite one of the PEC integrated circuits 100 and/or
PCBs 90 becoming defective,
albeit at a reduced printing speed.
In accordance with the above-described scalability of the printhead assembly
10 of the present
invention, the end-to-end assembly of the PCB supports 91 can be extended up
to the required length of the
printhead assembly 10 due to the modularity of the supports 91. For this
purpose, the busbars 71, 72 and 73
need to be extended for the combined length of the plurality of PCB supports
91, which may result in
insufficient power being delivered to each of the PCBs 90 when a relatively
long printhead assembly 10 is
desired, such as in wide format printing applications.
In order to minimise power loss, two power supplies can be used, one at each
end of the printhead
assembly 10, and a group of busbars 70 from each end may be employed. The
connection of these two busbar
groups, e.g., substantially in the centre of the printhead assembly 10, is
facilitated by providing the exemplary
connecting regions 71a, 72a and 73a shown in Fig. 28.
Specifically, the busbars 71, 72 and 73 are provided in a staggered
arrangement relative to each other
and the end regions thereof are configured with the rebated portions shown in
Fig. 28 as connecting regions
71a, 72a and 73a. Accordingly, the connecting regions 71a, 72a and 73a of the
first group of busbars 70
overlap and are engaged with the connecting regions 71a, 72a and 73a of the
corresponding ones of the
busbars 71, 72 and 73 of the second group of busbars 70.
The manner in which the busbars are connected to the power supply and the
arrangements of the end
plates 110 and 111 and the end housing(s) 120 which house these connections
will now be described with
reference to Figs. 1, 2 and 29 to 39.
Fig. 29 illustrates an end portion of an exemplary printhead assembly
according to one embodiment
of the present invention similar to that shown in Fig. 1. At this end portion,
the end housing 120 is attached to
the casing 20 of the printhead assembly 10 via the end plate 110.
The end housing and plate assembly houses connection electronics for the
supply of power to the
busbars 71, 72 and 73 and the supply of data to the PCBs 90. The end housing
and plate assembly also houses
connections for the internal fluid delivery tubes 6 to external fluid delivery
tubes (not shown) of the fluid
supply of the printing system to which the printhead assembly 10 is being
applied.
These connections are provided on a connector arrangement 115 as shown in Fig.
30. Fig. 30
illustrates the connector arrangement 115 fitted to the end plate 110 which is
attached, via screws as described
earlier, to an end of the casing 20 of the printhead assembly 10 according to
one embodiment of the present
invention. As shown, the connector arrangement 115 includes a power supply
connection portion 116, a data
connection portion 117 and a fluid delivery connection portion 118. Terminals
of the power supply
34
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WO 2005/070679 PCT/AU2004/000070
connection portion 116 are connected to corresponding ones of three contact
screws 116a, 116b, 116c
provided so as to each connect with a corresponding one of the busbars 71, 72
and 73. To this end, each of
the busbars 71, 72 and 73 is provided with threaded holes in suitable
locations for engagement with the
contact screws 116a, 116b, 116c. Further, the connection regions 71a, 72a and
73a (see Fig. 28) may also be
provided at the ends of the busbars 71, 72 and 73 which are to be in contact
with the contact screws 116a,
116b, 116c so as to facilitate the engagement of the busbars 71, 72 and 73
with the connector arrangement
115, as shown in Fig. 31.
In Figs. 30, 32A and 32B, only three contact screws or places for three
contact screws are shown, one
for each of the busbars. However, the use of a different number of contact
screws is within the scope of the
present invention. That is, depending on the amount of power being routed to
the busbars, in order to provide
sufficient power contact it may be necessary to provide two or more contact
screws for each busbar (see, for
example, Figs. 33B and 33C). Further, as mentioned earlier a greater or lesser
number of busbars may be
used, and therefore a corresponding greater of lesser number of contact
screws. Further still, those skilled in
the art will understand that other means of contacting the busbars to the
power supply via the connector
arrangements as are typical in the art, such as soldering, are within the
scope of the present invention.
The manner in which the power supply connection portion 116 and the data
connection portion 117
are attached to the connector arrangement 115 is shown in Figs. 32A and 32B.
Further, connection tabs 118a
of the fluid delivery connection portion 118 are attached at holes 1 15a of
the connector arrangement 115 so as
that the fluid delivery connection portion 118 overlies the data connection
portion 117 with respect to the
connector arrangement 115 (see Figs. 30 and 32C).
As seen in Figs. 30 and 32C, seven internal and external tube connectors 118b
and 118c are provided
in the fluid delivery connection portion 118 in accordance with the seven
internal fluid delivery tubes 6. That
is, as shown in Fig. 34, the fluid delivery tubes 6 connect between the
internal tube connectors 118b of the
fluid delivery connection portion 118 and the seven tubular portions 47b or
48b of the fluid delivery connector
47 or 48. As stated earlier, those skilled in the art clearly understand that
the present invention is not limited
to this number of fluid delivery tubes, etc.
Returni.ng to Figs. 32A and 32B, the connector arrangement 115 is shaped with
regions 115b and
115c so as to be received by the casing 20 in a manner which facilitates
connection of the busbars 71, 72 and
73 to the contact screws 116a, 116b and 116c of the power supply connection
portion 116 via region 115b and
connection of the end PCB 90 of the plurality of PCBs 90 arranged on the
casing 20 to the data connection
portion 117 via region 115c.
The region 115c of the connector arrangement 115 is advantageously provided
with connection
regions (not shown) of the data connection portion 117 which correspond to the
connection strips 90a or 90b
provided at the edge contacting region on the underside of the end PCB 90, so
tha`t one of the connecting
members 102 can be used to connect the data connections of the data connection
portion 117 to the end PCB
90, and thus all of the plurality of PCBs 90 via the connecting members 102
provided therebetween.
This is facilitated by using a support member 112 as shown in Fig. 33A, which
has a raised portion
112a and a recessed portion 112b at one edge thereof which is arranged to
align with the raised and recessed
CA 02550804 2006-06-21
WO 2005/070679 PCT/AU2004/000070
portions 91a and 91b, respectively, of the end PCB support 91 (see Fig. 24).
The support member 112 is
attached to the rear surface of the end PCB support 91 by engaging a tab 112c
with a slot region 91c on the
rear surface of the end PCB support 91 (see Figs. 17B and 17C), and the region
115c of the connector
arrangement 115 is retained at upper and lower side surfaces thereof by clip
portions 112d of the support
member 112 so as that the connection regions of the region 115c are in
substantially the same plane as the
edge contacting regions on the underside of the end PCB 90.
Thus, when the end plate 110 is attached to the end of the casing 20, an
abutting arrangement is
formed between the recessed portions 112b and 91b, similar to the abutting
arrangement formed between the
recessed portions 91b of the adjacent supports 91 of Fig. 24. Accordingly, the
connecting member 102 can be
accommodated compactly between the end PCB 90 and the region 115c of the
connector arrangement 115.
This arrangement is shown in Figs. 33B and 33C for another type of connector
arrangement 125 with a
corresponding region 125c, which is described in more detail below with
respect to Figs. 37, 38A and 38B.
This exemplary manner of connecting the data connection-portion 117 to the end
PCB 90 contributes
to the modular aspect of the present invention, in that it is not necessary to
provide differently configured
PCBs 90 to be arranged at the longitudinal ends of the casing 20 and the same
method of data connection can
be retained throughout the printhead assembly 10. It will be understood by
those skilled in the art however
that the provision of additional or other components to connect the data
connection portion 117 to the end
PCB 90 is also included in the scope of the present invention.
Returning to Fig. 30, it can be seen that the end plate 110 is shaped so as to
conform with the regions
115b and 115c of the connector arrangement 115, such that these regions can
project into the casing 20 for
connection to the busbars 71, 72 and 73 and the end PCB 90, and so that the
busbars 71, 72 and 73 can extend
to contact screws 116a, 1 16b and 116c provided on the connector arrangement
115. This particular shape of
the end plate 110 is shown in Fig. 35A, where regions 110a and 110b of the end
plate 110 correspond with the
regions 1 15b and 115c of the connector arrangement 115, respectively.
Further, a region 110c of the end plate
110 is provided so as to enable connection between the internal fluid delivery
tubes 6 and the fluid delivery
connectors 47 and 48 of the printhead module 30.
The end housing 120 is also shaped as shown in Fig. 35A, so as to retain the
power supply, data and
fluid delivery connection portions 116, 117 and 118 so that external
connection regions thereof, such as the
external tube connector 118c of the fluid delivery connection portion 118
shown in Fig. 32C, are exposed
from the printhead assembly 10, as shown in Fig. 29.
Fig. 35B illustrates the end plate 110 and the end housing 120 which may be
provided at the other
end of the casing 20 of the printhead assembly 10 according to an exemplary
embodiment of the present
invention. The exemplary embodiment shown in Fig. 35B, for example,
corresponds to a situation where an
end housing is provided at both ends of the casing so as to provide power
supply and/or fluid delivery
connections at both ends of the printhead assembly. Such an exemplary
printhead assembly is shown in Figure
36, and corresponds, for example, to the above-mentioned exemplary application
of wide format printing, in
which the printhead assembly is relatively long.
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WO 2005/070679 PCT/AU2004/000070
To this end, Fig. 37 illustrates the end housing and plate assembly for the
other end of the casing with
the connector arrangement 125 housed therein. The busbars 71, 72 and 73 are
shown attached to the
connector arrangement 125 for illustration purposes. As can be seen, the
busbars 71, 72 and 73 are provided
with connection regions 71a, 72a and 73a for engagement with connector
arrangement 125, similar to that
shown in Fig. 31 for the connector arrangement 115. The connector arrangement
125 is illustrated in more
detail in Figs. 38A and 38B.
As can be seen from Figs. 38A and 38B, like the connector arrangement 115, the
connector
arrangement 125 holds the power supply connection portion 116 and includes
places for contact screws for
contact with the busbars 71, 72 and 73, holes 125a for retaining the clips
118a of the fluid delivery portion
118 (not shown), and regions 125b and 125c for extension into the casing 20
through regions 110a and 110b
of the end plate 110, respectively. However, unlike the connector arrangement
115, the connector
arrangement 125 does not hold the data connection portion 117 and includes in
place thereof a spring portion
125d.
This is because, unlike the power and fluid supply in a relatively long
printhead assembly application,
it is only necessary to input the driving data from one end of the printhead
assembly. However, in order to
input the data signals correctly to the plurality of PEC integrated circuits
100, it is necessary to terminate the
data signals at the end opposite to the data input end. Therefore, the region
125c of the connector arrangement
125 is provided with termination regions (not shown) which correspond with the
edge contacting regions on
the underside of the end PCB 90 at the terminating end. These termination
regions are suitably connected with
the contacting regions via a connecting member 102, in the manner described
above.
The purpose of the spring portion 125d is to maintain these terminal
connections even in the event of
the casing 20 expanding and contracting due to temperature variations as
described previously, any effect of
which may exacerbated in the longer printhead applications. The configuration
of the spring portion 125d
shown in Figs. 38A and 38B, for example, enables the region 125c to be
displaced through a range of
distances from a body portion 125e of the connector arrangement 125, whilst
being biased in a normal
direction away from the body portion 125e. The spring portion is formed in the
connector arrangement 125 by
removing a section of the material making up the body portion 125e.
Thus, when the connector arrangement 125 is attached to the end plate 110,
which in turn has been
attached to the casing 20, the region 125c is brought into abutting contact
with the adjacent edge of the end
PCB 90 in such a manner that the spring portion 125d experiences a pressing
force on the body of the
connector arrangement 125, thereby displacing the region 125c from its rest
position toward the body portion
125e by a predetermined amount. This arrangement ensures that in the event of
any dimensional changes of
the casing 20 via thermal expansion and contraction thereof, the data signals
remain terminated at the end of
the plurality of PCBs 90 opposite to the end of data signal input as follows.
The PCB supports 91 are retained on the support frame 22 of the casing 20 so
as to "float" thereon,
similar to the manner in which the printhead module(s) 30 "float" on the
channel 21 as described earlier.
Consequently, since the supports 91 and the fluid channel members 40 of the
printhead modules 30 are formed
of similar materials, such as LCP or the like, which have the same or similar
coefficients of expansion, then in
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the event of any expansion and contraction of the casing 20, the supports 91
retain their relative position with
the printhead module(s) 30 via the clipping of the extending arm portions 94.
Therefore, each of the supports 91 retain their adjacent connections via the
connecting members 102,
which is facilitated by the relatively large overlap of the connecting members
102 and the connection strips
90a and 90b of the PCBs 90 as shown in Fig. 27. Accordingly, since the PCBs
90, and therefore the supports
91 to which they are mounted, are biased towards the connector arrangement 115
by the spring portion 125d
of the connector arrangement 125, then should the casing 20 expand and
contract, any gaps which might
otherwise form between the connector arrangements 115 and 125 and the end PCBs
90 are prevented, due to
the action of the spring portion 125d.
Accommodation for any expansion and contraction is also facilitated with
respect to the power supply
by the connecting regions 71a, 72a and 73a of the two groups of busbars 70
which are used in the relatively
long printhead assembly application. This is because, these connecting regions
71a, 72a and 73a are
configured so that the overlap region between the two groups of busbars 70
allows for the relative movement
of the connector arrangements 115 and 125 to which the busbars 71, 72 and 73
are attached whilst maintaining
a connecting overlap in this region.
In the examples illustrated in Figs. 30, 33B, 33C and 37, the end sections of
the busbars 71, 72 and
73 are shown connected to the connector arrangements 115 and 125 (via the
contact screws 116a, 116b and
116c) on the front surface of the connector arrangements 115 and 125 (with
respect to the direction of
mounting to the casing 20). Alternatively, the busbars 71, 72 and 73 can be
connected at the rear surfaces of
the connector arrangements 115 and 125. In such an alternative arrangement,
even though the busbars 71, 72
and 73 thus connected may cause the connector arrangements 115 and 125 be
slightly displaced toward the
cover portion 23, the regions 115c and 125c of the connector arrangements 115
and 125 are maintained in
substantially the same plane as the edge contacting regions of the end PCBs 90
due to the clip portions 112d
of the support members 112 which retain the upper and lower side surfaces of
the regions 115c and 125c.
Printed circuit boards having connecting regions printed in discrete areas may
be employed as the
connector arrangements 115 and 125 in order to provide the various above-
described electrical connections
provided thereby.
Fig. 39 illustrates the end plate 111 which may be attached to the other end
of the casing 20 of the
printhead assembly 10 according to an exemplary embodiment of the present
invention, instead of the end
housing and plate assemblies shown in Figs. 35A and 35B. This provides for a
situation where the printhead
assembly is not of a length which requires power and fluid to be supplied from
both ends. For example, in an
A4-sized printing application where a printhead assembly housing one printhead
module of 16 printhead tiles
may be employed.
In such a situation therefore, since it is unnecessary specifically to provide
a connector arrangement
at the end of the printhead module 30 which is capped by the capping member
49, then the end plate 111 can
be employed which serves to securely hold the support frame 22 and cover
portion 23 of the casing 20
together via screws secured to the threaded portions 22a, 22b and 23b thereof,
in the manner already described
(see also Fig. 2).
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Further, if it is necessary to provide data signal termination at this end of
the plurality of PCBs .90,
then the end plate 111 can be provided with a slot section (not shown) on the
inner surface thereof (with
respect to the mounting direction on the casing 20), which can support a PCB
(not shown) having termination
regions which correspond with the edge contacting regions of the end PCB 90,
similar to the region 125c of
the connector arrangement 125. Also similarly, these termination regions may
be suitably connected with the
contacting regions via a support member 112 and a connecting member 102. This
PCB may also include a
spring portion between the termination regions and the end plate 111, similar
to the spring portion 125d of the
connector arrangement 125, in case expansion and contraction of the casing 20
may also cause connection
problems in this application.
With either the attachment of the end housing 120 and plate 110 assemblies to
both ends of the casing
or the attachment of the end housing 120 and plate 110 assembly to one end of
the casing 20 and the end
plate 111 to the other end, the structure of the printhead assembly according
to the present invention is
completed.
The thus-assembled printhead assembly can then be mounted to a printing unit
to which the
15 assembled length of the printhead assembly is applicable. Exemplary
printing units to which the printhead
module and printhead assembly of the present invention is applicable are as
follows.
For a home office printing unit printing on A4 and letter-sized paper, a
printhead assembly having a
single printhead module comprising 11 printhead integrated circuits can be
used to present a printhead width
of 224 mm. This printing unit is capable of printing at approximately 60 pages
per minute (ppm) when the
20 nozzle speed is about 20 kHz. At this speed a maximum of about 1690x 106
drops or about 1.6896 ml of ink is
delivered per second for the entire printhead. This results in a linear
printing speed of about 0.32 ms 1 or an
area printing speed of about 0.07 sqms"1. A single PEC integrated circuit can
be used to drive all 11 printhead
integrated circuits, with the PEC integrated circuit calculating about 1.8
billion dots per second.
For a printing unit printing on A3 and tabloid-sized paper, a printhead
assembly having a single
printhead module comprising 16 printhead integrated circuits can be used to
present a printhead width of 325
mm. This printing unit is capable of printing at approximately 120 ppm when
the nozzle speed is about 55
kHz. At this speed a maximum of about 6758x 106 drops or about 6.7584 ml of
ink is delivered per second for
the entire printhead. This results in a linear printing speed of about 0.87 ms-
! or an area printing speed of
about 0.28 sqms"I. Four PEC integrated circuits can be used to each drive four
of the printhead integrated
circuits, with the PEC integrated circuits collectively calculating about 7.2
billion dots per second.
For a printing unit printing on a roll of wallpaper, a printhead assembly
having one or more printhead
modules providing 36 printhead integrated circuits can be used to present a
printhead width of 732 mm. When
the nozzle speed is about 55 kHz, a maximum of about 15206x106 drops or about
15.2064 ml of ink is
delivered per second for the entire printhead. This results in a linear
printing speed of about 0.87 ms"1 or an
area printing speed of about 0.64 sqms"1. Nine PEC integrated circuits can be
used to each drive four of the
printhead integrated circuits, with the PEC integrated circuits collectively
calculating about 16.2 billion dots
per second.
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For a wide format printing unit printing on a roll of print media, a printhead
assembly having one or
more printhead modules providing 92 printhead integrated circuits can be used
to present a printhead width of
1869 mm. When the nozzle speed is in a range of about 15 to 55 kHz, a maximum
of about 10598X106 to
38861 X 106 drops or about 10.5984 to 38.8608 ml of ink is delivered per
second for the entire printhead. This
results in a linear printing speed of about 0.24 to 0.87 ms 1 or an area
printing speed of about 0.45 to 1.63
sqms ". At the lower speeds, six PEC integrated circuits can be used to each
drive 16 of the printhead
integrated circuits (with one of the PEC integrated circuits driving 12
printhead integrated circuits), with the
PEC integrated circuits collectively calculating about 10.8 billion dots per
second. At the higher speeds, 23
PEC integrated circuits can be used each to drive four of the printhead
integrated circuits, with the PEC
integrated circuits collectively calculating about 41.4 billions dots per
second.
For a "super wide" printing unit printing on a roll of print media, a
printhead assembly having one or
more printhead modules providing 200 printhead integrated circuits can be used
to present a printhead width
of 4064 mm. When the nozzle speed is about 15 kHz, a maximum of about 23040x
106 drops or about 23.04
ml of ink is delivered per second for the entire printhead. This results in a
linear printing speed of about 0.24
ms' or an area printing speed of about 0.97 sqms I. Thirteen PEC integrated
circuits can be used to each drive
16 of the printhead integrated circuits (with one of the PEC integrated
circuits driving eight printhead
integrated circuits), with the PEC integrated circuits collectively
calculating about 23.4 billion dots per
second.
For the above exemplary printing unit applications, the required printhead
assembly may be provided
by the corresponding standard length printhead module or built-up of several
standard length printhead
modules. Of course, any of the above exemplary printing unit applications may
involve duplex printing with
simultaneous double-sided printing, such that two printhead assemblies are
used each having the number of
printhead tiles given above. Further, those skilled in the art understand that
these applications are merely
examples and the number of printhead integrated circuits, nozzle speeds and
associated printing capabilities of
the printhead assembly depends upon the specific printing unit application.
Print Engine Controller
The functions and structure of the PEC integrated circuit applicable to the
printhead assembly of the
present invention wiIl now be discussed with reference to Figs. 40 to 42.
In the above-descn'bed exemplary embodiments of the present invention, the
printhead integrated
circuits 51 of the printhead assembly 10 are controlled by the PEC integrated
circuits 100 of the drive
electronics 100. One or more PEC integrated circuits 100 is or are provided in
order to enable pagewidth
printing over a variety of different sized pages. As described earlier, each
of the PCBs 90 supported by the
PCB supports 91 has one PEC integrated circuit 100 which interfaces with four
of the printhead integrated
circuits 51, where the PEC integrated circuit 100 essentially drives the
printhead integrated circuits 51 and
transfers received print data thereto in a form suitable for printing.
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Referring to Fig. 40, the data flow and functions performed by the PEC
integrated circuit 100 will be
descn'bed for a situation where the PEC integrated circuit 100 is suited to
driving a printhead assembly having
a plurality of printhead modules 30. As described above, the printhead module
30 of one embodiment of the
present invention utilises six channels of fluid for printing. These are:
= Cyan, Magenta and Yellow (CMY) for regular colour printing;
= Black (K) for black text and other black or greyscale printing;
= Infrared (IR) for tag-enabled applications; and
= Fixative (F) to enable printing at high speed.
As shown in Fig. 40, documents are typically supplied to the PEC integrated
circuit 100 by a
computer system or the like, having Raster Image Processor(s) (RIP(s)), which
is programmed to perform
various processing steps 131 to 134 involved in printing a docunient prior to
transmission to the PEC
integrated circuit 100. These steps typically involve receiving the document
data (step 131) and storing this
data in a memory buffer of the computer system (step 132), in which page
layouts may be produced and any
required objects may be added. Pages from the memory buffer are rasterized by
the RIP (step 133) and are
then compressed (step 134) prior to transmission to the PEC integrated circuit
100. Upon receiving the page
data, the PEC integrated circuit 100 processes the data so as to drive the
printhead integrated circuits 51.
Due to the page-width nature of the printhead assembly of the present
invention, each page must be
printed at a constant speed to avoid creating visible artifacts. This means
that the printing speed cannot be
varied to match the input data rate. Document rasterization and document
printing are therefore decoupled to
ensure the printhead assembly has a constant supply of data. In this
arrangement, a page is not printed until it
is fully rasterized, and in order to achieve a high constant printing speed a
compressed version of each
rasterized page image is stored in memory. This decoupling also allows the
RIP(s) to run ahead of the printer
when rasterizing simple pages, buying time to rasterize more complex pages.
Because contone colour images are reproduced by stochastic dithering, but
black text and line
graphics are reproduced directly using dots, the compressed page image format
contains a separate foreground
bi-level black layer and background contone colour layer. The black layer is
composited over the coiitone
layer after the contone layer is dithered (although the contone layer has an
optional black component). If
required, a final layer of tags (in IR or black ink) is optionally added to
the page for printout.
Dither matrix selection regions in the page description are rasterized to a
contone-resolution bi-level
bitmap which is losslessly compressed to negligible size and which forms part
of the compressed page image.
The IR layer of the printed page optionally contains encoded tags at a
programmable density.
As described above, the RIP software/hardware rasterizes each page description
and compresses the
rasterized page image. Each compressed page image is transferred to the PEC
integrated circuit 100 where it
is then stored in a memory buffer 135. The compressed page image is then
retrieved and fed to a page image
expander 136 in which page images are retrieved. If required, any dither may
be applied to any contone layer
by a dithering means 137 and any black bi-level layer may be composited over
the contone layer by a
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compositor 138 together with any infrared tags which may be rendered by the
rendering means 139.
Retarning to a description of process steps, the PEC integrated circuit 100
then drives the printhead integrated
circuits 51 to print the composited page data at step 140 to produce a printed
page 141.
In this regard, the process performed by the PEC integrated circuit 100 can be
considered to consist
of a number of distinct stages. The first stage has the ability to expand a
JPEG-compressed contone CMYK
layer, a Group 4 Fax-compressed bi-level dither matrix selection map, and a
Group 4 Fax-compressed bi-level
black layer, all in parallel. In parallel with this, bi-level IR tag data can
be encoded from the compressed page
image. The second stage dithers the contone CMYK layer using a dither matrix
selected by a dither matrix
select map, composites the bi-level black layer over the resulting bi-level K
layer and adds the IR layer to the
page. A fixative layer is also generated at each dot position wherever there
is a need in any of the C, M, Y, K,
or IR channels. The last stage prints the bi-level CMYK+IR data through the
printhead assembly.
Fig. 41 shows an exemplary embodiment of the printhead assembly of the present
invention including
the PEC integrated circuit(s) 100 in the context of the overall printing
system architecture. As shown, the
various components of the printhead assembly includes:
= a PEC integrated circuit 100 which is responsible for receiving the
compressed page images
for storage in a memory buffer 142, performing the page expansion, black layer
compositing and sending the
dot data to the printhead integrated circuits 51. The PEC integrated circuit
100 may also communicate with a
master Quality Assurance (QA) integrated circuit 143 and a (replaceable) ink
cartridge QA integrated circuit
144, and provides a means of retrieving the printhead assembly characteristics
to ensure optimum printing;
= the memory buffer 142 for storing the compressed page image and for scratch
use during the
printing of a given page. The construction and working of memory buffers is
known to those skilled in the art
and a range of standard integrated circuits and techniques for their use might
be utilized in use of the PEC
integrated circuit(s) 100; and
= the master integrated circuit 143 which is matched to the replaceable ink
cartridge QA
integrated circuit 144. The construction and working of QA integrated circuits
is known to those skilled in the
art and a range of known QA processes might be utilized in use of the PEC
integrated circuit(s) 100;
As mentioned in part above, the PEC integrated circuit 100 of the present
invention essentially
performs four basic levels of fanctionality:
= receiving compressed pages via a serial interface such as an IEEE 1394;
= acting as a print engine for producing a page from a compressed form. The
print engine
functionality includes expanding the page image, dithering the contone layer,
compositing the black layer over
the contone layer, optionally adding infrared tags, and sending the resultant
image to the printhead integrated
circuits;
= acting as a print controller for controlling the printhead integrated
circuits and stepper
motors of the printing system; and
= serving as two standard low-speed serial ports for communication with the
two QA
integrated circuits. In this regard, two ports are used, and not a single
port, so as to ensure strong security
during authentication procedures.
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These functions are now described in more detail with reference to Fig. 42
which provides a more
specific illustration of the PEC integrated circuit architecture according to
an exemplary embodiment of the
present invention.
The PEC integrated circuit 100 incorporates a simple micro-controller CPU core
145 to perform the
following functions:
= perform QA integrated circuit authentication protocols via a serial
interface 146 between
print pages;
= run the stepper motor of the printing system via a parallel interface 147
during printing to
control delivery of the paper to the printhead integrated circuits 51 for
printing (the stepper motor requires a 5
KHz process);
= synchronize the various components of the PEC integrated circuit 100 during
printing;
= provide a means of interfacing with external data requests (programming
registers etc.);
= provide a means of interfacing with the corresponding printhead module's low-
speed data
requests (such as reading the characterization vectors and writing pulse
profiles); and
= provide a means of writing the portrait and landscape tag structures to an
external DRAM
148.
In order to perform the page expansion and printing process, the PEC
integrated circuit 100 includes
a high-speed serial interface 149 (such as a standard IEEE 1394 interface), a
standard JPEG decoder 150, a
standard Group 4 Fax decoder 151, a custom halftoner/compositor (HC) 152, a
custom tag encoder 153, a line
loader/formatter (LLF) 154, and a printhead interface 155 (PHI) which
communicates with the printhead
integrated circuits 51. The decoders 150 and 151 and the tag encoder 153 are
buffered to the HC 152. The
tag encoder 153 establishes an infrared tag(s) to a page according to
protocols dependent on what uses might
be made of the page.
The print engine function works in a double-buffered manner. That is, one page
is loaded into the
external DRAM 148 via a DRAM interface 156 and a data bus 157 from the high-
speed serial interface 149,
while the previously loaded page is read from the DRAM 148 and passed through
the print engine process.
Once the page has finished printing, then the page just loaded becomes the
page being printed, and a new page
is loaded via the high-speed serial interface 149.
At the aforementioned first stage, the process expands any JPEG-compressed
contone (CMYK)
layers, and expands any of two Group 4 Fax-compressed bi-level data streams.
The two streams are the black
layer (although the PEC integrated circuit 100 is actually colour agnostic and
this bi-level layer can be
directed to any of the output inks) and a matte for selecting between dither
matrices for contone dithering. At
the second stage, in parallel with the first, any tags are encoded for later
rendering in either IR or black ink.
Finally, in the third stage the contone layer is dithered, and position tags
and the bi-level spot layer
are composited over the resulting bi-level dithered layer. The data stream is
ideally adjusted to create smooth
transitions across overlapping segments in the printhead assembly and ideally
it is adjusted to compensate for
dead nozzles in the printhead assembly. Up to six channels of bi-level data
are produced from this stage.
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However, it will be understood by those skilled in the art that not all of the
six channels need be
present on the printhead module 30. For example, the printhead module 30 may
provide for CMY only, with
K pushed into the CMY channels and IR ignored. Alternatively, the position
tags may be printed in K if IR
ink is not available (or for testing purposes). The resultant bi-level CMYK-IR
dot-data is buffered and
formatted for printing with the printhead integrated circuits 51 via a set of
line buffers (not shown). The
majority of these line buffers might be ideally stored on the external DRAM
148. In the final stage, the six
channels of bi-level dot data are printed via the PHI 155.
The HC 152 combines the functions of halftoning the contone (typically CMYK)
layer to a bi-level
version of the same, and compositing the spotl bi-level layer over the
appropriate halftoned contone layer(s).
If there is no K ink, the HC 152 is able to map K to CMY dots as appropriate.
It also selects between two
dither matrices on a pixel-by-pixel basis, based on the corresponding value in
the dither matrix select map.
The input to the HC 152 is an expanded contone layer (from the JPEG decoder
146) through a buffer 158, an
expanded bi-level spotl layer through a buffer 159, an expanded dither-matrix-
select bitmap at typically the
same resolution as the contone layer through a buffer 160, and tag data at
full dot resolution through a buffer
(FIFO) 161.
The HC 152 uses up to two dither matrices, read from the external DRAM 148.
The output from the
HC 152 to the LLF 154 is a set of printer resolution bi-level image lines in
up to six colour planes. Typically,
the contone layer is CMYK or CMY, and the bi-level spotl layer is K. Once
started, the HC 152 proceeds
until it detects an "end-of-page" condition, or until it is explicitly stopped
via its control register (not shown).
The LLF 154 receives dot information from the HC 152, loads the dots for a
given print line into
appropriate buffer storage (some on integrated circuit (not shown) and some in
the external DRAM 148) and
formats them into the order required for the printhead integrated circuits 51.
Specifically, the input to the LLF
154 is a set of six 32-bit words and a DataValid bit, all generated by the HC
152. The output of the LLF 154
is a set of 190 bits representing a maximum of 15 printhead integrated
circuits of six colours. Not all the
output bits may be valid, depending on how many colours are actually used in
the printhead assembly.
The physical placement of the nozzles on the printhead assembly of an
exemplary embodiment of the
present invention is in two offset rows, which means that odd and even dots of
the same colour are for two
different lines. The even dots are for line L, and the odd dots are for line L-
2. In addition, there is a number
of lines between the dots of one colour and the dots of another. Since the six
colour planes for the same dot
position are calculated at one time by the HC 152, there is a need to delay
the dot data for each of the colour
planes until the same dot is positioned under the appropriate colour nozzle.
The size of each buffer line
depends on the width of the printhead assembly. Since a single PEC integrated
circuit 100 can generate dots
for up to 15 printhead integrated circuits 51, a single odd or even buffer
line is therefore 15 sets of 640 dots,
for a total of 9600 bits (1200 bytes). For example, the buffers required for
six colour odd dots totals almost 45
KBytes.
The PHI 155 is the means by which the PEC integrated circuit 100 loads the
printhead integrated
circuits 51 with the dots to be printed, and controls the actual dot printing
process. It takes input from the LLF
154 and outputs data to the printhead integrated circuits 51. The PHI 155 is
capable of dealing with a variety
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of printhead assembly lengths and formats. The internal structure of the PHI
155 allows for a maximum of six
colours, eight printhead integrated circuits 51 per transfer, and a maximum of
two printhead integrated circuit
51 groups which is sufficient for a printhead assembly having 15 printhead
integrated circuits 51 (8.5 inch)
printing system capable of printing on A4/Letter paper at full speed.
A combined characterization vector of the printhead assembly 10 can be read
back via the serial
interface 146. The characterization vector may include dead nozzle information
as well as relative printhead
module alignment data. Each printhead module can be queried via its low-speed
serial bus 162 to return a
characterization vector of the printhead module. The characterization vectors
from multiple printhead
modules can be combined to construct a nozzle defect list for the entire
printhead assembly and allows the
PEC integrated circuit 100 to compensate for defective nozzles during
printing. As long as the number of
defective nozzles is low, the compensation can produce results
indistinguishable from those of a printhead
assembly with no defective nozzles.
Fluid distribution stack
An exemplary structure of the fluid distribution stack of the printhead tile
will now be described with
reference to Fig. 43.
Fig. 43 shows an exploded view of the fluid distribution stack 500 with the
printhead integrated
circuit 51 also shown in relation to the stack 500. In the exemplary
embodiment shown in Fig. 43, the stack
500 includes three layers, an upper layer 510, a middle layer 520 and a lower
layer 530, and further includes a
channel layer 540 and a plate 550 which are provided in that order on top of
the upper layer 510. Each of the
layers 510, 520 and 530 are formed as stainless-steel or micro-moulded plastic
material sheets.
The printhead integrated circuit 51 is bonded onto the upper layer 510 of the
stack 500, so as to
overlie an array of holes 511 etched therein, and therefore to sit adjacent
the stack of the channel layer 540
and the plate 550. The printhead integrated circuit 51 itself is formed as a
multi-layer stack of silicon which
has fluid channels (not shown) in a bottom layer 51a. These channels are
aligned with the holes 511 when the
printhead integrated circuit 51 is mounted on the stack 500. In one embodiment
of the present invention, the
printhead integrated circuits 51 are approximately 1 mm in width and 21 mm in
length. This length is
detennined by the width of the field of a stepper which is used to fabricate
the printhead integrated circuit 51.
Accordingly, the holes 511 are arranged to conform to these dimensions of the
printhead integrated circuit 51.
The upper layer 510 has channels 512 etched on the underside thereof (Fig. 43
shows only some of
the channels 512 as hidden detail). The channels 512 extend as shown so that
their ends align with holes 521
of the middle layer 520. Different ones of the channels 512 align with
different ones of the holes 521. The
holes 521, in turn, align with channels 531 in the lower layer 530.
Each of the channels 531 carries a different respective colour or type of ink,
or fluid, except for the
last channel, designated with the reference numera1532. The last channe1532 is
an air channel and is aligned
with further holes 522 of the middle layer 520, which in turn are aligned with
further holes 513 of the upper
layer 510. The further holes 513 are aligned with inner sides 541 of slots 542
formed in the channel layer 540,
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so that these inner sides 541 are aligned with, and therefore in fluid-flow
communication with, the air channel
532, as indicated by the dashed line 543.
The lower layer 530 includes the inlet ports 54 of the printhead tile 50, with
each opening into the
corresponding ones of the channels 531 and 532.
In order to feed air to the printhead integrated circuit surface, compressed
filtered air from an air
source (not shown) enters the air channe1532 through the corresponding inlet
port 54 and passes through the
holes 522 and 513 and then the slots 542 in the middle layer 520, the upper
layer 510 and the channel layer
540, respectively. The air enters into a side surface 51b of the printhead
integrated circuit 51 in the direction
of arrows A and is then expelled from the printhead integrated circuit 51
substantially in the direction of
arrows B. A nozzle guard 51 c may be further arranged on a top surface of the
printhead integrated circuit 51
parhially covering the nozzles to assist in keeping the nozzles clear of print
media dust.
In order to feed different colour and types of inks and other fluids (not
shown) to the nozzles, the
different inks and fluids enter through the inlet ports 54 into the
corresponding ones of the channels 531, pass
through the corresponding holes 521 of the middle layer 520, flow along the
corresponding cbannels 512 in
the underside of the upper layer 510, pass through the corresponding holes 511
of the upper layer 510, and
then finally pass through the slots 542 of the channel layer 540 to the
printhead integrated circuit 51, as
described earlier.
In traversing this path, the flow diameters of the inks and fluids are
gradually reduced from the
macro-sized flow diameter at the inlet ports 54 to the required micro-sized
flow diameter at the nozzles of the
printhead integrated circuit 51.
The exemplary embodiment of the fluid distribution stack shown in Fig. 43 is
arranged to distribute
seven different fluids to the printhead integrated circuit, including air,
which is in conformity with the earlier
described exemplary embodiment of the ducts of the fluid channel member.
However, it will be understood by
those skilled in the art that a greater or lesser number of fluids may be used
depending on the specific printing
application, and therefore the fluid distribution stack can be configured as
necessary.
Nozzles and Actnators
Exemplary nozzle arrangements which are suitable for the printhead assembly of
the present
invention are described in the Applicant's following ; : granted applications:
U.S. Patent Nos. 6,188,415; 6,209,989; 6,213,588; 6,213,589; 6,217,153;
6,220,694; 6,227,652;
6,227,653; 6,227,654; 6,231,163; 6,234,609; 6,234,610; 6,234,611; 6,238,040;
6,338,547; 6,239,821;
6,241,342; 6,243,113; 6,244,691; 6,247,790; 6,247,791; 6,247,792; 6,247,793;
6,247,794; 6,247,795;
6,247,796; 6,254,220; 6,257,704; 6,257,705; 6,260,953; 6,264,306; 6,264,307;
6,267,469; 6,283,581;
6,283,582; 6,293,653; 6,302,528; 6,312,107; 6,336,710; 6,362,843; 6,390,603;
6,394,581; 6,416,167;
6,416,168; 6,557,977; 6,273,544; 6,299,289; 6,299,290; 6,309,048; 6,378,989;
6,420,196; 6,425,654;
6,439,689; 6,443,558; and 6,634,735, U.S. Patent Nos. 6,623,101;
6,406,129; 6,457,809; 6,457,812; 6,505,916; 6,550,895; 6,428,133; 6,305,788;
6,315,399; 6,322,194;
6,322,195; 6,328,425; 6,328,431; 6,338,548; 6,364,453; 6,383,833; 6,390,591;
6,390,605; 6,417,757;
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6,425,971; 6,426,014; 6,428,139; 6,428,142; 6,439,693; 6,439,908; 6,457,795;
6,502,306; 6,565,193;
6,588,885; 6,595,624; 6,460,778; 6,464,332; 6,478,406; 6,480,089; 6,540,319;
6,575,549; 6,609,786;
6,609,787; 6,612,110; 6,623,106; 6,629,745; 6,652,071; 6,659,590,
10
Of these, an exemplary nozzle arrangement will now be described with reference
to Figs. 44 to 53.
One nozzle arrangement which is incorporated in each of the printhead
integrated circuits 51 mounted on the
printhead tiles 50 (see Fig. 5A) includes a nozzle and corresponding actuator.
Fig. 44 shows an array of the
nozzle arrangements 801 formed on a silicon substrate 815. The nozzle
arrangements are identical, but in one
embodiment, different nozzle arrangements are fed with different coloured inks
and fixative. It will be noted
that rows of the nozzle arrangements 801 are staggered with respect to each
other, allowing closer spacing of
ink dots during printing than would be possible with a single row of nozzles.
The multiple rows also allow for
redundancy (if desired), thereby allowing for a predetermined failure rate per
nozzle.
Each nozzle arrangement 801 is the product of an integrated circuit
fabrication technique. As
illustrated, the nozzle arrangement 801 is constituted by a micro-
electromechanical system (MEMS).
For clarity and ease of description, the construction and operation of a
single nozzle arrangement 801
will be described with reference to Figs. 45 to 53.
Each printhead integrated circuit 51 includes a silicon wafer substrate 815.
0.42 Micron 1 P4M 12
volt CMOS microprocessing circuitry is positioned on the silicon wafer
substrate 815.
A silicon dioxide (or alternatively glass) layer 817 is positioned on the
wafer substrate 815. The
silicon dioxide layer 817 defines CMOS dielectric layers. CMOS top-level metal
defines a pair of aligned
aluminium electrode contact layers 830 positioned on the silicon dioxide layer
817. Both the silicon wafer
substrate 815 and the silicon dioxide layer 817 are etched to define an ink
inlet channel 814 having a generally
circular cross section (in plan). An aluminium diffusion barrier 828 of CMOS
metal 1, CMOS metal 2/3 and
CMOS top level metal is positioned in the silicon dioxide layer 817 about the
ink inlet channel 814. The
diffusion barrier 828 serves to inhibit the diffusion of hydroxyl ions through
CMOS oxide layers of the drive
circuitry layer 817.
A passivation layer in the form of a layer of silicon nitride 831 is
positioned over the aluminium
contact layers 830 and the silicon dioxide layer 817. Each portion of the
passivation layer 831 positioned over
the contact layers 830 has an opening 832 defined therein to provide access to
the contacts 830.
The nozzle arrangement 801 includes a nozzle chamber 829 defined by an annular
nozzle wal1833,
which terminates at an upper end in a nozzle roof 834 and a radially inner
nozzle rim 804 that is circular in
plan. The ink inlet channe1814 is in fluid communication with the nozzle
cbamber 829. At a lower end of the
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nozzle wall, there is disposed a movable rim 810, that includes a movable seal
lip 840. An encircling wall 838
surrounds the movable nozzle, and includes a stationary seal lip 839 that,
when the nozzle is at rest as shown
in Fig. 45, is adjacent the moving rim 810. A fluidic seal 811 is formed due
to the surface tension of ink
trapped between the stationary seal lip 839 and the moving seal lip 840. This
prevents leakage of ink from the
chamber whilst providing a low resistance coupling between the encircling
wal1838 and the nozzle wa11833.
As best shown in Fig. 52, a plurality of radially extending recesses 835 is
defined in the roof 834
about the nozzle rim 804. The recesses 835 serve to contain radial ink flow as
a result of ink escaping past the
nozzle rim 804.
The nozzle wall 833 forms part of a lever arrangement that is mounted to a
carrier 836 having a
generally U-shaped profile with a base 837 attached to the layer 831 of
silicon nitride.
The lever arrangement also includes a lever arm 818 that extends from the
nozzle walls and
incorporates a lateral stiffening beam 822. The lever arm 818 is attached to a
pair of passive beams 806,
formed from titanium nitride (TiN) and positioned on either side of the nozzle
arrangement, as best shown in
Figs. 48 and 51. The other ends of the passive beams 806 are attached to the
carrier 836.
The lever arm 818 is also attached to an actuator beam 807, which is formed
from TiN. It will be
noted that this attachment to the actuator beam is made at a point a small but
critical distance higher than the
attachments to the passive beam 806.
As best shown in Figs. 48 and 51, the actuator beam 807 is substantially U-
shaped in plan, defining a
current path between the electrode 809 and an opposite electrode 841. Each of
the electrodes 809 and 841 is
electrically connected to a respective point in the contact layer 830. As well
as being electrically coupled via
the contacts 809, the actuator beam is also mechanically anchored to anchor
808. The anchor 808 is
configured to constrain motion of the actuator beam 807 to the left of Figs.
45 to 47 when the nozzle
arrangement is in operation.
The TiN in the actuator beam 807 is conductive, but has a high enough
electrical resistance that it
undergoes self-heating when a current is passed between the electrodes 809 and
841. No current flows
through the passive beams 806, so they do not expand.
In use, the device at rest is filled with ink 813 that defines a meniscus 803
under the influence of
surface tension. The ink is retained in the chamber 829 by the meniscus, and
will not generally leak out in the
absence of some other physical influence.
As shown in Fig. 46, to fire ink from the nozzle, a current is passed between
the contacts 809 and
841, passing through the actuator beam 807. The self-heating of the beam 807
due to its resistance causes the
beam to expand. The dimensions and design of the actuator beam 807 mean that
the majority of the expansion
in a horizontal direction with respect to Figs. 45 to 47. The expansion is
constrained to the left by the anchor
808, so the end of the actuator beam 807 adjacent the lever arm 818 is
impelled to the right.
The relative horizontal inflexibility of the passive beams 806 prevents them
from allowing much
horizontal movement the lever arm 818. However, the relative displacement of
the attachment points of the
passive beams and actuator beam respectively to the lever arm causes a
twisting movement that causes the
lever arm 818 to move generally downwards. The movement is effectively a
pivoting or hinging motion.
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However, the absence of a true pivot point means that the rotation is about a
pivot region defined by bending
of the passive beams 806.
The downward movement (and slight rotation) of the lever arm 818 is amplified
by the distance of
the nozzle wall 833 from the passive beams 806. The downward movement of the
nozzle walls and roof
causes a pressure increase within the chamber 29, causing the meniscus to
bulge as shown in Fig. 46. It will
be noted that the surface tension of the ink means the fluid seal 11 is
stretched by this motion without allowing
ink to leak out.
As shown in Fig. 47, at the appropriate time, the drive current is stopped and
the actuator beam 807
quickly cools and contracts. The contraction causes the lever arm to commence
its return to the quiescent
position, which in tarn causes a reduction in pressure in the chamber 829. The
interplay of the momentum of
the bulging ink and its inherent surface tension, and the negative pressure
caused by the upward movement of
the nozzle chamber 829 causes thinning, and ultimately snapping, of the
bulging meniscus to define an ink
drop 802 that continues upwards until it contacts the adjacent print media.
Immediately after the drop 802 detaches, the meniscus forms the concave shape
shown in Fig. 45.
Surface tension causes the pressure in the chamber 829 to remain relatively
low until ink has been sucked
upwards through the inlet 814, which returns the nozzle arrangement and the
ink to the quiescent situation
shown in Fig. 45.
As best shown in Fig. 48, the nozzle arrangement also incorporates a test
mechanism that can be used
both post-manufacture and periodically after the printhead assembly is
installed. The test mechanism includes
a pair of contacts 820 that are connected to test circuitry (not shown). A
bridging contact 819 is'provided on a
finger 843 that extends from the lever arm 818. Because the bridging contact
819 is on the opposite side of
the passive beams 806, actuation of the nozzle causes the priding contact to
move upwardly, into contact with
the contacts 820. Test circuitry can be used to confirm that actuation causes
this closing of the circuit formed
by the contacts 819 and 820. If the circuit is closed appropriately, it can
generally be assumed that the nozzle
is operative.
Exemplary Method of Assembling Components
An exemplary method of assembling the various above-described modular
components of the
printhead assembly in accordance with one embodiment of the present invention
will now be described. It is
to be understood that the below described method represents only one example
of assembling a particular
printhead assembly of the present invention, and different methods may be
employed to assemble this
exemplary printhead assembly or other exemplary printhead assemblies of the
present invention.
The printhead integrated circuits 51 and the printhead tiles 50 are assembled
as follows:
A. The printhead integrated circuit 51 is first prepared by forming 7680
nozzles in an upper
surface thereof, which are spaced so as to be capable of printing with a
resolution of 1600 dpi;
B. The fluid distribution stacks 500 (from which the printhead tiles 50 are
formed) are
constructed so as to have the three layers 510, 520 and 530, the channel layer
540 and the plate
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550 made of stainless steel bonded together in a vacuum furnace into a single
body via metal
inter-diffusion, where the inner surface of the lower layer 530 and the
surfaces of the middle
and upper layers 520 and 510 are etched so as to be provided with the channels
and holes 531
and 532, 521 and 522, and 511 to 513, respectively, so as to be capable of
transporting the
CYMK and IR inks and fixative to the individual nozzles of the printhead
integrated circuit 51
and air to the surface of the printhead integrated circuit 51, as described
earlier. Further, the
outer surface of the lower layer 530 is etched so as to be provided with the
inlet ports 54;
C. An adhesive, such as a silicone adhesive, is then applied to an upper
surface of the fluid
distribution stack 500 for attaching the printhead integrated circuit 51 and
the (fine pitch) PCB
52 in close proximity thereto;
D. The printhead integrated circuit 51 and the PCB 52 are picked up, pre-
centred and then
bonded on the upper surface of the fluid distribution stack 500 via a pick-and-
place robot;
E. This assembly is then placed in an oven whereby the adhesive is allowed to
cure so as to fix
the printhead integrated circuit 51 and the PCB 52 in place;
F. Connection between the printhead integrated circuit 51 and the PCB 52 is
then made via a wire
bonding machine, whereby a 25 micron diameter alloy, gold or aluminium wire is
bonded
between the bond pads on the printhead integrated circuit 51 and conductive
pads on the PCB
52;
G. The wire bond area is then encapsulated in an epoxy adhesive dispensed by
an automatic two-
head dispenser. A high viscosity non-sump adhesive is firstly applied to draw
a dam around
the wire bond area, and the dam is then filled with a low viscosity adhesive
to fully encapsulate
the wire bond area beneath the adhesive;
H. This assembly is then placed on levelling plates in an oven and heat cured
to form the epoxy
encapsulant 53. The levelling plates ensure that no encapsulant flows from the
assembly
during curing; and
1. The thus-formed printhead tiles 50 and printhead integrated circuits 51 are
`wet' tested with a
suitable fluid, such as pure water, to ensure reliable performance and are
then dried out, where
they are then ready for assembly on the fluid channel member 40.
The units composed of the printhead tiles 50 and the printhead integrated
circuits 51 are prepared for
assembly to the fluid channel members 40 as follows:
J. The (extended) flex PCB 80 is prepared to provide data and power connection
to the printhead
integrated circuit 51 from the PCB 90 and busbars 71, 72 and 73; and
K. The flex PCB 80 is aligned with the PCB 52 and attached using a hot bar
soldering machine.
The fluid channel members 40 and the casing 20 are formed and assembled as
follows:
L. Individual fluid channel members 40 are formed by injection moulding an
elongate body
portion 44a so as to have seven individual grooves (channels) extending
therethrough and the
CA 02550804 2006-06-21
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two longitudinally extending tabs 43 extending therealong on either side
thereof. The
(elongate) lid portion 44b is also moulded so as to be capable of enclosing
the body portion
44a to separate each of the channels. The body and lid portions are both
moulded so as to
have end portions which form the female and male end portions 45 and 46 when
assembled
together. The lid portion 44b and the body portion 44a are then adhered
together with epoxy
and cured so as to form the seven ducts 41;
M. The casing 20 is then formed by extruding aluminium to a desired
configuration and length by
separately forming the (elongate) support frame 22, with the channe121 formed
on the upper
wa1127 thereof, and the (elongate) cover portion 23;
N. The end plate 110 is attached with screws via'the threaded portions 22a and
22b formed in the
support frame 22 to one (first) end of the casing 20, and the end plate 111 is
attached with
screws via the threaded portions 22a and 22b to the other (second) end of the
casing 20;
0. An epoxy is applied to the appropriate regions (i.e., so as not to cover
the channels) of either a
female or male connector 47 or 48, and either the female or male connecting
section 49a or
49b of a capping member 49 via a controlled dispenser;
P. An epoxy is applied to the appropriate regions (i.e., so as not to cover
the channels) of the
female and male end portions 45 and 46 of the plurality of fluid channel
members 40 to be
assembled together, end-to-end, so as to correspond to the desired length via
the controlled
dispenser;
Q. The female or male connector 47 or 48 is then attached to the male or
female end portion 46 or
45 of the fluid channel member 40 which is to be at the first end of the
plurality of fluid
channel members 40 and the female or male connecting section 49a or 49b of the
capping
member 49 is attached to the male or female end portion 46 or 45 of the fluid
channel member
40 which is to be at the second end of the plurality of fluid channel members
40;
R. Each of the fluid channel members 40 is then placed within the channel 21
one-by-one.
Firstly, the (first) fluid channel member 40 to be at the first end is placed
within the channe121
at the first end, and is secured in place by way of the PCB supports 91 which
are clipped into
the support frame 22, in the manner described earlier, so that the unconnected
end portion 45
or 46 of the fluid channel member 40 is left exposed with the epoxy thereon.
Then, a second
member 40 is placed in the channe121 so as to mate with the first fluid
channel member 40 via
its corresponding end portion 45 or 46 and the epoxy therebetween and is then
clipped into
place with its PCB supports 91. This can then be repeated until the final
fluid channel member
is in place at the second end of the channel 21. Of course, only one fluid
channel member
40 may be used, in which case it may have a connector 47 or 48 attached to one
end portion 46
35 or 45 and a capping member 49 attached at the other end portion 45 or 46;
S. This arrangement is then placed in a compression jig, whereby a compression
force is applied
against the ends of the assembly to assist in sealing the connections between
the individual
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fluid channel members 40 and their end connector 47 or 48 and capping member
49. The
complete assembly and jig is then placed in an oven at a temperature of about
100 C for a
predefined period, for example, about 45 minutes, to enhance the curing of the
adhesive
connections. However, other methods of curing, such as room temperature
curing, could also
be employed;
T. Following curing, the arrangement is pressure tested to ensure the
integrity of the seal between
the individual fluid channel members 40, the connector 47 or 48, and the
capping member 49;
and
U. The exposed upper surface of the assembly is then oxygen plasma cleaned to
facilitate
attachment of the individual printhead tiles 50 thereto.
The printhead tiles 50 are attached to the fluid channel members 40 as
follows:
V. Prior to placement of the individual printhead tiles 50 upon the upper
surface of the fluid
channel members 40, the bottom surface of the printhead tiles 50 are argon
plasma cleaned to
enhance bonding. An adhesive is then applied via a robotic dispenser to the
upper surface of
the fluid channel members 40 in the form of an epoxy in strategic positions on
the upper
surface around and symmetrically about the outlet ports 42. To assist in
fixing the printhead
tiles 50 in place a fast acting adhesive, such as cyanoacrylate, is applied in
the remaining free
areas of the upper surface as the adhesive drops 62 immediately prior to
placing the printhead
tiles 50 thereon;
W. Each of the individual printhead tiles 50 is then carefully aligned and
placed on the upper
surface of the fluid channel members 40 via a pick-and-place robot, such that
a continuous
print surface is defined along the length of the printhead module 30 and also
to ensure that that
the outlet ports 42 of the fluid channel members 40 align with the inlet ports
54 of the
individual printhead tiles 50. Following placement, the pick-and-place robot
applies a
pressure on the printhead tile 50 for about 5 to 10 seconds to assist in the
setting of the
cyanoacrylate and to fix the printhead tile 50 in place. This process is
repeated for each
printhead tile 50;
X. This assembly is then placed in an oven at about 100 C for about 45 minutes
to cure the epoxy
so as to form the gasket member 60 and the locators 61 for each printhead tile
50 which seal
the fluid connection between each of the outlet and inlet ports 42 and 54.
This fixes the
printhead tiles 50 in place on the fluid channel members 40 so as to define
the print surface;
and
Y. Following curing, the assembly is inspected and tested to ensure correct
alignment and
positioning of the printhead tiles 50.
The printhead assembly 10 is assembled as follows:
Z. The support member 112 is attached to the end PCB supports 91 so as to
align with the
recessed portion 91b of the end supports 91;
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AA. The connecting members 102 are placed in the abutting recessed portions
91b between the
adjacent PCB supports 91 and in the abutting recessed portions 112b and 91b of
the support
members 112 and end PCB supports 91, respectively;
BB. The PCBs 90, each having assembled thereon a PEC integrated circuit 100
and its associated
circuitry, are then mounted on the PCB supports 91 along the length of the
casing 20 and are
retained in place between the notch portions 96a of the retaining clips 96 and
the recessed
portions 93a and locating lugs 93b of the base portions 93 of the PCB supports
91. As
described earlier, the PCBs 90 can be arranged such that the PEC integrated
circuit 100 of one
PCB 90 drives the printhead integrated circuits 51 of four printhead tiles 50,
or of eight
printhead tiles 50, or of 16 printhead tiles 50. Each of the PCBs 90 include
the connection
strips 90a and 90b on the inner face thereof which communicate with the
connecting members
102 allowing data transfer between the PEC integrated circuits 100 of each of
the PCBs 90,
between the printhead integrated circuits 51 and PEC integrated circuits 100
of each of the
PCBs 90, and between the data connection portion 117 of the connector
arrangement 115;
CC. The connector arrangement 115, with the power supply, data and fluid
delivery connection
portions 116, 117 and 118 attached thereto, is attached to the end plate 110
with screws so that
the region 1 15c of the connector arrangement 115 is clipped into the clip
portions 1 12d of the
support member 112;
DD. The busbars 71, 72 and 73 are inserted into the corresponding channelled
recesses 95a, 95b
and 95c of the plurality of PCB supports 91 and are connected at their ends to
the
corresponding contact screws 116a, 116b and 116c of the power supply
connection portion
116 of the connector arrangement 115. The busbars 71, 72 and 73 provide a path
for power to
be distributed throughout the printhead assembly;
EE. Each of the flex PCBs 80 extending from each of the printhead tiles 50 is
then connected to the
connectors 98 of the corresponding PCBs 90 by slotting the slot regions 81
into the connectors
98;_
FF. The pressure plates 74 are then clipped onto the PCB supports 91 by
engaging the holes 74a
and the tab portions 74c of the holes 74b with the corresponding retaining
clips 99 and 96 of
the PCB supports 91, such that the raised portions 75 of the pressure plates
74 urge the power
contacts of the flex PCBs 80 into contact with each of the busbars 71, 72 and
73, thereby
providing a path for the transfer of power between the busbars 71, 72 and 73,
the PCBs 90 and
the printhead integrated circuits 51;
GG. The internal fluid delivery tubes 6 are then attached to the corresponding
tubular portions 47b
or 48b of the female or male connector 47 or 48; and
HH. The elongate, aluminium cover portion 23 of the casing 20 is then placed
over the assembly
and screwed into place via screws through the remaining holes in the end
plates 110 and 111
into the threaded portions 23b of the cover portion 23, and the end housing
120 is placed over
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the connector arrangement 115 and screwed into place with screws into the end
plate 110
thereby completing the outer housing of the printhead assembly and so as to
provide electrical
and fluid communication between the printhead assembly and a printer unit. The
external fluid
tubes or hoses can then be assembled to supply ink and the other fluids to the
channels ducts.
The cover portion 23 can also act as a heat sink for the PEC integrated
circuits 100 if the fin
portions 23d are provided thereon, thereby protecting the circuitry of the
printhead assembly
10.
Testing of the printhead assembly occurs as follows:
II. The thus-assembled printhead assembly 10 is moved to a testing area and
inserted into a final
print test machine which is essentially a working printing unit, whereby
connections from the
printhead assembly 10 to the fluid and power supplies are manually performed;
JJ. A test page is printed and analysed and appropriate adjustments are made
to finalise the
printhead electronics; and
KK. When passed, the print surface of the printhead assembly 10 is capped and
a plastic sealing
film is applied to protect the printhead assembly 10 until product
installation.
While the present invention has been illustrated and described with reference
to exemplary
embodiments thereof, various modifications will be apparent to and might
readily be made by those skilled in
the art without departing from the scope and spirit of the present invention.
Accordingly, it is not intended
that the scope of the claims appended hereto be limited to the description as
set forth herein, but, rather, that
the claims be broadly construed.
54
