Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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- 1 - CFO 11453 ~$
METHOD FOR PRODUCING LIQUID EJECTING HEAD AND LIQUID
EJECTING HEAD OBTAINED BY THE SAME METHOD
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a method for
producing a liquid ejecting head for ejecting a desired
liquid by generation of a bubble with application of
thermal energy to the liquid. More particularly, the
invention relates to a method for producing a liquid
ejecting head using a movable member arranged to
displace as utilizing generation of a bubble. Further,
the present invention concerns a liquid ejecting head,
a head cartridge using the liquid ejecting head, a
liquid ejecting apparatus, and a head kit.
The present invention is applicable to
equipment such as a printer, a copying machine, a
facsimile machine having a communication system, a word
processor having a printer portion or the like, and an
industrial recording device combined with various
processing device or processing devices, in which the
recording is effected on a recording material such as
paper, thread, fiber, textile, leather, metal, plastic
resin material, glass, wood, ceramic and so on.
In this specification, "recording" means not
only forming an image of letter, figure or the like
having specific meanings, but also includes forming an
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image of a pattern not having a specific meaning.
Related Backqround Art
An ink jet recording method of so-called bubble
jet type is known in which an instantaneous state
change resulting in an instantaneous volume change
(bubble generation) is caused by application of energy
such as heat to the ink, so as to eject the ink through
the ejection outlet by the force resulted from the
state change by which the ink is ejected to and
deposited on the recording material to form an image
formation. As disclosed in US Patent No. 4,723,129, a
recording device using the bubble jet recording method
generally comprises an ejection outlet for ejecting the
ink, an ink flow path in fluid communication with the
ejection outlet, and an electrothermal transducer as
energy generating means disposed in the ink flow path.
With such a recording method is advantageous in
that, a high quality image, can be recorded at high
speed and with low noise, and a plurality of such
ejection outlets can be located at high density, and
therefore, small size recording apparatus capable of
providing a high resolution can be provided, and color
images can be easily formed. Therefore, the bubble jet
recording method is now widely used in printers,
copying machines, facsimile machines or another office
equipment, and for industrial systems such as textile
printing device or the like.
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For such a bubble jet recording method, a
proposal was made to employ a structure incorporating a
movable member such as a valve or the like in a flow
path in order to improve the-ejection efficiency.
For example, Japanese Laid-Open Patent
Application No. 63-199972 describes a method for
producing valve elements in an ink jet recording head
with valves in flow paths.
In this publication patterns of the valves are
formed by photolithography of a photosensitive resin or
the like.
Further, Japanese Laid-Open Patent Application
No. 63-197652 describes a method for producing valves
in an ink jet recording head with check valves provided
on the upstream side of the flow paths.
In this publication, the valves are integrally
formed with a substrate, utilizing parts of the
substrate, by photolithography.
Japanese Laid-Open Patent Application No. 6-
31918 (United States Patent No. 5,278,585) discloses a
method for producing an ink jet head having one-way
valves. This is the method for producing the ink jet
head having a silicon substrate and movable members
patterned by photolithography and processed by
anisotropic etching. This publication also discloses a
method for forming the movable members of a silicon
dioxide layer in the silicon substrate, a method for
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forming the movable members in a surface region of a
silicon wafer by implantation or diffusion of boron, a
method for forming the movable members by patterned
etching stop occurring because of implantation of
boron, and so on.
As the background art of the present invention
there was a background art subject to enhance the
fundamental ejection characteristics up to a
conventionally unexpected level, from a conventionally
inconceivable standpoint, in the basically conventional
method for ejecting the liquid by forming a bubble
(particularly, a bubble formed by film boiling) in a
liquid flow path.
With this background art subject, some of the
present inventors came to find that the most
significant factor to considerably improve the ejection
characteristics was to take account of a growing
component downstream of the bubble, based on the
consideration of influence of energy given by the
bubble per se on an ejection amount. Namely, it was
found that the ejection efficiency and ejection speed
could be improved by efficiently directing the
component downstream of bubble into a direction of
ejection. Based on this finding, the inventors came to
an extremely high technical level, when compared with
the conventional technical level, to positively move
the downstream component of bubble to the free end side
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of the movable member.
Further, it was also found that it was
preferred to take account of structural elements such
as the movable member and liquid flow path related to
growth of bubble on the downstream side in a heating
region for forming the bubble, for example, on the
downstream side from the center line passing the center
of the area of an electrothermal transducer in the
direction of flow of liquid, or at the center of the
area of a surface contributing to bubble generation.
Based on the above findings, some of the
present inventors invented and already proposed a
liquid jet head of an utterly novel structure.
This head has a first path portion in fluid
communication with an ejection outlet, a second path
portion with an electrothermal transducer provided
therein, and a partition wall disposed between the
first path portion and the second path portion and
having a movable member arranged as displaceable to the
first path portion side, in which the first path
portion becomes in fluid communication with the second
path portion when the movable member is displaced.
This head is arranged to effect ejection in
such a way that a bubble is generated through drive of
the electrothermal transducer, the movable member comes
to be displaced to the first path portion side with
growth of the bubble, and the pressure thereof is
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guided toward the ejection outlet by the movable member
displaced.
In the liquid ejecting head using the movable
member displaced depending upon the bubble as described
above, the head is produced by positioning, jointing
and securing through a press (stop) spring a substrate
having the electrothermal transducer, side walls of the
second path portion, the partition wall having the
movable member, a grooved top plate having side walls
of the first path portion.
In the above method for producing the liquid
ejecting head, a gap, however, may sometimes occur
between the partition wall and the second path portion
walls because of variations in production. This is not
easily checked depending on manufacture control. If
the space appeared in this region the pressure for
discharging the bubble might escape through this gap so
as to cause ejection failure due to insufficient
ejection pressure. Since the pressure wave escaping
through the gap propagated into adjacent flow paths and
fluctuated the liquid therein, variations of ejection
amounts might sometimes occur upon continuous drive. A
conceivable means for avoiding the occurrence of the
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gap is to bond the partition wall with the second path
portion walls with an adhesive, but it is not preferred
because in that case the adhesive could intrude into
the space between the movable member and the partition
wall so as to disable movement of the movable member.
Further, the above producing method needs
positioning among the substrate, the partition wall,
and the grooved top plate, so that it takes a lot of
time for securing the positioning accuracy.
SUMMARY OF THE INVENTION
In view of the background art subject as
described above, a specific object of the present
invention is to provide a method for producing a
movable member, capable of effectively and usefully
regulating growth of bubble, applicable to general
valves or the new head and the ejection principle
described in the prior application filed by the present
inventors.
More particularly, a first object of the
present invention is to provide a method for producing
a head and an apparatus which are easily and cheaply
produced with high accuracy and which realize an ideal
configuration for the above ejection principle, by
constructing the liquid guide paths for supplying a
plurality of liquids, of a reduced number of parts.
A second object of the present invention is to
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provide a production method for realizing a head in an
ideal configuration for the above ejection principle
and further to provide a production method improved in
production cost and accuracy up to the level of
commercial products.
Typical features of the present invention for
achieving the above objects are as follows.
According to an aspect of the present
invention, there is provided a method for producing a
liquid ejecting head having an ejection outlet for
ejecting a liquid, a heat generating element for
applying thermal energy to said liquid, a liquid flow
path consisting of a first path portion in fluid
communication with said ejection outlet and a second
path portion located below said first path portion, in
a bottom surface of which said heat generating element
is positioned, a partition wall for partitioning said
liquid flow path into said first path portion and
second path portion, and a movable member disposed
above said heat generating element in said partition
wall so as to be displaceable to a side of the first
path portion in accordance with a bubble generated in
the liquid by said thermal energy, in which upon
generation of said bubble the first path portion is in
fluid communication with the second path portion and
the pressure is directed toward said ejection outlet by
said movable member displaced to eject the liquid
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droplet, said method comprising a step of preparing a
substrate provided with said heat generating element, a
step of forming a grooved partition wall having said
movable member and side walls of said second path
portion, and a step of joining said grooved partition
wall to said substrate to form said second path
portion.
According to another aspect of the present
invention, there is provided a method for producing a
liquid ejecting head having an ejection outlet for
ejecting a liquid, a heat generating element for
applying thermal energy to said liquid, a liquid flow
path consisting of a first path portion in fluid
communication with said ejection outlet and a second
path portion located below said first path portion, in
a bottom surface of which said heat generating element
is positioned, a partition wall for partitioning said
liquid flow path into said first path portion and
second path portion, and a movable member disposed
above said heat generating element in said partition
wall so as to be displaceable to a side of the first
path portion in accordance with a bubble generated in
the liquid by said thermal energy, in which upon
generation of said bubble the first path portion is in-
fluid communication with the second path portion andthe pressure is directed toward said ejection outlet by
said movable member displaced to eject the liquid
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droplet, wherein said movable member is formed by
providing said partition wall with a slit and the slit
of said movable member is formed by making said
partition wall by electroforming.
According to a further aspect of the present
invention, there is provided a method for producing a
liquid ejecting head, having an ejection outlet for
ejecting a liquid, a heat generating element for
applying thermal energy to said liquid, a liquid flow
path consisting of a first path portion in fluid
communication with said ejection outlet and a second
path portion located below said first path portion, in
a bottom surface of which said heat generating element
is positioned, a partition wall for partitioning said
liquid flow path into said first path portion and
second path portion, and a movable member disposed
above said heat generating element in said partition
wall so as to be displaceable in accordance with a
bubble generated in the liquid by said thermal energy,
wherein said movable member is formed by providing said
partition wall with a slit and the slit of said movable
member is formed by making said partition wall by
electroforming.
According to a further aspect of the present
invention, there is provided a liquid ejecting head
having an ejection outlet for ejecting a liquid, a heat
generating element for applying thermal energy to said
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liquid, a liquid flow path consisting of a first path
portion in fluid communication with said ejection
outlet and a second path portion located below said
first path portion, in a bottom surface of which said
heat generating element is positioned, a partition wall
for partitioning said liquid flow path into said first
path portion and second path portion, and a movable
member disposed above said heat generating element in
said partition wall so as to be displaceable to a side
of the first path portion in accordance with a bubble
generated in the liquid by said thermal energy, in
which upon generation of said bubble the first path
portion is in fluid communication with the second path
portion and the pressure is directed toward said
ejection outlet by said movable member displaced to
eject the liquid droplet, wherein the partition wall
provided with said movable member is integrally formed
with side walls of the second path portion.
According to a further aspect of the present
invention, there is provided a head cartridge having
the liquid ejecting head as described above and a
liquid container.
According to a further aspect of the present
invention, there is provided a liquid ejecting
apparatus having the liquid ejecting head as described
above and driving signal supply means for supplying a
driving signal for ejecting the liquid from the liquid
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ejecting head.
According to a further aspect of the present
invention, there is provided a liquid ejecting
apparatus having the liquid ejecting head as described
above and recording medium carrying means for carrying
a recording medium for receiving the liquid ejected
from the liquid ejecting head.
According to a further aspect of the present
invention, there is provided a head kit comprising the
liquid ejecting head as described above and a liquid
container for containing the liquid to be supplied to
the liquid ejecting head.
According to a further aspect of the present
invention, there is provided a head kit having the
liquid ejecting head as described above, a liquid
container for containing the liquid to be supplied to
the liquid ejecting head, and liquid filling means for
filling the liquid into the liquid container.
According to a further aspect of the present
invention, there is provided a recorded material having
received an ink ejected as the liquid by the liquid
ejection recording method as described above.
The above characteristic features of the
present invention enabled the movable member, capable
of effectively and usefully regulating growth of a
bubble for general valves or the ejection principle of
the novel head described in the prior application, to
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be accurately produced at low cost and with a reduced
number of parts at the level of practical use as
commercial products, and provided the head to exhibit
the maximum effect also in the conventional ejection
principle.
In more detail, by preliminarily integrally
forming the partition wall having the movable member
with the walls of the second path portion, no gap will
possibly be formed between the partition wall and the
walls of the second path portion, and a number of steps
in manufacturing the liquid ejecting head can be
decreased, thus improving the manufacturing throughput.
Further, since the slit width or the like can
be precisely processed by forming the partition wall
and the movable member separated in the predetermined
slit width from the partition wall by electroforming,
the ejecting liquid can accurately be ejected by a
desired amount by displacing the movable member in
accurate response to the pressure raised by bubble
generation of the liquid receiving heat from the
electrothermal transducer, which permits formation of
high-quality image.
The other effects of the present invention will
be understood from the description of the embodiments.
In the specification, the terms "upstream" and
"downstream" are defined with respect to a general
liquid flow from a liquid supply source through the
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liquid flow paths to the ejection outlet or are
expressed as expressions as to the direction in this
structure.
Further, a "downstream side" portion of the
bubble itself represents an ejection-outlet-side
portion of the bubble which directly functions mainly
to eject a liquid droplet. More particularly, it means
a downstream portion of the bubble in the above flow
direction or in the direction of the above structure
with respect to the center of the bubble, or a bubble
appearing in the downstream region from the center of
the area of the heat generating element.
In this specification, "substantially sealed"
generally means a sealed state in such a degree that
when a bubble grows, the bubble does not escape through
a gap (slit) around the movable member before motion of
the movable member.
In this specification, "partition wall" may
mean a wall (which may include the movable member)
interposed to separate the region in direct fluid
communication with the ejection outlet from the bubble
generation region, and more specifically means a wall
separating the liquid flow path including the bubble
generation region from the liquid flow path in direct
fluid communication with the ejection outlet, thereby
preventing mixture of the liquids in the respective
liquid flow paths.
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BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a schematic, exploded view for
explaining the structure of a major part in an
embodiment of the liquid ejecting head according to the
present invention;
Fig. 2 is a sectional view to show a portion of
an ejection outlet and liquid flow paths as a major
part of the liquid ejecting head shown in Fig. 1;
Fig. 3 is an exploded diagram to show a major
part of the liquid ejection head shown in Fig. l;
Fig. 4 is an exploded, perspective view to show
a major part of the liquid jet head according to the
present invention;
Fig. 5 is a diagrammatic, perspective view to
show a grooved partition wall in which a partition wall
and side walls of second path portions are integrally
formed;
Figs. 6A to 6H are explanatory drawings to show
steps for producing the partition wall in Embodiment 1
of the present invention;
Figs. 7A to 7D are explanatory drawings to show
steps for producing the partition wall in Embodiment 2
of the present invention;
Figs. 8A to 8C are explanatory drawings to show
steps for producing a matrix used in Embodiment 2 of
the present invention;
Figs. 9A to 9F are explanatory drawings to show
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steps for producing the partition wall in Embodiment 3
of the present invention;
Figs. lOA to lOE are explanatory drawings to
show steps for producing the partition wall in
Embodiment 4 of the present invention;
Figs. llA to llD are explanatory drawings to
show steps for producing the partition wall in
Embodiment 5 of the present invention;
Figs. 12A to 12D are explanatory drawings to
show steps for producing the partition wall in
Embodiment 6 of the present invention;
Figs. 13A to 13D are explanatory drawings to
show steps for producing the partition wall in
Embodiment 7 of the present invention;
Fig. 14 is a schematic, exploded, perspective
view of a liquid ejecting head cartridge incorporating
the liquid ejecting head of the present invention;
Fig. 15 is a schematic drawing of a liquid
ejecting apparatus incorporating the liquid ejecting
head of the present invention;
Fig. 16 is a block diagram of the whole of an
apparatus for operation of ink ejection recording
utilizing the liquid ejecting method and liquid
ejecting head applicable to the present invention;
Fig. 17 is a schematic, perspective view for
explaining the structure of an ink jet recording system
using the liquid ejecting head of the present
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invention;
Fig. 18 is a schematic plan view to show a head
kit having the liquid ejecting head of the present
invention;
Fig. 19 is a sectional view to show the major
structure of a head o a side shooter type as an
example of the liquid ejecting head according to the
present invention;
Figs. 20A to 20D are schematic drawings to show
an example of a liquid jet head achieving the novel
ejection principle applicable to the present invention;
Fig. 21 is a partly broken, sectional view of
the liquid jet head of Figs. 20A to 20D;
Fig. 22 is a schematic drawing to show a state
of pressure propagation from a bubble in the
conventional ejection principle;
Fig. 23 is a schematic drawing to show a state
of pressure propagation from a bubble in the novel
ejection principle applicable to the present invention;
Figs. 24A to 24C are schematic plan views to
show a configuration of a slit in the partition wall;
Fig.25A is an enlarged sectional view of the
slits produced by the electroforming and Fig.25B is an
enlarged sectional view of the slits formed by the
laser irradiation; and
Figs. 25C and 25D show deviations in the
movable member in the X-direction and the Y-direction.
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DESCRIPTION OF THE PREFERRED EMBODIMENTS
(Explanation of the principle)
The ejection principle applicable to the
present invention will be explained with reference to
the drawings.
Figs. 20A to 20D are schematic cross-sectional
views of the liquid discharge head taken along the
direction of the liquid flow path and Fig. 21 is a
partially broken perspective view of the liquid head.
The liquid ejecting head as shown in Figs. 20A
to 20D comprises a heat generating element 402 provided
on an element substrate 401 (a heat generating resistor
of 40 ~m x 105 ~um in this embodiment) as the ejection
energy generating element for supplying thermal energy
to the liquid to eject the liquid, and a liquid flow
path 410 formed above the element substrate 401
correspondingly to the heat generating element 402.
The liquid flow path 410 is in fluid communication with
a discharge port 418 and a common liquid chamber 413
for supplying the liquid to a plurality of such liquid
flow paths 410 which is in fluid communication with a
plurality of the ejection outlets 418.
Above the element substrate 401 in the liquid
flow path 410, a movable member or plate 431 having a
planer portion in the form of a cantilever of an
elastic material such as metal is provided faced to the
heat generating element 402. One end of the movable
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member 431 is fixed to a foundation (supporting member)
434 or the like provided by patterning of
photosensitivity resin material on the wall of the
liquid flow path 410 or the element substrate 401. By
this structure, the movable member 431 is supported,
and a fulcrum 433 (fulcrum portion) is constituted.
The movable member 431 is so positioned that it
has a fulcrum 433 (fulcrum portion which is a fixed
end) in an upstream side with respect to a great flow
of the liquid from the common liquid chamber 413 toward
the ejection outlet 418 through the movable member 431
caused by the ejecting operation and that it has a free
end (free end portion) 432 in a downstream side of the
fulcrum 433. Accordingly, the movable member 431 is
faced to the heat generating element 402 with a gap of
151um approx so that it covers the heat generating
element 402. A bubble gene~ation region is constituted
between the heat generating element and movable member.
The type, configuration or position of the heat
generating element or the movable member is not limited
to the ones described above, but may be changed as long
as the growth of the bubble and the propagation of the
pressure can be controlled. For the purpose of easy
understanding of the flow of the liquid which will be
described hereinafter, the liquid flow path 410 is
divided by the movable member 431 into a first liquid
flow path 414 which is directly in communication with
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the ejection outlet 418 and a second liquid flow path
416 having the bubble generation region 411 and the
liquid supply port 412.
By causing heat generation of the heat
generating element 402, the heat is applied to the
liquid in the bubble generation region 411 between the
movable member 431 and the heat generating element 402,
by which a bubble is generated in the liquid by the
film boiling phenomenon as disclosed in US Patent No.
4,723,129. The bubble and the pressure caused by the
generation of the bubble act mainly on the movable
member, so that the movable member 431 moves or
displaces to widely open toward the ejection outlet
side about the fulcrum 433, as shown in Figs. 20B and
20C or in Fig. 21. By the displacement of the movable
member 431 or the state after the displacement, the
propagation of the pressure caused by the generation of
the bubble and the growth of the bubble per se are
directed toward the ejection outlet.
Here, one of the fundamental ejection
principles according to the present invention will be
described. One of important principles of this
invention is that the movable member disposed faced to
the bubble is displaced from the normal first position
to the displaced second position on the basis of the
pressure of the bubble generation or the bubble per se,
and the displacing or displaced movable member 431 is
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effective to direct the pressure produced by the
generation of the bubble and/or the growth of the
bubble per se toward the downstream in which the
ejection outlet 418 is located.
More detailed description will be made with
comparison between the conventional liquid flow passage
structure not using the movable member (Fig. 22) and
the present invention (Fig. 23). Here, the direction
of propagation of the pressure toward the ejection
outlet is indicated by VA, and the direction of
propagation of the pressure toward the upstream is
indicated by VB.
In a conventional head as shown in Fig. 22,
there is not any structural element effective to
regulate the direction of the propagation of the
pressure produced by the bubble 440 generation.
Therefore, the direction of the pressure propagation of
the is normal to the surface of the bubble as indicated
by Vl-V8, and therefore, is widely directed in the
passage. Among these directions, those of the pressure
propagation from the half portion of the bubble closer
to the ejection outlet (Vl-V4) have the pressure
components in the VA direction which is most effective
for the liquid ejection. This portion is important
since it directly contributable to the liquid ejection
efficiency, the liquid ejection pressure and the
ejection speed. Furthermore, the component Vl is
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closest to the direction of VA which is the ejection
direction, and therefore, is most effective, and the V4
has a relatively small component in the direction VA.
On the other hand, in the case of the present
invention, shown in Fig. 23, the movable member 431 is
effective to direct, to the downstream (ejection outlet
side), the pressure propagation directions V1-V4 of the
bubble which otherwise are toward various directions as
shown in Fig. 22 and to direct to the pressure
propagation direction VA so that the pressure of the
bubble 440 is directly and efficiently contributable to
the ejection.
Further, the growth direction per se of the
bubble is directed downstream similarly to the pressure
propagation directions Vl-V4, and bubbles grow more in
the downstream side than in the upstream side. Thus,
the growth direction per se of the bubble is controlled
by the movable member, and the pressure propagation
direction from the bubble is controlled thereby, so
that the ejection efficiency, ejection force and
ejection speed or the like are fundamentally improved.
Referring back to Figs. 20A to 20D, the
ejecting operation of the liquid ejecting head in this
embodiment will be described in detail.
Fig. 20A shows a state before the energy such
as electric energy is applied to the heat generating
element 402, and therefore, no heat has yet been
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generated. It should be noted that the movable member
431 is so positioned as to be faced at least to the
downstream portion of the bubble generated by the heat
generation of the heat generating element. In other
words, in order that the downstream portion of the
bubble acts on the movable member, the liquid flow
passage structure is such that the movable member 431
extends at least to the position downstream (downstream
of a line passing through the center 403 of the area of
the heat generating element and perpendicular to the
length of the flow path) of the center 403 of the area
of the heat generating element.
Fig. 20B shows a state wherein the heat
generation of heat generating element 402 occurs by the
application of the electric energy to the heat
generating element 402, and a part of of the liquid
filled in the bubble generation region 411 is heated by
the thus generated heat so that a bubble is generated
as a result of film boiling.
At this time, the movable member 431 is
displaced from the first position to the second
position by the pressure produced by the generation of
the bubble 440 so as to guide the propagation of the
pressure of the bubble 440 toward the ejection outlet.
It should be noted that, as described hereinbefore, the
free end 432 of the movable member 431 is disposed in
the downstream side (ejection outlet side), and the
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fulcrum 433 is disposed in the upstream side (common
liquid chamber side), so that at least a part of the
movable member is faced to the downstream portion of
the bubble, that is, the downstream portion of the heat
generating element.
Fig. 20C shows a state in which the bubble 440
has further grown. By the pressure resulting from the
bubble 440 generation, the movable member 431 is
displaced further. The generated bubble grows more
downstream than upstream, and it expands greatly beyond
a first position (broken line position) of the movable
member. Thus, it is understood that in accordance with
the growth of the bubble 440, the movable member 431
gradually displaces, by which the pressure propagation
direction of the bubble 440, the direction in which the
volume movement is easy, namely, the growth direction
of the bubble, are directed uniformly toward the
ejection outlet, so that the ejection efficiency is
increased. When the movable member guides the bubble
and the bubble generation pressure toward the ejection
outlet, it hardly obstructs propagation and growth, and
can efficiently control the propagation direction of
the pressure and the growth direction of the bubble in
accordance with the degree of the pressure.
Fig. 20D shows a state wherein the bubble 440
contracts and extincts by the decrease of the pressure
in the bubble, peculiar to the film boiling phenomenon.
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The movable member 431 having been displaced to
the second position returns to the initial position
(first position) of Fig. 20A by the restoring force
provided by the spring property of the movable member
per se and the negative pressure due to the contraction
of the bubble. Upon the collapse of bubble, the liquid
flows back from the upstream (B), namely the common
liquid chamber side as indicated by VDl and VD2 and
from the ejection outlet side as indicated by Vc so as
to compensate for the volume reduction of the bubble in
the bubble generation region 411 and to compensate for
the volume of the ejected liquid.
In the foregoing, the description has been made
as to the operation of the movable member with the
generation of the bubble and the ejecting operation of
the liquid. Now, the description will be made as to
the refilling of the liquid in the liquid ejecting head
of the present invention.
When the bubble 440 enters the bubble
collapsing process after the maximum volume after the
state of Fig. 20C, a volume of the liquid enough to
compensate for the collapsing bubbling volume flows
into the bubble generation region from the ejection
outlet 418 side of the first liquid flow path 414 and
from the common liquid chamber 413 of the second liquid
flow path 416.
In the case of conventional liquid flow
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passage structure not having the movable member 431,
the amount of the liquid from the ejection outlet side
to the bubble collapse position and the amount of the
liquid from the common liquid chamber, are based on the
flow resistance of the portion closer to the ejection
outlet than the bubble generation region and the
portion closer to the common liquid chamber. (Based on
the flow resistance and the inertia of the liquid.)
Therefore, when the flow resistance at the
supply port side is smaller than the other side, a
large amount of the liquid flows into the bubble
collapse position from the ejection outlet side with
the result that the meniscus retraction is large. With
the reduction of the flow resistance in the ejection
outlet for the purpose of increasing the ejection
efficiency, the meniscus M retraction increases upon
the collapse of bubble with the result of longer
refilling time period, thus making high speed printing
difficult.
According to this arrangement, because of the
provision of the movable member 431, the meniscus
retraction stops at the time when the movable member
returns to the initial position upon the collapse of
bubble, and thereafter, the supply of the liquid to
fill a volume W2 is accomplished by the flow VD2
through the second flow path 416 (W1 is a volume of an
upper side of the bubble volume W beyond the first
2 1 74 1 82
- 27 -
position of the movable member 431, and W2 is a volume
of a bubble generation region ll side thereof). In the
prior art, a half of the volume of the bubble volume W
is the volume of the meniscus retraction, but according
to this arrangement, only about one half (Wl) is the
volume of the meniscus retraction.
Additionally, the liquid supply for the volume
W2 is forced to be effected mainly from the upstream
(VD2) of the second liquid flow path along the surface
of the heat generating element side of the movable
member 431 using the pressure upon the collapse of
bubble, and therefore, more speedy refilling action is
accomplished.
When the refilling using the pressure upon the
collapse of bubble is carried out in a conventional
head, the vibration of the meniscus is expanded with
the result of the deterioration of the image quality.
However, according to this embodiment, the flows of the
liquid in the first liquid flow path 414 at the
ejection outlet side and the ejection outlet side of
the bubble generation region 411 are suppressed, so
that the vibration of the meniscus is etremely reduced.
Thus, according to this arrangement applicable
to the present application, the high speed refilling is
accomplished by the forced refilling to the bubble
generation region through the liquid supply passage 412
of the second flow path 416 and by the suppression of
21 74182
- 28 -
the meniscus retraction and vibration. Therefore, the
stabilization of ejection and high speed repeated
ejections are accomplished, and when the embodiment is
used in the field of recording, the improvement in the
image quality and in the recording speed can be
accomplished.
The arrangement provides the following
effective function. It is a suppression of the
propagation of the pressure to the upstream side (back
wave) produced by the generation of the bubble. The
pressure due to the common liquid chamber 413 side
(upstream) of the bubble generated on the heat
generating element 402 mostly has resulted in force
which pushes the liquid back to the upstream side (back
wave). The back wave deteriorates the refilling of the
liquid into the liquid flow path by the pressure at the
upstream side, the resulting motion of the liquid and
the inertia force. In this arrangement, these actions
to the upstream side are suppressed by the movable
member 431, so that the refilling performance is
further improved.
The description will be made as to a further
characterizing feature and the advantageous effect.
The second liquid flow path 416 of this
arrangement has a liquid supply passage 412 having an
internal wall substantially flush with the heat
generating element 402 (the surface of the heat
2 1 74 1 82
- 29 -
generating element is not greatly stepped down) at the
upstream side of the heat generating element 402. With
this structure, the supply of the liquid to the surface
of the heat generating element 402 and the bubble
generation region 411 occurs along the surface of the
movable member 431 at the position closer to the bubble
generation region 411 as indicated by VD2.
Accordingly, stagnation of the liquid on the surface of
the heat generating element 402 is suppressed, so that
precipitation of the gas dissolved in the liquid is
suppressed, and the residual bubbles not extincted are
removed without difficulty, and in addition, the heat
accumulation in the liquid is not too much. Therefore,
the stabilized bubble generation can be repeated at a
high speed. In this arrangement, the liquid supply
passage 412 has a substantially flat internal wall, but
this is not limiting, and the liquid supply passage is
satisfactory if it has an internal wall with such a
configuration smoothly extended from the surface of the
heat generating element that the stagnation of the
liquid occurs on the heat generating element, and eddy
flow is not significantly caused in the supply of the
liquid.
The supply of the liquid into the bubble
generation region may occur through a gap at a side
portion of the movable member (slit 435) as indicated
by VD1. In order to direct the pressure upon the
2 i 74 1 82
- 30 -
bubble generation further effectively to the ejection
outlet, a large movable member covering the entirety of
the bubble generation region (covering the surface of
the heat generating element) may be used, as shown in
Figs. 20A to 20D. Then, the flow resistance for the
liquid between the bubble generation region 411 and the
region of the first liquid flow path 414 close to the
ejection outlet is increased by the restoration of the
movable member 431 to the first position, so that the
flow of the liquid to the bubble generation region 411
from VD1 can be prevented. However, according to the
head structure of this arrangement, there is a flow
effective to supply the liquid to the bubble generation
region, the supply performance of the liquid is greatly
increased, and therefore, even if the movable member
431 covers the bubble generation region 411 to improve
the ejection efficiency, the supply performance of the
liquid is not deteriorated.
The positional relation between the free end
432 and the fulcrum 433 of the movable member 431 is
such that the free end is at a downstream position of
the fulcrum as indicated in Fig. 23, for example. With
this structure, the function and effect of guiding the
pressure propagation direction and the direction of the
growth of the bubble to the ejection outlet side or the
like can be efficiently assured upon the bubble
generation. Additionally, the positional relation is
2174182
- 31 -
effective to accomplish not only the function or effect
relating to the ejection but also the reduction of the
flow resistance through the liquid flow path 410 upon
the supply of the liquid thus permitting the high speed
refilling. When the meniscus M retracted by the
ejection as shown in Fig. 23, returns to the ejection
outlet 418 by capillary force or when the liquid supply
is effected to compensate for the collapse of bubble,
the positions of the free end and the fulcrum 433 are
such that the flows S1, S2 and S3 through the liquid
flow path 410 including the first liquid flow path 414
and the second liquid flow path 416, are not impeded.
More particularly, in this arrangement, as
described hereinbefore, the free end 432 of the movable
member 431 is faced to a downstream position of the
center 403 of the area which divides the heat
generating element 402 into an upstream region and a
downstream region (the line passing through the center
(central portion) of the area of the heat generating
element and perpendicular to a direction of the length
of the liquid flow path). The movable member 431
receives the pressure and the bubble which are greatly
contributable to the ejection of the liquid at the
downstream side of the area center position 403 of the
heat generating element, and it guides the force to the
ejection outlet side, thus fundamentally improving the
ejection efficiency or the ejection force.
2174182
Further advantageous effects are provided using
the upstream side of the bubble, as described
hereinbefore.
Furthermore, it is considered that in the
structure of this embodiment, the instantaneous
mechanical movement of the free end of the movable
member 431, contributes to the ejection of the liquid.
The embodiments of the present invention will
be explained in detail with reference to the
accompanying drawings.
Fig. 1 is a schematic, exploded, perspective
view for explaining the major structure in an
embodiment of the liquid ejecting head according to the
present invention. Fig. 1 is illustrated as omitting
an orifice plate provided with ejection outlets. Fig.
2 is a sectional view to show a portion of an ejection
outlet and liquid flow paths as a major part of the
liquid ejecting head of Fig. l, and Fig. 3 is a
partial, schematic drawing to show a major part of the
liquid ejecting head of Fig. 1.
In Figs. 1 to 3, reference numeral 1 designates
an element substrate in which heat generating elements
2 are provided as elements for electrothermal
transduction for supplying the thermal energy for
generating a bubble to the liquid.
The element substrate 1 has patterned wiring
electrode (0.2 to 1.0 ,um thick) of aluminum (Al) or the
- 33 -
like and patterned electric resistance layer (0.01 to
0.2 ~m thick) of hafnium boride (HfB2), tantalum nitride
(TaN), tantalum aluminum (TaAl) or the like
constituting the heat generating elements 2 on a
silicon oxide (SiO2) film or silicon nitride (SiN) film
for electric insulation and thermal accumulation formed
on the substrate of silicon or the like. The heat
generating element 2 generates heat when a voltage is
applied to the resistance layer through the wiring
electrodes.
A protection layer of SiO2, SiN, or the like
(0.1 to 2.0 ,um thick) is provided on the resistance
layer (heat generating element 2) between the wiring
electrodes, and in addition, an anti-cavitation layer
of tantalum (Ta) or the like (0.1 to 0.6 ,um thick) is
formed thereon to protect the heat generating element 2
from various liquids such as ink.
The pressure and shock wave generated upon
bubble generation and collapse is so strong that the
durability of the protection film hard and relatively
fragile is considerably deteriorated. Therefore, a
metal material such as Ta or the like is preferably
used as a material for the anti-cavitation layer.
The protection layer on the heat generating
element 2 may be omitted depending upon the combination
of liquid, liquid flow path structure, and resistance
material. The material for the resistance layer not
2i74182
- 34 -
requiring the protection layer on the heat generating
element 2, includes, for example, iridium-tantalum-
aluminum (Ir-Ta-Al) alloy or the like.
Thus, the structure of the heat generating
element in the foregoing embodiments may include only
the resistance layer (heat generating portion) between
the electrodes as described, or may include a
protection layer for protecting the resistance layer.
In this embodiment, the heat generating element
has a heat generation portion having the resistance
layer which generates heat in response to the electric
signal. Without having to be limited to this, any
means well suffices if it creates a bubble enough to
eject the liquid in the first path portion, in the
liquid in the second path portion. For example, the
heat generation portion may be in the form of a
photothermal transducer which generates heat upon
receiving light such as laser, or a heat generating
element having the heat generation portion which
generates heat upon receiving high frequency wave.
Function elements such as a transistor, a
diode, a latch, a shift register, and so on for
selectively driving the electrothermal transducer may
also be integrally built in the element substrate 1, in
addition to the electrothermal transducer (heat
generating element) comprised of the resistance layer
and the wiring electrodes for supplying the electric
2 i 74 1 82
- 35 -
signal to the resistance layer, as described above.
On the element substrate 1 provided with the
heat generating element 2 there is the second path
portion 4 of a liquid flow path in the bottom surface
of which the heat generating element 2 is formed in
order to let the thermal energy generated by the heat
generating element 2 act on the liquid. Further, above
the second path portion 4 there is provided the first
path portion 3 of a liquid flow path in direct fluid
communication with the ejection outlet 9. The
partition wall 5 formed of a material having
elasticity, such as a metal, a resin, or the like, is
disposed between the second path portion 4 and the
first path portion 3, thereby separating the second
path portion from the first path portion.
A projection space in the direction
perpendicular to the surface where the heat generating
element 2 is formed (above the heat generating element
2) in the liquid flow paths (region A in the first path
portion and region B in the second path portion in Fig.
1) is an ejection pressure generating region where the
pressure for ejecting the liquid acts. The liquid jet
head of the present invention generates a bubble when
the liquid in the second path portion is heated by the
heat generating element, and the pressure raised with
growth of bubble upon generation of the bubble acts in
the ejection pressure generating region to eject the
Z17~1~2
- 36 -
liquid.
A movable member 6 is formed in a cantilever
beam shape by slit in the portion of the partition wall
5 located in this ejection pressure generating region.
This movable member 6 is formed in such an arrangement
that a free end 6a thereof is located on the side of
the ejection outlet 9 (on the downstream side in the
fluid flow direction or on the left side as facing Fig.
2) and a fulcrum 6b of the movable member 6 is located
on the side of a common liquid chamber 10 to the first
path portions 3 and a common liquid chamber 11 to the
second path portions 4.
Since the liquid ejecting head of the present
invention has the movable member 6 in the partition
wall 6 as facing the ejection pressure generating
region B in the second path portion, the movable member
6 operates to open to the side of the first path
portion 3 (or in the direction of the arrow in Fig. 2)
by the pressure caused by bubble generation of the
liquid in the second path portion, as described below.
The material for forming the partition wall 5
having the movable member 6 may be any material having
solvent resistance against the liquid in the liquid
flow paths, having elasticity enough to operate well as
the movable member, and permitting formation of fine
slit. Preferable examples of materials meeting these
requirements include resin materials having high heat
2~74i82
- 37 -
resistance, high solvent resistance, and high
moldability, more particularly recent engineering
plastic resin materials such as polyethylene,
polypropylene, polyamide, polyethylene terephthalate,
melamine resin, phenolic resin, epoxy resin,
polybutadiene, polyurethane, polyetheretherketone,
polyether sulfone, polyallylate, polyimide,
polysulfone, liquid crystal polymer (LCP), and so on,
chemical compounds thereof, or metals such as silicon
dioxide, silicon nitride, nickel, gold, stainless
steel, and so on, alloys and chemical compounds
thereof, or materials coated with titanium or gold.
The thickness of the partition wall S is
determined depending upon the material and
configuration used from the standpoints that the
strength necessary for the partition wall 5 can be
achieved and that the movable member 6 can operate
well, and generally is in the range of 0.5 ,um to 10 ~m,
desirably.
The configuration of the slit may be either
rectangular as shown in Fig. 24A, tapered toward the
fulcrum as shown in Fig. 24B, or widened toward the
fulcrum as shown in Fig. 24C. The configuration of
Fig. 24B facilitates the operation of the movable
member while the configuration of Fig. 24C improves the
durability of the movable member. Without having to be
limited to the above configurations of the slit, the
2i 74 i ~2
- 38 -
slit in the present invention may be any that can be
positioned in the second path portion.
If the bubble generation liquid is different
from the ejection liquid and if mixture of the two
liquids is desired to be prevented, the width of the
slit between the partition wall 5 and the movable
member 6 is determined to be a gap to form a meniscus
between the two liquids, thereby controlling fluid
communication between the two liquids. For example,
supposing the bubble generation liquid is a liquid
having the viscosity of about 2 cP (centipoise) and the
ejection liquid is a liquid having the viscosity of 100
or more cP, the slit of about 5 ~um is enough to avoid
mixture of the liquids, but a desirable width is not
more than 3 ,um.
The configuration of the second path portion 4
may be any configuration that can effectively transmit
the pressure caused with generation of bubble to the
movable member side. However, if the chamber (bubble
generation chamber) structure is such that the second
path portion 4 has a throat portion on the upstream
side of the heat generating element 2 (where the
"upstream side" means an upstream side in a large flow
from the liquid chamber side through the heat
generating element position, the movable member, and
the first path portion 3 to the ejection outlet) so as
to stop the pressure upon bubble generation from
2~74182
- 39 -
readily escaping to the upstream side of the second
path portion, the pressure upon bubble generation in
the second path portion 4 can be further prevented from
escaping to the surroundings, and the pressure can be
directed as concentrated to the movable member side,
thereby achieving higher ejection efficiency and
ejection force.
When the height of the second path portion 4 is
determined at such a value that a part of the bubble
generated in the second path portion 4 extends into the
first path portion, the ejection force can be improved
more than in the cases where the bubble does not extend
into the first path portion 3. For the bubble to
extend into the first path portion 3 in this manner,
the height of the second path portion 4 is desirably
determined to be lower than the height of the maximum
bubble, and, specifically, the height is desirably
determined in the range of several ~m to 30 ,um.
The first path portions 3 in communication with
the ejection outlets 9 are provided above the partition
wall 5, and the first path portions 3 are formed by
joining the partition wall 5 to the grooved top plate 8
in which first recesses 3a to become the first path
portions are formed. This grooved top plate 8 is
further provided with an orifice plate having the
ejection outlets 9, and a recess lOa to be a liquid
chamber for supplying the liquid to the liquid flow
2 1 74 1 82
- 40 -
paths.
Since this liquid ejecting head is arranged so
that the second path portion being a portion for
generating the bubble is separated from the first path
portion in fluid communication with the ejection outlet
by the partition wall, the liquid in the second path
portion may be different from the liquid in the first
path portion. The present embodiment shows the liquid
ejecting head of the two-path structure which permits
different liquids to be used between in the second path
portion and in the first path portion.
The top plate 8 has a first supply port 20 for
supply of the liquid into the first common liquid
chamber and a second supply port 21 for supplying the
liquid into the second common liquid chamber. The
second supply port is connected to a communication path
disposed outside the first common liquid chamber,
piercing the partition wall, and communicating with the
second common liquid chamber, and thanks to this
communication path the liquid to be supplied to the
second path portion can be supplied to the second
common liquid chamber without being mixed with the
liquid to be supplied to the first path portion.
The sizes, configurations, and locations of the
heat generating elements 2 and movable members 6 are
not limited to those described above, but they may be
determined so as to effectively utilize the pressure
21741~2
- - 41 -
upon generation of bubble as ejection energy.
In the present invention, the partition wall 5
and the side walls of the second path portions 4 are
formed in an integral fashion. The term "integral"
herein means that the partition wall 5 and the side
walls of the second path portions 4 compose a single
member when the partition wall 5 is joined to the
element substrate 1, and, therefore, the material for
the partition wall and the material for the side walls
of the second path portions may be the same or
different from each other. Since in the present
invention the partition wall 5 and the side walls of
the second path portions 4 are formed in an integral
fashion, no gap possibly occurs between the partition
wall 5 and the side walls of the second path portions
4, thereby improving the yield of the liquid ejecting
head. When the partition wall 5 and the side walls of
the second path portions 4 are formed in an integral
fashion, fitting grooves for fitting of walls of the
first path portions may be formed in portions of the
partition wall 5 in contact with the side walls of the
first path portions. The formation of the fitting
grooves in the partition wall 5 enables the grooved top
plate 8 having the side walls of the first path
portions to be easily positioned relative to the
partition wall 5, and also presents the effect that
positional deviation can be reduced between the first
2i74~2
- 42 -
path portions 3 and the movable members 6 when the
grooved top plate 8 is thermally expanded.
In the description of the present invention the
name "grooved partition wall" is used for a member in
which the partition wall 5 and the side walls of the
second path portions 4 are integrally formed, thereby
discriminating it from the ordinary partition wall.
Next explained is an example of a method for
assembling the major part of the liquid ejecting head
according to the present invention.
Fig. 4 is an exploded, perspective view to show
the major part of the liquid ejecting head of the
present invention. In this example, the top plate 8 is
first fixed upside down and the grooved partition wall
5 having the movable members 6 is set on the top plate
8, using a vacuum pump. After positioning the
partition wall by micro fine adjustment, the grooved
partition wall 5 is fit in the top plate 8.
Next, using a splicing machine, positions of
- 20 the electrothermal transducers on the substrate 1 are
measured on an image obtained by a TV camera or the
like and a position of the top plate 8 to be bonded at
a predetermined position is also measured on the image
as being moved, whereby positioning is achieved between
the electrothermal transducers formed in the substrate
1 and the ejection outlets 9. Then the top plate 8 and
substrate 1 are pressed to fit with each other by a
21741~
- 43 -
stop spring 102.
Another splicing method between the top plate 8
and the substrate 1 is exciting top connection. The
"exciting top connection" is carried out as follows.
The top plate 8 is first roughly positioned on the
substrate 1 provided with an engaging groove into which
a flow path wall of the top plate 8 is fitted and the
top plate 8 is lightly and normally pressed from the
top. In this state, a signal is supplied to a
piezoelectric device in contact with a front bottom
surface of a base plate 101 so that the flow path wall
is fitted into the engaging groove to position the top
plate and the substrate l. The piezoelectric device
for giving vibration (rectangular wave of about 5 kHz
lS in this example) to the substrate 1 vibrates in the
amplitude of approximately 1 ,um. The time is about 1
second. After stop of vibration, they are secured to
each other by the stop spring 102 or by an adhesive or
the like.
Further, the first liquid chamber 10 and the
second liquid chamber 11 are sealed with a sealant as
surrounding them, thereby maintaining airtightness.
Next explained in detail is a method for
producing the partition wall in particular in the
liquid ejecting head of the present invention.
Fig. 5 is a schematic, perspective view to show
the grooved partition wall integrally incorporating the
2 i 74 1 8~
- 44 -
partition wall and the side walls of the second path
portions according to the present invention.
In Fig. 5, numeral 5 denotes the grooved
partition wall, and a movable member 6 is formed by a
slit 6a in the grooved partition wall 5. Further, the
side walls of the second path portions are also
provided in the grooved partition wall 5 and the side
walls of the second path portions form second recesses
4a to be the second path portions.
Since this grooved partition wall 5 has the
integral arrangement of the partition wall and the side
walls of the second path portions, no gap will possibly
occur between the partition wall portion and the side
wall portions of the second path portions, which
reduces losses of ejection pressure and propagation of
the pressure into adjacent liquid flow paths, thereby
enabling to provide the liquid ejecting head excellent
in ejection characteristics. When this structure is
employed, the productivity of the liquid ejecting head
can be improved more than heretofore.
Further, it was difficult to form the fitting
grooves 5a for positioning of the walls of first path
portions in the partition wall because of insufficient
strength of the partition wall when the partition wall
was separately formed from the second path portions.
However, the integral structure of the partition wall
and the second path portions enables the fitting
2 1 7~
- 45 -
grooves 5a to be formed in the grooved partition wall
5.
The grooved partition wall 5 of the present
invention permits the partition wall portion and the
side wall portions of the second path portions to be
made of a same material or of different materials. The
slits 6a in the partition wall portion can be formed by
electroforming or laser irradiation. Especially, when
the partition wall is formed by electroforming, the
slits 6a can be formed at high accuracy even when the
slits of partition wall are considerably thin.
Further, since the slits 6a are also formed at the same
time as production of the partition wall, the process
can be simplified. Since the thickness of the
partition wall can be controlled evenly when the
partition wall is produced by electroforming,
performance of each movable member can be uniform even
when the partition wall has a plurality of movable
members.
When the slits are made by laser irradiation, a
resin as well as a metal can be used as a material for
forming the partition wall.
The side wall portions of the second path
portion in the grooved partition wall can be made by
electroforming or etching. For simplifying the
process, the partition wall can be made by
electroforming of a matrix having a mold of the second
2174182
- 46 -
recess.
Ends of the slits made by electroforming or
laser irradiation has an R-tapered shape or a straight
tapered shape as shown in the Figs.25A and 25B.
Fig.25A is an enlarged sectional view of the slits
produced by the electroforming and 25B is an enlarged
sectional view of the slits formed by the laser
irradiation. The tapered shapes of Figs.25A and 25B
have the following advantages. When the movable member
is displaced for a long time, an operation region of
the movable member may be deviated due to mechanical
fatigue (reduction of rigidity) in an X-direction or a
Y-direction as shown in Fig.25C. If the operation
region of the movable member is deviated, the
durability of the movable member may be reduced.
However, the ends of the slits are tapered, the tapered
shape of the movable member functions to correct the
deviation when the movable member operates as shown in
Figs.25C and 25D even if the operation region of the
movable member is deviated so that the durability of
the movable member can be improved. A taper angle a of
the slit ends varies in accordance with manufacturing
conditions. However, it is found that the above
advantage can be obtained if the taper angle is 2-45
in a direction of the thickness of the movable member.
Preferably, the taper angle of the slit ends is within
a range of 5-15.
- 47 -
Specific methods for producing the grooved
partition wall will be explained using the following
examples.
The partition wall obtained in each example to
follow is a member that can be suitably incorporated in
the liquid ejecting head of the present invention.
The explanatory drawings for explaining
Examples 1 to 7 all are cross sections along the A-A'
plane in Fig. 5.
(Example 1)
Figs. 6A to 6H are schematic, sectional views
to show steps for producing the partition wall, as an
example of the method for integrally producing the side
walls of the second path portions and the movable
members in the partition wall by two-stage
electroforming.
As shown in Fig. 6A, the SUS substrate 111
(SUS-316 in this example) as a stainless steel
substrate was first coated with a resist 112a 4 ~um
thick, and this resist was patterned in the shape
corresponding to the slit portion of movable member.
The resist 112a used was PMER P-AR900 (trade name,
available from Tokyo Ouka Sha). Exposure was carried
out using MPA-600 available from Canon Kabushiki
Kaisha, and exposure dose was 500 mJ/cm2. Development
was made using a developer, P-6G (trade name, available
from Tokyo Ouka Sha).
2l74l~2
- 48 -
Then, as shown in Fig. 6B, electroplating was
conducted to grow nickel in 5 ,um as a first plating
layer 113 on the substrate 111. The plating solution
used was the one containing nickel sulfamate, a stress
decrease material ZERO ALL (registered trade name,
available from WORLD METAL INC.), boric acid, a pit
prevention material NS-APS (trade name, available from
WORLD METAL INC.), and nickel chloride. The
electrolysis upon electroplating was established under
such conditions that the electrode was connected to the
anode, the SUS substrate 111 already patterned was
connected to the cathode, the temperature of the
plating solution was controlled at 50C, and the
current density was 5 A/dm2. The first plating layer
113 formed on the substrate 111 by electroplating as
described comprises a plate member 113a to constitute
the partition wall, and movable members 113b in a
cantilever beam shape separated from the plate member
113a by the predetermined slit.
Next, as shown in Fig. 6C, the SUS substrate
111 was immersed in a palladium catalyst solution, and
thereafter a resist 112b was formed in the thickness of
10 ~m on the SUS substrate 111. This resist was
patterned in the shape corresponding to the recesses
for the second path portions. The resist 112b used was
PMER P-AR900 (trade name, available from Tokyo Ouka
- Sha). Exposure was made using MPA-600 available from
2174182
- 49 -
Canon Kabushiki Kaisha, and the exposure dose was 1200
mJ/cm2. Development was carried out in the same manner
as in the step shown in Fig. 6A. The resist 112b was
formed in elongate band portions including the movable
members 113b of the first plating layer 113. The band
portions are portions to become the second path
portions 2 as second recesses.
After that, as shown in Fig. 6D, Ni-B based
electroless plating was carried out to form a film
approximately 3 ,um thick in exposed portions of the
first plating layer 113, and thereafter a plating layer
was grown in 7 ,um by the same method as the
electroplating described with Fig. 6B to form a second
plating layer 114. This plating step may be carried
out only by the Ni-B based electroless plating to form
the second plating layer 114 10 ,um thick. The second
plating layer 114, formed on the first plating layer
113 by the plating step discussed, is integrally joined
in sufficient strength with the first plating layer
113.
After completion of the above plating, as shown
in Fig. 6E, the resists 112a, 112b were then removed
and the nickel plates of the first plating layer 113
and second plating layer 114 were stripped off from the
SUS substrate 111 by means of ultrasonic vibration or
the like to form the second recesses 116 to become the
second path portions and the movable members 117 in the
2 1 74t ~2
- 50 -
partition wall, thereby obtaining a nickel plate 115
that can be used as a partition wall.
Grooves for positioning the walls of the first
path portions, if desired to be formed in the partition
wall, can be further produced according to the
following steps.
After the step of Fig 6E, as shown in Fig. 6F,
the substrate 111 stripped off at the step of Fig. 6E
was joined to the side of the second plating layer 114
of the nickel plate, and the stripped-side surface of
the nickel plate was coated with a resist 2 ,um thick.
Then the resist was patterned to remove portions
thereof to become the grooves for positioning the walls
of the first path portions.
Then, as shown in Fig. 6G, the nickel plate was
etched to form fitting grooves 119. The etchant used
may be ferric chloride, a mixture solution of nitric
acid, acetic acid, and acetone, or the like.
After that, as shown in Fig. 6H, the resist
112c was removed to form the second recesses 116 to
become the second path portions, the movable members
117 in the partition wall, and the grooves 119 for
positioning the walls of the first path portions, thus
obtaining the nickel plate 115 that can be used as a
partition wall. Here, reference numeral 118 in Fig. 6H
designates a recess for receiving a wall of a first
path portion in the top plate separately produced.
2i7418~
- 51 -
Since in this example the slit is formed by
electroforming between the partition wall 115 and the
movable member 117, the slit width can be precisely
controlled within a predetermined range and the
thickness of the partition wall 115 can also be
uniformly controlled.
(Example 2)
Figs. 7A to 7D are schematic, sectional views
to show steps for producing the partition wall as an
example for uniformly producing the side walls of
second path portions, the movable members, and the
grooves for positioning the walls of first path
portions by electroforming using a matrix.
Preliminarily prepared was a matrix 121 having
the second recesses to become the second path portions
as shown in Fig. 7A.
This matrix can be produced for example
according to the following steps.
As shown in Fig. 8A, a resist 112a
approximately 2 ,um thick was formed on the SUS
substrate 111 and the resist 112a was patterned by
photolithography to remove portions to become the
second path portions from an integral member for
partition wall. Then, as shown in Fig. 8B, exposed
portions of the substrate 111 were etched using a
mixture solution of alcohol, hydrochloric acid, and
hydrogen peroxide to form the second recesses to become
2 1 1~ ~ 8~`
- 52 -
the second path portions in the depth of approximately
10 ~m. After that, as shown in Fig. 8C, the resist
112a was removed to obtain a matrix 121 comprised of
the substrate 111 having the second recesses.
Preparing the matrix 121, as shown in Fig. 7B,
a coating of resist 112b 7 ~m thick was then formed in
the bottom portions in the second recess portions in
the matrix 121, and this resist was patterned to form
portions corresponding to the slit portions for the
movable members.
Then, as shown in Fig. 7C, electroplating was
carried out in the same manner as in Example 1 to form
a nickel plating layer 113 approximately 5 ~m thick
over the top surface of matrix 121 and the inner
surfaces of the second recesses.
Then, as shown in Fig. 7D, the resist 112b was
removed and the nickel plate comprised of the plating
layer 113 was stripped off from the matrix 121 to form
the second recesses 116 to become the second path
portions, the movable members 117 in the partition
wall, and the grooves 119 for positioning the walls of
the first path portions, thereby obtaining the nickel
plate 115 that can be used as a partition wall.
Since in this example the partition wall can be
formed by single electroplating by using the matrix
121, the step for forming the second recesses can be
eliminated, thus decreasing the number of steps.
2174182
- 53 -
Since also in this example the slits for the
movable members 117 are produced by electroforming
similarly as in Example 1, the slit width can be
precisely controlled in the predetermined range and the
thickness of the partition wall 15 can be uniformly
controlled.
(Example 3)
Figs. 9A to 9F are schematic, sectional views
to show steps for producing the partition wall as an
example for integrally forming the side walls of second
path portions and the movable members in the partition
wall by performing two-stage electroforming with
different materials and forming the second recesses by
etching.
First, as shown in Fig. 9A, the resist 112a was
formed in the thickness of 5 ,um on the SUS substrate
111, similarly as in Example 1, and this resist was
patterned to form portions corresponding to the slit
portions for the movable members. The width of the
resist 112a for forming the slit portions may be
arbitrarily determined within the range of 0.5 to 1 ,um.
Then, as shown in Fig. 9B, electroplating was
conducted to grow gold 5 ~um thick as a first plating
layer 113 in exposed portions of substrate 111. The
plating solution used was potassium gold cyanide and
potassium cyanide. Electrolysis upon electrodeposition
was effected under such conditions that the electrode
217~18~
- 54 -
was connected to the anode, the SUS substrate 111
already patterned was connected to the cathode, the
temperature of the plating solution was controlled at
65 C, and the current density was 3 A/dm2.
Next, as shown in Fig. 9C, electroplating was
carried out under the same conditions with the same
plating solution as in Example 1, on the surface of the
substrate 111 with the gold layer electrolytically
formed thereon as a first plating layer 113, so as to
grow a nickel layer 10 ,um thick as a second plating
layer 114.
Next, as shown in Fig. 9D, for forming the
second liquid flow paths, a resist 112b was formed on
the second plating layer 114, and patterning by
photolithography was carried out to remove the portions
to become the second path portions.
Then, as shown in Fig. 9E, exposed portions of
the second plating layer 114 were etched using the
etchant, either ferric chloride or the mixture solution
of nitric acid, acetic acid, and acetone to form
recesses ln the depth of approximately 10 ,um. These
recesses become the second path portions 116. Since
gold of the first plating layer is insoluble in the
etchant, only the second plating layer is etched.
Accordingly, the depth of the recesses to become the
second path portions can be controlled by the thickness
of the second plating layer, which permits high-
2 i 74 1 82
- 55 -
accuracy formation of the second path portions.
Finally, as shown in Fig. 9F, and the resists
112a and 112b were removed to form the second recesses
116 to become the second path portions and the movable
members 117 in the partition wall and a plate member
comprised of the first plating layer 113 and the second
plating layer 114 was striped off from the SUS
substrate lll, thereby obtaining the nickel plate 115
that can be used as a partition wall.
Since the present example allows an expensive
metal with a small Young's modulus to be used as a
material for forming the movable members 117 in the
partition wall 115 obtained by electroforming of two
types of metals, the durability can be improved.
(Example 4)
Figs. lOA to lOE are schematic, sectional views
to show steps for forming the partition wall as an
example for integrally forming the side walls of second
path portions and the movable members in the partition
wall by electroforming and dry film. First, as shown
in Fig. lOA, the portions corresponding to the slit
portions of the movable members were formed on the SUS
substrate 111 in the same manner as in Example 3. The
width of the resist 112a for forming the slit portions
can be arbitrarily determined within the range of 0.5
to 1 ~um.
Then, as shown in Fig. lOB, electroplating was
2i~4182
- 56 -
carried out to grow a nickel layer 5 ,um thick as a
first plating layer 113 in exposed portions of the
substrate 111. The plating solution used was the one
containing nickel sulfonate, a stress decrease material
ZERO ALL (registered trade name, available from WORLD
METAL INC.), boric acid, a pit prevention material NS-
APS (trade name, available from WORLD METAL INC.), and
nickel chloride. The electric field upon
electrodeposition was established under such conditions
that the electrode was connected to the anode, the SUS
substrate 111 already patterned was connected to the
cathode, the temperature of the plating solution was
controlled at 50 C, and the current density was 5
A/dm2. The first plating layer 113 thus formed on the
substrate 111 by electroplating comprises a plate
member 113a for forming the partition wall, and the
movable members 113b in the cantilever beam shape
separated by the predetermined slit from the plate
member 113a.
Next, as shown in Fig. lOD, a dry film 114 10
~um thick was placed on the electroformed surface, and
patterning by photolithography was carried out to form
recesses to become the second path portions.
Then, as shown in Fig. lOE, and the resists
112a and 112b were removed therefrom to form the second
recesses 116 to become the second path portions and the
movable members 117 in the partition wall and the plate
2 1 74 1 82
member comprised of the first plating layer 113 and the
dry film 114 was stripped off from the SUS substrate
111, thus obtaining the plate 115 made of nickel and
resin, which can be used as a partition wall,
Since in this example the side walls of the
second path portions can be produced by patterning of
the dry film, the partition wall can be produced easier
than in Example 1. Since the nickel plate and the dry
film are adhered to each other by adhesion of the dry
film itself, no gap will appear between the partition
wall portion and the portions of side walls of second
path portions.
Since in this example the slits for movable
members 117 are formed by electroforming similarly as
in Example 1, the slit width can be precisely
controlled within the predetermined range and the
thickness of the partition wall 15 can be uniformly
controlled.
(Example 5)
Examples 1 to 4 showed the methods for
producing the slit portions by electroforming, whereas
the present example shows an example for forming the
slits by laser.
Figs. llA to llD are schematic, sectional views
to show steps for producing the partition wall as an
example for integrally forming the side walls of the
second path portions and the movable members in the
- - 58 -
partition wall by forming the slit portions with laser
and forming the second path portions by etching.
First, as shown in Fig. llA, a nickel plate 129
15 ~m thick to become a partition wall was prepared,
and a mask 120 having slits in the width corresponding
to the width of the slit between the partition wall and
the movable member was located relative to the nickel
plate 129. After that, irradiation with YAG laser was
carried out to form fine recesses ll9a. A laser
irradiating apparatus used was LU100 available from
Hltachi Kenki, and the irradiation was carried out for
one second at the pulse energy of 5 J/cm2, the pulse
width of 1 ms, and 300 Hz. The mask 120 used may be a
perforated mask of nickel or a glass mask.
Next, as shown in Fig. llB, the SUS substrate
111 was joined to the laser-irradiated surface of the
nickel plate 129, and thereafter, for forming the
second path portions on the surface opposite thereto, a
coating of resist 112a 2 ,um thick was formed by the
photolithography technology and portions to become the
second path portions were removed by patterning by
photolithography.
Then, as shown in Fig. llC, etching was
effected in the depth of approximately 10 ~um to form
the second recesses to become the second path portions
in the exposed portions of the nickel plate 129. The
etchant used was ferric chloride or the mixture
2174i82
- 59 -
solution of nitric acid, acetic acid, and acetone.
Then, as shown in Fig. llD, the resist 112a was
removed to and the laser-irradiated surface of the
nickel plate 129 was stripped off from the SUS
substrate 111 and form the second recesses 116 to
become the second path portions and the movable members
117 in the partition wall, thereby obtaining the nickel
plate 115 that can be used as a partition wall.
The material for forming the partition wall in
the present example may be selected from copper, brass,
molybdenum, niobium, titanium, tungsten, or alloys
thereof, which can be well processed, in addition to
nickel. The present example permits a resin to be used
as a material for forming the partition wall, for
example plastics such as ABS, polysulfone,
polycarbonate, polyacetal, liquid crystal polymer, and
so on, which can be processed well. However, because
it is difficult to etch the resins, though processing
with laser is easy therewith, it is preferred to
process both the second path portions and movable
members with laser.
Since the present example used the laser and
etching for processing, the partition wall 115 can be
easily produced in the precise dimension. The present
example also permits the resin to be used as a material
for the partition wall.
(Example 6)
2i74i82
- 60 -
Figs. 12A to 12D are schematic, sectional views
to show steps for producing the partition wall as an
example for integrally forming the side walls of the
second path portions and the movable members in the
partition wall by forming the slit portions with laser
and forming the second path portions by etching.
First, as shown in Fig. 12A, a nickel plate 129
15 ~um thick to become the partition wall was prepared,
and the SUS substrate 111 was joined to the bottom
surface of the nickel plate 129. After that, for
forming the second path portions on the surface
opposite thereto, a coating of resist 112a 2 ~um thick
was formed by the photolithography technology, and
patterning by photolithography was carried out to
remove the portions to become the second path portions.
Then, as shown in Fig. 12B, etching was
conducted in the depth of approximately 10 ,um to form
the second recesses to become the second path portions
in the exposed portions of the nickel plate 129. The
etchant used was ferric chloride or the mixture
solution of nitric acid, acetic acid, and acetone. The
nickel plate 129 was stripped off from the SUS
substrate 111.
Then, as shown in Fig. 12C, a mask 120 having
slits in the width corresponding to the width of the
slit between the partition wall and the movable member
was located relative to the top surface of the nickel
2i741~2
- 61 -
plate 129, and thereafter irradiation with YAG laser
was carried out through the slits in the mask 120 to
form the movable members 117 in the cantilever beam
shape and in the above slit width in the bottom parts
of the second recesses in the nickel plate 129. The
laser irradiating apparatus used was LU100 available
from Hitachi Kenki, and the irradiation was carried out
for one second at the pulse energy of 5 J/cm2, the pulse
width of 1 ms, and 300 Hz. The mask 120 used may be a
perforated mask of nickel or a glass mask.
Next, as shown in Fig. 12D, the substrate 111
was stripped off from the bottom surface of the nickel
plate 129, and the resists 112a and 112b were removed
to form the second recesses 116 to become the second
path portions and the movable members 117 in the
partition wall, thereby obtaining the nickel plate 115
that can be used as a partition wall.
Since this example used the laser and etching
for processing, the partition wall 115 can be easily
produced in the precise dimension.
(Example 7)
Figs. 13A to 13D are schematic, sectional views
to show steps for producing the partition wall as an
example for integrally forming the second liquid flow
paths, the movable members in the partition wall, and
the grooves for positioning the first liquid flow paths
by using the matrix and performing electroforming and
2 1 ~ T ~
- 62 -
lasèr processing.
First, as shown in Fig. 13A, the matrix 121
produced in the same method as in Example 2 was
prepared, and then, as shown in Fig. 13B,
electroplating was carried out in the same manner as in
Example 1 to form a nickel plating layer 113
approximately 5 ,um thick over the top surface of the
matrix 121 and the inner surfaces of first recesses.
Then the nickel plate of the plating layer 113
was stripped off from the matrix 121, and, as shown in
Fig. 13C, a mask 120 having slits in the width
corresponding to the width of the slit between the
partition wall and the movable member was placed
relative to the plating layer 113 of the matrix 121.
After that, irradiation with YAG laser was carried out
in the same manner as in Example 5 through the slits of
the mask 120 to form the portions to become the movable
members in the cantilever beam shape in the bottom
portion of the plating layer 113.
Formed in this manner were the second path
portions 116, the movable members 117 in the partition
wall, and the grooves 119 for positioning the walls of
the first path portions, thereby obtaining the nickel
plate 115 that can be used as a partition wall.
Since this example uses the matrix similarly as
in Example 2, the number of steps can be reduced.
Since the nickel plate to become the partition wall 115
2~7~t~
- 63 -
is produced by electroforming, the thickness of the
partition wall 115 can also uniformly be controlled.
<Ejection liquid and bubble generation liquid>
As described in the foregoing embodiment,
according to the present invention, by the structure
having the movable member described above, the liquid
can be ejected at higher ejection force or ejection
efficiency than the conventional liquid ejecting head.
When the same liquid is used for the bubble generation
liquid and the ejection liquid, it is possible that the
liquid is not deteriorated, and that deposition on the
heat generating element due to heating can be reduced.
Therefore, a reversible state change is accomplished by
repeating the gassification and condensation. So,
various liquids are usable, if the liquid is the one
not deteriorating the liquid flow passage, movable
member or separation wall or the like.
Among such liquids, the one having the
ingredient as used in conventional bubble jet device,
can be used as a recording liquid.
The liquid ejecting head obtained according to
either one of the methods in the above examples permits
use of different liquids as an ejection liquid and as a
bubble generation liquid and can eject the ejection
liquid by the pressure raised with generation of a
bubble in the bubble generation liquid. With the
conventional liquid ejecting heads, a high-viscosity
2 1 ï41 82
- 64 -
liquid such as polyethylene glycol did not show
sufficient bubble generation even with application of
heat and had insufficient ejection force. In contrast
with it, the liquid ejecting head of the present
invention can eject such a high-viscosity liquid well
in such a manner that the high-viscosity liquid is
supplied to the first liquid flow path and a liquid
easy to generate a bubble (a mixture solution of
ethanol and water at 4:6 having the viscosity of
approximately 1-2 cP or the like) is supplied as a
bubble generation liquid to the second liquid flow
path. Further, since the structure of the liquid
ejecting head of the present invention involves the
effects as explained in the foregoing examples, the
high-viscosity liquid can be ejected at further high
ejection efficiency and high ejection pressure.
In the case of a liquid weak against heat being
used, if this liquid is supplied as an ejection liquid
to the first liquid flow path and a liquid easy to
generate a bubble and resistant to heat is supplied to
the second liquid flow path, the liquid can be ejected
at the high ejection efficiency and high ejection
pressure without thermally damaging the liquid weak
against heat.
When the two-flow-path structure of the present
invention is used with different ejection liquid and
bubble generation liquid, the bubble generation liquid
t~`2
- 65 -
having the above-described property is used, more
particularly, the examples includes: methanol, ethanol,
n-propyl alcohol, isopropyl alcohol, n-hexane,
n-heptane, n-octane, toluene, xylene, methylene
dichloride, trichloroethylene, Freon TF, Freon BF,
ethyl ether, dioxane, cyclohexane, methyl acetate,
ethyl acetate, acetone, methyl ethyl ketone, water, and
a mixture thereof.
As for the ejection liquid, various liquids are
usable without paying attention to the degree of bubble
generation property or thermal property. The liquids
which have not been conventionally usable, because of
low bubble generation property and/or easiness of
property change due to heat, are usable.
However, it is desired that the ejection liquid
by itself or by reaction with the bubble generation
liquid, does not impede the ejection, the bubble
generation or the operation of the movable member or
the like.
The ink of the following ingredient was used as
the recording liquid usable for both of the ejection
liquid and the bubble generation liquid, and the
recording operation was carried out. Since the
ejection speed of the ink is increased, the shot
accuracy of the liquid droplets is improved, and
therefore, highly desirable images were recorded.
Dye ink viscosity of 2cp
21741~
-- 66 --
( C~ I ~ood black ~ dye 3 wt ~-
d~ethylene glycol10 wt
Thio ~iglycol 5 wt. ~-
Ethanol ~ wt.
Water 77 wt
R~oordin~ op~ration~ were al-o carr~ed out
u~ing th~ following aombination of th~ liquids ~or the
bu~ble generatio~ liquid and the e~ection li~uid. As a
re~ult, the ~iqui~ having a ten and ~everal cps
viscosity, ~hich wa~ unable to be eject~d her~toor~,
wa~ pr~perly e~ected, and e~en 150cps liquid was
properly ejec~e~ to provide high quality ima~e
Bubble genera~iOn llquid 1:
~thanol 40 wt.
Water 60 wt.
subble gen~rati~n liquid 2:
Water 100 wt
~ubble generation liq~id 3:
I~oprop~1 alcoholic10 w~.
Water 90 wt.
Ej ection liguid 1;
(Pigment ink approx . 15 cps )
Carbon black 5 wt. %
Stylene-acryllc acld-acrylate ethyl
c~pol~ner toxide 140,
weight average molec~la~ weight 8,000
2~ 741 82
- 6? -
Mono-ethanol amine ~,~5 wt.
Glyc~rin 69 wt. ~
Thiodiglycol 5 wt. %
~thanol 3 wt.
water lG.75 wt.
Ei0ction liq~id 2 (55cps~:
Polyethylene glycol 200 100 wt. %
Ejectio~ liquid 3 (150cps):
Polyethylene glycol 600 100 w~. ~
In the ca~e of th~ liqui~ which has no~ ~een
ea~ily eje~ted, the ejeGtion ~pe~d is low, and
therefore, thE3 ~r~riation in the ejection direct~.i.on is
e~panded on the ~ecording paper with the result of poor
c2hot accuracy. ~ddition~lly, variation o~ ejectian
amo~nt occurs due to the ejection instability, thu~
preventin~ the recording of high quali~y image.
However, ~ccording to the embodiments, the use of the
~ubble gener~tion li~id per~itq ~ufficlenl and
sta~illzed generation ~f the bubble Tnu~ the
~0 in~L~Y~Ient ln the shot ~ccu~acy of the li quid droplet
and the stabiliza~ion of the ink eject~on amount can be
accompllshed, thus improving the recorded image qu~lity
remarkably,
~Liquid ejec~ion he~d cartridge~
The de~cription will be made as to a li~uid
ejection head cartridge having a liquid ejecting head
accordlng to an emb~ nt of the pr~sent in~ntion.
2 1 74 1 82
- 68 -
Fig. 14 is a schematic exploded perspective
view of a liquid ejection head cartridge including the
above-described liquid ejecting head, and the liquid
ejection head cartridge comprises generally a liquid
ejecting head portion 200 and a liquid container 80.
The liquid ejecting head portion 200 comprises
an element substrate 1, a separation wall 30, a grooved
member 50, a confining spring 78, liquid supply member
90 and a supporting member 70. The element substrate 1
is provided with a plurality of heat generating
resistors for supplying heat to the bubble generation
liquid, as described hereinbefore. A bubble
generation liquid passage is formed between the element
substrate 1 and the separation wall 30 having the
movable wall. By the coupling between the separation
wall 30 and the grooved top plate 50, an ejection flow
path (unshown) for fluid communication with the
ejection liquid is formed.
The confining spring 78 functions to urge the
grooved member 50 to the element substrate 1, and is
effective to properly integrate the element substrate
1, separation wall 30, grooved and the supporting
member 70 which will be described hereinafter.
Supporting member 70 functions to support an
element substrate 1 or the like, and the supporting
member 70 has thereon a circuit board 71, connected to
the element substrate 1, for supplying the electric
2i74182
_ - 69 -
signal thereto, and contact pads 72 for electric signal
transfer between the device side when the cartridge is
mounted on the apparatus.
The liquid container 90 contains the ejection
liquid such as ink to be supplied to the liquid
ejecting head and the bubble generation liquid for
bubble generation, separately. The outside of the
liquid container 90 is provided with a positioning
portion 94 for mounting a connecting member for
connecting the liquid ejecting head with the liquid
container and a fixed shaft 95 for fixing the
connection portion. The ejection liquid is supplied to
the ejection liquid supply passage 81 of a liquid
supply member 80 through a supply passage 81 of the
connecting member from the ejection liquid supply
passage 92 of the liquid container, and is supplied to
a first common liquid chamber through the ejection
liquid supply passage 83, supply and 21 of the members.
The bubble generation liquid is similarly supplied to
the bubble generation liquid supply passage 82 of the
liquid supply member 80 through the supply passage of
the connecting member from the supply passage 93 of the
liquid container, and is supplied to the second liquid
chamber through the bubble generation liquid supply
passage 84, 71, 22 of the members.
In such a liquid ejection head cartridge, even
if the bubble generation liquid and the ejection liquid
217~i~2
- 70 -
are different liquids, the liquids are supplied in good
order. In the case that the ejection liquid and the
bubble generation liquid are the same, the supply path
for the bubble generation liquid and the ejection
liquid are not necessarily separated.
After the liquid is used up, the liquid
containers may be supplied with the respective liquids.
To facilitate this supply, the liquid container is
desirably provided with a liquid injection port. The
liquid ejecting head and liquid container may be
unseparably integral, or may be separable.
<Liquid ejecting device>
Fig. 15 is a schematic illustration of a liquid
ejecting device used with the above-described liquid
ejecting head. In this embodiment, the ejection liquid
is ink, and the apparatus is an ink ejection recording
apparatus. The liquid ejecting device comprises a
carriage HC to which the head cartridge comprising a
liquid container portion 90 and liquid ejecting head
portion 200 which are detachably connectable with each
other, is mountable. The carriage HC is reciprocable
in a direction of width of the recording material 150
such as a recording sheet or the like fed by a
recording material transporting means.
When a driving signal is supplied to the liquid
ejecting means on the carriage from unshown driving
signal supply means, the recording liquid is ejected to
2 i 7 4 1 8 2
- 71
the recording material from the liquid ejecting head in
response to the signal.
The liquid ejecting apparatus of this
embodiment comprises a motor 111 as a driving source
for driving the recording material transporting means
and the carriage, gears 112, 113 for transmitting the
power from the driving source to the carriage, and
carriage shaft 115 and so on. By the recording device
and the liquid ejecting method using this recording
device, good prints can be provided by ejecting the
liquid to the various recording material.
Fig. 16 is a block diagram for describing the
general operation of an ink ejection recording
apparatus which employs the liquid ejection method, and
the liquid ejection head, in accordance with the
present invention.
The recording apparatus receives printing data
in the form of a control signal from a host computer
300. The printing data is temporarily stored in an
input interface 301 of the printing apparatus, and at
the same time, is converted into processable data to be
inputted to a CPU 302, which doubles as means for
supplying a head driving signal. The CPU 302 processes
the aforementioned data inputted to the CPU 302, into
printable data (image data), by processing them with
the use of peripheral units such as RAMs 304 or the
like, following control programs stored in an ROM 303.
2 ~ 74 1 8~
- 72 -
Further, in order to record the image data onto
an appropriate spot on a recording sheet, the CPU 302
generates driving data for driving a driving motor
which moves the recording sheet and the recording head
in synchronism with the image data. The image data and
the motor driving data are transmitted to a head 200
and a driving motor 306 through a head driver 307 and a
motor driver 305, respectively, which are controlled
with the proper timings for forming an image.
As for recording medium, to which liquid such
as ink is adhered, and which is usable with a recording
apparatus such as the one described above, the
following can be listed; various sheets of paper; OHP
sheets; plastic material used for forming compact
disks, ornamental plates, or the like; fabric; metallic
material such as aluminum, copper, or the like; leather
material such as cow hide, pig hide, synthetic leather,
or the like; lumber material such as solid wood,
plywood, and the like; bamboo material; ceramic
material such as tile; and material such as sponge
which has a three dimensional structure.
The aforementioned recording apparatus includes
a printing apparatus for various sheets of paper or OHP
sheet, a recording apparatus for plastic material such
as plastic material used for forming a compact disk or
the like, a recording apparatus for metallic plate or
the like, a recording apparatus for leather material, a
21~t8;~
- 73 -
recording apparatus for lumber, a recording apparatus
for ceramic material, a recording apparatus for three
dimensional net-like recording medium such as sponge or
the like, a textile printing apparatus for recording
images on fabric, and the like recording apparatuses.
As for the liquid to be used with these liquid
ejection apparatuses, any liquid is usable as long as
it is compatible with the employed recording medium,
and the recording conditions.
<Recording System>
Next, an exemplary ink jet recording system
will be described, which records images on recording
medium, using, as the recording head, the liquid
ejection head in accordance with the present invention.
Fig. 17 is a schematic perspective view of an
ink jet recording system employing the aforementioned
liquid ejection head 201 in accordance with the present
invention, and depicts its general structure. The
liquid ejection head in this embodiment (p.58) is a
full-line type head, which comprises plural ejection
orifices aligned with a density of 360 dpi so as to
cover the entire recordable range of the recording
medium 150. It comprises four heads, which are
correspondent to four colors; yellow (Y), magenta (M),
cyan (C) and black (Bk). These four heads are fixedly
supported by a holder 1202, in parallel to each other
and with predetermined intervals.
2 1 7~ 1 82
- 74 -
These heads are driven in response to the
signals supplied from a head driver 307, which
constitutes means for supplying a driving signal to
each head.
Each of the four color inks (Y, M, C and Bk) is
supplied to a correspondent head from an ink container
204a, 204b, 205c or 204d. A reference numeral 204e
designates a bubble generation liquid container from
which the bubble generation liquid is delivered to each
head.
Below each head, a head cap 203a, 203b, 203c or
203d is disposed, which contains an ink absorbing
member composed of sponge or the like. They cover the
ejection orifices of the corresponding heads,
protecting the heads, and also maintaining the head
performance, during a non-recording period.
A reference numeral 206 designates a conveyer
belt, which constitutes means for conveying the various
recording medium such as those described in the
preceding embodiments. The conveyer belt 206 is routed
through a predetermined path by various rollers, and is
driven by a driver roller connected to a motor driver
305.
The ink jet recording system in this embodiment
comprises a pre-printing processing apparatus 251 and a
postprinting processing apparatus 252, which are
disposed on the upstream and downstream sides,
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respectively, of the ink jet recording apparatus, along
the recording medium conveyance path. These processing
apparatuses 251 and 252 process the recording medium in
various manners before or after recording is made,
respectively.
The pre-printing process and the postprinting
process vary depending on the type of recording medium,
or the type of ink. For example, when recording medium
composed of metallic material, plastic material,
ceramic material or the like is employed, the recording
medium is exposed to ultra-violet rays and ozone before
printing, activating its surface. In a recording
material tending to acquire electric charge, such as
plastic resin material, the dust tends to deposit on
the surface by static electricity. The dust may impede
the desired recording. In such a case, the use is made
with ionizer to remove the static charge of the
recording material, thus removing the dust from the
recording material. When a textile is a recording
material, from the standpoint of feathering prevention
and improvement of fixing or the like, a pre-processing
may be effected wherein alkali property substance,
water soluble property substance, composition
polymeric, water soluble property metal salt, urea, or
thiourea is applied to the textile. The pre-processing
is not limited to this, and it may be the one to
provide the recording material with the proper
2 i 7 4 1 8~
- 76 -
temperature.
On the other hand, the post-processing is a
process for imparting, to the recording material having
received the ink, a heat treatment, ultraviolet
radiation projection to promote the fixing of the ink,
or a cleaning for removing the process material used
for the pre-treatment and remaining because of no
reaction.
In this embodiment, the head is a full line
head, but the present invention is of course applicable
to a serial type wherein the head is moved along a
width of the recording material.
<Head Kit>
Hereinafter, a head kit will be described,
which comprises the liquid ejection head in accordance
with the present invention. Fig. 18 is a schematic
view of such a head kit. This head kit is in the form
of a head kit package 501, and contains: a head 510 in
accordance with the present invention, which comprises
an ink ejection section 511 for ejecting ink; an ink
container 510, that is, a liquid container which is
separable, or nonseparable, from the head; and ink
filling means 530, which holds the ink to be filled
into the ink container 520.
After the ink in the ink container 520 is
completely depleted, the tip 530 (in the form of a
hypodermic needle or the like) of the ink filling means
~ I -14 i ~
- 77 -
is inserted into an air vent 521 of the ink container,
the junction between the ink container and the head, or
a hole drilled through the ink container wall, and the
ink within the ink filling means is filled into the ink
container through this tip 531.
When the liquid ejection head, the ink
container, the ink filling means, and the like are
available in the form of a kit contained in the kit
package, the ink can be easily filled into the ink
depleted ink container as described above; therefore,
recording can be quickly restarted.
In this embodiment, the head kit contains the
ink filling means. However, it is not mandatory for
the head kit to contain the ink filling means; the kit
may contain an exchangeable type ink container filled
with the ink, and a head.
Even though Fig. 18 illustrates only the ink
filling means for filling the printing ink into the ink
container, the head kit may contain means for filling
the bubble generation liquid into the bubble generation
liquid container, in addition to the printing ink
refilling means.
The present invention can be applied to the
liquid ejecting heads as described above, including not
only the heads of the so-called edge shooter type
having an ejection outlet at one end of the liquid flow
path in the direction along the surface of the heat
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- 78 -
generating element 2 as shown in Fig. 1, but also the
heads of the so-called side shooter type having an
ejection outlet on the side opposite to the surface of
the heat generating element 2, for example, as shown in
Fig. 19. Namely, the liquid ejecting head of the side
shooter type can also be produced through the
production steps, for example, shown in the foregoing
examples.
The liquid ejecting head of the side shooter
type shown in Fig. 19 is similar to the liquid ejecting
head of the edge shooter type as described above in
that, for each ejection outlet, a first path portion 4
in a bottom surface of which a heat generating element
is positioned is formed on a substrate 1 provided with
the heat generating element 2 for giving thermal energy
for generating a bubble to the liquid, a second path
portion 3 in direct fluid communication with the
ejection outlet 9 is formed above it, a partition wall
5 made of a material having elasticity, such as a metal
or the like, is provided between the second path
portion 3 and the first path portion 4, and the liquid
in the second path portion 3 is separated from the
liquid in the first path portion 4 by the partition
wall 5.
The liquid ejecting head of the side shooter
type is characterized in that the ejection outlet 9 is
provided in the portion immediately above the heat
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- 79 -
generating element 2, in the orifice plate 14
positioned above the second path portion 3. The
partition wall 5 between the ejection outlet 9 and the
heat generating element 2 is provided with a pair of
movable members 6 which open like a double-leafed
hinged door. Namely, the two movable members 6 are
formed each in a cantilever beam shape with their free
ends facing each other as being sightly separated by a
slit 8 located i m~e~; ately below the central portion of
the ejection outlet 9 during a period without ejection.
During a period of ejection, the two movable members 6
open to the side of the second path portion by bubble
generation of the liquid in the region B generating the
bubble, as shown by the arrows in Fig. 19. They are
closed by contraction of the liquid. This region A is
refilled with the liquid supplied from an ejection
liquid tank described below to get into an ejection-
ready state, thereby preparing for next bubble
generation of the liquid.
The second path portion 3, together with the
second path portions of other ejection outlets 9, is in
communication with a tank (not shown) for reserving the
ejection liquid through the second common liquid
chamber 10, while the first path portion 4, together
with the first path portions of other ejection outlets
9, is in communication with a tank (not shown) for
reserving the liquid for generating the bubble through
2~7418~
- 80 -
the first common liquid chamber 11.
The liquid ejecting head of the side shooter
type having the above structure can also achieve the
excellent effect that the liquid can be ejected at high
ejection energy efficiency and high ejection pressure
as improving refilling of the liquid ejected, almost
similarly as the head of the edge shooter type does.
