Note: Descriptions are shown in the official language in which they were submitted.
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2025506
1 Ink-jet Recording Apparatus and
Temperature Control Method Therefor
BACRGROUND OF THE INV ~:N 11ON
Field of the Invention
The present invention relates to an ink-jet
recording apparatus for causing a recording head to
discharge an ink to a recording medium to perform
recording, and a temperature control method therefor.
Related Background Art
A recording apparatus such as a printer, a copying
machine, a facsimile apparatus, or the like records an
image consisting of a dot pattern on a recording medium
such as a paper sheet or a plastic thin plate.
The recording apparatus can be classified as an
ink-jet type, wire dot type, thermal type, laser-beam
type, and the like according to a recording method. Of
these apparatuses, in the ink-jet type apparatus
(ink-jet recording apparatus), an ink droplet
(recording liquid) is discharged ~_Lli~d from a
~ `discharge port of a recording head, and is attached to
a recording medium, thereby performing recording.
In recent years, a large number of recording
apparatuses have been used, and are required to have a
high recording speed, a high resolution, high image
quality, and low noise.
As a recording apparatus which satisfies these
2025506
1 requirements, the ink-jet recording apparatus is known.
In the ink-jet recording apparatus, since
recording is performed by discharging an ink from a
recording head, the apparatus is considerably
influenced by the temperature of the recording head.
For this reason, a conventional ink-jet recording
apparatus employs a so-called closed-loop control
method wherein a temperature sensor and a temperature
control heater which increase cost are arranged in a
recording head unit, so that the temperature of the
recording head is controlled to fall within a desired
range on the basis of the detected temperature of the
3 recording head. As the temperature control heater, a
heating ~c~t~ member joined to a recording head unit
or a discharge heater in a bubble-jet recording
apparatus, proposed by CANON INC., for discharging an
ink droplet by growing bubbles by film boiling of an
ink is used. When the discharge heater is used, it
must be energized so as not to generate bubbles.
In particular, in a bubble-jet recording apparatus
(which is proposed by CANON INC., and forms bubbles in
a sol;~ ~ta~c or liquid ink using a heat energy to
obtain an ink droplet to be discharged), since its
discharge characteristics are largely varied depending
on the temperature of the recording head, as is
conventionally known, closed-loop temperature control
tends to be performed. Alternatively, only an
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2025506
1 inexpensive printer which is used for a compact
electronic calculator which disregards printing
quality, density nonuniformity, and the like is
available.
However, in recent years, since portable OA
equipments such as laptop personal computers have
become popular, portable printers are required to have
high quality. A disposable cartridge type printer in
which a head and an ink tank are integrated will lead
the portable printers since it has a compact structure.
In addition, the disposable cartridge type printer will
become more popular in terms of maintenance due to an
increase in popularity of home- or personal-use
' JA ~ .: '`a ~ I~N C~
bS ~ A` ~ wordprocessors, personal computers,~facsimile
apparatuses.
In this case, since the temperature sensor and the
heater for temperature control are incorporated in the
disposable cartridge, the following drawbacks are
posed.
(1) Variation in temperature measurement values due to
variation in temperature sensor
Since a disposable head is an expendable supply, a
sensor having a variation in characteristics is
connected to the printer main body every time the head
is exchanged.
In a bubble-jet recording head, since a discharge
heater is manufactured in a semiconductor process, a
202SS06
1 diode sensor for detecting a temperature of a recording
head must be integrally formed in a single process to
decrease cost. Since the diode sensor suffers from a
variation in the manufacture, it does not have high
precision like in a temperature sensor as a selected
product, and may often cause a difference of 15C or
more among manufacturing lots as measurement values of
an ambient temperature.
For this reason, closed-loop control using the
temperature sensor of the recording head requires a
complicated adjustment operation for adjusting a
variation in temperature sensor of the recording head
in an adjustment process, or mounting a temperature
sensor which is measured and ranked in a main body, and
correcting it using an adjustment selection switch.
These operations considerably increase
manufacturing cost, and impair operability. An
increase in signal processing volume caused by these
operations, and a considerable increase in processing
volume of an MPU caused by closed-loop control itself
exert a heavy load on design of a compact or portable
printer main body apparatus.
(2) Countermeasure against electrostatic noise
Since a disposable head is an expendable supply, a
' - '' P6T~ c~
A 2~ user frequently attaches or d~L~chcd it to or from a
main body. For this reason, contacts of the main body
are always exposed.
2025506
1 Since the output from the temperature sensor is
directly supplied to a circuit on a printed circuit
board of the main body through a carriage and a
flexible wiring, a temperature measurement circuit is
S~5~p~L6 1-
~
- ~& ~very 7~Q~k Gy~illD~-electrostatic noise. Since a compact
or portable printer cannot have a sufficient shield
effect in its housing, it is further weak against
electrostatic noise.
Therefore, in a conventional temperature detection
method, an electrostatic shield, and parts as a
countermeasure against electrostatic noise must be
added at respective portions for only a single
temperature sensor, thus considerably disturbing a
compact structure, a decrease in cost, and high image
quality.
SUMM~Y OF THE INVENTION:
It is a principal object of the present invention
to provide an ink-jet recording apparatus which can
control a temperature of a recording head to fall
within a desired range without arranging a temperature
sensor in the recording head, and a temperature control
method therefor.
It is another object of the present invention to
provide an ink-jet recording apparatus which can
control a temperature of a recording head to fall
within a-desired range even when a print rate is
changed, and a temperature control method therefor.
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202550S
1 It is still another object of the present
invention to provide an ink-jet recording apparatus
which can control a temperature of a recording head to
fall within a desired range even when a difference
between a temperature in the recording apparatus and a
temperature of the recording head occurs, and a
temperature control method therefor.
It is still another object of the present
invention to provide an ink-jet recording apparatus
which can prevent a temperature of a recording head
from being increased to an abnormal high temperature,
and a temperature control method therefor.
In order to achieve the principal object,
according to a preferred aspect of the present
invention, there is provided an ink-jet recording
apparatus for causing a recording head to discharge an
ink droplet to perform recording, comprising:
heat means for heating the recording head;
temperature measurement means for measuring an
ambient temperature;
timer means for measuring a time associated with a
temperature variation of the recording head in
association with a recording operation; and
control means for controlling an energy to be
supplied to the heat means on the basis of the ambient
temperature measured by the temperature measurement
means and the time measured by the timer means.
20~5506
1 In order to achieve another object, according to
another preferred aspect of the present invention,
there is provided an ink-jet recording apparatus for
causing a recording head to discharge an ink droplet to
perform recording, comprising:
heat means for heating the recording head;
temperature measurement means for measuring an
ambient temperature;
print rate measurement means for measuring a print
rate in a predetermined time of the recording head; and
control means for controlling an energy to be
supplied to the heat means on the basis of the ambient
temperature measured by the temperature measurement
means and the print rate measured by the print rate
measurement means.
In order to achieve still another object,
according to still another preferred aspect of the
present invention, there is provided an ink-jet
recording apparatus for causing a recording head to
discharge an ink droplet to perform recording,
comprising:
temperature measurement means for measuring an
ambient temperature;
print rate measurement means for measuring a print
rate in a predetermined time of the recording head; and
temperature increase anticipating means for
anticipating a temperature increase caused by a
2025506
1 recording operation of the recording head itself on the
basis of the print rate measured by the print rate
measurement means; and
temperature increase protection means for limiting
supply of a recording energy to the recording head on
the basis of the temperature increase anticipated by
the temperature increase anticipating means.
In order to achieve still another object,
according to still another preferred aspect of the
present invention, there is provided an ink-jet
recording apparatus for causing a recording head to
discharge an ink droplet to perform recording,
comprising:
heat means for heating the recording head;
an electronic element for supplying an energy to
the recording head;
temperature measurement means for measuring a
temperature of the electronic element; and
control means for estimating a temperature of the
recording head on the basis of the temperature of the
electronic element measured by the temperature
measurement means.
BRIEF DESCRIPTION OF THE DRAWINGS:
Fig. 1 is a schematic perspective view of an
arrangement suitable for the present invention;
Fig. 2 is an exploded perspective view of a
cartridge suitable for the present invention;
-
- 9 - 2025506~ -
1 Fig. 3 is a perspective view showing an assembly
of the cartridge shown in Fig. 2;
Fig. 4 is a perspective view of a mounting portion
of an ink-jet unit IJU;
Fig. 5 is a view for explaining a mounting
operation of the cartridge IJU to an apparatus;
Fig. 6 is a perspective view showing an outer
appearance of an apparatus suitable for the present
invention;
Fig. 7 is a perspective view of a recording head;
Fig. 8 is a sectional view showing in detail
Fig. 7;
Fig. 9 is a sectional view showing another
arrangement of the recording head;
Fig. 10 is a graph showing a change in temperature
of the recording head obtained when temperature control
before printing is performed;
Figs. 11 and 17 are graphs showing a change in
temperature of the recording head obtained when only
temperature control during printing is performed;
Figs. 12 and 18 are graphs showing a change in
temperature control of the recording head obtained when
only temperature control before printing and
temperature control during printing are performed;
Fig. 13 is a graph showing a change in temperature
of the recording head obtained when no temperature
control is performed;
-
-- 10 --
2025506
1 Fig. 14 is a graph showing a change in temperature
of the recording head obtained when a print operation
is performed according to the first embodiment;
Fig. 15 is a flow chart showing temperature
control according to the first embodiment of the
present invention;
Fig. 16 is a graph showing an over heat state of
the recording head;
Figs. l9A to l9C are graphs showing a change in
temperature of the recording head obtained when
printing is performed according to the second
embodiment of the present invention;
Fig. 20 is a flow chart showing temperature
control according to the second embodiment of the
present invention;
Fig. 21 is a block diagram showing a control
arrangement suitable for the present invention;
Figs. 22, 23, and 25 are graphs showing a change
in temperature in the machine near a temperature
sensor, and a change in temperature of the recording
head;
Fig. 24 is a flow chart showing temperature
control according to the third embodiment of the
present invention;
Fig. 26 is a graph showing a change in temperature
in the machine near a temperature sensor and a change
in correction temperature;
2025506
1 Fig. 27 is a timing chart showing timings for
performing temperature control;
Fig. 28 is a timing chart showing output timings
of temperature control pulses;
Fig. 29 is a flow chart showing temperature
control according to the fourth embodiment of the
present invention;
Fig. 30 is a graph showing an equilibrated
temperature of a recording head according to a print
rate;
Fig. 31 is a graph showing an increase and a
decrease in temperature of the recording head according
to the print rate;
Figs. 32 and 33 are flow charts showing
temperature control according to the fifth embodiment
of the present invention;
Fig. 34 is a perspective view showing an ink-jet
recording apparatus suitable for carrying out
temperature control according to the sixth embodiment
f the present invention;
Fig. 35 is a partial perspective view showing a
structure of a recording head shown in Fig. 34;
Fig. 36 is a graph showing the relationship
between a temperature of the recording head shown in
Fig. 34 and a temperature of a power transistor for
driving a discharge heater;
Fig. 37 is a block diagram showing a temperature
- 12 -
2025506
1 control system of the recording head shown in Fig. 34;
Fig. 38 is a partial perspective view showing a
structure of a recording head for performing
temperature control according to the seventh embodiment
of the present invention;
Fig. 39 is a sectional view of a printed circuit
board according to the seventh embodiment of the
present invention;
Fig. 40 is a block diagram of a temperature
control system according to the seventh embodiment of
the present invention;
Figs. 41A and 41B are sectional views of a printed
circuit board used in the eighth embodiment of the
present invention;
Fig. 42 is a sectional view of a printed circuit
board used in the ninth embodiment of the present
invention; and
Fig. 43 is a block diagram of a control system
according to the ninth embodiment of the present
invention.
DETATT.~n DESCRIPTION OF THE PREFERRED EMBODIMENTS:
Figs. 2 to 6 are views for explaining an ink-jet
unit IJU, an ink-jet head IJH, an ink tank IT, an
ink-jet cartridge IJC, an ink-jet recording apparatus
main body IJRA, and a carriage HC, and the relationship
among these components. The arrangement of these
portions will be described below with reference to
202s506
1 Figs. 2 to 6.
The ink-jet cartridge IJC in this embodiment has
an increased ink storage ratio, as can be seen from the
perspective view of Fig. 3, and has a shape in which
the distal end portion of the ink-jet unit IJU slightly
projects from the front surface of the ink tank IT.
The ink-jet cartridge IJC is fixed and supported by a
positioning means and electrical contacts (to be
described later) of the carriage HC (Fig. 5) placed on
the ink-jet recording apparatus main body IJRA, and is
of a disposable type which can be detachable from the
carriage HC. Since Figs. 2 to 6 of this embodiment
show arrangements to which various inventions which
have been made in establishment of the present
invention are applied, the overall arrangement will be
described below while briefly explaining these
arrangements.
(i) Arrangement of Ink-jet Unit IJU
The ink-jet unit IJU is a bubble-jet type unit for
performing recording using an electrothermal conversion
element for generating a heat energy for causing film
boiling of an ink according to an electrical signal.
In Fig. 2, a heater board 100 is prepared by
forming a plurality of electrothermal conversion
element arrays (discharge heater), a temperature
control heater, and Al electrical wirings for supplying
an electric power to these heaters on an Si substrate
-
- 14 -
2025506
1 by a film formation technique. A wiring circuit board
200 is arranged for the heater board 100, and has
wirings corresponding to those of the heater board 100
(e.g., these wirings are connected by wire bonding),
S and pads 201, located at the end portions of these
wirings, for receiving electrical signals from the
apparatus main body.
A grooved top plate 1300, on which partition walls
for dividing a plurality of ink paths, a common ink
chamber, and the like are arranged, is formed by
integrally molding an ink reception port 1500 for
receiving an ink supplied from the ink tank and guiding
it to the common ink chamber, and an orifice plate 400
having a plurality of discharge ports. As a material
for integrally molding these components, polysulfone is
preferable, but other molding resin materials may be
used.
A metal support member 300 supports the rear
surface of the wiring circuit board 200 on a plane, and
serves as a bottom plate of the ink-jet unit. A
pressing spring 500 has an M shape, and presses the
common ink chamber at the central portion of its "M" shape
at a low pressure. In addition an apron portion 501
of the spring 500 presses a portion of an ink path at a
line pressure. The leg portions of the pressing spring
are engaged with the rear surface side of the support
member 300 via holes 3121 of the support member 300 to
- 15 - 202S506
1 sandwich the heater board 100 and the top plate 1300
therebetween, thereby engaging these components. Thus,
the heater board 100 and the top plate 1300 are pressed
and fixed by the biasing force of the pressing spring
500 and its apron portion 501. The support member 300
has positioning holes 312, 1900, and 2000 which are
respectively engaged with the two positioning
projections 1012 of the ink tank IT, and positioning
and thermal fusion bonding projections 1800 and 1801.
The support member 300 also has positioning projections
2500 and 2600 for the carriage HC of the apparatus main
body IJRA on its rear surface. In addition, the
support member 300 has a hole 320 for allowing an ink
supply pipe 2200 (to be described later) extending
- ~5 ~ therethrough to supply ~ink from the ink tank. The
' wiring circuit board 200 is mounted on the support
member 300 by adhesion using an adhesive. Note that
recess portions 2400 of the support member 300 are
formed near the positioning projections 2500 and 2600.
These recess portions are present on a plurality of
extending lines of parallel grooves 3000 and 3001
formed on the three side surfaces around the distal end
region of the head portion of the assembled ink-jet
cartridge IJC (Fig. 3). For this reason, unnecessary
matters such as dust or an unnecessary ink moved along
the parallel grooves 3000 and 3001 are prevented from
reaching the projections 2500 and 2600. A lid member
- 16 - 20~5506
1 800 on which the parallel groove 3000 is formed defines
an outer wall of the ink-jet cartridge IJC, as can be
seen from Fig. 5, and also defines a space portion for
storing the ink-jet unit IJU together with the ink tank
IT. An ink supply member 600 on which the parallel
groove 3001 is formed forms an ink guide pipe 1600
continuous with the ink supply pipe 2200 as a
cantilever which is fixed at the supply pipe 2200 side,
and a sealing pin 602 for assuring a capillarity
between the fixed portion of the ink guide pipe and the
ink supply pipe 2200 is inserted in the member 600.
Note that a packing 601 provides a coupling seal
between the ink tank IT and the supply pipe 2200, and a
filter 700 is arranged at the end portion on the side
of the tank of the supply pipe.
Since the ink supply member 600 is formed by
molding, it is inexpensive, has high positioning
precision, and can eliminate a decrease in precision in
the manufacture. In addition, since the ink guide pipe
1600 has a cantilever structure, a pressing contact
state of the guide pipe 1600 against the ink reception
port 1500 can be stabilized. Thus, the ink supply
member 600 is also suitable for mass-production. In
this embodiment, a sealing adhesive is fed from the ink
supply member side in this pressing contact state, thus
reliably attaining a complete communication state. The
ink supply member 600 can be easily fixed to the
CA2025506
support member 300 in such a manner that pins (not shown) on the rear
surface of the ink supply member project through holes 1901 and 1902 of
the support member 300, and the projecting portions on the rear surface of
the support member 300 are thermally fused. The small thermally fused
projection regions on the rear surface portion can be housed in a recess (not
shown) of the wall surface of the ink tank IT on which the ink jet unit IJU is
mounted. Therefore, a positioning surface of the unit IJU can be precisely
obtained.
(ii) Arrangement of Ink Tank IT
0 The ink tank is constituted by a cartridge main body 1000, an ink
absorber 900, and a lid member 1100 for sealing the ink absorber 900 after
the ink absorber is inserted from a side surface opposite to the unit IJU
mounting surface of the cartridge main body 1000.
The ink absorber 900 is impregnated with an ink, and is arranged in
the cartridge main body 1000. A supply port 1200 supplies ink to the unit
IJU consisting of the components 100 to 600, and also serves as an
injection port. That is, when ink is injected from the supply port 1200
before the unit is arranged on a portion 1010 of the cartridge main body
1000, ink is impregnated in the absorber 900.
In this embodiment, portions capable of supplying an ink are an air
communication port 1 401 and this
- 18 -
2025505
1 supply port 1200. In order to satisfactorily supply an
ink from the ink absorber, an intra-tank air region
defined by ribs 2300 in the main body 1000 and partial
ribs 2301 and 2302 of the lid portion 1100 is formed to
be continuous with the air communication port 1401 side
over a corner area farthest from the ink supply port
1200. Therefore, it is important to relatively
satisfactorily and uniformly supply an ink to the
absorber from the side of the supply port 1200. This
method is very effective in a practical application.
The ribs 2300 include four ribs parallel to the moving
direction of the carriage, which are formed on the
surface of the rear portion of the ink tank main body
~iQ6
1000 so as to prevent the absorber from being in æight
'contact with the surface of the rear portion. The
partial ribs 2301 and 2302 are similarly formed on the
inner surface of the lid member 1100 on the
corresponding extending lines of the ribs 2300, but are
divided unlike the ribs 2300 to increase an air space
as compared to the ribs 2300. Note that the partial
ribs 2301 and 2302 are dispersed on a surface portion
1/2 or less the entire surface of the lid member 1100.
With these ribs, an ink in a corner area farthest from
the ink supply port 1200 of the ink absorber can
reliably guided toward the supply port 1200 by a
capillarity force while being stabilized. The air
communication port 1401 is formed in the lid member to
-- 19 --
202~06
1 cause the interior of the cartridge to communicate with
outer air. A waterproof member 1400 is arranged inside
the air communication port 1401 to prevent an ink from
leaking from the air communication port 1401.
An ink storage space of the ink tank IT has a
rectangular shape, and its long side corresponds to a
side surface. Therefore, the above-mentioned
arrangement of the ribs are particularly effective.
When the storage space has a long side parallel to the
moving direction of the carriage, or has a cubic shape,
the ribs are formed on the entire lid member 1100 to
stabilize ink supply from the ink absorber 900. In
order to store an ink in a limited space as much as
possible, a cubic shape is suitable. However, in order
to efficiently use the stored ink for recording, as
described above, it is important to form ribs capable
of performing the above-mentioned operation on two
surface regions adjacent to the corner portion.
Furthermore, the ribs 2301 and 2302 on the inner
surface of the ink tank IT in this embodiment are
arranged at an almost uniform distribution with respect
to the direction of thickness of the cubic ink absorber
900. This structure is important since it can uniform
an atmospheric pressure distribution with respect to
ink consumption of the overall absorber, and can make
an ink residue almost zero.
Furthermore, the technical idea of the arrangement
- 20 - 2025506~
1 of the ribs will be described below in more detail.
When an arc having a long side as a radius is drawn to
have a position obtained by projecting the ink supply
port 1200 of the ink tank onto the square upper surface
of the cube as the center, it is important to arrange
the above-mentioned ribs on a surface portion outside
the arc so that an atmospheric pressure is given
earlier to the absorber portion located outside the
arc. In this case, the position of the air
communication port 1401 of the tank is not limited to
that of this embodiment as long as air can be
introduced to the rib arrangement region.
In this embodiment, the ink-jet cartridge IJC has
a flat rear surface portion with respect to the head to
m;nimize a necessary space when it is assembled in the
apparatus, and to m~xiri ze an ink storage amount.
Therefore, the cartridge of this embodiment has an
excellent structure since the apparatus can be rendered
compact, and an exchange frequency of cartridges can be
decreased. A projecting portion for the air
communication port 1401 is formed by utilizing a rear
portion of a space for integrating the ink-jet unit
IJU, and the interior of the projecting portion is
hollowed to form an atmospheric pressure supply space
2S 1402 for the total thickness of the absorber 900, as
described above. With this arrangement, an excellent
cartridge which cannot be realized by the conventional
2025506
1 technique can be provided.
Note that the atmospheric pressure supply space
1402 is considerably larger than a conventional one,
and the air communication port 1401 is located above
this space. Therefore, even if an ink is released from
the absorber due to any abnormality, the atmospheric
pressure supply space 1402 can temporarily store the
released ink, and can reliably recover it to the
absorber. Thus, an efficient cartridge can be
provided.
Fig. 4 shows an arrangement of the unit IJU
mounting surface of the ink tank IT. If a straight
line which passes almost the center of a projecting
port of the orifice plate 400 and is parallel to the
bottom surface of the tank IT or the mounting reference
surface for the surface of the carriage is represented
by L1, the two positioning projections 1012 to be
engaged with the holes 312 of the support member 300
are located on the straight line L1. The height of
each projection 1012 is slightly smaller than the
thickness of the support member 300, and this
projection positions the support member 300. A pawl
2100 to be engaged with a 90 engaging surface 4002 of
a positioning hook 4001 of the carriage is located on
the extending line of the straight line L1 on this
drawing, so that a positioning force for the carriage
acts on a surface region parallel to the reference
- 22 - 202550-6
1 surface including the straight line Ll. As will be
described later with reference to Fig. 5, these
relationships are effective since the positioning
precision of only the ink tank is equivalent to that of
a discharge port of the head.
Projections 1800 and 1801 of the ink tank
corresponding to the fixing holes 1900 and 2000 of the
support member 300 to the side surface of the ink tank
are longer than the above-mentioned projections 1012,
and extend through the support member 300. The
projecting portions of these projections are thermally
fused to fix the support member 300 on the side surface
of the ink tank. When a straight line perpendicular to
the above-mentioned line Ll and passing the projection
1800 is represented by L3 and a straight line passing
through the projection 1801 is represented by L2, since
almost the center of the supply port 1200 is located on
the straight line L3, the above-mentioned projections
stabilize a coupling state between the supply port 1200
and the supply pipe 2200, and can reduce a load caused
by dropping or a shock to the coupling state, resulting
in a preferable arrangement.
The straight lines L2 and L3 do not coincide with
each other, and the projections 1800 and 1801 are
present around the projections 1012 on the discharge
port side of the head IJH, thus reinforcing a
positioning effect of the head IJH with respect to the
- 23 -
2025~06
1 tank. Note that a curve indicated by L4 represents an
outer wall position when the ink supply member 600 is
mounted. Since the projections 1800 and 1801 are
present along the curve L4, they can provide a
sufficient mechanical strength and position precision
against to the weight of the arrangement on the distal
end side of the head IJH. Note that a distal end
collar 2700 of the ink tank IT is inserted in a hole of
a front plate 4000 of the carriage HC to cope with an
abnormal state wherein the ink tank is extraordinarily
displaced. A removal stopper 2101 for the carriage HC
is arranged near a bar (not shown) of the carriage HC,
and serves as a projection member which is inserted
below this bar at a position where the cartridge IJC is
turned and mounted, as will be described later, and
maintains a mounting state even when an upward force
for releasing the carriage from the aligned position
accidentally acts.
The ink tank IT is covered with the lid member 800
after the unit IJU is mounted thereon, thus defining a
shape for surrounding the unit IJU excluding a lower
opening. As for the ink-jet cartridge IJC, since a
lower opening to be mounted on the carriage HC is
adjacent to the carriage HC, a substantially four-way
surrounded space is formed. Therefore, heat generated
by the head IJH located in the surrounded space is
effective for keeping a temperature in this space but
- - 24 - 202550C
1 corresponds to a small temperature increase when the
apparatus is continuously used for a long period of
time. For this reason, in order to assist natural heat
dissipation of the support member, a slit 1700 having a
smaller width than this snace is formed, so that a
uniform temperature distribution of the entire unit IJU
does not depend on an environment while preventing a
temperature increase.
When the ink-jet cartridge IJC is assembled, an
ink is supplied from the interior of the cartridge into
the supply member 600 via the supply port 1200, the
hole 320 formed on the support member 300, and an inlet
port formed on the central rear surface of the supply
member 600. After the ink passes through the interior
of the supply member 600, it flows into the common ink
chamber via an appropriate supply pipe and the ink
reception port 1500 of the top plate 1300. Packings
of, e.g., silicone rubber or butyl rubber are arranged
in connected portions for ink communication in the
above arrangement, thus providing a seal to assure an
ink supply path.
In this embodiment, the top plate is formed of a
resin such as polysulfone, polyethersulfone,
polyphenylene oxide, polypropylene, or the like, and is
simultaneously molded by molds together with the
orifice plate portion 400.
As described above, since the integrally molded
- 25 - 202550~ .
1 parts are the ink supply member 600, an integrated
member of the top plate 1300 and the orifice plate 400,
and the ink tank main body 1000, high assembly
precision can be attained, and quality in
mass-production can be improved. Since the number of
parts can be decreased, excellent predetermined
characteristics can be reliably exhibited.
In this embodiment, in an assembled shape, as
shown in Figs. 2 to 4, a slit S is formed between an
upper surface portion 603 of the ink supply member 600
and an end portion 4008 of a roof portion having the
slit 1700 of the ink tank IT, as shown in Fig. 3, and a
slit similar to the slit S is formed between a lower
surface portion 604 and a head end portion 4011 of a
thin plate member to which the lower lid member 800 of
the ink tank IT is adhered. These slits between the
ink tank IT and the ink supply member 600 essentially
perform an operation for promoting heat radiation of
the slit 1700, and can prevent an unnecessary pressure
applied to the tank IT from directly applying to the
supply member, and the ink-jet unit IJU.
In any case, the above arrangements of this
embodiment are unique ones, can independently provide
advantages, and can also provide a systematic
arrangement as a whole.
(iii) Mounting of Ink-jet Cartridge IJC to Carriage HC
In Fig. 5, a platen roller 5000 guides a recording
-
- 26 - 20255~6
1 medium P from a lower side of the drawing toward an
upper side. The carriage HC is moved along the platen
roller 5000, and is provided with the front plate 4000
(thickness = 2 mm) located on the front surface side of
the ink-jet cartridge IJC on the side of the front
platen of the carriage, an electrical connecting
portion support plate 4003 for holding a flexible sheet
4005 comprising pads 2011 corresponding to the pads 201
of the wiring circuit board 200 of the cartridge IJC
and a rubber pad sheet 4007 for generating an elastic
force for pressing the sheet 4005 against the pads 2011
from the rear surface side, and the positioning hook
4001 for fixing the ink-jet cartridge IJC to the
recording position. The front plate 4000 has two
positioning projection surfaces 4010 corresponding to
the above-mentioned positioning projections 2500 and
2600 of the support member 300 of the cartridge. After
the cartridge is mounted, the front plate receives a
force perpendicular to the projection surfaces 4010.
For this reason, a plurality of reinforcement ribs (not
shown) along the direction of the force are arranged on
the front plate 4000 on the side of the platen roller.
These ribs also form head protection projections
slightly projecting (about 0.1 mm) from a front surface
position L5 of the cartridge IJC when the cartridge IJC
is mounted.
The electrical connecting portion support plate
- 27 -
2025S06
1 4003 has a plurality of reinforcement ribs 4004 not in
a direction of the above-mentioned ribs but in a
direction perpendicular thereto. A sideward projecting
amount is decreased from the platen side toward the
hook 4001. This also serves to provide a function of
inclining the cartridge mounting position, as shown in
Fig. 5-
The support plate 4003 has two hook-side
projection surfaces 4006 for applying a force to the
cartridge in a direction opposite to a direction of a
force applied from the two positioning projection
surfaces 4010 to the cartridge to form a pad contact
region between these two positioning surfaces, and to
uniquely define deformation amounts of projections of
the rubber pad sheet 4007, which projections correspond
to the pads 2011. These positioning surfaces are in
contact with the surface of the wiring circuit board
200 when the cartridge IJC is fixed at a recording
position. In this embodiment, since the pads 201 of
the wiring circuit board 200 are distributed to be
symmetrical about the above-mentioned line L1, the
deformation amounts of the projections of the rubber
pad sheet 4007 can be uniformed to much stabilize
contact pressures of the pads 2011. In this
embodiment, the pads 201 are distributed in a 2 x 2
matrix.
The hook 4001 has an elongated hole to be engaged
- 28 - 202550~
1 with a stationary shaft 4009. The hook 4001 is pivoted
counterclockwise from the illustrated position by
utilizing a moving space of this elongated hole, and
thereafter, is moved to the left along the platen
roller 5000, thereby positioning the ink-jet cartridge
IJC with respect to the carriage HC. The hook 4001 may
- r-- ~5 y ,~ 6-U(0~ ~ S
A be moved i.. h..y other p~ttorn~, but l.~Gy ~C preferably
moved by, e.g., a lever. When the hook 4001 is
pivoted, the cartridge IJC is moved toward the platen
roller, and the positioning projections 2500 and 2600
are moved to positions where they can be brought into
contact with the positioning surfaces 4010 of the front
plate. When the hook 4001 is moved to the left, the
90 engaging surface 4002 is brought into tight contact
with the 90 surface of the pawl 2100 of the cartridge
IJC, and the cartridge IJC is turned about the contact
regions between the positioning surfaces 2500 and 4010
in the horizontal plane as the center. Finally, the
pads 201 and 2011 begin to be brought into contact with
each other. When the hook 4001 is held at a
predetermined position, i.e., a fixing position, a
complete contact state between the pads 201 and 2011, a
complete surface contact state between the positioning
surfaces 2500 and 4010, a two-surface contact state
between the 90 engaging surface 4002 and the 90
surface of the pawl, and a surface contact state
between the wiring circuit board 200 and the
- 29 - 20255S
1 positioning surfaces 4007 and 4008 are simultaneously
formed, thus completing holding of the cartridge IJC
with respect to the carriage HC.
(iv) Apparatus Main Body
Fig. 6 is a schematic perspective view of the
ink-jet recording apparatus main body IJRA on which the
above-mentioned cartridge is mounted. The carriage HC
which is engaged with a spiral groove 5004 of a lead
screw 5005 rotated through driving force transmission
gears 5011 and 5009 in cooperation with a
forward/reverse rotation of a driving motor 5013 has
pins (not shown), and is reciprocally moved in
directions of arrows a and b. A sheet pressing plate
5002 presses a sheet against the platen roller S000
along the carriage moving direction. Photocouplers
5007 and 5008 serve as home position detection means
for detecting the presence of a lever 5006 of the
carriage HC in a corresponding region to switch, e.g.,
a rotational direction of the motor 5013. A member
5016 supports a cap member 5022 for capping the front
surface of the recording head. A suction means SOlS
draws the interior of this cap member by vacuum
suction, i.e., performs a suction/recovery operation of
the recording head through an opening 5023 in the cap
member. A cleaning blade 5017 and a member 5019 for
allowing the blade 5017 to be movable in the
back-and-forth direction are supported on a main body
- 30 - 2 025506
1 support plate 5018. The blade is not limited to that
of this embodiment, but a known cleaning blade may be
applied to this embodiment, as a matter of course. A
lever 5021 is used to start the suction/recovery
operation, and is moved upon movement of a cam 5020
which is engaged with the carriage HC. The lever 5021
is subjected to movement control by a known
transmission means such as a clutch for switching a
driving force from the driving motor.
These capping, cleaning, and suction/recovery
operations can be performed at their corresponding
positions upon operation of the lead screw 5005 when
the carriage HC reaches the home position region.
However, any other means may be applied to this
embodiment as long as desired operations are performed
at known timings. The respective arrangements
described above are excellent inventions not only
solely but also systematically, and are preferable ones
to apply the present invention.
The present invention which can be applied to the
arrangements shown in Figs. 2 to 6 will be described
below with reference to Fig. 1, Fig. 7, and subsequent
drawings.
Figs. 1, 7, and 15, and Tables 1 and 2 show the
first embodiment of the present invention. In Fig. 1,
a recording head 2 (IJH) is coupled to an ink tank 1
(IT). As shown in Fig. 7, the ink tank 1 and the
- 31 -
2025506
1 recording head 2 form an integrated disposable
cartridge. A carriage 3 (HC) is used to mount the
cartridge on the printer main body. A guide 4 scans
the carriage in a sub-scanning direction. A flexible
cable 6 supplies a driving signal pulse current and a
head temperature control current to the recording head
2. A printed circuit board 7 comprises an electrical
circuit for controlling the printer. A sensor 8
measures an ambient temperature in the printer. Fig. 7
shows the disposable cartridge. In Fig. 7, a nozzle
portion ~discharges ink droplets.
Fig. 8 shows the recording head 2 in detail. The
heater board 100 formed by a semiconductor
manufacturing process is arranged on the upper surface
of the support member 300. The heater board 100
comprises a temperature control heater (temperature
increase heater) 10 for keeping and controlling the
temperature of the recording head 2. The wiring
circuit board 200 is arranged on the support member
300. The wiring circuit board 200, the temperature
control heater 10, and a discharge heater 13 are
electrically connected by, e.g., wire-bonding (wirings
are not shown). The temperature control heater 10 may
be formed by adhering a heater member, which is formed
in a process different from that for the heater board
100, to, e.g., the support member 300, as shown in
Fig. 9.
-
- 32 - 20255-06
1 A bubble 14 is formed upon heating of the
discharge heater 13. The bubble 14 is then discharged
as an ink droplet 15. A common ink chamber 12 supplies
ink to be discharged ~n~ the recording head.
Open-loop temperature control according to the
first embodiment will be briefly described below.
In this embodiment, in order to control the
temperature of the recording head to a target
temperature determined by concerning discharge
characteristics, e.g., a print density, temperature
control before printing and temperature control during
printing are performed. In the temperature control
before printing, a heating amount of the temperature
control heater is determined on the basis of a lapse of
time from the previous printing operation (wait time
and non-print time) and the present ambient
temperature, and heating is performed immediately
before printing. In the temperature control during
printing, the heating amount is determined on the basis
of the lapse of time from the previous printing
operation and the present ambient temperature, and
heating is performed during printing. "During
printing'~ means not only an instance when printing is
actually performed (a heating period of a print
heater), but also a series of operation periods for
performing printing, e.g., an acceleration or
deceleration period of the carriage, and a reverse
~ 33 ~ 2025506
1 period in a bidirectional print mode.
Table 1 Temperature Control Data Table Before Printing
Ambient Temperature 25C 25 21 17 13C
or to to to or
Wait Time higher 21C 17C 13C higher
0 or 120 sec or more 0% 40Z 60% 80~ 100%
60 to 120 sec 0~ 10~ 40% 60% 80%
30 to 60 sec 0~ 0% 20Z 40% 60%
15 to 30 sec 0~ 0% 0~ 20% 40
15 sec or less 0~ 0~ 0~ 02 20%
Table 2 Temperature Control Data Table During Printing
Ambient Temperature 25C 25 21 17 13C
or to to to or
Print Time higher 21C 17C 13C higher
0 to 60 sec OZ 60% 80% 90% 100%
60 to 360 sec 0% 30Z 40Z 45% S0%
360 sec or more 0% 20~ 30% 35% 40%
Tables 1 and 2 show control parameter data tables
used when the temperature control operations before and
during printing are performed, and these tables are
stored in a ROM. In each table, "100%~ represents
supply of a maximum energy, and "0%" represents supply
of no energy. In this embodiment, an energy supply
amount is controlled according to an energization time
(heating pulse width) to the temperature control
heater. In the temperature control before printing, a
maximum energization time is set to be about 6 sec, and
2 5 in the temperature control during printing, it is set
to be about 120 msec. Note that the energy supply
amount may be controlled by an energization voltage in
_ 34 _ 202~S0~
1 place of the energization time, or may be controlled by
both the energization time and voltage.
In either of the temperature control operations
before and during printing, as an ambient temperature
is lower, the energy supply amount is increased to
increase a temperature increase amount, so that the
head temperature is closer to the target temperature.
In the temperature control before printing, since it
can be considered that the recording head radiates more
heat as a wait time is longer, the energy supply amount
is set to be large to cause the head temperature to
approach the target temperature. On the other hand, in
the temperature control during printing, since it can
be considered that the temperature of the head is
increased due to heat accumulation as a print time is
longer, the energy supply amount is set to be small.
When the temperature control is performed as
described above, the temperature of the recording head
can be controlled to the target temperature without
using conventional closed-loop control. This
temperature control will be described in detail below.
Fig. 10 shows a change in actual temperature (TH)
of the recording head with respect to an ambient
temperature (TA) and a target temperature (To) when
only the temperature control before printing is
performed. Fig. 11 similarly shows a change in
temperature of the recording head when only the
CA2025506
, .
- 35 -
temperature control during printing is performed, and Fig. 12 shows a
change in temperature of the recording head when both the temperature
control operations before and during printing are performed.
Fig. 13 shows a change in temperature of the recording head caused
solely by printing (self temperature increase) without the temperature
control .
Fig. 14 shows a change in temperature of the recording head when
printing is performed with the temperature control operations before and
during printing.
The temperature (TH) of the recording head is switched at positions of
60 sec and 360 sec since the data in the temperature control data table
during printing shown in Table 2 (temperature control parameter) is changed.
A thermal equilibrated temperature (TE) shown in Figs. 1 1 and 12
means a temperature which can be naturally reached by only a temperature
control energy on the basis of a heat capacity of the head, and is determined
by data shown in Tables 1 and 2. The thermal equilibrated temperature is
set to be slightly lower than the target temperature, so that the sum of the
thermal equilibrated temperature and a temperature increase (self
temperature increase) caused by self heating of the recording head shown in
Fig.1 3
-
- 36 - 202S~06
1 corresponds to the target temperature.
The temperature control according to the first
embodiment of the present invention will be described
below with reference to the flow chart shown in
Fig. 15. Note that a change in temperature of the
recording head caused by this temperature control
corresponds to Fig. 14.
When the power switch is turned on, a wait time
counter and a print time counter are reset to zero to
initialize the control parameters in step S101. In
step S102, the control waits until a print signal is
input.
When the print signal is input, an ambient
temperature is read from the temperature sensor 8 on
the printed circuit board 7 of the main body in step
S103. In step S104, a wait time of the wait time
counter is read. However, the wait time counter is
reset to ~'0" as described above immediately after
power-on. In step S105, the temperature control data
table before printing (Table l) is referred to on the
basis of the ambient temperature and the wait time of
the wait time counter. Immediately after power-on,
since there is no temperature increase due to printing,
the temperature of the recording head is equal to the
room temperature. For this reason, a table output
becomes one of 0% to 100% according to the ambient
temperature, and is larger than those obtained in
2025506
1 correspondence with other wait times. In step S106,
the temperature control heater 10 shown in Fig. 8 is
heated on the basis of this output data to increase the
temperature of the nozzle portion 9 and the common ink
chamber 12. In this embodiment, as the ambient
temperature is lower, the table output is increased to
increase a temperature increase amount.
Upon completion of energization, the start of
printing may be waited for about 1 sec to disperse an
abrupt temperature distribution formed in the recording
head. At that time, the wait time counter is reset
(step S107).
In step S108, the print time counter is started to
print the first line (step S109).
Thereafter, in step S110, the print time of the
print time counter is read. In step S111, the
temperature control data table during printing (Table
2) is referred to on the basis of the read print time
and the ambient temperature. The count value of the
print time counter is not so incremented immediately
after the start of printing, either. For this reason,
the table output becomes one of 0% to 100% according to
the ambient temperature, and is larger than those
obtained in correspondence with other count values.
Temperature control conditions of the data are
corrected according to the content of the print signal.
When a line feed (LF) signal is input, correction is
- 38 - 2025506
1 performed (steps S112 and S113). Since the line feed
operation has no temperature increase due to printing
itself, if the LF signals are successively input, the
temperature of the recording head is immediately
decreased if no temperature control is performed.
Since a time required for the line feed operation is
very short, an energy supply amount per unit time
becomes too large unless the output data is corrected.
For this reason, according to this embodiment, a
program for correcting a parameter to supply an energy
1/10 original output data to the recording head per
one-line feed operation is employed.
The temperature control conditions are then
corrected on the basis of a length of one main scanning
line (steps S114 and S115). In this embodiment, the
temperature control heater 10 is energized during
carriage acceleration periods on two sides outside a
print range. For this reason, when a carriage moving
amount is small, an energy supply amount per unit time
becomes too large. When the carriage mounting amount
does not correspond to a full width, a problem for
multiplying a correction coefficient proportional to an
actual moving amount corresponding to the full width
with the parameter is employed.
The temperature control heater 10 is energized on
the basis of these corrected data to perform
temperature control during printing (step S116), and
2025506
1 another line is then printed (step S117). When the
print operation further continues (step S118), the
value of the print time counter is repetitively read.
As described above, as the print time is increased, the
output data from the table is decreased. Thus, the
energy supply amount is decreased.
When the print operation is completed, the print
time counter is reset (step Sll9), and the wait time
counter is started (step S120) to measure a time until
the next print signal is input.
When the next print signal is input, the contents
of the wait time counter and the ambient temperature
are read (steps S102 to S104), and an energy level
output from the temperature control data table before
printing is determined again on the basis of the read
wait time and the ambient temperature. Thereafter, the
same control operations as described above are
repeated. In this embodiment, the wait time counter
counts up to 120 sec, and when it exceeds 120 sec, the
counter is reset to 0 under the assumption that the
temperature is returned to the ambient temperature.
In this embodiment, the disposable cartridge type
recording head is used. The present invention is not
limited to the disposable cartridge type, but may be
effective when it is applied to a permanent type head
which does not require exchange of heads.
In this embodiment, both the print time counter
-
- 40 -
2025506
1 and the wait (non-print) time counter are used to
perform both the temperature control operations during
and before printing. However, as for a printer having
a small print amount such as a printer for an
electronic calculator, or a printer for outputting only
characters, in which a temperature increase caused by
the print operation itself is smaller than that caused
by a graphic printer, only the wait (non-print) time
counter may be employed depending on an output quality
level of the recording apparatus to perform only the
temperature control before printing. As for a printer
exclusively used for cut sheets or a recording
apparatus having a long non-print time, only the print
time counter may be employed to perform only the
temperature control during printing.
In order to determine an output energy level in
temperature control, a hysteresis of output data
obtained before printing may be used in addition to
output data obtained by referring to the data table on
the basis of the count values (wait time and print
time) upon printing. When a correction coefficient of
output data is to be calculated on the basis of a
carriage moving amount, not only a moving amount of the
present line but also moving amounts of the next and
subsequent lines may be taken into consideration.
As a means for heating the recording head, a known
means may be used. In place of measuring the print
- 41 - 2025506
1 time, the number of print lines or the number of print
characters may be counted.
As described above, according to the first
embodiment, if conventional closed-loop temperature
control by the temperature sensor incorporated in the
recording head is not performed, a means for measuring
an ambient temperature is arranged in a recording
apparatus main body such as a printer, and a control
software program utilizing heating/cooling thermal
characteristics uniquely determined by a heat capacity
of the recording head itself is employed, so that the
temperature of the recording head can be controlled to
a desired temperature.
In particular, when the disposable cartridge type
recording head is used, a signal current from the
temperature sensor of the recording head need not be
detected. Thus, a variation in print performance among
heads, as a major drawback of temperature control posed
when the disposable type is employed, can be
eliminated. Thus, a variation in print performance
among heads can be eliminated, and uniform print
quality can be obtained. Furthermore, since the
temperature sensor can be omitted from the cartridge of
the recording head as an expendable supply, a
temperature sensor selection process, or a temperature
sensor adjustment process so far can be omitted to
greatly reduce cost. In addition, since the
- 42 - 2025506
1 temperature sensor itself can be omitted, a
manufacturing yield can be greatly increased to further
reduce cost.
In view of an electrical circuit, a small signal
current from the head need not be detected, and a
countermeasure against exposure of contacts upon
attachment/detachment of the disposable cartridge from
the recording apparatus main body, and an electrostatic
countermeasure for patterns of a flexible wiring and a
printed circuit board between the recording apparatus
main body and the recording head can be simplified.
The above features are particularly effective for
a compact or portable recording apparatus which cannot
take a sufficient countermeasure such as a shield on
the casing or an electrical circuit. In addition, this
also leads to a considerable cost-down effect.
The second embodiment of the present invention
will be described below with reference to Figs. 17 to
21 and Tables 3 and 4.
In the second embodiment, sufficient temperature
control attained by developing open-loop control of the
first embodiment can be performed even in a recording
method such as a bubble-jet method in which heat
generation or radiation occurs upon printing.
In the first embodiment, an energy level to be
applied to the recording head for att~in;ng a
temperature increase is determined with reference to
_ 43 - 20 25506-
1 control data tables on the basis of an ambient
temperature and a print time and a non-print time of
the recording head before the present print operation
is started, so that temperature control can be realized
by open-loop control by using only an adjusted
temperature sensor of a main body.
In a printer for mainly printing characters, since
a print rate of a character itself is low, an average
print rate is about several % to 30%. Therefore, a
temperature can be sufficiently anticipated by
open-loop temperature control on the basis of data
anticipated by the main body according to operation
control parameters such as a print time and a non-print
time which can be easily measured by the printer like
in the first embodiment, and a temperature control
energy supply amount can be adjusted.
However, in a printer for mainly printing graphic
data at high speed, since an average print rate is
largely changed between several % to 100%, an over heat
state tends to occur, as shown in Fig. 16, by only
operation control parameters such as a print time and a
non-print time when a temperature control energy and a
heat generation energy caused by a discharge operation
at a high print rate overlap each other. For this
reason, irregular discharge problems such as a
non-discharge state, splash, a fixing error caused by
an excessive discharge amount, density nonuniformity,
- 44 - Z025506
1 and the like are posed, and a graphic printer which is
required to have high print quality becomes
unsatisfactory.
o~/6l~H6A I 6~
A~ In order to prevent an ovcLk~ state caused by a
high print rate, a thermal equilibrated temperature may
be set to be lower than that of a character printer
under an assumption of a high average print rate. At
this time, when a print pattern having a low print rate
is to be printed, since a self temperature increase is
small in the above-mentioned open-loop temperature
control during printing, the actual temperature of the
recording head is shifted to a lower temperature, and
low density or density nonuniformity occurs. Thus,
only an unsatisfactory print result is obtained by a
high-speed graphic printer.
During a print operation of a graphic pattern
having a high print rate, when a temperature at the end
of the first page becomes very high, and in particular,
when the print operation of the page is completed
immediately before the temperature reaches an over heat
temperature, a cooling operation requires more time
than that at an assumed average print rate. For this
reason, in the open-loop temperature control before
printing, a temperature increase energy excessively
larger than that required for the next print operation
may be undesirably supplied.
Open-loop temperature control according to the
- - 45 - 20255 06
1 second embodiment will be briefly described below.
In this embodiment, temperature control operations
before and during printing are performed like in the
first embodiment. At this time, according to a
characteristic feature of this embodiment, a
temperature of the recording head is anticipated upon
completion of the previous print operation, and a
temperature control power before printing is corrected
on the basis of the anticipated temperature.
10 Furthermore, according to another characteristic
feature of this embodiment, a print rate is obtained
every second, and a temperature control power during
printing is corrected on the basis of an average print
rate. When the above-mentioned power correction
15 operations are performed, open-loop temperature control
can be appropriately performed in a graphic printer
which must print a pattern having a high print rate.
Tables 3 to 5 respectively show temperature
control data tables before and during printing, and a
20 print rate correction control parameter data table.
Tables 3 and 4 correspond to Tables 1 and 2 of the
first embodiment, respectively.
-- 2025506
- 46 -
1 Table 3 Temperature Control Data Table Before Printing
Ambient Temperature 25C 25 21 17 13C
or to to to or
Wait Time Timer higher 21C 17C 13C higher
O or 120 sec or moreOZ 40Z 60Z 80Z lOOZ
60 to 120 sec OZ lOZ40Z 60Z 80Z
30 to 60 sec OZ OZ 20% 40% 60Z
15 to 30 sec OZ OZ OZ 20Z 40Z
15 sec or less OZ OZ OZ OZ OZ
Table 4 Temperature Control Data Table During Printing
Ambient Temperature 25C 25 21 17 13C
or to to to or
Higher 21C 17C 13C higher
Initial Operation
Amount PLINE~ of 60Z 80Z 90Z lOOZ
Temperature ontrol
During Printing
Table S Duty Correction Data Table
Duty OZ or 6.25Z 12.5Z 25Z 50
more or or or or
more more more more
Correction lOOZ 87.5Z 75Z 50Z OZ
Coefficient
Fig. 17 shows a change in actual temperature of
the recording head with respect to an ambient
temperature and a target temperature when only
temperature control during printing (without
correction) is performed. Note that a change in
temperature of the recording head obtained when only
the temperature control before printing (without
correction) is performed is the same as that shown in
Fig. 10, and is omitted. Fig. 18 similarly shows a
2025S06
1 change in temperature of the recording head when both
the temperature control operations before and during
printing (without correction) are performed.
Fig. l9A shows a change in print rate, Fig. l9B
shows a change in temperature of the recording head in
correspondence with a change in print rate shown in
Fig. l9A when the temperature control operations before
and during printing according to the second embodiment
of the present invention are performed, and Fig. l9C
shows a change in operation amount of a temperature
control energy.
A thermal equilibrated temperature shown in
Figs. 17 and 18 is set to be higher than those shown in
Figs. 11 and 12. The first embodiment takes self
heating of the recording head into consideration when
the thermal equilibrated temperature is set. In this
embodiment, however, since a self heating portion is
corrected in the temperature control during printing,
the self heating portion need not be taken into
consideration when the thermal equilibrated temperature
is set.
For this reason, an energy supply amount of the
temperature control during printing according to this
embodiment is slightly larger than that in the first
embodiment.
Temperature control according to the second
embodiment of the present invention will be described
-
- 48 -
202s506
1 below with reference to the flow chart shown in
Fig. 20. Note that a change in temperature of the
recording head by this temperature control corresponds
to Fig. 19.
When the power switch is turned on, a wait time
counter, a print time counter, a print pulse counter, a
correction coefficient memory, and the like are reset
to ~'0" (step S201) to initialize control parameters.
The control then waits until a print signal is input
(step S202).
When the print signal is input, an ambient
temperature T obtained by the temperature sensor 8 on
the printed circuit board 7 of the main body is read
(step S203). An anticipated temperature TFINI upon
completion of the previous print operation (to be
described in detail later) is then read (step S2~04). A
S-r6 p ~ 5~
- A ~it time tw is then read from the wait time counte~.
At this time, the counter is reset to "0" as described
above. The temperature control data tables before and
during printing (Tables 3 and 4) are referred to on the
basis of the wait time tw and the ambient temperature
( S ~G ~ S~
(Etop ~205). At this time, since there is no
temperature increase caused by the print operation and
an ambient temperature is the same as the room
temperature, output data as a determination value of
the temperature control power Ppreo table before
printing becomes one of 0 to 100% according to the
- 49 -
2025S06
1 ambient temperature, and has a larger value than those
obtained in correspondence with other wait times (step
S206).
On the basis of this output data, a temperature
control operation amount Ppre before printing = Ppreo x
f(TFINI) is calculated (step S207). The function f has
a negative correlation with the anticipated temperature
TFINI upon completion of the previous print operation.
~ ,~he temperature control heater 10 shown in Fig. ~ is
heated on the basis of the calculated operation amount
Ppre, and the temperatures of the nozzle portion 9 and
the common ink chamber 12 of the recording head 2 are
increased (step S208). In this embodiment, an
energization time is prolonged as a temperature becomes
lower. After completion of energization, a print start
timing is waited for about 1 sec to disperse an abrupt
temperature distribution formed in the recording head.
At that time, the wait time counter is reset (step
S209), and the print time counter is started (step
S210).
Temperature control conditions of the initial
operation amount PLINEo during printing obtained in
step S206 are then corrected according to the content
of the print signal. The temperature control
conditions are corrected according to the length of one
sub-sc~nning line. Like in steps S114 and S115
(Fig. 15) in the first embodiment, a power correction
CA 2l~25506
- 50 -
coefficient L for multiplying a correction coefficient proportional to a ratio of
an actual moving amount to the full width of the carriage is calculated (step
S21 1 ) .
Discharge pulses for one second (number of print dots) of the next
print content to be printed are counted to calculate an average print rate
(print duty) (step S2 1 2) .
Power correction coefficients P, and P2 are calculated on the basis of
the average print rate for every second (step S213). In this case, the power
correction coefficient P, is a low-response correction coefficient, and is
0 based on an average of average print rates for every second during the
previous 100 seconds. The power correction coefficient P2 is a high-
response correction coefficient, and is based on an average of average print
rates for every second during the previous 10 seconds. These correction
coefficients P, and P2 can be obtained by referring to the data table (Table 5)
on the basis of the average print rate.
A temperature control operation amount PLINE during printing is
calculated on the basis of the obtained data.
In this embodiment, PLINE = PLINEO X P, X P2 x L (step S2 14)
As described above, PLINEO represents the
- 51 -
202S506
1 temperature control initial operation amount during
printing, and the correction coefficient L is one based
on the carriage moving amount. The correction
coefficient is normalized to a range between 0 to 1 (0%
to 100%). As can be apparent from the above equation,
when the low- or high-response average print rate is
high, and its correction coefficient P1 or P2 is small,
the temperature control operation amount PLINE during
printing becomes small. Therefore, an over heat state
by the temperature control during printing can be
prevented.
For this reason, a program for correcting a
parameter to supply an energy 1/10 the original
unt PLINE during printing to the recording
head 2 per one-line feed operation is employed (step
S216).
The temperature control heater 10 is energized on
the basis of these corrected data (step S217) to print
one line (step S218). The wait time counter is then
started (step S219), and the anticipated temperature
TFINI upon completion of printing is stored (step
S220). The anticipated temperature TFINI upon
completion of printing is calculated by the following
equation based on a parameter of the power correction
coefficient Pl (low response):
TFINI = Target Temperature x k(0.3 + Pl)
(where k is an appropriate coefficient)
- 52 -
2025506
1 When (0.3 + P1) < 1, TFINI = target temperature is
set. As a result, when the low-response power
correction coefficient exceeds 0.7, this means that a
print operation at a high print rate continues for a
long period of time, and there is a high possibility
that the head temperature exceeds the target
temperature. For this reason, an error of the
temperature control power Ppreo before printing
calculated based on the wait time at the beginning of
the next print operation can be prevented.
When the print operation continues, the control
operations shown in Fig. 20 are repeated. In this
case, since the value of the wait time counter is not
so incremented, an output of 0% is obtained at any
ambient temperature, and temperature control before
printing can be prevented from being performed for each
line. When the print operation is completed (step
S221), the print time counter is reset (step S222), and
the control operations shown in Fig. 20 are repeated
when the next print signal is input.
In this embodiment, the wait time counter also
counts up to 120 sec, and when it exceeds 120 sec, the
counter is reset to 0 under the assumption that the
temperature is returned to the ambient temperature.
Fig. 21 is a block diagram showing a control
arrangement for executing temperature control according
to the second embodiment. This arrangement can be
202~506
1 applied to the first embodiment.
F' ~ In Fig. 21, a host ~such as a computer generates
; A l~ command signal, a print signal, and the like. A
....
counter 21 serves as a counting means consisting of the
wait time counter, the print time counter, the print
pulse counter, and the like. A sensor 8 serves as a
temperature measurement means for measuring an ambient
temperature. A head driving means 25 drives the
recording head 2, and heats the head to increase its
temperature. A control unit 22 as a temperature
control means controls the print operation of a normal
ink-jet recording apparatus according to a program
stored in the ROM (read-only memory) 24. The control
unit 22 adjusts a temperature control energy for
attaining a temperature increase applied to the
recording head 2 by the head driving means 25 on the
basis of the measurement results of the sensor 23 and
the counter 21.
In this embodiment, both the temperature control
operations during and before printing are performed
using both the print time counter and the wait
(non-print) time counter. However, as for a printer
exclusively used for cut sheets or a recording
apparatus having a long non-print time, only the print
time counter may be employed to execute only the
temperature control during printing.
In place of measuring the print time, the number
-
- 54 -
20255~6
1 of print lines or the number of print characters may be
counted. An average print rate per second may be
calculated as one for each line. The average rate may
be calculated by other averaging methods, e.g.,
weighting.
A low-response print rate may be calculated as an
average of average print rates for every 10 seconds
during previous 100 seconds. In this embodiment, a
common correction data table (Table 5) is used for low-
and high-response data, but different tables may be
prepared.
The temperature control operation amount Ppre
before printing may be corrected using the correction
coefficients Pl and P2 in place of using the function
f(TFINE)-
According to the second embodiment as described
above, since a temperature control power is controlled
according to a print rate, high-precision temperature
control can be attained in a graphic printer having a
large change in print rate in addition to the effects
of the first embodiment.
Since a temperature control power is controlled on
the basis of low- and high-response print rates, the
control can cope with both slow and abrupt changes in
print rate.
In the second embodiment, the temperature control
power is controlled on the basis of the low- and
- 55 -
2025506
1 high-response print rates, but may be controlled one of
these parameters. Furthermore, a middle-response print
rate may be calculated to control the temperature
` control power on the basis of the low-, middle-, and
high-response print rates.
The third embodiment of the present invention will
be described below with reference to Figs. 22 to 26 and
Table 6.
In the third embodiment, high-precision
temperature control can be performed even when a
position of a recording head is physically separated
from a position of a temperature sensor for measuring
an ambient temperature.
In the first embodiment of the present invention
described previously, the temperature sensor for
measuring an ambient temperature is arranged not on a
recording head unit but on an apparatus main body on
which the recording head unit is mounted, and an
anticipated control method is adopted wherein a
temperature of the recording head is anticipated on the
basis of a thermal time constant determined based on a
heat capacity of the recording head, a print time, and
a non-print time to control a temperature control
amount.
According to this method, since the recording head
does not have a temperature sensor, cost of the
recording head as an expendable supply can be greatly
- 56 - 2025506
1 reduced, and this can provide a considerably large
merit in, especially, a disposable cartridge in which
the recording head and an ink tank are integrated.
` In the first embodiment, however, since the
position of the recording head is physically separated
from the position of the temperature sensor for
measuring an ambient temperature, a temperature
detected by the temperature sensor cannot often
indicate a correct temperature at the position of the
recording head. When a power supply circuit is
incorporated in the apparatus, a temperature in the
machine is increased due to heat generated by the power
supply circuit. In this case, an increase in
temperature in the machine varies depending on
positions in the machine. Since the temperature sensor
and the recording head have quite different orders of
thermal time constant, even if the ambient temperature
sensor and the recording head have the same temperature
in the machine, a small error occurs between the
temperature at the position of the recording head and
the ambient temperature of the ambient temperature
sensor before a lapse of a given time after power-on
although these temperatures are finally equal to each
other after the lapse of the given time. For this
reason, in the first embodiment, a temperature control
parameter for anticipated control is often determined
on the basis of the temperature data including an
2025506
1 error. Even if the identical apparatus and the
identical recording head are used, a print density of
prints may often be varied.
Open-loop temperature control according to the
third embodiment will be described below. In this
control, a temperature control parameter determined by
parameters such as an ambient temperature, a print
time, a non-print time, and the like is corrected
according to an energization time of the apparatus main
body or components in the machine which generate heat,
so that a local difference in temperature increase in
the machine, or an error in an anticipated temperature
of the recording head caused by a time difference due
to a difference in thermal time constant are corrected,
thus att~ining precise temperature control.
Fig. 22 shows a temperature increase in the
machine near the temperature sensor for measuring an
ambient temperature, and an actual temperature of the
recording head at that time. Fig. 22 exemplifies data
when a heat generation portion is separated from the
recording head unit, and the recording head unit does
not suffer from a temperature increase in the machine.
Fig. 23 shows an ambient temperature near the
temperature sensor for measuring the ambient
temperature, and an actual temperature of the recording
heat at that time. Fig. 23 exemplifies data when the
recording head unit suffers from a temperature increase
- 58 -
2025506
1 in the machine.
Note that basic data of a change in actual
temperature of the recording head with respect to the
` ambient temperature and the target temperature obtained
when only the temperature control before printing is
performed in a state wherein there is no temperature
increase in the machine near the recording head is the
same as that shown in Fig. 10, basic data similarly
obtained when only the temperature control during
printing is performed is the same as that shown in
Fig. 11, and basic data obtained when the temperature
control operations before and during printing are
performed is the same as that shown in Fig. 12. In
addition, a change in temperature of the recording head
obtained when only printing is performed without
temperature control is the same as that shown in
Fig. 13.
Table 6 shows a correction table of a temperature
increase in the machine in correspondence with Fig. 22.
Note that above Tables 3 and 2 are used as temperature
control data tables before and during printing.
- 59 -
2025506
1 Table 6 Correction Data Table for Temperature
Increase in Machine
Correction Timer for O to 2 to 5 to 15 to 30
Temperature Increase 2 5 15 30 min or
in Machine min min min min more
Correction Value 0C -2C -4C -6C -7C
Temperature control according to the third
embodiment of the present invention will be described
below with reference to the flow chart shown in
Fig. 24. Note that a change in temperature of the
recording head caused by this temperature control is
the same as that shown in Fig. 14.
When the power switch is turned on, a wait time
counter, and a print time counter are reset to "0", and
a correction timer for a temperature increase in the
machine is started (step S301). In step S302, the
control waits until a print signal is input.
When the print signal is input, the print time
counter is started (step S303), and an ambient
temperature is read from the temperature sensor 8 on
the printed circuit 7 of the main body in step S304.
In step S305, the value of the correction timer is
read, and in step S306, the value of the ambient
temperature read in step S304 is corrected on the basis
of the value of the correction timer. The correction
value is determined by the correction table for a
temperature increase in the machine shown in Table 6.
The correction table as Table 6 corresponds to
- 60 -
202S506~
1 Fig. 22. In the case of Fig. 23, data obtained by
subtracting the temperature of the recording head unit
from the temperature of the ambient temperature sensor
` unit may be input to the correction table.
In step S307, a wait time of the wait time counter
is read. The wait time counter is reset to "0", as
described above, immediately after power-on. In step
S308, the temperature control data table (Table 3) is
referred to on the basis of the corrected ambient
temperature and the wait time of the wait time counter.
In step S309, the temperature control heater 10 shown
in Fig. 8 is heated on the basis of this output data to
increase the temperatures of the nozzle portion 9 and
the common ink chamber 12 of the recording head. Upon
completion of energization, the wait time counter is
reset (step S310).
In step S311, a print time of the print time
counter is read. The count value of the print time
counter is not so incremented just after the start of
the print operation. In step S312, reference output
data is determined with reference to the temperature
control data table during printing (Table 2).
Temperature conditions of this data are corrected
according to the content of the print signal (steps
S313 to S316). These steps are the same as steps S112
to S115 in Fig. 15, and a detailed description thereof
will be omitted.
- 61 - 2025506
1 The temperature control heater 10 is energized
using these corrected data to perform temperature
control during printing (step S317), and one line is
` then printed (step S318).
The wait time counter is started (step S319).
When the print operation further continues, the print
time counter is repetitively read in step S311 via step
S320, and as the print time is increased, an energy
supply amount is deceased on the basis of the data on
the temperature control data table during printing
(Table 2). When the print operation continues, since
the value of the wait time counter is not almost
incremented, an output of 0% is obtained at any ambient
temperature, as shown in Table 3, temperature control
before printing can be prevented from being performed
for each line.
Once the print operation is completed, the print
time counter is reset (step S321), and the wait time
counter measures a time until the next print signal is
input.
When the next print signal is input, the values of
the wait time counter, the ambient temperature, and the
correction table for a temperature increase in the
machine are read (step S304 to S307), an output energy
level is similarly determined again on the basis of the
temperature control data table before printing (step
S308), thus repeating the same control operations.
-
- 62 - 202550~
1 In the third embodiment, a program having a table
for correcting a temperature of the sensor unit by a
difference in temperature between the ambient
` temperature sensor unit and the recording head unit is
adopted. A temperature keeping current for correcting
a temperature difference may be supplied to the
recording head unit under the control of the correction
table to attain the same temperature increase as that
of the ambient temperature sensor unit. With this
arrangement, the same effect as described above can be
obtained.
Alternatively, when a temperature keeping current
is not corrected based on the correction table, a small
temperature keeping current may be supplied to the
recording head unit during an ON period of a power
supply, so that the recording head unit can have
substantially the same temperature increase as that of
the ambient temperature sensor unit. In this case, a
current which is determined in correspondence with a
thermal time constant of temperature increase
characteristics of the recording head depending on a
time from power-on regardless of a software program is
supplied to the recording head. This control is
equivalent to temperature correction in correspondence
with a power-ON time. It is difficult more or less to
correct the temperature of the recording head to be
quite the same as the temperature increase of the
- 63 -
2025506
1 ambient temperature sensor since the temperature
increase of the ambient temperature sensor is attained
by complex factors such as convection of air, heat
` transmitted from the circuit board, heat generated by
the recording head itself, and the like. However, this
control is satisfactory to correct a temperature
increase in the machine.
In the above embodiment, heat generation according
to a power-ON time is taken into consideration.
Furthermore, heat generation according to an
energization time of a discharge control driver such as
a transistor or IC for printing may be taken into
consideration. In this case, a read value of a
temperature detected by the sensor unit is corrected on
the basis of a sum of correction data for a temperature
increase in the machine according to an energization
time of the power supply unit and correction data for a
temperature increase in the machine according to an
energization time of, e.g., a transistor for printing.
According to this arrangement, correction can be more
reliably performed.
Of printers which are operated by an AC power
supply, when an AC plug is connected, a main power
supply unit is energized to initialize a control unit,
and the like, and an actual print operation is
performed after a power switch (software power switch)
is turned on to energize the respective units of the
- 64 -
202550~
1 main body. In a printer of this type, if an
energization time of the main power supply unit is
referred to as a hardware power-on time and an
energization time in which the respective units are
energized by actually turning on the software power
switch is referred to as a software power-on time, if
these times cause different heat generation amounts,
the hardware and software power-on times are
independently measured, and a sum of correction values
from the corresponding correction tables may be
subtracted according to their lapses of time.
Fig. 26 is a view for explaining a temperature
increase in the printer, and its correction operation.
Tables 7 and 8 show temperature correction tables
according to hardware and software power-on times. As
can be seen from Fig. 26, correction temperatures shown
in Tables 7 and 8 are set in correspondence with a
temperature increase in the machine ( T of the sensor
temperature), and temperature increase correction can
be precisely performed. The software and hardware
power on times are measured up to a m~;mum of 60
minutes, and when they exceed 60 minutes, values at 60
minutes are held.
- 65 -
2025~06
1 Table 7
Hardware Power-ON O 10 20 40 50
-Time min or min or min or min or min or
more more more more more
~ Correction Temperature 0C -0.5C -1C -1.5C -2.0C
S Table 8
Software Power-ON O 2 5 10 30
Time min or min or min or min or min or
more more more more more
Correction Temperature 0C -1.0C -1.5C -2.0C -2.5C
Note that correction according to energization
times of the transistors and motors may be performed in
addition to the above-mentioned temperature increase
correction.
- When software is turned off or a print operation
is completed, a temperature may be subtracted on the
basis of the software power-ON time or a print time.
For example, when the software is turned off in
Fig. 26, a timer for software power-ON (a timer for
software power-OFF may be added) is incremented from 0
to measure a software power-OFF time until the software
is turned on again. A value obtained by subtracting a
correction temperature obtained with reference to Table
8 on the basis of the software power-OFF time from the
correction temperature when the software is turned off
is set as a final correction temperature. For example,
in Fig. 26, since a correction temperature when the
software is turned off is -2.5C, if the software is
turned on 10 minutes later, the correction temperature
- - 66 - 2025S0$
1 of -2.0C is subtracted from the correction temperature
of -2.5C, and a difference of -0.5C is determined as
a final correction temperature.
~ As described above, according to the third
embodiment, if conventional closed-loop temperature
control by a temperature sensor incorporated in the
recording head is not performed, a means for measuring
an ambient temperature is arranged in a recording
apparatus main body such as a printer, and a means for
measuring an energization time of a heat generation
element of the apparatus main body is arranged to
correct a value measured by the means for measuring the
ambient temperature, so that a temperature of the
recording head can be more precisely controlled to a
desired temperature by open-loop control than in a
conventional system.
Thermal problems in apparatus design such as the
relative positional relationship among the temperature
sensor, the printed circuit board, and the recording
head, ventilations, and the like can be solved, thus
greatly improving a degree of freedom in apparatus
design.
Furthermore, an ambient temperature is corrected
according to energization times of the apparatus main
body and components in the machine which generate heat,
so that a local difference in temperature increase in
the machine, or an error in an anticipated temperature
-
- 67 - 202550S
1 of the recording head caused by a time difference due
to a difference in thermal time constant are corrected,
thus attaining precise temperature control.
According to the present invention, a detection
limit of a temperature sensor to be used is finely set,
e.g., in units of 1 degree or 0.5 degree or less, and a
temperature is corrected according to an energization
time, thus attAi n; ng a more stable recording state.
The fourth embodiment of the present invention
will be described with reference to Figs. 27 to 29 and
Table 9.
In this embodiment, another correction operation
different from correction (steps S114, S115, S211,
S315, and S316) using a carriage moving amount and
performed in the first to third embodiments in a
temperature increase during printing will be described
below. In either embodiment, an energization timing of
a temperature control heater 10 falls within the
acceleration (line-up) intervals at both sides of a
printable range shown in Fig. 27. When the temperature
control time (heater energization time) exceeds the
above acceleration intervals in temperature control
before printing, the heater 10 is energized prior to
the acceleration time. For this reason, an output
interval of temperature control pulses for driving the
temperature control heater 10 in temperature control
during printing corresponds to a carriage moving
-
- 68 -
202550~
1 amount.
A correction coefficient is obtained on the basis
of a pulse interval of the temperature control pulses,
` and carriage movement correction (pulse interval
correction) in temperature control during printing is
performed. Table 9 shows a data table used for pulse
interval correction. These data are obtained as
correction coefficients as the percentage with respect
to a reference interval (100%) when a period (1.2
seconds in this embodiment) required for moving the
carriage throughout the width is defined as the
reference interval.
Table 9
Pulse 0% or 25% or 50% or 75% or
Intervalmore more more more
Correction
Coefficient25% 50% 95% 100%
Pulse interval correction will be described with
reference to Fig. 28 showing output timings of the
temperature control pulses and Fig. 29 showing a flow
chart of pulse interval correction.
When a temperature control pulse is output in step
S401, an interval between the previous temperature
control pulse and the current temperature control pulse
is measured. In step S403, a temperature control pulse
interval correction table is referred to on the basis
of the measured pulse interval, thereby obtaining a
- 69 ~ 2025506
1 correction coefficient. A temperature control
operation amount during printing is corrected on the
basis of the obtained correction coefficient.
On the other hand, when it is determined in step
S401 that the temperature control pulse is not output,
it is determined in step S404 whether 1.2 seconds have
passed after the previous output. If NO in step S404,
the flow returns to step S401. In a normal printing
operation, since the temperature control pulse has a
m~imum of 1.2-second interval, the flow returns to
step S401.
However, when the next print signal is waited, 1.2
seconds have often passed. In this case, the flow
advances to step S405. It is determined in step S405
whether a capping state is set. If YES in step S405,
no operation is performed, and the flow is ended.
However, if YES in step S405, capping (Fig. 28) is
performed in this embodiment when six seconds have
passed upon completion of printing although capping is
performed by a known means. In this case, the six
seconds have passed to prevent a decrease in throughput
occurring when capping is performed upon completion of
printing because capping and uncapping require much
time.
If NO in step S405, a temperature control pulse H
is automatically output in step S406 to maintain the
head temperature to the same temperature as in a
-
2025S06
1 carriage stop state. Since capping is performed when
six seconds have passed upon completion of printing, a
maximum of five temperature control pulses H are
output. The flow then advances to steps S402.
In this embodiment, the same correction as in
carriage moving amount correction is performed by
measuring the temperature control pulse interval.
A ~ ince the temperature control pulses H are ~e~ output
to maintain the head temperature constant until capping
is performed even upon completion of printing,
temperature control having higher precision than that
in a printing restart mode can be performed.
The fifth embodiment of the present invention will
be described with reference to Figs. 30 to 33 and
Tables 10 to 12.
This embodiment exemplifies an operation for
protecting the recording head from an over heat state
although the recording head itself generates heat.
In the second embodiment described above, the
over heat which tends to occur at a high print rate is
prevented by correcting a temperature control power in
accordance with a print rate. For example, when a
print rate is 50% or more, as shown in Table 5, the
correction coefficient is set to be 0%, and temperature
control is not performed.
However, when a high print rate exceeding 50% is
continued for a long period of time, an over heat state
- 71 -
2025506
1 occurs by heat generated by the recording head itself.
As is apparent from Tables 1 to 4, in order to prevent
over heat, temperature control is not performed.
However, in this case, an over heat state occurs due to
heat generated by the recording head itself.
In this embodiment, the self temperature increase
in the recording head is anticipated on the basis of a
print rate. When an over heat state is determined by
the anticipated temperature increase and an ambient
temperature, printing in both directions is changed to
printing in one direction, thereby preventing over
heat.
Table 10 Sum Data Table
Low-response 0% or 12.5% or 25% or 40% or 60% or 80% or
Duty more more more more more more
1 5 Sum 0 1 20 100 240 500
Max Value - 180 2500 3400 11300 13000
Table 11 Difference Data Table
Protect 0 or 150 or 1300 or 5300 or 11000 or
Valuemore more more more more
Difference1 20 100 240 500
Table 12 Limit Data Table
Ambient 35C or 30C or 25C~ or 20C or 15C or 15C or
T: , ~L~,a more less less less less less
Limit Value 100 100 400 2600 8000 16000
Tables 10 and 11 are data tables of self
temperature increase control anticipation parameters,
- 72 - 2025506
1 and Table 12 is a data table of self temperature
increase determination control parameters.
A protect value is calculated to anticipate a self
temperature increase in the recording head during
printing. The protect value is obtained by adding a
sum (Table 10) weighted with a low-response print rate
every one-line printing. However, when the protect
value exceeds the MAX value corresponding to the
low-response print rate, the addition is not performed.
As shown in Fig. 30, since a practical recording head
has an equilibrated temperature corresponding to a
print duty, a protect value has an upper limit
corresponding to the print rate. Fig. 30 shows a
relationship between the temperature increase in the
recording head and the corresponding protect value when
printing is performed at a predetermined print rate.
When the low-response print rate is smaller than
the previous print rate, a difference (Table 11)
weighted by the protect value is subtracted every
printing of one line. If the difference is smaller
than zero, no subtraction is performed because the
discharge amount of the recording head is determined
not by the print rate but by the increased temperature
(protect value), as shown in Fig. 31. Fig. 31 shows a
temperature increase/decrease in the printing head when
printing is started at the predetermined print rate and
the print rate is decreased during printing. The
- 2025506
1 differences in Table 11 correspond to operations
performed when the print rate is decreased to 0~. When
the duty ratio is decreased to any value except for
` zero, the corresponding sum is added in correspondence
with the given print rate. Therefore, the differences
in Table lI correspond to those in Fig. 31.
When the calculated protect value exceeds the
corresponding limit value (Table 12), over heat
protection is performed. This protection operation is
performed by changing printing in both directions to
printing in one direction. When printing in one
direction is set, the print rate is reduced to 1/2 that
in printing in both directions, thereby preventing over
heat.
The low-response print rate is used to calculate
the protect value because the low-response print rate
corresponds to a temperature increase for a long period
of time, i.e., heat storage, and a high-response print
rate corresponds to a local, instantaneous temperature
increase.
An over heat protection operation of this
embodiment will be described with reference to flow
charts in Figs. 32 and 33.
A wait time counter, a print time counter, and a
temperature increase correction timer are set (step
S501) upon power-on operation. The correction timer is
then started (step S502). In step S503, a wait time is
- 74 -
202550~
1 read. When the count of the wait time counter
represents 30 seconds or more, the print time counter
is reset in step S504 due to a reason to be described
`- later.
Operations in steps S505 to S515 are the same as
those (temperature increase correction in the machine
and temperature control before printing) in steps S302
to S312 in Fig. 24, and a detailed description thereof
will be omitted.
It is determined in step S516 on the basis of a
protect value whether a protect mode is required. If
YES in step S516, printing in both directions is
inhibited in step S517. If a carriage moving amount is
1/2 or less of the overall width in step S518, the mode
is set in step S519 so that temperature control is not
performed in printing in one direction. The operations
in steps S518 and S519 are another series of correction
operations corresponding to correction operations
performed by the carriage moving amount in the first to
fourth embodiments.
After the temperature control heater 10 is
energized to perform temperature control during
printing in step S520, printing of one line is
performed in step S521. The wait time counter is
started (step S523). When printing is completed (step
S523), the flow returns to step S503.
In the third embodiment shown in Fig. 24, when
-
- 75 -
2025506
1 printing is completed, the print time counter is always
reset (steps S320 and S321). However, in this
embodiment, the wait time timer is reset (steps S523,
S503, and S504) when the wait time exceeds 30 seconds.
When the wait time falls within 30 seconds, printing is
assumed to be continued. Therefore, the temperature
control power in temperature control during printing is
set to be low.
The details of steps S516 and S517 will be
described below with reference to Fig. 33.
It is determined in step S601 whether a wait time
is equal to or more than 120 seconds. If YES in step
S601, the protect value is reset to "0" in step S602.
When printing is not performed for a period of 120
seconds or more, the temperature of the recording head
is assumed to be decreased near the ambient
temperature, thereby releasing the protect mode.
In step S603, the number of printing dots for 15
seconds is counted. In step S604, an average
low-response print duty for past 120 seconds (8 times)
is calculated of the number of printing dots counted in
step S603. In step S605, the sum data table (Table 10)
is referred to on the basis of the low-response print
duty to obtain a sum. ThiS sum is compared with the
value and if the protect value does not exceed the
MAX value, the sum is added to the protect value (steps
S606 and S607).
- - 76 -
2025S06
1 In step S608, when the low-response print duty is
smaller than the previous low-response print duty
obtained in step S604, discharge is taken into
consideration. That is, in step S609, the difference
data table (Table 11) is referred to on the basis of
the protect value to obtain a difference. In step
S610, the difference is subtracted from the protect
value. In this case, when the protect value is smaller
than zero, it is set to be zero (steps S611 and S612).
A limit value is obtained with reference to the
limit data table on the basis of the ambient
temperature (step S613). If the protect value does not
exceed this limit value, printing in both directions is
set (steps S614 and S615). Therefore, this state is
canceled in printing in one direction (to be described
later).
If the protect value exceeds the limit value,
over heat is determined. In step S616, printing in one
direction is set. In this state, the print duty is set
to 1/2 that in printing in both directions, over heat
can be prevented. Furthermore, when the ambient
temperature exceeds 30C, the wait time is set so that
a period of 1.2 seconds is inserted before printing
(steps S617 and S618). The print duty is decreased to
1/3 that in printing in both directions. Even if the
ambient temperature is high, the temperature of the
recording head can be quickly decreased.
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2025506
1 According to the fifth embodiment, as described
above, the increase in temperature of the recording
head is anticipated on the basis of the print rate, and
over heat of the recording head is detected. When over
heat of the recording head is determined, printing is
changed from printing in both directions to printing in
one direction to reduce a print speed. An energy
applied to the recording head in unit time can be
reduced to prevent over heat.
In addition, the equilibrated temperature
corresponding to the print rate and a discharge amount
caused by a decrease in print rate is taken into
consideration, thereby anticipating a temperature
increase in the recording head. Therefore,
high-precision protection against a temperature
increase can be achieved.
When the temperature increase state is canceled by
temperature increase protection, the mode is restored
to printing in both directions to increase a recording
Speed.
In this embodiment, over heat of the recording
head is protected by changing the mode from printing in
both directions to printing in one direction. However,
any method may be employed if an energy applied to the
recording head in unit time can be reduced. For
example, a predetermined wait time may be provided
prior to printing of the next line, and the pulse width
-
- 78 -
202550~
1 of the discharge heater may be shortened.
In the first to fifth embodiments described above,
print time data, wait time data, the energization time
data, and the like are preferably stored or timer
operations are preferably continued during the
power-off state due to the following reason. When data
is lost upon a power-off operation, the previous
temperature of the recording head is unknown when the
power switch is turned on again. As a result, proper
temperature control cannot be performed.
The sixth embodiment of the present invention will
be described with reference to the accompanying
drawings.
Fig. 34 is a perspective view illustrating an
ink-jet recording apparatus which can suitably employ a
temperature control method of the present invention.
The ink-jet recording apparatus is of a serial
scan type in which a head cartridge integrally
including a recording head and an ink tank is mounted
on a carriage moved along a recording medium P such as
a paper sheet or a plastic thin sheet.
This ink-jet recording apparatus includes an ink
tank 1 and a recording head 2.
The recording head 2 is an ink-jet recording head
which discharges an ink by utilizing heat energy. The
recording head 2 comprises an electrothermal conversion
element array.
-
- 79 -
2025~0~
1 The ink-jet recording head 2 discharges an ink
from a discharge port upon growth of bubbles by film
boiling generated by heat energy applied by the
electrothermal conversion element, thereby recording
information.
The ink tank 1 and the recording head 2 are
integrally arranged to constitute a disposable
(exchangeable) head cartridge as a whole.
The head cartridge is mounted on a carriage 3, and
the carriage 3 is reciprocated in directions indicated
by a double-headed arrow A along guide rails 4 so as to
move along the recording medium P. The recording
medium P is brought into tight contact with a platen
roller 5 constituting a recording surface and is fed in
a direction indicated by an arrow f upon driving of the
platen roller 5. A flexible cable 6 comprises signal
lines for supplying ink discharge signal pulse currents
and recording head temperature adjustment currents to
the recording head 2 through the carriage 3. A printed
circuit board 7 comprises an electrical circuit for
controlling the recording apparatus.
In the illustrated arrangement, a temperature
sensor 8, a head drive constant voltage source power
transistor 18a, an A/D converter 16, a microprocessing
unit (MPU) 17, and the like are mounted on the printed
circuit board 7. The power transistor 18a is one of
the components constituting the electrical circuit on
- 80 - 202550S
1 the printed circuit board 7. The power transistor 18a
controls an ink discharge signal current to the
recording head 2. The temperature sensor 8 comprises a
temperature sensor consisting of a thermistor for
measuring a temperature. The temperature sensor 8 is
mounted in contact with the power transistor 18a. The
A/D converter 16 converts an analog signal from the
temperature sensor 9 to a digital signal. The
microprocessing unit (MPU) 17 controls the respective
components in the recording apparatus and performs a
processing sequence such as temperature control.
Fig. 35 is a partial perspective view showing a
detailed structure of the recording head 2. Referring
to Fig. 35, an ink path 20 which communicates with each
discharge port 25 and a common ink chamber 12 for
supplying an ink to each ink path 20 are formed in a
base plate 24. A discharge heater 13 serving as a
discharge energy generating element for applying
discharge heat energy to an ink in each ink path 20 is
arranged in each ink path 20.
When recording is to be performed, an ink is
filled from the ink tank 1 in the common ink chamber 12
and each ink path 20 through ink supply pipes (not
shown).
An electrical signal (e.g., an image signal) is
applied from the printed circuit board 7 to each
discharge heater 13 through the flexible cable 6. Each
- 81 -
2025506
1 discharge heater 13 is heated to instantaneously
generate bubbles in part of the ink. Flying ink
droplets are discharged from each discharge port 25
located at the downstream of the corresponding
discharge heater 13. Each ink droplet is attached to
the recording medium P to perform recording.
Fig. 36 is a graph showing results obtained by
simultaneously measuring temperatures of the base plate
24 of the recording head 2 and the temperatures of the
power transistor 18a when a predetermined pattern is
continuously recorded on eight recording media by the
ink-jet recording apparatus described above.
As shown in Fig. 36, the temperature of the power
transistor 18a is increased with an increase in
temperature of the recording head 2. The temperature
of the power transistor 18a as this electronic driving
element is read by the temperature sensor 9, and the
temperature of the recording head 2 can be measured.
Fig. 37 is a block diagram of a control system for
suitably practicing the temperature control method of
the sixth embodiment.
As described above, a certain correlation is
present between the temperatures of the recording head
2 and the temperatures of the power transistor 18a.
However, different temperature curves are obtained due
to differences between the heat capacities of the
recording head 2 and the power transistor 18a.
-
- 82 - 2025506
1 For this reason, a power transistor is selected so
that the heat capacity of the power transistor 18a
becomes equal to that of the recording head 2, or a
heat sink is coupled to the power transistor.
Alternatively, an arithmetic operation is performed to
correct a temperature of the power transistor 18a by
the MPU 17 so as to uniquely determine the temperature
of the recording head 2 from the temperature of the
power transistor 18a. When the current temperature is
lower then a predetermined temperature, a short pulse
which does not cause formation of bubbles and discharge
of an ink is applied to the discharge heater 13 in a
non-recording mode to heat the recording head 2. When
the current temperature exceeds the predeter~ined
temperature, supply of the short pulse to the discharge
heater in the non-recording mode is stopped to adjust
over heat of the recording head 2.
Fig. 38 is a partial perspective view showing a
recording head 2 used for performing temperature
control according to the seventh embodiment of the
present invention. Referring to Fig. 38, a temperature
control heater 10 is arranged to heat the recording
head 2 near the ink path 20 of the recording head 2 in
addition to a discharge heater 13 of each ink path 20.
Fig. 39 is a sectional view showing part of a
printed circuit board 7 of this embodiment. Referring
to Fig. 39, a constant voltage source power transistor
- 83 -
2325S06
1 18b for driving the temperature control heater 10 is
arranged on the printed circuit board 7 in addition to
a recording head driving power transistor 18a.
Temperature sensors 8 are arranged in contact with the
power transistors 18a and 18b, respectively.
Fig. 40 is a block diagram of a control system
suitably employing a temperature control method of this
embodiment.
Referring to Fig. 40, power transistors are
selected so that each of the heat capacities of the
discharge heater drive power transistor 18a and the
temperature control driving power transistor 18b is set
to be 1/2 the heat capacity of the recording head 2.
Alternatively, a heat sink is coupled to each power
transistor to set so that a temperature increase in
each power transistor 18a or 18b is doubled from the
temperature increase in the recording head 2.
The temperatures of the power transistors 18a and
18b are measured by temperature sensors 8, and
temperature signals from the sensors 8 are converted
into digital signals by A/D converters 16. The digital
signals are multiplied with each other in the MPU 17,
and the product is additionally multiplied with a
correction coefficient, thereby uniquely determining
the temperature of the recording head from the
temperatures of the power transistors 18a and 18b.
An ambient temperature (room temperature) sensor
- 84 -
2025506
1 may be arranged and combined with the two temperature
sensors 8 attached to the power transistors 18a and
i8b, thereby correcting the measuring temperatures.
When the measured temperatures of the two power
transistors 18a and 18b are lower than a predetermined
temperature, the temperature control heater 10 is
turned on, and a short pulse which does not cause
formation of bubbles of the ink is applied to it,
thereby heating the recording head 2.
When the measured temperatures of the two power
transistors 18a and 18b exceed the predetermined
temperature, at least one of the temperature control
heater 10 is turned off, and supply of a short pulse to
the discharge heater 13 is stopped is performed to
prevent over heat of the recording head 2.
Figs. 4lA and 4lB are partial sectional views of
printed circuit boards 7 for performing temperature
control according to the eighth embodiment of the
present invention.
Referring to Fig. 41A, a discharge heater driving
power transistor 18a and a temperature control heater
driving power transistor 18b are in contact with one
temperature sensor 9.
Referring to Fig. 41B, a discharge heater driving
power transistor 18a and a temperature control heater
driving power transistor 18b are in contact with a heat
sink 28. In addition, a temperature sensor 8 is
-
- 85 - 2025506
1 thermally coupled to the heat sink 28.
The temperature control method of this embodiment
can be practiced using the same arrangement as the
control system shown in Fig. 40.
In the arrangement of Fig. 41A, a total heat
capacity of the two power transistors 18a and 18b is
set to be equal to that of the recording head 2, or an
analog signal from the temperature sensor 8 is
converted into a digital signal by an A/D converter,
and the digital signal is subjected to correction
processing in an MPU 17. Therefore, the temperature of
the recording head 2 can be uniquely determined from
the temperatures measured by the temperature sensor 8.
When the measured temperature is the predetermined
temperature or less, at least one of the temperature
control heater 10 and the discharge heater 13 is used
to heat the recording head 2. When the measured
temperature exceeds the predetermined temperature,
heating of the recording head by at least one of the
temperature control heater 10 and the discharge heater
13 is stopped, thereby performing temperature control
of the recording head 2.
In the arrangement of Fig. 4lB, a total heat
capacity of the two power transistors 18a and 18b and
the heat sink 28 is selected to be equal to that of the
recording head 2. Alternatively, the analog signals
from the temperature sensor 8 are converted into
- 86 -
2025506
1 digital signals by the A/D converters 16, and the
digital signals are subjected to correction processing
in the MPU 17. Therefore, the temperature of the
recording head 2 is uniquely determined in accordance
with the temperatures measured by the temperature
sensor 8. In the same manner as described above, when
the measured temperatures are the predetermined
temperature or less, the recording head 2 is heated by
at least one of the temperature control heater 10 and
the discharge heater 13. However, when the measured
temperatures exceed the predetermined temperature,
heating of the recording head 2 by at least one of the
temperature control heater 10 and the discharge heater
13 is stopped, thereby controlling the temperature of
the recording head 2.
Fig. 42 is a partial sectional view of a printed
circuit board for performing temperature control
according to the ninth embodiment of the present
invention. Fig. 43 is a block diagram of a control
system suitably performing the temperature control of
this embodiment.
Referring to Fig. 42, a temperature sensor 8 is
located near a discharge heater driving power
transistor 18a. In this case, in order to cause the
temperature sensor 8 to effectively sense radiation
heat or convection heat from the discharge heater
driving power transistor 18a, the temperature sensor 8
-
- 87 -
202550~
1 is preferably located at a level higher than a heating
source of the discharge heater driving power transistor
18a since heat is accumulated in the upper portion.
Referring to Fig. 43, in the control system of
this embodiment, radiation heat and reflection heat
from the power transistor 18a for the discharge heater
13 are measured by the temperature sensor 8, and an
analog signal from the temperature sensor 8 is
converted into a digital signal by the A/D converter
16. Thereafter, the digital signal is subjected to
correction processing, thereby anticipating the
temperature of the recording head 2.
The temperature of the recording head 2 can be
stably controlled to a predetermined temperature by the
above control system.
According to the sixth to ninth embodiments as
described above, closed-loop temperature control by the
temperature sensor incorporated in a conventional
recording head need not be performed. By using the
temperature sensor 8 arranged in the recording
apparatus, the temperature of the heat-generating power
transistor (driving element) for applying a heat energy
to the recording head 2 is measured. The temperature
of the recording head is indirectly measured, and the
temperature of the recording head 2 can be controlled
to a desired temperature.
An expensive recording head temperature sensor can
- 88 -
202S506
1 be eliminated, variations in temperature measurement
values of the recording head can be eliminated, the
manufacturing cost can be greatly reduced, and the
product yield can be greatly increased.
Each embodiment described above exemplifies a
disposable cartridge type recording head. However, the
temperature control method of the present invention is
not limited to this. The present invention is equally
applicable to use of a recording head of a type which
does not substantially require replacement, thereby
obtAining the same effect as described above.
In each embodiment, the power transistor is used
as a driving element for applying a heat energy to the
recording head 2. However, the drive element is not
limited to the power transistor.
Each embodiment described above exemplifies a
serial scan type ink-jet recording apparatus using a
serial scan type ink-jet recording head (head
cartridge) mounted on the carriage 3. However, the
present invention is also applicable to a line type
ink-jet recording apparatus using a line type ink-jet
recording head which covers a recording area in the
widthwise direction of the recording medium, and
ink-jet recording apparatuses employing other recording
schemes to obtain the same effect as described above.
The present invention is used in a variety of
applications regardless of the number of recording
~ - 89 -
2025S06
1 heads.
The present invention has excellent effects in a
bubble-jet type recording head and its recording
apparatus in the ink-jet recording schemes.
As its typical arrangement and principle, the
~ ~ r~ 6~
- A ~X basic principles disclosed in, e.g., u.~.r. Nos.
4,723,129 and 4,740,796 are preferable. This scheme
can be applied to any one of an on-demand type scheme
and a continuous type scheme. In particular, when the
above principle is applied to the on-demand type
scheme, at least one driving signal corresponding to
recording information is applied to an electrothermal
conversion element located in correspondence with a
sheet having a liquid (ink) layer or an ink path so as
to obtain an abrupt temperature increase, thereby
causing the electrothermal conversion element to
generate a heat energy. Film boiling is caused on the
heat application surface of the recording head, and a
bubble can be effectively formed in a liquid (ink) in a
one-to-one correspondence with this driving signal.
The liquid (ink) is discharged through the
corresponding discharge opening upon growth and
contraction of this bubble, thereby forming at least
one droplet. When this driving signal is a pulse
signal, the bubble is instantaneously grown and
contracts, high-speed liquid (ink) discharge can be
more preferably performed. Preferable pulse shapes are
CA2325506
..
- 90 -
disclosed in U.S. Patent Nos. 4,463,359 and 4,345,262. When conditions
associated with a temperature increase rate of the heat application surface,
as disclosed in U.S. Patent No. 4,313,124 is employed, better recording can
be performed.
A recording head arrangement with heat application portions arranged
in bent passages, as disclosed in U.S.P. Nos. 4,558,333 and 4,459,600, is
also incorporated in the present invention in addition to a combination (linear
ink path or a right-angled flow path) of a discharge port, an ink path, and an
electrothermal conversion element, as disclosed in each specification of the
prior art. In addition, the present invention is effective with an arrangement
having a common slit as a discharge portion of the electrothermal conversion
elements, disclosed in Japanese Laid-Open Patent Application No. 59-
123670 and to an arrangement having a correspondence between an
opening for absorbing an energy pressure wave and a discharge port, as
disclosed in Japanese Laid-Open Japanese Application No . 59- 138461.
As a full-line type recording head having a length corresponding to the
width of the maximum recording medium used in the recording apparatus, a
plurality of recording heads disclosed in the above specifications may be
combined to cover the entire recording length, or a single recording head
may be used. The present
-
-- 91 --
2025506
1 invention can further enhance the effect as described
above.
In addition, the present invention is also
effective when an exchangeable chip type recording head
capable of being electrically connected to the
A ~pparatus main body and supplying1n~ ink from the
apparatus main body, or a cartridge type recording head
integrally formed with the recording head is mounted in
the apparatus main body.
A recording head recovery means and a
supplementary assisting means are preferably arranged
as constituting components of the recording apparatus
of the present invention to further enhance stability
of the effect of the present invention. Examples are a
recording head capping means, a recording head cleaning
means, a recording head pressing means, a recording
head suction means, an electrothermal conversion
element, another heating element, a combination of the
electrothermal conversion element and this heating
element, and an arrangement for setting a preliminary
discharge mode for discharging independently of
recording so as to perform stable recording.
A recording mode of the recording apparatus is not
limited to a recording mode for only a major color such
as black. An integral full-color recording head or a
plurality of single-color recording heads may be used.
h~ J~,~
The present invention is also effective ~ an apparatus
_ 92
2025506
1 having at least one of a plurality of different colors
or a color ~i~ing full-color mode.
In each embodiment described above, a liquid ink
- is used. However, an ink which is solidified at room
temperature or less, an ink which is softened or melted
even at room temperature, or the like may be used.
Alternatively, an ink which is solidified or melted in
the general temperature control range of 30C to 70C
may be used in ink-jet printing. That is, any ink may
be used when it is melted when a print signal is
applied to the recording head. A temperature increase
by a heat energy may be positively prevented by using a
phase transition from the solid phase to the liquid
phase, or an ink which is solidified in an exposed
state to aim at prevention of evaporation of the ink
may be used. In either case, an ink which is melted
upon reception of the print signal of the heat energy
may be used. In this case, the melted ink is
discharged. In addition, an ink which is solidified at
the time of its arrival on the recording medium, or an
ink which is melted upon reception of heat energy may
be applied to the present invention. In this case, as
described in Japanese Laid-Open Patent Application
-t ~ ~o. 54-S6847 or 60-71260, ~n~ ink may oppose the
corresponding electrothermal conversion element while
the ink is held in a recess portion of a porous sheet
or held as a liquid or solid body in a through hole.
-
- 93 -
2025506
1 According to the present invention, a film boiling
scheme is most effective for these inks.
In addition, as the form of an ink-jet recording
apparatus, the apparatus may be used as an image output
terminal for a data processing unit such as a computer,
a copying machine as a combination with a reader or the
like, and a facsimile apparatus having a
transmission/reception function.
According to the present invention, as has been
described above, correction associated with the
temperature of the control circuit area is performed
for a control object member (the ink-jet recording
apparatus recording means in each embodiment) to
eliminate a control error as in a technique for
detecting the state of the recording means while a
direct temperature measurement is performed. Since
detection or anticipation precision is better than
temperature control by the conventional temperature
sensor and the detection error range of the temperature
sensor itself, execution modes based on various
temperatures can be accurately performed.
In addition to the ink-jet recoding head utilizing
a heat energy, the present invention is applicable to
heating elements driven individually or in units of
predetermined groups, such as a thermal head for
applying a heat energy to an ink ribbon or a porous ink
convey unit. In this case, any temperature sensor need
- 94 _
202550~
1 not be arranged directly on or near the heating
element. Disconnections of the sensor and sensor
wiring lines can be eliminated, and the measurement is
free from sensor variations. In particular, in a
recording heating element array, each heating portion
is locally heated to slightly change the response of
the temperature sensor, thereby disabling accurate
determin~tion. The present invention can solve this.
In particular, the present invention provides
marvelous effects in a control object member (e.g., an
ink-jet recording head using an ink (solid or liquid))
having various thermal parameters such as an ink heat
capacity, a head structure, and heating of the above
member. These parameters cause variations in position
for accurately determining the temperature due to a use
or drive state. Therefore, it is difficult to
determine a timing at which accurate determination is
performed. However, the present invention can solve
this drawback.
In a bubble-jet machine utilizing an ink-jet
A ~ boiling film, proposed by C~ NON INC., the film
temperature locally exceeds 300 C due to
heat-insulating expansion of bubbles. Even if the
parameters having large variations are included, or a
local heating portion such as a driving switching diode
is included, variation factors can be systematically
determined to perform temperature control, thus proving
-
- 95 -
202~506
1 superiority of the present invention over the prior
arts.
In the scanning type recording apparatus for
scAnning a recording head to perform recording, an
operation error of the temperature detection sensor
occurs due to a scAnning speed and a difference between
speeds during scAnning and the stop state. The present
invention can solve this problem.
In the embodiments described above, technical
arrangements based on the description of the respective
components, and their modifications may be incorporated
in the present invention in a combination without
epartingtthe spirit and scope of the invention.
