[0001] This invention relates to an ink cartridge for holding ink that is supplied to a
recording head, that is removably attached to recording heads used in image forming
apparatuses, and to an ink volume detection method for the ink cartridge.
[0002] Image forming apparatuses such as ink jet printers eject ink droplets from nozzles
in a recording head mounted on a carriage, thereby recording images on recording media.
The ejection of the ink droplets is accomplished by driving actuators such as electric-to-mechanical
converter elements or electric-to-thermal converter elements positioned inside the
recording head to generate pressure waves. The ink is supplied from an ink cartridge
mounted on the recording head so that it can be easily removed and replaced. When
air bubbles are mixed in with the ink liquid that is supplied from the ink cartridge,
however, this has an adverse effect on the ejection of ink from the nozzles in the
recording head.
[0003] In Fig. 20 is diagrammed an example of an ink cartridge structure as disclosed in
Japanese Patent Application Laid-Open No. H9-70982/1997. An ink cartridge 150 has
an ink supply hole 153 for supplying ink to a recording head 137, and an atmosphere
connection hole 155 communicating to the outside atmosphere so as to allow air to
flow in from outside the cartridge 150 as the ink volume is diminished by the consumption
of ink absorbed in a porous material 152. Accordingly, after the ink cartridge 150
is filled with ink during fabrication, both of these openings (i.e. the ink supply
hole 153 and atmosphere connection hole 155) are closed off by a sealing material.
Also, as disclosed in Japanese Patent Application Laid-Open No. H7-132611/1995 (gazette),
for example, at the time of shipment from the factory, the ink cartridge containing
ink is sealed in a reduced-pressure condition inside a packaging bag to prevent ink
leakage and the intrusion of air into the case prior to cartridge use. When it is
time for use, the user removes the ink cartridge from the packaging bag, peels away
the sealing material, thereby opening the atmosphere connection hole, and connects
the ink supply hole to the recording head.
[0004] It is desirable to have the ink supply hole and the atmosphere connection hole located
some distance apart in order both to prevent air from being drawn from the atmosphere
connection hole into the ink supply hole via a short circuit and to facilitate use
of the ink contained in the case without waste. For this reason, the ink supply hole
and atmosphere connection hole are located on mutually opposing sides of the case,
as diagrammed in Fig. 20. When filling the ink cartridge 150 with ink during the manufacturing
process, on the other hand, the ink supply hole 153 serves also as the ink filling
hole, and the atmosphere connection hole 155 is used as a pressure-reduction hole
in order to reduce the pressure inside the case. Thus ink is filled in through the
ink supply hole while effecting reduced pressure inside the case.
[0005] In the process of filling the ink cartridge 150 with ink, it is necessary to bring
an ink filling apparatus and a pressure reduction apparatus up against both sides
(the right side and left side in Fig. 20) of the ink cartridge 150. After the ink
filling operation, sealing tape has been used to seal the ink supply hole 153 and
the atmosphere connection hole 155. However, in the case of a cartridge structure
such as that diagrammed in Fig. 20, the sealing tape must be pulled all the way around
the case, from the upper surface (right side surface in Fig. 20) to the lower surface
(left side surface in Fig. 20). Not only does this require a long length of tape,
but, when the sealing tape is applied using a roller mechanism, the operation cannot
be accomplished from one side of the case, so the sealing tape must be pulled around
the case from the upper surface to the lower surface while rotating the case, thus
involving an inefficient operation.
[0006] After sealing the ink filling hole (ink supply hole) with the sealing tape, the sealing
tape has been heat welded by the application of heat. If the ink filling hole is wet
with ink, however, heat welding cannot be adequately performed. When more heat is
applied to avoid this, a problem arises in that the ink supply hole is deformed so
that it cannot be properly connected to the recording head.
[0007] During the ink filling operation, moreover, when the interior of the case is placed
under reduced pressure by the pressure reduction apparatus, the entire case is sometimes
deformed, whereupon the case cannot be efficiently filled with ink.
[0008] When the configuration is such that a porous material 152 is accommodated inside
the cartridge case to absorb the ink, as diagrammed in Fig. 20, it is demanded that
the filling be done efficiently so that the ink reaches to the corners inside the
porous material 152.
[0009] It is also demanded that, when the ink cartridge is being replaced, the user can
easily peel away the sealing tape and efficiently utilize the ink in the case.
[0010] With this type of ink cartridge, furthermore, the remaining ink volume is continually
or periodically detected by a detector installed in the recording apparatus. When
it is detected that the remaining ink volume is low, the recording apparatus advises
the user to replace the ink cartridge. This detection of the remaining ink quantity.
inside the ink cartridge is generally performed by detecting the ink liquid level.
However, because the liquid level tends to shake and fluctuate because the ink cartridge
is mounted on a carriage that moves in a sweeping motion in the width direction of
the recording medium, erroneous detections often to occur. That being so, one measure
known in the prior art for reducing the liquid level fluctuations (shaking) is that
of providing rib-shaped members inside the cartridge case. This measure, however,
requires the case structure to be complex. Also known is the method of directing light
onto the porous material absorbing the ink inside the case and detecting the remaining
ink quantity from the light reflected back. With this method, however, it is difficult
to detect the remaining ink quantity accurately because the presence or absence of
ink in the porous material differs from location to location therein.
[0011] In an ink jet type of image forming apparatus, in order to restore the ink ejection
function, a suction cap connected to a suction pump is used to cover the recording
head and suck out large amounts of ink from the recording head. When the ink liquid
level inside the ink cartridge falls rapidly due to this suction, not all of the ink
in contact with the wall surfaces of the ink cartridge moves instantly to the same
height position, more or less, as the ink liquid level. Some of this ink remains adhering
to the wall surfaces. This phenomenon becomes increasingly pronounced as the distance
from the corners of the outer walls of the ink cartridge (i.e. the ridges thereof)
increases, that is, the closer the center of the flat wall surfaces is approached.
Accordingly, in cases where the detection site for a sensor is located near the center
of the cartridge wall surface, even when the ink liquid level falls, so that there
is little actual remaining ink quantity, that fact cannot be detected, wherefore erroneous
detections occur, which is a problem.
[0012] When the remaining ink quantity inside the ink cartridge is being detected with a
sensor, particularly one that is of the reflected light type, in order to accurately
eject light onto a detection site from a light emitting element, and have the light
reflected at the inner surface of the outer wall of the ink cartridge that is the
detection site received without fail by a light receiving element, the positions of
the light emitting element and light receiving element relative to the detection site
must be accurately established. However, the ink cartridge is made so that it can
be freely attached to and detached from the recording head so that the user can replace
it. The condition in which the ink cartridge is mounted will be slightly different,
therefore, every time the user replaces it. In some cases, moreover, variation in
the positions in which the reflected light sensors are attached relative to the carriage
will arise at the stage of recording apparatus manufacture. Thus, when there are slight
irregularities in the distance between the reflected light sensor and the detection
site, or in the attachment position or angle of the reflected light sensor relative
to the detection site, the light receiving element cannot properly detect the reflected
light, so that the remaining ink quantity inside the ink cartridge cannot be detected
or the remaining ink quantity detection precision sharply declines.
[0013] With this type of ink cartridge, furthermore, ink sometimes travels along the inner
walls of the ink chamber holding the ink and reaches the atmosphere connection chamber
adjacent to the. ink chamber. This ink sometimes also passes through the atmosphere
connection hole and leaks to the outside. If the case is transparent or semi-transparent,
the case will become unsightly once ink penetrates into the atmosphere connection
chamber. If the ink plugs up the atmosphere connection hole, that will impair the
supply of ink to the recording head.
[0014] A type of ink cartridge is also known wherein, inside the ink cartridge case, a first
chamber is provided for accommodating the porous material absorbing ink, and a second
chamber is provided downstream from the first chamber, such that ink is supplied to
the recording head via an ink supply hole from the second chamber. With such a structure
as this, when air bubbles intrude into the second chamber from the first chamber,
and those air bubbles are drawn to the recording head from the second chamber, there
is a danger that the recording head will become incapable of ink ejection due to the
air bubbles.
[0015] In a vacuum pack such as is described in the foregoing, furthermore, in order to
maintain the interior thereof at reduced pressure for extended periods of time, it
is necessary that there be space between the ink cartridge and the packaging bag of
the pack, which space has a higher degree of vacuum than the interior of the ink cartridge.
Supposing that a substantially rectangular ink cartridge is contained in a packaging
bag, and that the packaging bag adheres tightly to the cartridge, outside air that
gradually penetrates through the packaging bag will relatively quickly fill the slight
gap between the packaging bag and the ink cartridge, making it difficult to maintain
the reduced pressure condition for any extended period of time. Japanese Patent Application
Laid-Open No. H10-250111/1998 discloses a cartridge wherein, in order to secure a
prescribed volume for the reduced pressure space, the exterior shape is not made a
simple rectangle but rather is made so that a part thereof projects, thus forming
a space alongside the projecting part where the packaging bag does not tightly adhere.
With this cartridge, holes are sometimes opened in the packaging bag by the cartridge
corners. In Japanese Patent Application Laid-Open No. 7-132611, art is disclosed for
inserting other components (spacers) inside the packaging bag such as corrugated cardboard
or urethane foam which contain air internally and through which air readily passes.
When separate components are inserted inside the packaging bag, however, the number
of manufacturing processes increases, costs rise, and the exterior shape of the packaging
bag becomes large, which is undesirable in the interest of smaller size.
SUMMARY OF THE INVENTION
[0016] The present invention has been devised for the purpose of resolving the problems
with the prior art described in the foregoing. A first object thereof is to provide
an ink cartridge wherewith bringing a filling apparatus and a pressure reduction apparatus
close to the cartridge package for ink filling is rendered easy, and the operation
of applying seals to the case openings is made simple.
[0017] A second object of the present invention is to provide an ink cartridge wherewith
the case can be efficiently filled with ink all the way 'to the corners thereof, wherewith
case. deformation due to reduced pressure during filling is prevented, and wherewith
filling can be done even more efficiently.
[0018] A third object of the present invention is to provide an ink cartridge that is made
so that the remaining ink quantity can be detected utilizing the space that is for
filling the case with ink, which suppresses ink liquid level fluctuation even though
the case has a simple structure, and wherewith the remaining ink quantity can be detected
accurately.
[0019] A fourth object of the present invention is to provide an ink cartridge wherewith,
even when the liquid level fluctuates rapidly due to ink being drawn out from the
recording head, and even when there is variation in the position where the sensor
is attached in the recording apparatus, accurate remaining ink quantity detection
is made possible.
[0020] A fifth object of the present invention is to provide an ink cartridge wherein the
intrusion of ink to the atmosphere connection hole side from the ink chamber is prevented,
and wherein, even when there is a slight occurrence of such ink intrusion, leakage
to the outside and blocking of the atmosphere connection hole is prevented.
[0021] A sixth object of the present invention is to provide an ink cartridge wherewith,
when ink is being supplied successively from a first chamber to a second chamber in
an ink chamber, air bubbles are not drawn directly into the recording head even when
air bubbles intrude into the second chamber, and wherewith ink ejection problems caused
by air bubbles are prevented.
[0022] A seventh object of the present invention is to provide an ink cartridge wherewith
the inside of the packaging bag used to hermetically seal the ink cartridge is maintained
at reduced pressure for an extended period of time, wherewith there is no particular
need for any separate component for forming space for that purpose, and wherewith
manufacturing costs can be reduced and achieving smaller size is rendered easy.
[0023] An eighth object of the present invention is to provide a remaining ink quantity
detection method wherewith the remaining ink quantity inside the ink cartridge can
be accurately detected.
[0024] According to a first aspect of the present invention, an ink cartridge is provided
which is removably attached to a recording head and which holds ink supplied to the
recording head, comprising: a case having a first surface and a second surface in
mutual opposition, the first surface whereof is open, a first cover for covering the
first surface, a partitioning wall for separating the interior of the case into a
first chamber and a second chamber, respectively, for holding the ink, a porous material
accommodated in the first chamber, an ink filling hole formed in the first cover for
filling the first chamber and the second chamber with ink, and a pressure reduction
hole formed in the first cover and connected to a reduced pressure source for reducing
the pressure in the first chamber and the second chamber, wherein the first chamber
and the second chamber are connected near the second surface inside the case.
[0025] As based on this structure, the ink filling hole and the pressure reduction hole
are in the first surface of the case, wherefore, when performing ink filling in the
manufacturing stage, it is only necessary to bring the filling apparatus and the pressure
reduction apparatus close to one side of the case, and, after that, sealing need only
be effected from one side of the case, thereby rendering the operation easy. During
ink filling, moreover, the ink passes successively to the second chamber and the first
chamber, from the ink filling hole toward the pressure reduction hole, wherefore both
chambers can be filled with ink efficiently. In addition, with this structure, there
is no need to open the upper and lower ends, as in a case to be described further
below, and if at least one surface is opened, that is sufficient. Also, as will be
described subsequently, ink may be supplied to the recording head from the first chamber
through the second chamber, or, alternatively, ink may be supplied to the recording
head from the second chamber through the first chamber.
[0026] In the ink cartridge of the present invention, an ink supply port for supplying ink
in either the first chamber or the second chamber may be formed in the second surface
of the case. When configured in this way, the ink supply hole is provided in a different
surface from the ink filling hole and the pressure reduction hole, wherefore the ink
supply hole can be closed off with sealing material prior to ink filling. For this
reason, the application of a seal to the ink supply hole is not interfered with by
ink adhering to the supply hole as in conventional cartridges. As a result, the ink
supply hole can be securely sealed prior to cartridge shipment, and ink can be prevented
from leaking out when a user mounts the cartridge onto the recording head.
[0027] In the ink cartridge of the present invention, the second surface may also be opened,
a second cover provided for covering the second surface, and the ink supply hole formed
in the second cover. When configured in this way, both end surfaces of the case are
open, wherefore it is easy to form the first chamber and the second chamber. Also,
while it is necessary to wash the case so that the ink properties are not changed,
washing and drying are easy because both end surfaces are open. Because porous material
is inserted into the first chamber and covered by a cover member, moreover, assembly
is simple. Furthermore, the operation of applying the sealing material for sealing
the ink filling hole and the pressure reduction hole in one surface and the sealing
material for sealing the ink supply hole in the other surface can be easily done with
a roller or the like while the ink cartridge is being conveyed along during manufacture.
[0028] In the ink cartridge of the present invention, an atmosphere connection hole for
communicating with the first chamber may be formed in the second cover. When configured
in this way, both the ink supply hole and the atmosphere connection hole are provided
on the same surface, wherefore the ink supply hole and the atmosphere connection hole
can be simultaneously sealed with sealing material during manufacture.
[0029] According to a second aspect of the present invention, an ink cartridge is provided
which is removably attached to a recording head and which holds ink supplied to the
recording head, comprising: a case having a first surface and a second surface in
mutual opposition and containing ink therein, wherein, an ink filling hole for filling
the case with ink and a pressure reduction hole connected to a reduced pressure source
for reducing the pressure inside the case are formed in the first surface, an ink
supply hole for supplying ink to the recording head is formed in the second surface,
the ink filling hole and the pressure reduction hole are closed off by a first sealing
material applied to the first surface, and the ink supply hole is closed off by a
second sealing material applied to the second surface so that it can be peeled away.
[0030] As based on this structure, the operation of applying the first sealing material
for sealing the ink filling hole and the pressure reduction hole in one surface and
of applying the second sealing material for sealing the ink supply hole in the other
surface can be easily done with a roller or the like while the ink cartridge is being
conveyed along during manufacture. The ink supply hole is not used during ink filling,
wherefore ink does not leak from the ink supply hole so as to impair the sealability
thereof as conventionally. Also, when the cartridge is being mounted on the recording
head by a user, it is easy to peel away only the second sealing material in preparation
therefor.
[0031] In an ink cartridge based on the second aspect of the present invention, an atmosphere
connection hole is formed which communicates between the inside and the outside of
the case. This atmosphere connection hole may be closed off by the second sealing
material which can be peeled away. As a consequence of being configured in this way,
when a user loads the cartridge onto the recording head of an ink jet printer or the
like, both the ink supply hole and the atmosphere connection hole can be opened simultaneously
by peeling away only the second sealing material.
[0032] According to a third aspect of the present invention, an ink cartridge is provided
which is removably attached to a recording head and which holds ink supplied to the
recording head, comprising: a case having a first surface and a second surface in
mutual opposition, the second surface is open, a partitioning wall for separating
the interior of the case into an ink chamber for holding ink and an atmosphere connection
chamber, wherein the ink chamber and the atmosphere connection chamber are open on
the second surface side, one end of the atmosphere connection chamber communicates
to the ink chamber on the first surface side, and the other end of the atmosphere
connection chamber communicates to the outside of the case, and a cover for covering
the second surface, wherein is formed an ink supply hole for supplying ink to the
recording head, connected to the ink chamber.
[0033] With an ink cartridge implemented according to the third aspect of the present invention,
ink is supplied to the recording head from the ink chamber via the ink supply hole
formed on the second surface side, while air is inducted into the ink chamber on the
first surface side via an atmosphere connection path. Consequently, air is not readily
admitted to the ink chamber, and the ink in the ink chamber can be used efficiently.
Also, this cartridge has a simple structure, and can be easily assembled by covering
the second surface with the cover. The ink chamber may also contain a first chamber
and a second chamber, as in the specific example of the present invention, but it
may also be configured with a single chamber only.
[0034] With an ink cartridge implemented according to the third aspect of the present invention,
the cover may cover the open surfaces of the ink chamber and the atmosphere connection
path, and have a second connecting hole communicating to the atmosphere connection
path.
[0035] According to a fourth aspect of the present invention, an ink cartridge is provided
which is removably attached to a recording head and which holds ink supplied to the
recording head, comprising: a case having a first surface and a second surface in
opposition, both surfaces whereof are open, a partitioning wall for separating the
interior of the case into an ink chamber for' holding ink and an atmosphere connection
path communicating to the outside of the case, wherein the ink chamber is open on
the first surface and the second surface sides, a first cover for covering the first
surface of the case so that a path is formed for communicating between the ink chamber
and the atmosphere connection path, a second cover for covering the second surface
of the case, and an ink supply hole that connects to the recording head, formed in
the second cover so as to communicate with the ink chamber.
[0036] With an ink cartridge implemented according to the fourth aspect of the present invention,
the opposing first and second surfaces of the case are open, respectively, wherefore
it is easy to form the ink chamber and the atmosphere connection path inside the case.
It is necessary to wash the inside of the case beforehand so that the ink characteristics
do not change. Both surfaces are open in this cartridge, making washing and drying
convenient. Also, assembly is rendered simple by covering the first and second surfaces,
respectively, with the first cover and the second cover. The cartridge may have a
second partitioning wall for dividing the ink chamber into a first chamber for accommodating
the porous material absorbing ink and a second chamber for accommodating ink. One
of the chambers, i.e. the first chamber or the second chamber, may be covered by the
first cover while the other chamber is covered by the second cover. In that case,
in this type of ink cartridge, the first chamber may communicate with the atmosphere
connection path near the first surface and also communicate with the second chamber
near the second surface, while the second chamber communicates with the ink supply
hole. Based on this aspect, during a recording operation, ink is supplied to the recording
head under a suitable pressure from the ink supply hole via the second chamber by
the suction force of the porous material in the first chamber. When ink in the second
chamber flows out from the ink supply hole, ink is replenished in the second chamber
from the porous material in the first chamber while air is taken into the first chamber
from the atmosphere connection path. As a result, after the first chamber ink is consumed,
the second chamber ink is consumed, whereupon all the ink is used effectively.
[0037] According to a fifth aspect of the present invention, an ink cartridge is provided
which is removably attached to a recording head and which holds ink supplied to the
recording head, comprising: a cartridge case having a mutually opposed first side
wall and second side wall, a first partitioning wall positioned substantially parallel
to the first side wall of the case so as to separate the interior of the cartridge
case into a first chamber and a second chamber, respectively, for accommodating ink,
and a second partitioning wall positioned substantially parallel to the first side
wall of the case for separating the interior of the case into a first chamber and
an atmosphere connection path for communicating with the atmosphere outside the case,
wherein one end of the second chamber communicates with one end of the first chamber,
the other end of the second chamber is open the outside of the case as an ink supply
hole, one end of the atmosphere connection path communicates with the other end of
the first chamber, and the other end of the atmosphere connection path is open to
the outside of the case.
[0038] With an ink cartridge implemented according to the fifth aspect of the present invention,
a second partitioning panel (or a first partitioning panel) is placed substantially
parallel to a first side wall, wherefore the side wall becomes a two-ply structure
so that the strength of the cartridge is increased. For this reason, when the cartridge
is being filled with ink, the cartridge is prevented from deforming, even when the
interior thereof is under reduced pressure, and ink filling can be accomplished efficiently.
[0039] In a cartridge based on the fifth aspect, the atmosphere connection path may be demarcated
between the first side wall and the second partitioning wall, and the second chamber
demarcated between the second side wall and the first partitioning wall. Also, an
ink supply hole for supplying ink to the recording head may be provided near the one
end of the second chamber and the ink in the first chamber supplied to the recording
head from the ink supply hole via the second chamber. Given this structure, the cartridge
is arranged so that the ink supply hole is normally positioned below, wherefore, even
should air bubbles flow into the second chamber from the first chamber together with
the ink, air bubbles are prevented from floating up toward the top of the second chamber
and being drawn into the ink supply hole. For this reason, ink discharge failure from
the recording head can be prevented. In a cartridge based on the fifth aspect, the
other end of the first chamber may be open, the open part covered by the first cover,
the one end of the second chamber open, the open portion covered by the second cover,
and the ink supply hole formed in the second cover. With this cartridge, a case can
be used which is open on both sides and easily formed, and a cartridge can be easily
manufactured by adding a first and a second cover to this case.
[0040] In a cartridge based on the fifth aspect, furthermore, a third partitioning wall
may be provided which extends substantially perpendicular to the first side wall inside
the case and connects the lower ends of the first partitioning wall and the second
partitioning wall, the first chamber divided by the first, second, and third partitioning
walls, and a connecting hole formed in the third partitioning wall to connect between
the first and second chambers. In this case, one end of the first chamber may be open,
the open portion covered by the first cover, the ink filling hole connecting the second
chamber and the outside of the case formed in the first cover, one end of the second
chamber open, the open portion covered by the second cover, and an atmosphere connection
hole communicating with the atmosphere connection path formed in the second cover.
[0041] According to a sixth aspect of the present invention, an ink cartridge is provided
which is removably attached to a recording head and which holds ink supplied to the
recording head, comprising: a cartridge case having an upper case surface and a lower
case surface, a partitioning wall for dividing the inside of the case into first and
second chambers for accommodating ink, respectively, wherein the first and second
chambers mutually communicate near the lower case surface, an ink filling hole for
filling the second chamber with ink, formed in the upper case surface, a sealing material
for closing off the ink filling hole, an ink supply hole for supplying ink to the
recording head from the second chamber, formed in the lower case surface, and an atmosphere
connection hole for connecting the first chamber to the atmosphere, wherein the second
chamber is formed between one side wall of the case and the partitioning wall, and
at least one portion of the one side wall is either transparent or semi-transparent.
[0042] In a cartridge based on the sixth aspect, when the ink is supplied to the recording
head from the ink supply hole of the ink cartridge, ink is supplied from the first
chamber to the second chamber, whereupon the first chamber ink decreases in volume
first. When the first chamber ink is depleted, air flows into the second chamber and
the second chamber ink decreases in volume. Hence the remaining ink quantity can be
known by detecting a fall in the ink liquid level in the second chamber, either visually
or with a sensor. Also, ink is filled from the second chamber via the ink filling
hole, and the filling hole is closed off with a sealing material after the second
chamber and the first chamber have been filled, wherefore the second chamber can be
completely filled. Thus erroneous detections of the initial remaining ink quantity
can be prevented.
[0043] In a cartridge based on the sixth aspect, the first chamber may be given a larger
capacity than the second chamber and made to accommodate the porous material absorbing
ink. Even when a large volume of ink is present in the first chamber, due to the suction
force of the porous material, ink can be supplied to the recording head from the ink
supply hole under suitable pressure. Also, by detecting the remaining ink quantity
in the second chamber of smaller capacity, erroneous detections caused by ink wave
formation can be prevented. In this case, the upper case surface may be configured
with a cover attached to the case, and the ink filling hole formed in the cover. When
this is done, the structure of the ink cartridge becomes simple. If a sheet material
is used as the sealing material, this can be easily applied to the cover so as to
close off the ink filling hole.
[0044] In a cartridge based on the sixth aspect, the inner surface of the transparent or
semi-transparent portion of the one side wall may have undulating ribs running vertically
up and down.
[0045] Based on this configuration, when, for example, a remaining ink quantity sensor is
used that comprises a light emitting component and a light receiving component, the
light emitted by the light emitting component is reflected at the inner surface of
the side wall of the second chamber, whereupon it is scattered by the undulating ribs
on that inner surface in directions perpendicular to the undulating ribs, and the
reflected light advances toward the light receiving component while spreading out
in a plane that includes the light emitting component, the light receiving component,
and the detection site on the main case body. Therefore, even in cases where the interval
between the detection site and the sensor has slightly changed due to slight differences
in the ink cartridge mounting position or sensor attachment position, the light receiving
component can safely capture the reflected light. Accordingly, the remaining ink quantity
inside the ink cartridge can be unambiguously detected even when there is some degree
of variation in the sensor attachment condition or ink cartridge mounting condition.
[0046] According to a seventh aspect of the present invention, an ink cartridge is provided
which is removably attached to a recording head and wherein the remaining ink quantity
inside the cartridge is detected by an optical detector having a light emitting component
and a light receiving component, comprising: a cartridge case having in its interior
an ink chamber for holding ink, and a remaining ink quantity detection site provided
on the case, wherein the inner case surface at the detection site has undulating ribs
extending in a direction perpendicular to a plane containing the detection-light light
emitting component, the light receiving component, and the detection site, and the
remaining ink quantity inside the ink chamber is detected by illuminating light to
the detection site and receiving the light that is reflected therefrom.
[0047] Based on this configuration, the inner surface of the ink chamber that constitutes
the site for detecting by the reflected light sensor has undulating ribs extending
in a direction perpendicular to a plane that contains the light emitting component
and light receiving component of the emitted light sensor and the detection site in
the ink chamber, wherefore when light emitted by the light emitting component is reflected
at the inner surface of the ink chamber side wall, it is scattered by the undulating
ribs on that inner surface in directions perpendicular to the undulating ribs, and
advances toward the light receiving component while spreading out in a plane that
includes the reflected-light light emitting component and light receiving component
and the detection site. Therefore, even in cases where the interval between the detection
site and the reflected-light sensor has slightly changed due to slight differences
in the ink cartridge mounting position or in the reflected-light sensor attachment
position, the light receiving component can safely capture the reflected light. Accordingly,
the remaining ink quantity inside the ink chamber can be unambiguously detected even
when there is some degree of variation in the reflected-light sensor attachment condition
or ink cartridge mounting condition.
[0048] The cartridge case having undulating ribs can be formed using a die. In the ink cartridge
based on the seventh aspect, the outer case surface at the detection position may
have undulating ribs extending parallel to a plane containing the light emitting component,
the light receiving component, and the detection site. Based on this configuration,
light reflected at the outer surface of the outer wall of the main case body is scattered
by the undulating ribs on that outer surface in directions perpendicular to those
undulating ribs, and the reflected light advances to the light receiving component
while spreading out outside of the plane containing the light emitting component and
the light receiving component of the reflected-light sensor and the detection site
on the main case body, wherefore it is difficult for the light receiving component
to capture light reflected at the outer surface of the outer wall which does not contribute
to remaining ink quantity detection. Accordingly, of the reflected light captured
by the light receiving component, the ratio of that component of the light reflected
from the inner surface of the outer wall contributing to remaining ink quantity detection
rises, whereupon the precision wherewith the remaining ink quantity is detected is
improved.
[0049] According to an eighth aspect of the present invention, an ink cartridge is provided
which is removably attached to a recording head and which holds ink supplied to the
recording head, comprising: a cartridge case having an upper case surface and a lower
case surface, a partitioning wall for separating the interior of the cartridge case
into a first chamber for holding ink and an atmosphere connection chamber for communicating
with the atmosphere outside the case, one end of the wall is joined to the upper case
surface, and a path for connecting the first chamber and the atmosphere connection
chamber, formed in the upper case surface, wherein the path and the first chamber
are connected via a portion of a surface which does not contain an intersection line
formed by the intersection of a surface and a surface.
[0050] Based on the ink cartridge according to the eighth aspect of the present invention,
the first chamber holding the ink is not connected by an intersection line (or ridge
line) formed by the intersection of a surface and a surface, such as the intersection
line formed by the upper case surface and the partitioning wall. With the cartridge
of the present invention, the first chamber and the path are connected via a curved
surface such as the inner surface of the pressure reduction hole diagrammed in Fig.
12, wherefore the ink in the first chamber is prevented from traveling along the intersection
line formed by the upper case surface and the partitioning wall and advancing into
the path. The upper case surface, moreover, need not be integral to the case, but
may be a cover member that can be placed over the opening in the empty main case body
during manufacture. When this is done, the path can be formed in the cover member,
making fabrication of the case itself simple.
[0051] In the ink cartridge based on the eighth aspect of the present invention, porous
material absorbing ink may be accommodated in the first chamber. The cartridge case
may also be configured such that a projecting part that projects inside the first
chamber is formed on the upper case surface, at a position apart from the partitioning
wall, such that the projecting part pushes against the porous material inside the
first chamber. This projecting part corresponds to the wall 27 in Fig. 12. The wall
27 juts out toward the ink chamber, and the inner wall thereof does not contain an
intersection line formed by the intersection of a surface and a surface. By making
the upper ink surface a cover member, as described in the foregoing, an upper case
surface can be easily formed which has a projecting part.
[0052] In the ink cartridge based on the eighth aspect of the present invention, the path
is formed by a concavity extending from the first chamber on the outer side surface
of the upper case surface to the atmosphere connection chamber, a first hole connecting
the concavity and the first chamber, a second hole connecting the concavity and the
atmosphere connection chamber, and sealing material covering the concavity. With this
structure, the path can be fabricated easily with few parts.
[0053] According to a ninth aspect of the present invention, an ink cartridge is provided
which is removably attached to a recording head and which holds ink supplied to the
recording head, comprising: a cartridge case having an upper surface and a lower surface,
and a partitioning wall for dividing the interior of the case into an ink chamber
for holding ink and an atmosphere connection path for communicating to the ink chamber
and also communicating to the atmosphere outside the case, wherein the atmosphere
connection path extends from the lower surface of the case to the upper surface thereof,
a part of the inner wall of the lower surface of the case projects into the atmosphere
connection path inside the case, and a connecting hole is passed through the projecting
part for communicating between the outside of the case and the atmosphere connection
path, whereby ink can be accumulated in the atmosphere connection path inside the
case.
[0054] With the ink cartridge based on the ninth aspect of the present invention, even if
ink leaks from the ink cartridge chamber and flows into the atmosphere connection
path, a connecting hole is formed in the projecting part that projects from the lower
surface of the cartridge case toward the interior of the case (cf. 18a in Fig. 4),
wherefore the ink will not immediately block the connecting hole. In other words,
the ink is accumulated above the lower surface inside the case, and so, until it exceeds
the height of the projecting part, will not pass through the connecting hole and leak
to the outside of the case.
[0055] According to a tenth aspect of the present invention, an ink cartridge is provided
which is removably attached to a recording head and which holds ink supplied to the
recording head, comprising: a cartridge case having an upper case surface and a lower
case surface; a partitioning wall for dividing the inside of the cartridge case into
a first chamber for accommodating a porous material absorbing ink and a second chamber
for holding ink, wherein the partitioning wall has a first part that is in opposition
to the lower surface of the case, whereby a portion of the second chamber exists between
the partitioning wall and the lower case surface, and a connecting hole for connecting
the first chamber and the second chamber is formed in the first part of the partitioning
wall; an ink supply hole, formed in the lower case surface, for supplying ink from
the second chamber to the recording head; and a baffle plate, provided between the
connecting hole and the ink supply hole, for preventing air bubbles from flowing into
the ink supply hole from the connecting hole.
[0056] With the ink cartridge based on the tenth aspect of the present invention, when ink
is ejected from the recording head with the ink cartridge mounted on the recording
head, ink is drawn by the negative pressure developed in the recording head from the
second chamber through the ink supply hole and, at the same time, ink from the first
chamber is drawn into the second chamber through the connecting hole. Air bubbles
produced at this time are prevented from flowing into the ink supply hole by the baffle
plate. For this reason, ink ejection problems associated with the inflow of air bubbles
to the recording head are prevented from occurring. Due to the baffle plate, the air
bubbles rise up toward the upper case surface inside the second chamber.
[0057] In the ink cartridge based on the tenth aspect, the lower case surface is a cover
member installed in the case at the time of ink cartridge fabrication. The ink supply
hole is formed in this cover member, and the baffle plate is formed in either the
cover member or the partitioning wall, or in both. If the lower case surface is made
a cover member that can be assembled in the main case body at the time of ink cartridge
fabrication, instead of being made integral with the main case body, assembly is made
easy, and, even if the baffle plate forms a complex flow path, it may be easily provided
in either the cover member or the partitioning wall.
[0058] In the ink cartridge based on the tenth aspect, the partitioning wall may have a
second part that extends from the end of the first part toward the upper case surface,
and the second chamber made so that it is divided between a first and second partitioning
wall and a case interior wall. If a second chamber is configured in this way, air
bubbles will be guided by the baffle plate and rise inside the second chamber along
the second part of the partitioning wall and accumulate at the top of the second chamber.
[0059] In the ink cartridge based on the tenth aspect, the first part of the partitioning
wall from the connecting hole to the second part should be inclined toward the upper
case surface. If the first part of the partitioning wall is inclined in this way,
air bubbles originating from the connecting hole will readily float along the first
part of the partitioning wall up to the upper part of the second chamber, whereupon
the influx of air bubbles into the ink supply hole is prevented even more effectively.
[0060] According to an eleventh aspect of the present invention, an ink cartridge is provided
which is removably attached to a recording head and which holds ink supplied to the
recording head, comprising: a cartridge case, and a partitioning wall for dividing
the inside of the cartridge case into an ink chamber for holding ink and an empty
chamber that communicates to the outside of the case, wherein the ink chamber and
the empty chamber do not mutually communicate.
[0061] Based on the ink cartridge of the eleventh aspect of the present invention, there
is an empty chamber (space) inside the cartridge case, wherefore, when the cartridge
is sealed in a bag and the pressure inside the bag is reduced, that reduced-pressure
condition can be maintained for an extended period of time. That is, when the bag
is rendered in a reduced-pressure state, although air will gradually find its way
into the bag with the passage of time, due to the presence of the empty chamber, the
reduced-pressure state can be maintained for a comparatively long period of time.
With the present invention, this empty chamber can be secured without the necessity
of any other parts, wherefore fabrication is simple, and manufacturing costs can be
reduced.
[0062] In the ink cartridge of the eleventh aspect of the present invention, the cartridge
case may be configured from a main case body one end whereof is open, and a cover
member for covering the open part of the main case body, the empty chamber formed
by the cover member and the partitioning wall, and a hole provided in the cover member
for connecting the empty chamber to the outside of the case. By configuring the case
in this manner, the empty chamber can be easily formed inside the case.
[0063] In the ink cartridge of the eleventh aspect of the present invention, a bag may be
used which hermetically seals the ink cartridge and the ink cartridge may be accommodated
in a bag under reduced pressure. By maintaining the ink cartridge inside the bag in
this manner, the ink can be maintained for extended periods of time with the air evacuated.
[0064] In the ink cartridge of the eleventh aspect of the present invention, the ink chamber
may have a first chamber for accommodating porous material absorbing ink, and a second
chamber that holds ink and communicates with the first chamber via a connecting hole,
the second chamber whereof is covered by the cover member, an ink supply hole for
supplying ink to the recording head from the second chamber formed in the cover member,
and the empty chamber formed adjacent to the second chamber.
[0065] In the ink cartridge of the eleventh aspect of the present invention, the ink supply
hole for transferring ink from the ink chamber to the recording head may be formed
in the cover member, the ink supply hole and the atmosphere connection hole closed
off with a sealing material that can be peeled away, and the cartridge case sealed
in a bag under reduced pressure. By sealing the cartridge in the bag under reduced
pressure after closing off the ink supply hole and the atmosphere connection hole
with the sealing material, the ink inside the cartridge can be maintained for long
periods of time with the air evacuated.
[0066] According to a twelfth aspect of the present invention, a remaining ink quantity
detection method is provided for detecting the remaining quantity of ink in an ink
cartridge having a case divided by a plurality of wall surfaces the interior whereof
is filled with ink, comprising the steps of: directing detection light onto a ridge
part that is formed by the intersection of at least two side surfaces which extend
vertically up and down in the case and that extends vertically up and down, and detecting
light reflected from the ridge part.
[0067] Based on this method, capillary action is induced at the ridge part extending vertically
up and down and formed by the intersection of at least two inner surfaces of the ink
chamber, whereby ink adhering to the inner surfaces of the ink chamber moves immediately,
in conjunction with the fall in the ink liquid level, to a point proximate to that
ink liquid level, wherefore there will be no erroneous detections of the presence
or absence of ink at the detection site, and the remaining ink quantity in the ink
chamber can be detected precisely.
[0068] With the remaining ink quantity detection method described above, the remaining ink
quantity may be detected using an optical sensor, which optical sensor may be positioned
opposite the ridge part. The ridge part may be made of a transparent or semi-transparent
material, and the sensor may have a light receiving component and a light emitting
component facing the ridge part. The case may comprise a first chamber that communicates
with the atmosphere and accommodates a porous material absorbing ink, and a second
chamber, the upper part of which is sealed, that communicates with the first chamber
and holds ink and the ridge part exists on the second chamber.
[0069] With the remaining ink quantity detection method described in the foregoing, the
ink cartridge may further comprise a partitioning wall for dividing the interior of
the case into a first chamber and a second chamber for holding ink, at least part
of the wall surface of the second chamber whereof is transparent or semi-transparent,
a connecting hole for mutually communicating between the first chamber and the second
chamber, an ink filling hole, formed in the upper end of the second chamber, for filling
the first chamber with ink from the second chamber via the connecting hole, a sealing
member for closing off the ink filling hole, an ink supply hole, formed in the lower
end of the second chamber, for supplying ink to the recording head, and an atmosphere
connection hole for connecting the first chamber to the atmosphere. With this cartridge,
the remaining ink quantity in the second chamber will begin dropping after the ink
in the first chamber has been depleted, wherefore the decline in the remaining ink
quantity can be detected unambiguously.
[0070] With the remaining ink quantity detection method described in the foregoing, the
interior surface of the case at the ridge part may have undulating ribs extending
perpendicular to a plane containing the light emitting component and the light receiving
component of the optical sensor and the ridge part.
[0071] The present invention will be more clearly understood from the following description,
given by way of example only, with reference to the accompanying drawings in which:
Fig. 1 is a cross-sectional view depicting an ink cartridge according to a first embodiment
of the present invention mounted on a recording head;
Fig. 2 is an external view of the ink cartridge;
Fig. 3 is a cross-sectional view of the ink cartridge;
Fig. 4 is an exploded cross-sectional view of the ink cartridge;
Fig. 5 is a cross-sectional view in the B-B plane of Fig. 1;
Fig. 6 is a bottom view of a case with the lower cover member of the ink cartridge
removed;
Fig. 7 is a top view of the ink cartridge before applying the upper cover member seal;
Fig. 8 is a top view of the ink cartridge after applying the upper cover member seal;
Fig. 9 is a bottom view of the ink cartridge;
Fig. 10 is a cross-sectional view in the A-A plane;
Fig. 11 is an enlarged diagonal view of the configuration of the path 16b between
the first chamber and the atmosphere connection path;
Fig. 12 is an enlarged diagonal view of an improved configuration for the connecting
part in Fig. 11;
Fig. 13 is an enlarged diagonal view of a further improved configuration for the connecting
part in Fig. 11;
Fig. 14 is a side elevation of the ink cartridge;
Fig. 15 is a horizontal cross-sectional view that conceptually diagrams the way light
is reflected at the remaining ink quantity detection site;
Fig. 16 is a horizontal cross-sectional view that conceptually diagrams the way light
is reflected at the remaining ink quantity detection site;
Fig. 17 is a vertical cross-sectional view that conceptually diagrams the way light
is reflected at the remaining ink quantity detection site;
Fig. 18 is a diagram for explaining the ink cartridge ink filling operation;
Fig. 19 is a cross-sectional view of the ink cartridge when accommodated in a packaging
bag; and
Fig. 20 depicts an example of a conventional ink cartridge structure.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0072] A specific embodiment of the present invention is now described with reference to
the drawings.
[0073] Fig. 1 is a diagram of the ink cartridge according to this embodiment, showing it
connected to a recording head. A head holder 50 for supporting the recording head
72 is mounted on a carriage 52 which moves so as to sweep across a recording medium.
In this holder 50 is loaded the ink cartridge 1 so that it can be detached. An ink
supply hole 17 made in the bottom surface of the ink cartridge 1 fits into a joint
member 74 on the head holder 50 side, and ink is distributed through a manifold member
73 to many ink ejection channels in the recording head 72. The recording head 72 ejects
ink from the ink ejection channels by the action of actuators consisting of piezoelectric
elements or heating elements.
[0074] The ink cartridge 1 according to this embodiment comprises a case 2 made in a rectangular
shape from a transparent or semi-transparent resin material, and upper and lower cover
members 3 and 4. The case 2 consists of a pair of opposing first side walls 2a and
2b, and, connecting between that pair of side walls, a pair of second side walls 2c
and 2d (cf. Fig. 2) so as to form a rectangular tube open at both the upper and lower
ends. The upper and lower cover members 3 and 4 are heat welded so as to cover the
open upper and lower tube ends. The case 2 is formed so that it is divided in the
interior thereof by partitioning walls 5 and 6 that extend substantially parallel
to the first side walls 2a and 2b (the left and right walls in Fig. 3), a bottom partitioning
wall 7 that joins the lower ends of those two partitioning walls and extends substantially
parallel to the open bottom tube end, and partitioning walls 7a, 7b, and 7c that extend
vertically from the bottom partitioning wall 7 toward the bottom open tube end. The
partitioning walls 5 and 6, the bottom partitioning wall 7, and the partitioning walls
7a and 7b extend so as to bridge between the second side walls 2c and 2d (cf. Fig.
2).
[0075] In the space enclosed by the partitioning walls 5 and 6, the bottom partitioning
wall 7, and the second side walls 2c and 2d is formed a first chamber 9, the upper
face whereof is open at the upper end of the case 2, which accommodates porous material
8 such as polyurethane foam absorbing ink. In the space enclosed by one of the first
side walls 2a, the partitioning wall 5, and the second side walls 2c and 2d is formed
a second chamber 10, while in the space enclosed by the other first side wall 2b,
the partitioning wall 6, and the second side walls 2c and 2d is formed an atmosphere
connection path 11. The second chamber 10 and the atmosphere connection path 11 are
each open at their upper ends at the upper surface of the case 2, while the lower
ends thereof bend around the lower surface of the bottom partitioning wall and have
their lower ends open at the lower surface of the case 2 (cf. Fig. 4).
[0076] The upper cover member 3 covers the upper ends, respectively, of the first chamber
9, the second chamber 10, and the atmosphere connection path 11, and is secured by
heat welding to the upper ends of the side walls 2a, 2b, 2c, and 2d and the partitioning
walls 5 and 6, making the chambers 9 and 10 and the path 11 independent. The lower
cover member 4 covers the lower ends, respectively, of the second chamber 10 and the
atmosphere connection path 11, and is secured by heat welding to the lower ends of
the side walls 2a, 2b, 2c, and 2d and the partitioning walls 7a and 7b, making the
second chamber 10 and the path 11 independent. As a result, the second chamber 10
and the atmosphere connection path 11 substantially constitute an L shape with a vertical
part 10a along the side walls 2a and 2b, and horizontal parts 10b and 11b positioned
below the first chamber 9. The vertical part 11a and the horizontal part 11b of the
atmosphere connection path 11 are connected through a connecting hole 30 provided
in the partitioning wall 7b.
[0077] In the bottom partitioning wall 7 is formed a connecting hole 15 that connects the
first chamber 9 and the second chamber 10. Ink is accommodated in both the first chamber
9 and the second chamber 10, and both of these chambers form the ink chamber. The
second chamber 10 serves as a path during ink filling, as is described below, and
serves as a relay chamber when ink is being supplied from the first chamber 9 to the
recording head 72. The first chamber 9 is formed such that it is sufficiently larger
than the second chamber 10. The atmosphere connection path 11 admits air to the first
chamber 9 when ink in the first chamber 9 is consumed. A separation is made between
the second chamber 10 and the atmosphere connection path 11 by the partitioning wall
7a at the lower surface of the bottom partitioning wall 7. As described in the foregoing,
the partitioning walls 5 and 6 are made substantially parallel with the side walls
2a and 2b on either side of the case 2, rendering the sides in a more or less double-walled
structure and strengthening the case. The case 2 shaped in this way can be easily
formed of resin by a die that separates vertically up and down.
[0078] In the upper cover member 3 is formed an ink filling hole 13 corresponding with the
open face at the upper end of the second chamber 10, and a pressure reduction hole
14 for reducing the pressure inside the case during ink filling, facing the open face
at the upper end of the first chamber 9. The connecting hole 15 that mutually connects
the second chamber 10 and the first chamber 9 is located at the end that is far from
the side on which the ink filling hole 13 and pressure reduction hole 14 are located,
that is, on the side opposite thereto, thereby enhancing ink filling efficiency and
ink consumption efficiency, as will be described below.
[0079] The first chamber 9 and the atmosphere connection path 11 are connected by a path
16 formed so as to cross the upper end of the partitioning wall 6 in the upper cover
member 3. More specifically, this path 16 has a concavity formed in the upper surface
of the upper cover member 3, one end whereof communicates to the first chamber 9 via
the pressure reduction hole 14, and the other end whereof communicates with the atmosphere
connection path 11 via a through hole 16a. The upper cover member 3 has a wall 27
that is in contact with the upper surface of the porous material 8 projecting into
the first chamber 9 (cf. Fig. 4). More specifically, the upper cover member 3 is formed
so as to be thicker in the portion thereof corresponding with the first chamber 9,
so as to slightly compress the ink absorbing material 8. The wall 27 is separated
by an interval from the inner surface of the first chamber 9, as will be described
below, and the pressure reduction hole 14 is positioned further to the inside of the
first chamber 9 than the outer periphery of the wall 27.
[0080] In the lower cover member 4 is formed an ink supply hole 17 for supplying ink from
the second chamber 10 to the recording head, corresponding to the open face at the
lower end of the second chamber 10, and an atmosphere connection hole 17 corresponding
to the open face at the lower end of the atmosphere connection path 11. As diagrammed
in Fig. 6, the connecting hole 15 and the ink supply hole 17 are positioned so as
to be mutually offset as seen from the bottom. In the second chamber 10, a rib-shaped
baffle plate 31 is formed across the shortest path connecting the connecting hole
15 and the ink supply hole 17. This baffle plate 31 is made to project integrally
from the partitioning wall 7 of the case 2, and it is preferable that it be formed
so as to join the inner wall surface of the lower cover member 4, but there is no
reason why it cannot be made to project integrally from the lower cover member 4.
The lower surface 7d of the bottom partitioning wall 7 (cf. Fig. 3) forms an inclined
surface that rises from the lower end of the connecting hole 15 toward the vertical
part of the second chamber 10. One end of the baffle plate 31 is positioned at the
side of the connecting hole 15, while the other end thereof extends to a point near
the vertical part of the second chamber 10. Thus, when ink is drawn from the second
chamber 10 by the negative pressure developed by the ejection of ink from the recording
head 72, the ink flow coming out of the connecting hole 15 from the first chamber
9 detours around the baffle plate 31, as indicated by the arrow 31, passes through
the vertical part 10a of the second chamber 10, again enters the horizontal part 10b
of the second chamber 10, and arrives at the ink supply hole 17.
[0081] As diagrammed in Fig. 4, the ink filling hole 13 and the pressure reduction hole
14, after ink filling, are closed off by first sealing materials 21 and 22 applied
to the outer surface of the upper cover member 3 by heat welding or the like. Th sealing
material 22 covers the upper surface thereof so as to secure the path 16. The ink
supply hole 17 and the atmosphere connection hole 18 are closed off by a second sealing
material 23 that is applied by heat welding or the like such that it can be peeled
away. The ink filling hole 13 and the ink supply hole 17 are separated, wherefore
the second sealing material 23 is applied to the ink supply hole 17 prior to ink filling.
For this reason, the periphery of the ink supply hole 17 is not wet by ink during
filling as with a conventional ink supply hole that doubles as the ink filling hole,
wherefore an adequate sealing effect can be obtained even with mild heat welding such
as will not deform the ink supply hole. The sealing materials 21 and 22 do not need
to be peeled away, wherefore they may be heat welded more strongly even to the point
of slightly deforming the upper cover member 3. The sealing materials 21, 22, and
23 are made of a resin, metal foil, or laminated material thereof that is not penetrable
by air.
[0082] A stainless steel screen filter 24 is attached to the face of the ink supply hole
17 on the second chamber 10 side. The screen holes of this filter 24 are of a size
such that the ink inside the second chamber 10 will not naturally leak out due to
surface tension.
[0083] As diagrammed in Fig. 10, a partitioning wall 29 for partitioning the atmosphere
connection path 11 into an upper and lower part is formed midway along the vertical
part 11a of the atmosphere connection path 11. This partitioning wall 29 extends so
that there are differences in height in the vertical direction of the atmosphere connection
path 11. A through hole 28 is formed in the high portion thereof, and a concavity
is formed so as to provide an ink sump 29a positioned lower than the upper end surface
of the through hole 28. The partitioning wall 29 can be molded with the separating
parts of a die that separates vertically up and down when molding the case 2 out of
resin, thus requiring no special process.
[0084] By having the peripheral wall 18a of the atmosphere connection hole 18 in the lower
cover member 4 project upward, moreover, an ink sump 4a is formed about the periphery
thereof. By this means, ink that leaks out through the path 16 from the first chamber
9 when the ink cartridge falls over, etc., accumulates in the ink sump 29. The ink
in the ink sump 29, even if it enters the through hole 28 by the ink cartridge being
tilted, etc., will collect in the ink sump 4a below. Accordingly, the atmosphere connection
path 11 and atmosphere connection hole 18 will not be plugged, nor will ink leak out
to the outside.
[0085] As diagrammed in Fig. 6 and Fig. 19, in the case 2, a space 33 is formed adjacent
to the horizontal parts 10b and 11b of the second chamber 10 and the atmosphere connection
path 11. This space 33 is divided by the partitioning wall 7c that bridges between
the partitioning walls 7a and 7b, is covered below by the lower cover member 4, and
does not communicate with the second chamber 10, the first chamber 9, or the atmosphere
connection path 11, but does communicate with the outside of the case through an opening
34 provided in the lower cover member 4. When an ink cartridge 1 that has been filled
with ink is shipped, it is accommodated in a reduced pressure condition inside a packaging
bag 81, as diagrammed in Fig. 19. The packaging bag 81 accommodates the ink cartridge
1 inside a tubular material, the interior whereof is evacuated with reduced pressure,
and both open ends whereof are given fused closures 82. The packaging bag 81 is made
of a resin, metal foil, or laminated material thereof that is not penetrable by air.
The cross-section of the ink cartridge 1 diagrammed in Fig. 19 corresponds to a cross-section
in the C-C plane in Fig. 9. The opening 34 is not covered by the second sealing material
23. When the packaging bag 81 is rendered in a reduced pressure condition, the space
33 is also rendered in a reduced pressure state, and acts, by the capacity thereof,
to maintain the interior of the sealed packaging bag 81 in a reduced pressure condition
for an extended period of time. Thus is the ink inside the case, prior to use, prevented
from being exposed to air.
[0086] Fig. 11, 12, and 13 show details of the configuration of the path 16 parts. The configuration
diagrammed in Fig. 11 is given as a reference for explaining problems. In this figure,
the path 16b is formed so as to pass through the upper cover member 3a, thus mutually
communicating between the first chamber 9 and the atmosphere connection path 11. The
upper face of the path 16b is covered by the sealing material 22 (not shown). In this
case, the intersection (ridge line) E1 formed by the partitioning wall 6 and the side
walls 2c and 2d, and the intersection E2 formed by the partitioning wall 6 and the
upper cover member 3, readily collect ink through capillary action. Furthermore, because
the intersections E1 and E2 are continuous with the intersection E3 formed by the
inner surface of the path 16b and the partitioning wall 6, ink collected at the intersections
E1 and E2 flow to the intersection E3 by capillary action, as indicated by the arrow
R, and from there flow out along an intersection E4 inside the atmosphere connection
path 11. When ink penetrates from the first chamber 9 toward the atmosphere connection
path 11, an unsightly condition develops if the case is transparent or semi-transparent,
and ink can also leak out to the exterior of the case or plug the atmosphere connection
path 11. When this happens, the ink supply to the recording head 11 from the first
chamber 9 is sometimes blocked.
[0087] In order to resolve the problem described above, an interval K is opened with the
inner surface of the first chamber 9 about the periphery of the wall 27 that projects
from the upper cover member 3 toward the first chamber 9, as diagrammed in Fig. 12.
The pressure reduction hole 14 is given a circular cylindrical or rounded rectangular
shape which does not have intersections on its inner surface, and positioned at the
end of the wall 27, removed from the partitioning wall 6. With this configuration,
the inside edge or intersection of the partitioning wall 6 on the first chamber 9
side does not connect with the path 16 or atmosphere connection path 11 only by an
inside edge or intersection formed by two planes. In other words, the lower surface
of the wall 27, the outer circumference of the wall 27, and the inner surface of the
pressure reduction hole 14 are formed so that they do not have inside edge or intersections
formed by two planes, and the intersection of the partitioning wall 6 on the first
chamber 9 side connects with the atmosphere connection path 11 via these surface portions(flat
portions). Accordingly, ink that oozes out when the porous material 8 is compressed
by the wall 27 and ink collecting at the intersections on the first chamber 9 side
are prevented from flowing out by capillary action to the path 16 or the atmosphere
connection path 11. There are also no intersections on the inner surface of the pressure
reduction hole 14 in contact with the porous material 8, and, in addition, since the
pressure reduction hole 14 is positioned in the thick part of the upper cover member
3 and the height of the pressure reduction hole 14 is sufficient, the ink inside the
porous material 8 is prevented from flowing along the inside of the pressure reduction
hole 14 and penetrating to the path 16. Even supposing that the gap between the partitioning
wall 6 and the outer periphery of the wall 27 is small and that ink rises through
the gap due to capillary action, ink will not penetrate to the atmosphere connection
path 11 because the upper end of the partitioning wall 6 is fused to the cover member
3.
[0088] When the pressure reduction hole 14 is shaped so that there is an intersection on
the inner surface, the same effect can be realized by giving the inner surface of
the path 16 an edgeless (no intersection) cross-section that has the shape of a semicircular
cylinder or rounded rectangle.
[0089] In Fig. 13 is diagrammed an example of the path 16 portion diagrammed in Fig. 12
the structure of which has been modified. With the structure diagrammed in Fig. 13,
the wall 27 has been eliminated, wherefore ink is prevented from rising along that
wall to the path 16.
[0090] A remaining ink quantity detection sensor 60 is provided in the carriage 52 of the
ink jet printer. More specifically, while the ink cartridge 1 is in the unused state,
ink is filled into the porous material 8 in the first chamber 9 and in the second
chamber 10 so that no space is left remaining. When the ink is consumed by a recording
operation, however, and the ink in the first chamber 9 is depleted, due to the pressure
wherewith the ink is drawn by the recording head 72, air enters the second chamber
10 from the first chamber 9, a gap portion develops at the top of the second chamber
10, and the ink liquid level falls. The remaining ink quantity detection sensor 60
detects whether or not there is a remaining ink quantity from changes in the light
reflected according to whether or not ink is present on the inner wall surface of
that second chamber 10.
[0091] The remaining ink quantity sensor 60 is configured, as shown in Fig. 15, with a light
emitting element 61 and a light receiving element 62 provided on either side of a
detection site α, with a prescribed interval opened in the horizontal direction of
the second chamber 10, so that the light emitting element 61 emits light at the detection
site α that is established at a prescribed height position on the side wall 2a of
the case 2 looking toward the second chamber 10, and so that the light receiving element
62 can capture the light that is reflected from the inner surface of the side wall
at that detection site α (cf. Fig. 5). For this purpose, the case 2 need only have
that portion at the detection site α made transparent or semi-transparent in order
to secure light transmissivity.
[0092] The detection site α is established, as diagrammed in Fig. 15, at the place (corner)
where the ridge line is formed by the intersection of the inner surface of the side
wall 2a and the side wall 2d adjacent thereto and extends up and down, inside the
second chamber 10 of the ink cartridge 1. If the detection site α is established thusly
at the ridge line (corner) of the second chamber 10, then, as will be described below,
when the height of the ink fluid level inside the second chamber 10 falls precipitously
from level h1 to level h2, as diagrammed in Fig. 14, even if the ink L adhering to
the inner surface of the side wall 2a is held in the vicinity of level h1 in the center
of the side wall 2a, the ink L that was adhering near the corner on the inner surface
of the side wall 2a will move immediately to the vicinity of level h2 at the same
height as the ink liquid level due to capillary action exhibited by the corner, wherefore
the presence or absence of ink inside the second chamber 10 at the detection site
α can be detected precisely. Such a precipitous fall in the liquid level will occur
when, after ink liquid level h2 has been shaken to h1 by the sweeping movement of
the carriage, a suction cap (not shown) is connected to the recording head 72 and
ink is drawn out.
[0093] It is also possible to provide a rib that protrudes from the inner surface of the
side wall 2a into the second chamber 10 and extends in the height direction of the
second chamber 10, and establish the detection site α at the ridge line formed by
that rib and the inner surface of the side wall 2a. However, by establishing the detection
site α in the corner that exists in an ordinary ink cartridge, as described in the
foregoing, the detection precision of the remaining ink quantity sensor 60 can be
enhanced without making the structure of the ink cartridge 1 complex.
[0094] Also, as discussed in the foregoing, by detecting the remaining ink quantity in the
second chamber 10 where the ink liquid level fluctuation finally appears after almost
all of the ink in the first chamber 9 has been consumed, the remaining ink quantity
at the point in time where the ink cartridge 1 should be replaced can be made extremely
small, so that ink waste that occurs when the ink cartridge 1 is replaced can be held
to a minimum.
[0095] Furthermore, as diagrammed in Fig. 15, many finely undulating ribs 63 are formed
on the inner surface of the side wall 2a looking into the second chamber 10 where
the detection site α is established in a direction perpendicular to the plane containing
the light emitting element 61, the light receiving element 62, and the detection site
α, that is, in the vertical up and down direction of the ink cartridge 1, while on
the outer surface of the side wall 2a where the detection site α is established, many
finely undulating ribs 64 are formed in a direction parallel to the plane containing
the light emitting element 61, the light emitting element 62, and the detection site
α, that is, in the fore-and-aft direction of the ink cartridge 1.
[0096] In a state wherein ink is present up to the height of the detection site α in the
second chamber 10, the light emitted from the light emitting element 61 advances into
the ink (arrow B) due to the refractive indexes of the side wall 2a and the ink, but
advances almost not at all toward the light emitting element 62. In a state wherein
ink is not present at the detection site α, light is reflected by the inner surface
of the side wall 2a and advances toward the light emitting element 62. At this time,
if many fine undulating ribs 63 are formed on the inner surface of the side wall 2a
of the case 2, extending vertically up and down, then, as indicated by the solid lines
in Fig. 15, the light emitted from the light emitting element 61, when reflected by
the inner surface of the side wall 2a of the case 2, is scattered in a substantially
horizontal direction (i.e. in a direction parallel to the plane containing the light
emitting element 61, the light emitting element 62, and the detection site α) by the
undulating ribs 63, and advances toward the light emitting element 62 while spreading
out in the plane containing the light emitting element 61 and the light emitting element
62 of the sensor 60 and the detection site α on the case 2. The light reflected when
no such undulating ribs are formed on the inner surface of the side wall 2a is indicated
by the double-dotted lines in the same figure. Accordingly, as indicated by the solid
lines and the double-dotted lines in Fig. 16, the light emitting element 62 can capture
the reflected light in a definite way even when there are slight changes in the distance
between the sensor 60 and the detection site α. In other words, even when variation
in the sensor 60 attachment position relative to the carriage 52 arises during manufacture
of the ink jet printer, or the ink cartridge 1 mounting position is shifted slightly
when the user replaces the ink cartridge 1, the remaining ink quantity can be detected
unambiguously. In the drawing, for convenience, the light is represented as being
emitted from the light emitting element 61 in a parallel state, but the same benefit
can be realized even if the light is emitted so that it spreads.
[0097] Furthermore, when many finely undulating ribs 64 are formed on the inner surface
of the side wall 2a extending in a fore and aft direction, as described in the foregoing,
the light that is reflected at the outer surface of the side wall 2a of the case 2
is scattered vertically upward and downward by the undulating ribs 64, and the light
reflected at the outer surface of the side wall 2a proceeds toward the light emitting
element 62 while spreading outside of the plane containing the light emitting element
61 and light emitting element 62 of the sensor 60 and the detection site α, wherefore
it becomes difficult for the light emitting element 62 to capture that light that
is reflected at the outer surface of the side wall 2a which does not contribute to
the detection of the remaining ink quantity. That being so, of the reflected light
that is captured by the light emitting element 62, the proportion of those components
of the light reflected by the inner surface of the side wall 2a that do contribute
to remaining ink quantity detection becomes high, whereupon remaining ink volume detection
precision is enhanced. Hypothetically, in a case where the undulating ribs on the
inner face of the side wall 2a extend in the horizontal direction, light would be
scattered vertically up and down, wherefore, when the distance between the sensor
60 and the detection site α has changed, as diagrammed in Fig. 16, the allowable position
whereat the light emitting element 62 can capture the reflected light would significantly
more limited than in the embodiment described above.
[0098] The case 2 configured as described in the foregoing is formed in a die. In the die
used for this purpose, the die face corresponding to the inner surface of the side
wall 2a where the detection site α is established is polished in a direction perpendicular
to the plane containing the light emitting element 61, the light emitting element
62, and the detection site α, and the die face corresponding to the outer surface
of the side wall 2a where the detection site α is established is polished in a direction
parallel to the plane containing the light emitting element 61, the light emitting
element 62, and the detection site α. By subjecting the die faces to polishing in
this manner, the many finely undulating ribs extending in the prescribed directions
are formed on the two die faces, respectively. Accordingly, by using such a die as
this, an ink cartridge 1 can be easily manufactured wherein many undulating ribs 63
and 64 are formed in the prescribed directions on the inner surface and outer surface,
respectively, of the side wall 2a where the detection site α is established.
[0099] With this embodiment, moreover, the light emitting element 61 and the light emitting
element 62 are positioned in a horizontal orientation, but this does not constitute
a limitation, and it is possible to position the light emitting element 61 and the
light emitting element 62 in the vertical dimension of the ink cartridge 1. In that
case, however, the orientations of the undulating ribs 63 and 64 formed in the inside
and outside surfaces of the side wall 2a, respectively, must be reversed.
[0100] The method of fabricating the ink cartridge 1 is described next. The case 2 is first
molded out of resin, then washed and dried. At this time, both the upper and lower
faces of the case 2 are open, wherefore the case 2 can be easily molded with a die
that separates up and down. The case must be washed well so that the ink properties
do not change, but, with this case shape, the washing liquid readily reaches into
the interior portions, so washing can be done easily. Drying can also be performed
so that no washing liquid remains.
[0101] As diagrammed in Fig. 4, the porous material 8 is inserted into the first chamber
9 from the upper open end of the case 2. This porous material 8 is accommodated in
a compressed condition because the upper cover member 3 pushes against it. The upper
cover member 3 is heat welded around the lip of the upper opening in the case 2 and
at the upper ends of the partitioning walls 5 and 6. The lower cover member 4 is secured
by heat welding around the lip of the lower opening in the case 2 and at the lower
ends of the partitioning walls 7a, 7b, and 7c. To the ink supply hole 17 and atmosphere
connection hole 18 in the lower cover member 4 is applied a sealing material 23, which
can be peeled away, for covering them. Thus the top and bottom of the case 2 are formed
in a substantially open condition. By mounting the cover members 3 and 4 from the
top and bottom, the various types of chamber described earlier can be formed, making
the assembly thereof easy. The ink supply hole 17 and the atmosphere connection hole
18 are lined up on one side of the cartridge, wherefore the sealing material 23 for
covering these can be applied easily, without the need of being pulled around the
outer periphery of the cartridge as conventionally.
[0102] The operation of filling the inside of the ink cartridge 1 with ink is next described.
As diagrammed in Fig. 18, with the ink supply hole 17 and the atmosphere connection
hole 18 in the lower cover member 4 sealed as described above, an ink filling apparatus
101 is tightly fitted to the ink filling hole 13 and a pressure reduction apparatus
102 is tightly fitted to the pressure reduction hole 14 in the upper cover member
3, as diagrammed in Fig. 18, and the apparatuses are activated. Because the ink filling
hole 13 and the pressure reduction hole 14 are lined up on one side of the cartridge,
the apparatuses need only be brought up against one side of the cartridge 1. The air
inside the first chamber 9 is sucked out from the pressure reduction hole 14 prior
to ink filling. The pressure in the first and second chambers 9 and 10 is thereby
reduced, whereupon the ink passes from the ink filling hole 13 through the second
chamber 10 and the connecting hole 15 and thus fills the porous material 8 inside
the first chamber 9. When this is done, the second chamber 10 becomes an ink filling
path. The ink enters the second chamber 10 from one end, passes through the connecting
hole 15 that is maximally separated therefrom, and enters the first chamber 9, after
which it reaches the pressure reduction hole 14 that is maximally separated from the
connecting hole 15, wherefore the second chamber 10 itself can be completely filled
with ink, while, at the same time, the first chamber 9 can also be efficiently filled
with ink. Also, as described in the foregoing, the outside of the case 2 is a reinforced
double-walled structure, wherefore the case 2 will not be deformed very much during
pressure reduction, for which reason also the two chambers 9 and 10 can be efficiently
filled with ink. The pressure in the atmosphere connection path 11 is also reduced
simultaneously with the first chamber 9, and the reduced pressure state is maintained
even after the sealing material is applied.
[0103] For the ink loaded by this process, ink (so-called deaerated ink) is used from which
bubbles and air dissolved therein has been removed to the extent possible. The purpose
of this is to avoid ink ejection problems that arise when bubbles and air penetrate
into the recording head 72. And the ink cartridge is hermetically sealed under reduced
pressure in the packaging bag 8, as described earlier, in order to prevent bubbles
and air from again being dissolved in the deaerated ink.
[0104] After ink filling, sealing materials 21 and 22 are applied to the ink filling hole
13 and the pressure reduction hole 14. The sealing materials 21 and 22 may be applied
in a single strip if, afterwards, only the necessary portions are left remaining.
Thus, in the manufacturing stage, the filling apparatus 101 and the pressure reduction
apparatus 102 need only be brought up against the case 2 from one side, and the seals
need be only applied from one side of the case 2 also, making for efficient operations.
[0105] The ink cartridge 1 fabricated in this manner is shipped after being hermetically
sealed under reduced pressure inside the packaging bag 81, as described earlier.
[0106] When the ink cartridge 1 is used by the user, the user peels away the sealing material
23 applied to the ink supply hole 17 and the atmosphere connection hole 18 of the
ink cartridge 1, and couples the ink supply hole 17 via the joint member 74 to the
manifold 73 in the recording head 72. Then a suction cap is connected to the recording
head 72 and the recording head 72 is filled with ink from the ink cartridge 1, as
is commonly known.
[0107] During a recording operation, due to the suction force of the porous material 8 inside
the first chamber 9, that is, due to capillary action, a negative pressure is caused
to act on the ink supplied to the recording head from the second chamber 10. The actuators
in the recording head 72 perform an ink ejecting action, thereby producing a negative
pressure in the ejection direction and drawing out ink from the ink cartridge 1. When
the ink in the second chamber 10 flows out from the ink supply hole 17, ink is replenished
in the second chamber 10 from the porous material 8 in the first chamber 9, and air
is inducted from the atmosphere connection hole 18 through the atmosphere connection
path 11 into the first chamber 9 as the ink in the first chamber 9 is consumed. The
upper end of the second chamber 10 is sealed by the sealing material 21. Therefore,
because the second chamber 10 completely filled with ink, atmospheric pressure does
not act on the ink in the second chamber 10, wherefore the ink in the second chamber
10 will be consumed after the ink in the first chamber 9 is almost completely depleted.
In other words, when the ink in the first chamber 9 is gone, due to the pressure of
the recording head 72 drawing the ink, the ink in the second chamber 10 is consumed
while air from the first chamber 9 enters the second chamber 10, whereupon a gap develops
at the top of the vertical part of the second chamber 10 and the ink liquid level
therein begins to fall.
[0108] Thus, in the first chamber 9, atmospheric air is drawn in from the side distant from
the connecting hole 15, so that not only is the ink in the first chamber 9 utilized
effectively, but all of the ink, including the ink that is in the second chamber 10,
is used effectively. Also, because the second chamber 10 is completely filled from
the beginning as an ink filling path, during remaining ink quantity detection, detection
errors will not be made due to inadequate ink filling here. The operation of removing
the sealing material 23 is also easy because it is done only on one side of the cartridge.
[0109] As described in the foregoing, furthermore, there is a gap 31 between the connecting
hole 15 and the ink supply hole 17, wherefore, when ink is drawn from the first chamber
9 through the connecting hole 15 into the second chamber 10 by the pressure caused
by the recording head 72 sucking ink, when air bubbles are mixed into that ink, or
the ink in the first chamber 9 is consumed so that air is drawn into the second chamber
10 as described earlier, those bubbles and air can be blocked from flowing into the
recording head 72. In other words, when the ink flow detours around the baffle plate
31, as indicated by the arrow 32 in Fig. 6, in the vicinity corresponding to the vertical
part 10a of the second chamber 10, the air and bubbles travel toward the top of the
vertical part 10a due to buoyancy, and hence do not reach the ink supply hole 17.
The ceiling surface of the horizontal part 10b of the second chamber 10, that is,
the lower surface 7d of the bottom partitioning wall 7, is inclined so that it rises
from the lower end of the connecting hole 15 toward the vertical part 10a of the second
chamber 10, wherefore air and bubbles do not become trapped at the lower surface of
the bottom partitioning wall 7 but rather flow toward the top of the vertical part
10a. That being so, bubbles and air can be prevented from penetrating to the recording
head 72 and causing ink ejection failures.