Note: Descriptions are shown in the official language in which they were submitted.
CA 02229871 1998-02-18
Liquid container for ink jet head
FIELD OF THE INVENTION AND RELATED ART
The present invention relates to a liquid
container for accommodating liquid to be used for
recording by an ejection head(ink jet head) which
forms images by ejection of droplets onto sheets.
In conventional printers, an ejection head
for image formation by ejection of droplets onto
sheets, can be carried on a carriage which makes
reciprocal movement in a direction perpendicular to
the sheet feeding direction in a plane parallel to the
sheet.
In such a scanning type apparatus, the
carriage is moved on a line in response to
instructions, and simultaneously, the droplets are
ejected in response to ejection signals to effect the
image formation on the sheet, and thereafter, the
sheet is fed through a predetermined distance by a
feeding device, and these operations are repeated.
As for the droplet ejecting type, there are a type
using an electrothermal transducer element(heater) and
a type using a piezoelectric element(piezoelectric),
in either of which the ejections of the ink droplets
are controllable by an electrical signals. In the
liquid droplet ejecting method using the
electrothermal transducer element, an electric signal
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is supplied to the electrothermal transducer element
so that ink adjacent the electrothermal transducer
element is instantaneously boiled, and the droplet is
ejected at a high speed by an abrupt growth of a
bubble caused by the instantaneous of the ink by the
boiling.
Since the liquid is consumed during the image
formation, the ejection head has to be always supplied
with the liquid. To accomplish this there is a system,
for example, wherein an ink container is provided in a
main assembly of the ink jet recording apparatus, and
an ink supply tube is extended from the ink container
to the recording head to supply the ink with negative
pressure provided by a static head difference between
the ink jet head and the ink container. Such a type,
however, results in bulky structure, and therefore, it
is unsuitable to a popular type machines from the
standpoint of the size and the price.
As another system, there is a so-called
liquid container carrying type wherein a liquid
container which is detachably mountable relative to
the ejection head carried on the carriage, an is
connected to a liquid supply port of the ejection
head. In this system, the liquid container is
exchanged with a new one after the liquid therein is
consumed up.
In such a liquid container carrying type, the
CA 02229871 1998-02-18
ejection head is usually disposed below the liquid
container. Therefore, if the liquid container has an
open-to-ambience structure, a means has to be provided
to produce a predetermined negative pressure to
prevent the liquid from leaking out through the
droplet ejection outlet(orifice) of he ejection head.
Additionally, in order to stabilize the ejection
property, a stable meniscus should be maintained at
the droplet ejection outlet of the ejection head. In
such a liquid container, the negative pressure is
adjusted to a predetermined level in consideration of
the static head difference between the ejection
portion of the ejection head and the liquid surface in
the container so as to maintain the stabilized
meniscus at the ejection outlet. Therefore, the
state of the liquid in the liquid container is
influential to the liquid droplet ejection performance
from the ejection head.
In order to generate such negative pressure,
Japanese Laid-open Patent Application No. SHO- 56-
67269 and Japanese Laid-open Patent Application No.
SHO- 59-98857, for example, proposes a spring urged
bladder ink container type using an ink bladder urged
by a spring in an ink container. With such a type,
the manufacturing step is complicated, and therefore,
the manufacturing cost is high, and in addition the
ink content per unit volume of the ink container,
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i.e., the ink holding rate is smaller if the thickness
of the container is smaller, with the result of higher
running cost.
For example, Japanese Laid-open Patent
Application No. HEI- 2-21466 discloses a container,
the inside of which is divided into a plurality of ink
chambers, which in turn are communicated through a
fine hole which is capable of producing a negative
pressure. In this type, however, the ink does not
exist at the fine hole portion depending on the
orientation of the ink container, with the result of
no negative pressure, or the negative pressure tends
to reduce by the expansion of the air in the ink
chamber due to the ambient temperature or the like, so
that ink leaks relatively easily.
There is a further known system wherein an
absorbing material occupies the entire inside space of
the ink container, and the ink is retained by the
absorbing material. The absorbing material is a
liquid absorbing material in the form of a porous
material such as a sponge, and it is ordinary that
absorbing material has originally a size larger than
the inside volume of the container, and is compressed
when it is placed therein.
With such a system, the ink amount which can
be actually used from the container is smaller than
the total volume of the ink container since the ink
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amount which can be contained in the absorbing
material is limited to provide the stable negative
pressure to avoid the ink leakage or the like, and
since the ink in the absorbing material sometimes
cannot be completely used up since the absolute value
of the negative pressure increases with the
consumption of the ink retained in the absorbing
material.
There is a further system, which is a so-
called half-sponge ink container type which increases
the amount of the ink which can be consumed. An
example of this is disclosed in Japanese Laid-open
Patent Application No. HEI- 6-40043 wherein the
container includes a liquid retaining member
accommodating portion accommodating a liquid retaining
member for negative pressure production, and an ink
accommodating portion accommodating the ink next to
the liquid retaining member accommodating portion and
communicating therewith through a passage. This
container for ink jet printer, therefore, is provided
with a liquid retaining member accommodation chamber
for accommodating the liquid retaining member and the
ink accommodation chamber for accommodation the ink,
so that ink holding rate is improved while stabilizing
the negative pressure, with a simple structure, thus
accomplishing the low manufacturing cost, low running
cost, highly reliable and the downs1zing of the
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apparatus.
A detailed description will be made as to the
structure of liquid containers.
Figures 15 and 16 show conventional liquid
containers.
The container of Figure 15 supplies the
recording liquid to a wire dot head, and the liquid
absorbing material 101 has a thicknesses which is
different at the front side portion and the rear side
portion, wherein when it i.s placed in the main body
102 of the container, the front side portion is
compressed by the cap 103. With this structure, the
capillary force provided by the liquid absorbing
material 101 increases toward the liquid supply port
104 so that ink can be concentrated at the ink supply
port side efficiently.
In Figure 16, the container is integral with
an ink jet head, and three chambers of the container
accommodates the liquid absorbing materials 201,
respectively, wherein an ejection head 203 is provided
at the bottom portion of the main body 202. The
liquid absorbing material 210 is press-contacted to
the supply pipe 205 which is in communication with the
orifices 204 of the ejection head 203 ((Japanese Laid-
open Patent Application No. SH0- 63-87242). With
such a structure, the portion of the liquid absorbing
material 210 which is contacted to the supply pipe 205
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is compressed, and therefore, the capillary force of
the portion is larger so that ink is efficiently
collected to the supply pipe 205. Japanese Laid-open
Patent Application No. SHO- 55-161661 discloses a
structure using fiber as the absorbing material, and
the configuration of the container per se is reduced
toward the connecting portion to improve the supply of
the ink.
Figure 17 shows another liquid container.
This is disclosed in Japanese Laid-open Patent
Application No. HEI- 7-125239, wherein a negative
pressure producing member accommodating chamber 401
accommodating a negative pressure producing member 402
is in fluid communication with a liquid containing
chamber 403 accommodating liquid 404 through a fluid
communication path 405, wherein a bottom portion of
the negative pressure producing member accommodating
chamber 401 between the fluid communication path 405
and the liquid supply port 406 provided at the bottom
portion is lowered, so that compression of the
negative pressure producing member 402 is eased at the
lowered portion to provide a liquid rich region 408.
The above described liquid containers involve
a problem arising from the compression required for
placing it in the container.
Figure 18 is a schematic sectional view
illustrating insertion of the liquid absorbing
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material into the main body of the container having a
flat thin type rectangular parallelopiped
configuration, and Figure 19 is a schematic sectional
view of the liquid container after the liquid
absorbing material is placed therein.
As shown in Figure 18, the liquid absorbing
material 303 is inserted into the main body 304 of the
container while compressing it in the longitudinal
direction, and more particularly, it is compressed
down to less than the inner longitudinal dimension of
the main body 304 using compression plates 305 and
306. At this time, the compression ratio is high in
the neighborhood of the compression plates 305 and
306, and it is low in the neighborhood of the center.
When the liquid absorbing material 303 is placed into
the main body 304 of the container with this state,
this compression ratio distribution of the liquid
absorbing material 303 remains at it is after it is
inserted into the main body 304, as shown in Figure
19.
With such non-uniform compression ratio, the
pore sizes of the porous material are not uniform, and
therefore, the capillary forces of the liquid
impregnated in the absorbing material are locally
different. Therefore, only the liquid at the central
portion where the capillary force is small is
consumed, and the liquid adjacent the container side
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wall surface where the capillary force is strong is
left, with the result that supply performance is
deteriorated, for example, the continuity of the
liquid is stopped before the liquid is used up.
This problem is eased by use of the structure
shown in said Figures 15, 16, but the non-uniform
compression still exists in Figure 15, and in the
Figure 16 structure, the compression unevenness still
exists although the compression ratio adjacent the
supply pipe is high. With the structure of Figure
17, the supply of the liquid is sufficient.
In the case of the flat thin type liquid
container, the size of the maximum area side of the
container necessarily increases with the increase of
the accommodation capacity of the liquid. The air
vent of the liquid container is sealed by a sealing
material so as to avoid evaporation of the liquid
during the transportation or in storage. Therefore,
if the liquid container which is made of thermoplastic
resin material is kept under a high temperature
ambience, the maximum area side which is relatively
easily deformed is expanded by the internal pressure
even to such an extent of plastic deformation with the
result of increase of outer dimensions. As a result,
the container may be unable to be mounted to the
carriage particularly in the case of the downsized
apparatus.
CA 02229871 1998-02-18
--10--
Accordingly, it is a principal object of the
present invention to provide a liquid container which
can stably supply the liquid as much as possible to
the ejection head.
It is another object of the present invention
to provide a liquid container which can be mounted to
the carriage even if the outer dimension is increased
due to the plastic de~formation under the high
temperature ambience during transportation or the
like
Since the above described half-sponge ink
container type is provided with the absorbing
material, the same problem arises. When the amount
of the ink in the ink accommodation chamber becomes
very small, the ink tends to remain at the corner
portions, at the marginal areas of the bottom surface
in the ink accommodation chamber or adjacent the
projection, so that consumable amount of the ink
reduces. When the ink remaining amount detection of
the ink accommodation chamber is effected, the
remaining amount detection is unstable due to the
remainder ink, with the result that small printing
warning may be produced prior to the appropriate
timing, or that forced print stop timing may be
appropriate.
It is a further object of the present
invention to provide a liquid container for an ink jet
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recording apparatus with which a large amount of the
ink can be stably supplied.
SUMMARY OF THE INVENTION
According to an aspect of the present
invention, there is provided a liquid container
comprising a main body for accommodating liquid
contributable to image formation; a liquid absorbing
material, accommodated in said main body, for holding
the liquid; a liquid supply port, in said main body,
for supplying the liquid toward an ejection head for
the image formation; an air vent for fluid
communication between said main body and an ambience;
wherein a projected surface is projected toward inside
of said main body at a part of an inner surface of
said main body adjacent said liquid supply port.
It is preferable that said projected surface
is spaced apart from narrow walls not having said
supply port.
It is preferable that said main body has an
outer appearance of flat thin and substantially
rectangular parallelopiped configuration, and said
liquid supply port is provided in a narrow side
thereof, wherein said projected surface is provided at
each of maximum area side walls sandwiching the side
having the liquid supply port adjacent said liquid
supply port.
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It is preferable that an outer surface of a
substantially central portion of each of maximum area
side walls of said main body is recessed.
According to another aspect of the present
invention, there is provided an ink container
comprising a first chamber accommodating a liquid
absorbing material and having a liquid supply port for
supplying liquid toward an ejection head for image
formation and an air vent for fluid communication with
a communication; a second chamber for containing the
liquid to be supplied to said first chamber, said
second chamber being in fluid communication with said
first chamber through a communicating portion provided
adjacent a bottom portion of said main body, in use,
being substantially hermetically sealed except for
said comm~lnicating portion; a partition wall for
separating said first chamber and second chamber and
defining a top end of said fluid communication path,
wherein said container has a substantially flat thin
and rectangular parallelopiped configuration; and
wherein a projected surface is projected toward inside
of said main body at a part of an inner surface of
each of lateral side of said first chamber sandwiching
a side having a liquid supply port, adjacent said
liquid supply port.
It is preferable that said liquid supply port
is disposed in a bottom portion of said first chamber
CA 02229871 1998-02-18
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in use, and said partition wall is provided with an
ambience introduction path extending from a non-end
part of said partition wall to said communicating
portion, and wherein said projected surface is
provided between the bottom portion to a direction of
a top end of said ambience introduction path.
It is preferable that said projected surface
said projected surface is spaced apart from said
partition wall and from a narrow walls not having said
supply port.
It is preferable that ~n outer surface of a
substantially central portion of each of maximum area
side walls of said first chamber is recessed.
In the present invention, the liquid
absorbing material may be of non-compression type
which has been compressed to a desired compression
ratio at the time of placing it into the main body of
the container or of a heat compression type which has
been compressed to a desired compression ratio before
it is placed into the main body. The liquid
contributable to the image formation may be color ink
including a coloring component such as yellow, cyan,
magenta or black coloring component or a liquid
containing a component which reacts with the color
ink.
According to the above-described first aspect
of the present invention, the projected surface is
CA 02229871 1998-02-18
effective to compress the low compression ratio of the
-liquid absorbing material so that compression ratio
becomes relatively uniform in the longitudinal
direction. Therefore, a larger amount of the liquid
in the container can be used up.
During the transportation of the liquid
container in which the air vent is usually sealed, the
maximum area side wall tends to be expanded by the
internal pressure with the possible result of the
plastic deformation and therefore the expansion of the
outer dimension of the container~ Since, however,
the outer surface is inwardly recessed in the
preferred example, the maximum width (shortest
dimension) can be maintained even if the maximum area
side wall expands outwardly. Accordingly, the
container can be mounted into a mounting space with
small tolerance.
The projected surface is effective to
compress the low compression ratio of the liquid
absorbing material in the first chamber so that
compression ratio becomes relatively uniform in the
longitudinal direction. Therefore, the liquid level
in the first chamber can be maintained without
reaching to the wall having the supply port to ensure
the liquid supply from the second chamber while
permitting ambience introduction.
Since, however, the outer surface is inwardly
CA 02229871 1998-02-18
recessed in the preferred example of this aspect, the
maximum width (shortest dimension) can be maintained
even if the maximum area side wall expands outwardly.
Accordingly, the container can be mounted into a
mounting space with small tolerance.
According to a further aspect of the present
invention, there is provided an ink container, wherein
a liquid retaining member accommodation chamber
accommodating a liquid retaining member is in fluid
communication with an ink accommodation chamber
accommodating ink through a fluid communication path;
CHARACTERIZED IN THAT an ink introduction groove
extending to said fluid communication path is provided
in said ink accommodation chamber.
In a preferred form of this aspect of the
present invention, the inclination is such that
portion adjacent said second chamber is lower.
According to this aspect of the present
invention, the ink introduction groove is effective to
provide liquid paths between the absorbing material
and the ink at various portions in the ink
accommodation chamber, and therefore, the ink can be
supplied to the ink retaining member accommodation
chamber with certainty even when the amount of the ink
in the ink accommodating chamber becomes very small.
In the preferred example, the inclination of
the bottom surface of the ink accommodation chamber is
CA 02229871 1998-02-18
-16-
effective to maintain that bottom surface of the ink
accommodation chamber is horizontal or lower at the
fluid communication path side, even when the ink
container is mounted to the carriage, thus assisting
the proper ink motion.
According to a further aspect of the present
invention, there is provided an ink container
comprising: a first chamber accommodating a liquid
absorbing material and having a liquid supply port for
supplying liquid toward an ejection head for image
.formation and an air vent for fluid communication with
a communication; a second chamber for containing the
liquid to be supplied to said first chamber, said
second chamber being in fluid communication with said
first chamber through a communicating portion provided
adjacent a bottom portion of said main body, in use,
being substantially hermetically sealed except for
said communicating portion; a partition wall for
separating said first chamber and second chamber and
defining a top end of said fluid communication path,
wherein said container has a substantially flat thin
and rectangular parallelopiped configuration; and
wherein a projected surface is projected toward inside
of said main body at a part of an inner surface of
each of lateral side of said first chamber sandwiching
a side having a liquid supply port, adjacent said
liquid supply port, and wherein said second chamber is
CA 02229871 1998-02-18
provided with an ink introduction groove extending to
said communicating portion.
These and other objects, features and
advantages of the present invention will become more
apparent upon a consideration of the following
description of the preferred embodiments of the present
invention taken in conjunction with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a schematic view of a liquid
container according to an embodiment of the present
invention.
Figure 2 is a cross-section taken along a
line A-A' in the projected region of the main body of
the container shown in Figure 1.
Figure 3 is a cross-section taken along a
line A-A' in the projected region of the main body of
the container shown in Figure 1 according to another
example~
Figure 4 is a cross-section taken along a
line A-A' in the projected region of the main body of
the container shown in Figure 1 according to a further
example.
Figure 5 is a cross-section taken along a
line A-A' in the projected region of the main body of
the container shown in Figure 1 according to a yet
CA 02229871 1998-02-18
further example.
Figure 6 is a cross-section taken along a
line B-B' in the recessed region of the main body of
the container shown in Figure 1 according to an
example.
Figure 7 is a cross-section taken along a
line B-B' in the recessed region of the main body of
the container shown in Figure 1 according to another
example.
Figure 8 is a schematic sectional view
illustrating a liquid container according to another
embodiment of the present invention.
Figure 9 shows an outer appearance of the
liquid container of Figure 8, wherein (a) is a top
plan view, and (b) is partly broken side view.
Figure 10, (a) is a view as seen in the
direction D in (b), and (b) is a view taken along a
line C-C' of Figure 9, (b}.
Figure 11 illustrates consumption process of
the liquid in the liquid container shown in Figure 8.
Figure 12 illustrates consumption process of
the liquid in the liquid container shown in Figure 8.
Figure 13 illustrates consumption process
when the liquid container is not provided with the
inner projected region.
Figure 14 illustrates consumption process
when the liquid container is not provided with the
CA 02229871 1998-02-18
--19--
inner projected region.
Figure 15 shows an example of a conventional
liquid container.
Figure 16 shows another example of a
conventional liquid container.
Figure 17 shows another example of a
conventional liquid container.
Figure 18 is a schematic sectional view
illustrating insertion of a liquid absorbing material
into a main body of a flat thin type rectangular
parallelopiped configuration container.
Figure 19 is a schematic sectional view of a
liquid container of Figure 18 after the liquid
absorbing material is placed therein.
Figure 20 is a schematic view of a second
chamber according to an embodiment of the present
invention, wherein (a) is a cross-sectional view, and
(b)is a sectional view taken along a line E-E, and (c)
is a sectional view taken along a line F-F.
Figure 21 is a schematic view of a second
chamber according to a further embodiment of the
present invention, wherein (a) is a sectional view,
and (b) is a sectional view taken along a line G-G.
Figure 22 is a schematic view of a second
chamber according to a further embodiment, wherein (a)
is a sectional view, (b) is a sectional view taken
along a line H-H, and (c) is a sectional view taken
CA 02229871 1998-02-18
-20-
along a ling I-I.
Figure 23 iS a schematic view of the second
chamber according to a further embodiment of the
present invention, wherein (a) is a sectional view,
and (b) is a sectional view taken along a line J-J.
Figure 24 iS a schematic sectional view of
the second chamber according to a further embodiment
of the present invention.
Figure 25 iS a schematic view of the second
chamber according to a further embodiment of the
present invention., wherein (a) is a partially
sectional view, (b) is a sectional view taken along a
line K-K.
Figure 26 is a schematic sectional view of a
container according to a further embodiment of the
present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the accompanying drawings, the
embodiments of the present invention will be
described.
(First Embodiment)
Figure l is a schematic view of a liquid
container according to a first embodiment of the
present invention. The liquid container of this
embodiment is provided with a main body l of the
container for accommodating the liquid contributable
CA 02229871 1998-02-18
to the image formation, a liquid absorbing material 2
for holding the liquid in the main body 1 of the
container, a liquid supply port 3 for supplying the
liquid out to an ejection head(unshown) provided in a
bottom portion(in use) of the main body of the
container. In this embodiment, the outer appearance
of the container is thin flat type rectangular
parallelopiped configuration.
As shown in Figure 1, each of side walls
having the maximum area and sandwiching the wall
provided with the liquid supply port 3, is provided
with inwardly projected inner region(projected
surface) and an inwardly recessed inner
region(recessed surface). The inner projected region
5 is formed at the region at least adjacent to the
liquid supply port 3 on inside surfaces of the maximum
area sides. The inner projected region 5 is provided
away from the narrow side which is vertical during
use.
Figures 2-5 show examples as sectional views
of the projected regions 5 of the main body 1 of the
container taken along a line A-A. The inner
projected region 5 may be of trapezoidal projection
formed only on the inside as shown in Figure 2 or of
projected curved surface configuration (convex) as
shown in Figure 3. Alternatively, the inside may be
trapezoidal configuration without changing the
CA 02229871 1998-02-18
-22-
thickness of the side wall as shown in Figure 4, or
may be curved as shown in Figure 5. In this Figure,
the inner projected region L2 is smaller to 40%-80%
relative to the longitudinal inner dimension Ll of the
main body 1 of the container, and the inner dimension
W2 is smaller by 5%-20% relative to the inner
widthwise dimension Wl of the main body 1 of the
container.
Here, the description will be made as to the
function of the inner projected region 5. As has
been described in conjunction with Figures 18 and 19,
the liquid absorbing material 2 is placed in the main
body 1 of the container with the longitudinal
direction dimension of the liquid absorbing material 2
being compressed to less than the inner longitudinal
dimension of the main body 1. Without the inward
projected portion, the compression ratio of the liquid
absorbing material 2 tends to be large adjacent the
narrow vertical wall (in use), and that at the central
portion is small. However, according to this
embodiment, the inner projected region 5 presses such
a portion of the liquid absorbing material 1 as has
the low compression ratio portion, but not the portion
having the high compression ratio. As a result, the
compression ratio distribution of the liquid absorbing
material 2 is substantially uniform in the
longitudinal direction. Therefore, when the ejection
CA 02229871 1998-02-18
-23-
head (unshown) is driven so that liquid retained in
the liquid absorbing material 2 is consumed toward the
ejection head through the liquid supply port 3, the
liquid is continuously supplied out without being left
adjacent the side surfaces.
Referring back to Figure l, the outer recess
regions 6 are inwardly recessed substantially on the
outsides of the maximum area sides at the central
portions except for the inner projected regions 5
Figures 6 and 7 are sectional views taken
along a line B-B' of the outer recess region 6 of an
example of the main body 1 of the container shown in
Figure 1. As for the outside recessed region 6, only
the outer surface of the maximum area side is a
trapezoidal recess as shown in Figure 6, or it may be
of a curved recessed configuration as shown in Figure
7.
The description will be made as to the
function of the outer recess region 6. During the
transportation of the liquid container l, an air vent
4 of the container is usually sealed by a sealing
material to prevent evaporation of the liquid or the
liquid leakage due to the liquid expansion in the
container. When the liquid container l is placed or
kept under a high temperature ambience during
transportation, the maximum area side wall of a
thermoplastic resin material, which is relatively
CA 02229871 1998-02-18
easily deformed, may be expanded by the increased
internal pressure even to the extent of the plastic
deformation with the result of increase of the outer
dimension. According to this embodiment, however,
only the substantially central portion of the maximum
area side constitutes the outside recessed region 6,
and therefore, the outermost widthwise dimension
remains the same even if the maximum area sides expand
outwardly. Accordingly, the container can be mounted
into a mounting space with small tolerance.
(Second Embodiment)
In the foregoing embodiment, the description
has been made as to the liquid container of a so-
called full sponge type wherein the liquid absorbing
material occupies substantially the entire space of
the container. Next, the description will be made as
to an example of a liquid container of so-called half
sponge type.
Figure 8 is a schematic sectional view of a
liquid container according to a second embodiment of
the present invention. Figure 9 are detailed outer
appearance of the liquid container of Figure 8. In
Figure 10, (a) and (b) are an outer appearances as
seen in the direction D of (b), and a sections taken
along a line C-C'. The same reference numerals as in
the first embodiment are assigned to the elements
having the corresponding functions, and detailed
CA 02229871 1998-02-18
-25-
descriptions thereof are omitted for simplicity.
The liquid container 1 is a container having
a substantially flat thin type rectangular
parallelopiped configuration. The container 1
comprises a first chamber 7 for accommodating a liquid
absorbing material 2, and a second chamber 9 for
accommodating liquid 11 adjacent the first chamber 7,
said second chamber 9 being separated by a partition
wall 8 from the first chamber 7. The bottom
portion(in use) of the first chamber 7 is provided
with a liquid supply port 3 for supplying the liquid
toward the ejection head(unshown), and the upper
portion (in use) of the first chamber 7 is provided
with an air vent 4. The liquid supply port 3 may be
provided with a fibrous member(press-contact member
for ink discharge) to permit satisfactory discharge of
the liquid. The first chamber 7 is in fluid
communication with the second chamber 9 through a
communicating portion 10 formed adjacent the bottom
2~ portion of the partition wall 8. The upper portion
of the second chamber 9 is provided with a liquid
filling port 12 for filling the ink thereinto. The
liquid filling port 12 is sealed by a ball seal 13, so
that second chamber 9 is substantially hermetically
sealed except for the communicating portion 10.
Adjacent the communicating portion at the bottom
portion of the second chamber 9, a remainder detecting
CA 02229871 1998-02-18
-26-
portion 14 for permitting optical monitoring of the
remaining amount of the liquid 11. The surface of
the first chamber 7 of the partition wall 8 is
provided with an ambience introduction path 15
including a groove extended toward the communicating
portion 10 from non-end part thereof. Japanese Laid-
open Patent Application No. HEI- 6-40043 is
incorporated here as to the detailed structure of the
structure of the ambience introduction path 15. An
outside of a narrow wall which is vertical (in use) is
provided with a latch lever 16, which functions to
securedly engage the main body 1 of the container with
the carriage(unshown).
In the first chamber 7, each of the maximum
area side walls sandwiching the wall provided with the
liquid supply port 3, has an inner projected region 5
and an outside recessed region 6. The inner
projected region 5 is so formed that at least the
region, adjacent the liquid supply port 3, of the
inside of the maximum area side is projected toward
the inside of the first chamber 7. The inner
projected region 6 is spaced from the narrow vertical
(in use) wall of the first chamber 7. The inner
projected region 5 is extended from the bottom portion
of the first chamber 7 to the neighborhood of the top
end Pa of the ambience introduction path 15. Cross-
sectional views of the container of Figure 8 taken
CA 02229871 1998-02-18
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along a line B-B ' through the inner projected region
5, are the same as that shown in Figure 2 or 3.
On the other hand, the inner recess region 6
in the first chamber 7 iS formed at the substantially
central portion except for the inner projected region
5, on the outside of each of the maximum area sides,
and is inwardly recessed. Cross-sectional views of
the container of Figure 8 taken along a line A-A'
through the outer recessed region 5, are the same as
that shown in Figure 6 or 7.
The operation principle of the liquid
container of this embodiment will be described.
Figures 11 and 12 show the consumption process of the
liquid in the liquid container 1 of Figure 8.
As shown in Figures Figure 18 and 19, the
liquid absorbing material 2 is placed in the first
chamber 7 of the main body 1 of the container with the
longitudinal dimension of the liquid absorbing
material 2 being compressed to less than the inner
longitudinal dimension of the first chamber 7 of the
main body 1. As a result, after the liquid absorbing
material 2 iS placed in the first chamber, the
compression ratio of the liquid absorbing material 2
is large adjacent the narrow vertical wall (in use),
and that at the central portion is small.
If the liquid is ejected through the orifice
of the ejection head(unshown), the liquid held in the
CA 02229871 1998-02-18
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liquid absorbing material 2 of the first chamber 7 is
first supplied to the ejection head through the liquid
supply port 3. With continued ejecting operation,
the amount of the liquid in the liquid absorbing
material 2 decreases due to the liquid supply
(consumption). Since the compression ratio of the
liquid absorbing material 2 iS high adjacent the
narrow vertical wall of the liquid container 1 and
adjacent the partition wall 8, the liquid remains
there, but only the liquid at the central portion of
the fir.st chamber l where the capillary force is
small, is supplied out. Therefore, the liquid
surface in the liquid absorbing material 2 lowers at
the central portion of the first chamber 7 as shown in
Figure ll.
When the liquid i.s consumed from the liquid
absorbing material 2, the liquid surface in the liquid
absorbing material 2 reaches the inner projected
region 5. The inner projected region 5 presses the
liquid absorbing material 1 only at the low
compression ratio portion not the high compression
ratio portion thereof, so that liquid level in the
central portion of the first chamber 7, particularly
the lowered level rises. As a result, the liquid
level in the liquid absorbing material 2 having
reached the inner projected region 5 maintains
substantially constant.
CA 02229871 1998-02-18
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Since the inner projected region 5 starts
with a level substantially equal to the top end Pa of
the ambience introduction path 15, the air at the
liquid level in the liquid absorbing material 2 can be
introduced into the second chamber 9 through the
ambience introduction path 15 and through the
communicating portion when the liquid level in the
liquid absorbing material 2 reaches the predetermined
level. At this time, the static head provided by the
ejection portion of the ejection head, the reduced
pressure in the second chamber 9 and the capillary
force in the liquid absorbing material 2 are balanced.
Since the top end of the ambience introduction path
and the upper portion of the inner projected region
are substantially at the same level, the introduction
of the air from the ambience introduction path is
stabilized, and the static head difference can be
maintained constant, and therefore, the ejection of
the ink through the head is also stabilized. The same
level feature is preferable from the standpoint of the
stabilized ink supply.
When the liquid supply(consumption) occurs
from the liquid ejection outlet 3, the liquid quantity
in the first chamber 7 does not reduce, and the liquid
11 in the second chamber 9 is consumed. Thus, the
amount of the liquid corresponding to the liquid
supply is consumed from the second chamber 9, and the
CA 02229871 1998-02-18
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corresponding amount of the ambient air is introduced
into the first chamber 7 through the air vent 4,
without changing the liquid distribution in the first
chamber 7. As long as the liquid is consumed from
the second chamber 9, the actions are repeated so that
constant negative pressure is provided in the main
body 1 of the container.
As soon as the liquid consumption from the
second chamber 9 ends, the liquid is supplied again
from the liquid absorbing material 2 in the first
chamber 7. Since the density distribution of the
liquid absorbing material 2 is uniform, the liquid is
consumed continuously to the end through the liquid
supply port 3, similarly to the first embodiment.
As compared with this embodiment, the
function will be described as to when the inner
projected region 5 is not provided. Figures 13 and 14
show the consumption process of the liquid when the
liquid container 1 is not provided with the inner
projected region 5.
In this case, too, the compression ratio of
the liquid absorbing material 2 is high adjacent the
narrow vertical wall of the liquid container 1 and
adjacent the partition wall 8 due to the insertion of
the liquid absorbing material 2 into the first chamber
7. Therefore, with the liquid consumption, the liquid
surface in the liquid absorbing material 2 lowers at
CA 02229871 1998-02-18
-31-
he central portion of the first chamber 7 shown in
Figure 13. With the continued liquid ejection, the
liquid surface at the central portion of the first
chamber 7 lowers greatly, sometimes even to such an
extend to reach the inner bottom surface of the first
chamber 7 before the ambience adjacent to the liquid
level in the liquid absorbing material 2 reaches the
top end Pa of the ambience introduction path 15.
Depending on the non-uniformity of the liquid
absorbing material 2, the liquid may be discontinued
at the bottom portion as shown in Figure 13. If this.
occurs, the liquid 11 cannot be supplied from the
second chamber 9 into the first chamber 7, and in
addition, the air is introduced into the ejection head
through the liquid supply port 3 with the result that
ejection becomes unstable even to the extent of
ejection failure.
According to this embodiment, however, the
lowering of the liquid level with the liquid
consumption at the central portion where the
compression ratio is low due to the insertion of the
liquid absorbing material 2, is suppressed by the
inner projected region 5, thus maintaining the liquid
level constant. In this manner, it can be avoided
that liquid level in the liquid absorbing material 2
in the first chamber reaches the bottom portion having
the liquid supply port 3 before the start of the gas-
CA 02229871 1998-02-18
liquid exchange between the first chamber 7 and the
second chamber 9 with the result of disabled
introduction of the ambience to the liquid supply
port, so that stabilized ejection property can be
maintained.
As regards the function of the outer recess
region 6 is the same as with the first embodiment. In
brief, since the only the central portion of the outer
surface of the maximum area side constitutes the inner
recess region 6 (toward the inner side), the outermost
width of the container can be maintained even if the
maximum area wall expands outwardly due to the high
temperature ambience occurring during transportation
or the like. Accordingly, the container can be
mounted into a mounting space with small tolerance.
The liquid absorbing material 2 usable with
the first and second embodiments, may be of any
material if it can retain the liquid despite the
weight of the liquid and the small scale vibration
imparted thereto. It may be cotton-like member
comprising fiber net or a porous material having
through pores. A sponge material such as foam
polyurethane resin material is preferable since the
liquid retaining force and the negative pressure
production is easily adjustable. The foam is
preferable since the adjustment is possible so as to
provide the desired compression ratio (porosity)
CA 02229871 1998-02-18
during the manufacturing of the liquid absorbing
material. There are, for example, a heat compression
type wherein the compression ratio has been controlled
to a predetermined level by the heat compression
treatment prior to placing into the main body of the
container, and a non-compression type wherein a foam
having a predetermined porosity per unit volume is cut
into predetermined dimensions to provide a desired
compression ratio when it is placed in the main body
of the container. The problem of the compression
distribution arising from the insertion of the
absorbing material into the main body of the container
exists both in the heat compression type and the non-
compression type.
The liquid ll contributable to the image
formation, may be color ink containing a coloring
component such as yellow, cyan, magenta black or the
like.
In another example, before or after the image
formation on the sheet material with the color ink,
processing liquid may be applied to the same area, or
processing liquid may be applied to the entire surface
of the sheet material to improve the fixing effect of
the ink on the sheet material. In such a case, the
liquid 11 may be liquid containing a component
reactable with the color ink. Examples of such
liquid include the ones using anion or cation
CA 02229871 1998-02-18
-34-
reaction.
As described in the foregoing, the present
invention is usable with a liquid container having the
main body, the liquid absorbing material accommodated
in the main body, the liquid supply port, to the
ejection head, provided in the main body, and an air
vent for fluid communication with the ambience, with
the following technical advantages. By the projected
surface described above, the density distribution of
the compression ratio of the liquid absorbing material
when the liquid absorbing material is compressed in
the longitudinal direction and inserted into the main
body, is uniform. As a result, the liquid can be
used up continuously without leaving it adjacent the
side wall of the container.
The present invention is usable with a liquid
container having substantially flat thin type
rectangular parallelopiped configuration, comprising
the first chamber open to ambience, the second chamber
containing the liquid to be supplied to the first
chamber and substantially hermetically sealed except
for the com~llnicating portion through which the first
and second chambers are in fluid communication with
each other, and a partition wall between the and the
first chamber and the second chamber and extending
above the communicating portion, with the following
technical advantages. When the liquid absorbing
CA 02229871 1998-02-18
-35-
material is inserted into the main body of the
container while the longitudinal dimension thereof is
reduced, the projected surface pressed the low
compression ratio portion, not the high compression
ratio portion. Therefore, the lowering of the liquid
level due to the liquid consumption at the central
portion where the compression ratio of the liquid
absorbing material is low, can be suppressed, so that
substantially constant liquid level can be maintained.
Since the projected surface is substantially
at the same level as the top end of the ambience
introduction path, the ambience adjacent to the liquid
surface is enabled to be in fluid communication with
the second chamber through the ambience introduction
path and the communicating portion at the time when
the liquid level in the liquid absorbing material
reaches a predetermined level. In this manner, it
can be avoided that liquid level in the liquid
absorbing material 2 in the first chamber reaches the
bottom portion having the liquid supply port 3 before
the start of the gas-liquid exchange between the first
chamber 7 and the second chamber 9 with the result of
disabled introduction of the ambience to the liquid
supply port, so that stabilized ejection property can
be maintained.
As soon as the liquid consumption in the
second chamber, the liquid in the liquid absorbing
CA 02229871 1998-02-18
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material in the first chamber is consumed again, and
the liquid can be consumed continuously from the
liquid supply port since the compression ratio
distribution is made uniform by the inner projected
region.
Since the only the central portion of the
outer surface of the maximum area side constitutes the
inner recess region 6 (toward the inner side), the
outermost width of the container can be maintained
even if the maximum area wall expands outwardly due to
the high temperature ambience occurring during
transportation or the like. Accordingly, the
container can be mounted into a mounting space with
small tolerance.
The structure of the second chamber according
to an embodiment of the present invention will be
described.
Figure 20 shows an ink container using a
structure of the second chamber (ink accommodation
chamber) according to this embodiment. In this
Figure, (a) is a vertical cross-section taken at a
substantially longitudinal center, and (b) is a
sectional view taken along a line E-E, and (c) is a
sectional view taken along a line F-F'.
In Figure 20, designated by reference numeral
1 is a half-sponge ink container; 7 is a liquid
retaining member accommodation chamber for
CA 02229871 1998-02-18
accommodating a liquid retaining member 2 having a
liquid absorption property, such as urethane sponge; 9
is an ink accommodation chamber for accommodating
liquid(ink) 11; 4 is an air vent for introducing the
ambience into the liquid retaining member
accommodation chamber 7; 11 indicated by hatched
portions is ink therein; 23 is a press-contact member
of a fibrous member such as PP (polypropylene) or
felt. To the press-contact member, a filter portion
at the end of an ink receiving tube of the recording
head is contacted to supply the ink to the recording
head.
Further, designated by 3 is an ink supply
port into which the filter is inserted; 10 is a fluid
communication path for fluid communication between the
liquid retaining member accommodation chamber 7 and
the ink accommodation chamber 9; 15 is an ambience
introduction groove for introducing the ambience into
the ink accommodation chamber 9 when the ink in the
liquid retaining member 2 is used to a predetermined
level; and 21 is an ink introduction groove which is
peculiar to this embodiment.
The ink introduction groove 21 is, as shown
in Figure 20, (c), is provided as a groove at the
peripheral portion of the bottom surface of the ink
accommodation chamber 9, and as shown in Figure 20,
(b), it encloses the bottom surface of the ink
CA 02229871 1998-02-18
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accommodation chamber 9, and connects to the liquid
retaining member 2 through the fluid communication
path 10.
Because of this structure, the ink 11 at the
peripheral portion or the corner portion of the bottom
surface of the ink accommodation chamber 9 is absorbed
in the liquid retaining member 2 through the ink
introduction groove 21, the amount of the remainder
ink in the ink accommodation chamber 9 without being
used, is significantly reduced.
By reducing the capillary force of the ink
introduction groove 21 to less than the capillary
force of the liquid retaining member 2, the ink 11 in
the ink introduction groove 21 can be completely
absorbed, so that usage efficiency of the ink 11 is
further improved. In addition, by reducing the
cross-sectional area of the ink introduction groove 21
is reduced toward the fluid communication path 10, the
ink can be positively moved, and therefore, this is
preferable.
Figure 21, (a) and (b) are a view
corresponding to Figure 1, (b) and a sectional view
taken along a line G-G'. In the embodiment of Figure
20, the bottom levels of the liquid retaining member
accommodation chamber 7 and the ink accommodation
chamber 9 are the same, and the ink introduction
groove 21 ends at the fluid communication path 10. In
CA 02229871 1998-02-18
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this embodiment, however, the level of the bottom
surface of the liquid retaining member accommodation
chamber 7 is lowered to the level of the bottom level
of the ink introduction groove 21, so that ink
introduction groove 21 does not end at the fluid
communication path 10, and therefore, it continues to
the liquid retaining member accommodation chamber 7.
Because of this structure, the ink absorption
into the liquid retaining member 2 through the ink
introduction path 21 is further stabilized. The
latitude of the mold division for the manufacturing is
increased.
Figure 22, (a), (b)and (c)show a further
embodiment wherein (a) shows a view corresponding to
said Figure 21, (a), (b) is a sectional view taken
along a line H-H, and (c) is a sectional view taken
along a line I-I'.
In the embodiments of Figures 20 and 21, the
recess constituting the ink introduction groove 21 is
provided only in the bottom surface, but in this
embodiment, the recess is formed in the side of the
fluid communication path :10 to constitute the ink
introduction groove 21.
In order to maintain the connection between
the ink accommodation chamber 9 and the ink
introduction groove 21, the bottom surface of the
fluid communication path 10 is lower than the bottom
CA 02229871 1998-02-18
-40-
surface of the ink accommodation chamber 9 as shown in
Figure 22, (c).
Thus, the liquid retaining member 2 assuredly
enters the ink introduction groove 21, and the
absorption of the ink through the ink introduction
groove 21 is stabilized.
The latitude of the mold division is
increased.
Figure 23, (a) and (b) show this embodiment,
wherein (a) shows a view corresponding to the Figure
22, (a), and a sectional view taken along a line J-J'.
In the embodiment of Figure 22, the recess is
formed only in the fluid communication path 10 to
constitute the ink introduction groove 21, but in this
embodiment, the recess is formed also in the side
surface of the ink accommodation chamber 9.
By doing so, the connection property between
the ink accommodation chamber 9 and the ink
introduction groove 21 of the fluid communication path
10 is improved, so that stability of the ink suction-
out from the ink accommodation chamber 9 through the
ink introduction groove 21 is stabilized.
The ink introduction groove 21 in the side
surface may be constitution by a projection.
Figure 24 is an illustration according to a
further embodiment, and show a view corresponding to
said Figure 23, (a).
CA 02229871 1998-02-18
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In the embodiments of Figures 20-23, the ink
introduction path 21 is provided only in the
circumference of the ink accommodation chamber 9, but
in this embodiment, a plurality of ink introduction
grooves 21 are provided in the bottom surface of the
ink accommodation chamber. By doing so, the
stability of the ink sucking out is further improved.
Figure 25 illustrates a further embodiment,
wherein (a)is a cross-sectional view showing a bottom
surface configuration of the ink container according
to this embodiment, and (b)is a top plan view of the
internal structure.
In this embodiment, the ink introduction
groove 21 is used, and in addition, the bottom surface
of the ink accommodation chamber 9 is inclined, so
that even if the recording head is mounted to the
carriage with some inclination, it is assured that
fluid communication path 10 is lower to some extent,
and therefore, the ink in the ink accommodation
chamber 9 flows into the fluid communication path 10
by the gravity.
As shown in Figure 25, (a) (cross-sectional
view) (b) which is a sectional view taken along a line
K-K', the ink accommodation chamber 9 has an inclined
surface 24 lowering toward a fluid communication path
10 for fluid communication with the liquid retaining
member accommodation chamber 7 By the provision of
CA 02229871 1998-02-18
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the inclined surface 24, the liquid can be properly
introduced to the fluid communication path 10. In
addition, in this example, there is provided an ink
introduction groove 21 formed as a recess along a
bottom portion of the outermost circumference of the
ink accommodation chamber 9. The ink introduction
groove 21 functions, as described hereinbefore, to
introduce the ink from the ink accommodation chamber 9
into the fluid communication path 10.
The circumference portion of the bottom
surface of the ink accommodation chamber 9 has a
larger capillary force than at the bottom surface flat
surface portion, so that ink tends to remain.
Particularly, the corner portion where the walls are
intersect, has a larger capillary force, and
therefore, the ink tends to remain. At the final
stage of the ink consumption, the liquid passage to
the liquid retaining member is discontinued, and the
ink flow ends while the ink remains at the corner
ao portion or the peripheral portion. Thus the ink
remains in the ink accommodating chamber undesirably.
Therefore, it is preferable that ink introduction
groove 21 is formed at the corner portion and the
circumference portion of the bottom of the ink
accommodating chamber 9, and that it is extended along
the bottom surface circumference to assure the fluid
communication with the liquid retaining member
CA 02229871 1998-02-18
-43-
accommodation chamber 7.
The ink introduction groove 21 is connected
with the groove 25 provided in the side surface of the
wall constituting the fluid communication path 10 at
the fluid communication path 10. By doing so, a
continuous groove region is constituted over the ink
introduction groove 21 of the ink accommodation
chamber 9 and the liquid retaining member
accommodation chamber 7.
As shown in Figure 21, the bottom surface of
the ink accommodation chamber 9 is at a level higher .
than the bottom surface of the liquid retaining member
accommodation chamber 7, and in order to assure the
continuity of the surface from the bottom surface of
the ink accommodation chamber 9 to the fluid
communication path 10, there is provided a second
inclined surface 22 having an inclination angle
diffe}ent from that of the main inclined surface 24 of
the ink accommodation chamber. It is for maintaining
the continuity between the bottom surface of the ink
accommodation chamber 3 and the surface of the fluid
communication path 10, and by using this, there is no
part which impede the movement of the ink, thus
further reducing the remaining amount of the ink.
It is preferable that corner portion of the
ink accommodation chamber 9 is formed into a curved
surface. If the corner portion has an acute angle, a
CA 02229871 1998-02-18
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capillary force may be produced with the result of
retaining a small amount of the ink. The structure of
the bottom surface of the ink accommodation chamber 9
is not limited to those described in the foregoing,
and the entire inclination may be toward the fluid
communication path 10, and the ink introduction groove
21 shown in Figure 24 may be provided.
The structure of the groove 25 provided at
each of the sides of the fluid communication path 10
is not limited to those described above, and may be in
the form of a reces$ at the bottom side;
alternatively, the recess is not inevitable if the
corner constituting the fluid communication path 10 is
enough to produce the capillary tube force. The ink
introduction path 11 may by converged toward the fluid
communication path 8 stepwisely. Then, the ink can be
supplied properly toward the liquid retaining member
accommodation chamber.
By employing the above-described structure,
the ink can be moved smoothly from the ink chamber to
the fluid communication path portion, and therefore,
the ink in the ink accommodation chamber can be
further smoothly supplied.
As described in the foregoing, the provision
of the ink introduction groove is effective to reduce
the amount of the ink which remains unusably in the
ink accommodation chamber to increase the usage
CA 02229871 1998-02-18
-45-
efficiency of the ink, thus reducing the running cost.
When the ink remaining amount detection is
effected for the ink accommodation chamber, the
remaining amount detection is stabilized, since the
amount of the remaining is very small, thus avoiding
damaging the print data. The warning is correct, and
the printing operation may be forcedly stopped.
By the provision of inclination of the bottom
surface of the ink accommodation chamber, the ink can
be assuredly sucked out from the ink accommodation
chamber even when the ink container is mounted to the
carriage inclinedly, so that amount of the unusably
remaining ink can be reduced, thus increasing the
usage efficiencY Of the ink, and reducing the running
cost.
When the ink remaining amount detection is
effected for the ink accommodation chamber, the
remaining amount detection is stabilized, since the
amount of the remaining is very small, thus avoiding
damaging the print data. The warning is correct, and
the printing operation may be forcedly stopped.
Figure 26 shows a further embodiment.
In this embodiment, there are provided the
ink introduction groove 21, the main inclined surface
24, the second inclined surface 22 and the groove 25
as shown in Figure 25, as the structure around the
fluid communication path 10 and the ink accommodation
CA 02229871 1998-02-18
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chamber 9. The structure of the liquid retaining
member accommodation chamber 7 is as shown in Figure
9. The descriptions of each of the structures is
omitted for simplicity.
Using these structures, even when the amount
of the ink in the ink accommodation chamber 9 becomes
very small, the combination of the main inclined
surface 24 and the ink introduction groove 21 permits
the smooth movement of the ink toward the
communicating portion 10, and the combination of the
groove 25 and the second inclined surface 22 provided
at the region of the communicating portion lO permits
the movement of the small amount of the remaining ink
toward the liquid retaining member accommodation
chamber 7.
On the other hand, at the liquid retaining
member accommodation chamber 7, the static head for
the head can be properly maintained to accomplish the
stabilized ink supply, because of the provision of the
inner projected region constituting the stable ink
region. As regards the ink, the state of the liquid
retaining member in the inner projected region is
quite uniform so that amount of the remaining ink can
be extremely reduced.
Therefore, this embodiment accomplishes the
stable ink supply and the high use efficiency of the
ink.
CA 0222987l l998-02-l8
-47-
While the invention has been described with
reference to the structures disclosed herein, it is not
confined to the details set forth and this application
is intended to cover such modifications or changes as
may come within the purposes of the improvements or the
scope of the following claims.
