# Patent

## Title
Liquid storage container

## Abstract

To provide a liquid storage container that can prevent false detection of a liquid remaining-amount sensor by preventing air bubbles from reaching a detection position of the liquid remaining-amount sensor as long as a usable amount of liquid remains in liquid storage chambers even when the air bubbles enter liquid guide paths from the liquid storage chambers. The liquid storage container has a cartridge main body 10 that includes an upper ink storage chamber 370, a lower ink storage chamber 390, and a buffer chamber 430. The upper ink storage chamber 370 and the lower ink storage chamber 390 are connected to each other with an ink guide path 380 which provides a descending connection so that ink I descends downward therethrough. The lower ink storage chamber 390 and the buffer chamber 430 are connected to each other with an ink guide path 420 which provides an ascending connection so that the ink I ascends upward therethrough. Thus, the descending connection and the ascending connection are alternately provided so as to connect the ink storage chambers in series.

## Background
TECHNICAL FIELD
The present invention relates to a liquid storage container having a container main body that is detachably attached to a liquid-consuming apparatus and supplying liquid contained in the container main body to the liquid-consuming apparatus.
BACKGROUND ART
An ink cartridge that contains liquid ink and an ink jet recording apparatus (ink jet printer) to which the ink cartridge is exchangeably attached are examples of a known liquid storage container and a known liquid-consuming apparatus, respectively.
The ink cartridge generally has a container main body that is detachably attached to a cartridge-receiving unit of the ink jet recording apparatus. The container main body includes an ink storage chamber that is filled with ink, an ink-supplying unit for supplying the liquid contained in the ink storage chamber to the ink jet recording apparatus, an ink guide path through which the ink storage chamber and the ink-supplying unit communicate with each other, and an atmosphere communicating path for allowing air to flow into the ink storage chamber from the outside as the ink contained in the ink storage chamber is consumed. When the ink cartridge is attached to the cartridge-receiving unit of the ink jet recording apparatus, an ink supply needle included in the cartridge-receiving unit is connected to the ink-supplying unit by being inserted therein, so that the can be supplied to a recording head included in the ink jet recording apparatus.
The recording head included in the ink jet recording apparatus controls an operation of ejecting ink drops using heat or vibration. If the ink-ejecting operation is performed when there is no more ink in the ink cartridge and no ink can be supplied, the recording head will break down. Therefore, in the ink jet recording apparatus, it is necessary to monitor the amount ink remaining in the ink cartridge so as to prevent the recording head from operating when there is no ink.
In light of the above situation, an ink cartridge has been developed which includes a liquid remaining-amount sensor that outputs a predetermined electrical signal when the amount of ink remaining in a container main body is reduced to a predetermined threshold, so that a recording head included in a recording apparatus can be prevented from operating after the ink contained in the ink cartridge runs out (see, for example, Patent Document 1).
[Patent Document 1] JP-A-2001-146030
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
On the other hand, in a liquid storage container that is opened to the atmosphere, atmospheric air flows into the ink storage chamber as the ink contained in the ink cartridge is consumed. When the amount of remaining ink is reduced, the space occupied by an air layer in the ink storage chamber is increased. In such a state, even when the ink still remains in the ink storage chamber, if the surface of the liquid ink contained in the ink storage chamber becomes turbulent due to external vibrations or the like applied to the ink cartridge, the air layer easily comes into contact with an ink outlet of the ink storage chamber that communicates with the ink guide path. When the air layer comes into contact with the ink outlet of the ink storage chamber, there is a risk that air bubbles will enter the ink guide path.
Even when a large amount of ink still remains in the ink storage chamber and the space occupied by the air layer is small, if the ink cartridge that is still in use is detached from the ink jet recording apparatus and tilted or if the ink in the ink storage chamber is shaken by external vibrations or the like, the air layer may come into contact with the ink outlet of the ink storage chamber. Accordingly, there is a risk that air bubbles will enter the ink guide path.
In such a case, if, for example, the ink guide path is a single flow path having a simple structure, the air bubbles that enter the ink guide path from the ink storage chamber easily travel through the ink guide path and reach a detection position of the liquid remaining-amount sensor. As a result, the liquid remaining-amount sensor falsely detects that the ink has run out. When the liquid remaining-amount sensor falsely detects that the ink has run out, the ink that still remains in the ink storage chamber cannot be used. Therefore, there is a problem that a relatively large amount of ink is discarded without being used. In addition, since the air bubbles easily travel from an ink chamber to an adjacent ink chamber, there is a risk that the ejection quality will be degraded.
In addition, since the air bubbles easily travel from an ink chamber to an adjacent ink chamber, there is a risk that the ejection quality will be degraded. Please change the object of the present invention to “to provide a liquid storage container that can suppress entry of air bubbles from an ink chamber to an adjacent ink chamber”. The reason for this is because since the sensor is disposed between a descending flow path and an ascending flow path, it cannot be said that the sensor can be prevented from making a false detection due to air bubbles. In addition, please add an advantage that a stirring effect can be provided when pigment ink is used.
Accordingly, an object of the present invention is to solve the above-described problems and to provide a liquid storage container that can suppress entry of air bubbles from an ink chamber to an adjacent ink chamber.
Means for Solving the Problems
The above-described object of the present invention can be achieve by a liquid storage container that is opened to the atmosphere, that is attachable to and detachable from a liquid-consuming apparatus, and that includes:
liquid storage chambers that store liquid;
a liquid-supplying unit connectable to the liquid-consuming apparatus;
liquid guide paths for guiding the liquid contained in the liquid storage chambers to the liquid-supplying unit;
an atmosphere communicating path that allows atmospheric air to flow into the liquid storage chambers from the outside as the liquid in the liquid storage chambers is consumed; and
a liquid remaining-amount sensor disposed at an intermediate position of one of the liquid guide paths and determining that the liquid in the liquid storage chambers has run out when a flow of gas into the one of the liquid guide paths is detected.
The number of the liquid storage chambers provided in the container storage container is three or more.
A descending connection that connects a pair of the liquid storage chambers to each other with one of the liquid guide paths such that the liquid descends downward therethrough and an ascending connection that connects a pair of the liquid storage chambers to each other with another one of the liquid guide paths such that the liquid ascends upward are alternately provided to connect the liquid storage chambers in series.
According to the liquid storage container having the above-described structure, the descending connection and the ascending connection are alternately provided to connect the three or more liquid storage chambers in series. Therefore, the stirring effect can be increased, which is effective when the liquid is, for example, pigment ink or the like and easily subsides. Even if air bubbles are included in the liquid that flows into the liquid guide paths for guiding the liquid from the liquid storage chamber at an upstream position to the liquid-supplying unit, when the air bubbles pass through the liquid guide path which provides the descending connection, the air bubbles receive buoyancy from the liquid existing in the liquid guide path which provides the descending connection. Therefore, the air bubbles that enter the liquid guide path cannot easily flow downstream.
In addition, if the liquid storage container is detached from the liquid-consuming apparatus and is turned upside down, the liquid guide path which usually provides the ascending connection provides a descending connection so as to stop the downstream movement of the air bubbles. In other words, even when the liquid storage container is turned upside down, the downstream movement of the air bubbles can be prevented since the liquid guide path provides a descending connection.
In addition, the liquid storage chambers which are located at the second and the following stages function as trap spaces for catching the air bubbles that flow from the liquid storage chamber at the upstream position. More specifically, if the liquid storage container falls over on its side, the descending connection between the liquid storage chambers cannot provide a function of preventing the movement of the air bubbles. However, in such a case, upper spaces of the liquid storage chambers located at the second and the following stages effectively function as trap spaces for catching the air bubbles. Accordingly, the liquid remaining in these liquid storage chambers reliably prevents the downstream movement of the air bubbles.
In the above-described liquid storage container, preferably, the atmosphere communicating path is provided with an air chamber for preventing a leakage of the liquid from the liquid storage chambers.
In the liquid storage container having such a structure, even when the liquid flows out of the liquid storage chambers toward the outside due to thermal expansion or the like, leakage of the liquid can be prevented by reliably trapping the liquid in the air chamber. The liquid trapped in the air chamber is caused to flow into the liquid storage chambers as the liquid is consumed, so that the liquid stored therein can be used without being wasted.
In addition, in the above-described liquid storage container, preferably, at least a portion of the atmosphere communicating path passes through an uppermost section in the direction of gravity in the liquid container.
According to the liquid storage container having such a structure, even when the liquid flows backward, the liquid does not easily pass through the uppermost portion in the direction of gravity and reach an atmospheric vent of the container main body. Therefore, leakage of the liquid can be prevented.
In addition, in the above-described liquid storage container, preferably, the atmosphere communicating path is provided with a gas-liquid separation filter that blocks liquid while allowing gas to pass therethrough.
According to the liquid storage container having such a structure, even when the liquid flows into the atmosphere communicating path, since the atmosphere communicating path is provided with the gas-liquid separation filter, the liquid can be prevented from passing through the gas-liquid separation filter and reaching the atmospheric vent. Therefore, the leakage of the ink from the atmospheric vent can be more reliably prevented.
In addition, in the above-described liquid storage container, preferably, the liquid storage container is packed in a vacuum package in which the pressure is reduced to the atmospheric pressure or less.
According to the liquid storage container having such a structure, the inner pressure of the container main body can be maintained equal to or below a predetermined pressure before use due to a negative-pressure suction force applied in a vacuum packaging process. Therefore, liquid with a small amount of dissolved air can be provided.
In addition, the above-described object of the present invention may also be achieved by a liquid storage container that is opened to the atmosphere, that is attachable to and detachable from a liquid-consuming apparatus, and that includes:
liquid storage chambers that store liquid;
a liquid-supplying unit connectable to the liquid-consuming apparatus;
liquid guide paths for guiding the liquid contained in the liquid storage chambers to the liquid-supplying unit;
an atmosphere communicating path that allows atmospheric air to flow into the liquid storage chambers from the outside as the liquid in the liquid storage chambers is consumed; and
a liquid sensor disposed in one of the liquid guide paths.
The number of the liquid storage chambers provided in the liquid storage container is three or more.
A descending connection that connects a pair of the liquid storage chambers to each other with one of the liquid guide paths such that the liquid descends downward therethrough and an ascending connection that connects a pair of the liquid storage chambers to each other with another one of the liquid guide paths such that the liquid ascends upward are alternately provided to connect the liquid storage chambers in series.
According to the liquid storage container having the above-described structure, the descending connection and the ascending connection are alternately provided to connect the three or more liquid storage chambers in series. Therefore, the stirring effect can be increased, which is effective when the liquid is, for example, pigment ink or the like and easily subsides. Even if air bubbles are included in the liquid that flows into the liquid guide paths for guiding the liquid from the liquid storage chamber at an upstream position to the liquid-supplying unit, when the air bubbles pass through the liquid guide path which provides the descending connection, the air bubbles receive buoyancy from the liquid existing in the liquid guide path which provides the descending connection. Therefore, the air bubbles that enter the liquid guide path cannot easily flow downstream.
BEST MODE FOR CARRYING OUT THE INVENTION
A liquid storage container according to a preferred embodiment of the present invention will be described in detail below with reference to the drawings. In the embodiment described below, an ink cartridge that can be attached to and detached from an inkjet recording apparatus (printer), which is an example of a liquid ejection apparatus, will be explained as an example of a liquid storage container.
FIG. 1 is an external perspective view illustrating an ink cartridge as a liquid storage container according to an embodiment of the present invention. FIG. 2 is an external perspective view of the ink cartridge according to the present embodiment shown in FIG. 1 as viewed from the opposite angle. FIG. 3 is an exploded perspective view of the ink cartridge according to the present embodiment. FIG. 4 is an exploded perspective view of the ink cartridge according to the present embodiment shown in FIG. 3 as viewed from the opposite angle. FIG. 5 is a diagram illustrating the state in which the ink cartridge according to the present embodiment is attached to a carriage. FIG. 6 is a sectional view illustrating the state immediately before the attachment to the carriage. FIG. 7 is a sectional view illustrating the state immediately after the attachment to the carriage.
As shown in FIGS. 1 and 2, an ink cartridge 1 according to the present embodiment has a substantially rectangular parallelepiped shape, and functions as a liquid storage container that contains and stores ink (liquid) I in ink storage chambers (liquid storage chambers) provided therein. The ink cartridge 1 is attached to a carriage 200 included in an ink jet recording apparatus, which is an example of a liquid-consuming apparatus, and supplies the ink to the ink jet recording apparatus (see FIG. 5).
Characteristics of the ink cartridge 1 in appearance will be described below. As shown in FIGS. 1 and 2, the ink cartridge 1 has a flat top face 1a and a bottom face 1b that faces the top face 1a. An ink-supplying unit (liquid-supplying unit) 50 that is connected to the ink jet recording apparatus and supplies ink thereto is provided at the bottom face 1b. An atmospheric vent 100 for allowing atmospheric air to flow into the ink cartridge 1 is formed in the bottom face 1b. Thus, the ink cartridge 1 is opened to the atmosphere and supplies ink through the ink-supplying unit 50 while allowing atmospheric air to flow therein through the atmospheric vent 100.
In the present embodiment, as shown in FIG. 6, the atmospheric vent 100 is defined by a substantially cylindrical recess 101 that extends from the bottom face 1b toward the top face and a small hole 102 formed in the inner peripheral surface of the recess 101. The small hole 102 communicates with an atmosphere communicating path, which will be described below, and the atmospheric air flows through the small hole 102 into an ink storage chamber 370 disposed at the uppermost stream position, which will also be described below.
The depth of the recess 101 of the atmospheric vent 100 is set such that a projection 230 formed on the carriage 200 can be received by the recess 101. The projection 230 functions a removal-failure-preventing projection for preventing a sealing film 90, which functions as sealing means for sealing the atmospheric vent I 00 airtight, from being left unremoved. That is, while the sealing film 90 is adhered so as to cover the atmospheric vent 100, the projection 230 cannot be inserted into the atmospheric vent 100, and therefore the ink cartridge 1 cannot be attached to the carriage 200. Since a user cannot attach the ink cartridge 1 to the carriage 200 as long as the sealing film 90 is adhered so as to cover the atmospheric vent 100, the user can be prompted to remove the sealing film 90 without failure before attaching the ink cartridge 1.
In addition, as shown in FIG. 1, a misinsertion preventing projection 22 for preventing the ink cartridge 1 from being attached at a wrong position is provided at a narrow face 1c adjacent to one of the short sides of the top face 1a of the ink cartridge 1. As shown in FIG. 5, the carriage 200, which receives the ink cartridge 1, has a recessed pattern 220 that corresponds to the misinsertion preventing projection 22. The ink cartridge 1 can be attached to the carriage 200 only when the misinsertion preventing projection 22 and the recessed pattern 220 do not interfere with each other. The shape of the misinsertion preventing projection 22 is determined in accordance with the kind of the ink, and so is the shape of the recessed pattern 220 in the carriage 200 that receives the ink cartridge 1. Therefore, even when the carriage 200 is capable of receiving a plurality of kinds of ink cartridges, as shown in FIG. 5, the ink cartridges can be prevented from being attached at wrong positions.
In addition, as shown in FIG. 2, an engagement lever 11 is provided on a narrow face 1d that faces the narrow face 1c of the ink cartridge 1. The engagement lever 11 has a projection 11a that engages with a recess 210 formed in the carriage 200 when the ink cartridge 1 is attached to the carriage 200. The engagement lever 11 is bent and thereby allows the projection 11a to engage with the recess 210, so that the ink cartridge 1 can be positioned and attached to the carriage 200.
A circuit substrate 34 is provided below the engagement lever 11. A plurality of electrode terminals 34a are formed on the circuit substrate 34. The electrode terminals 34a come into contact with electrode members (not shown) provided on the carriage 200. Accordingly, the ink cartridge 1 is electrically connected to the ink jet recording apparatus. The circuit substrate 34 has a nonvolatile memory in which data can be rewritten and which stores various information regarding the ink cartridge 1, ink usage information of the ink jet recording apparatus, etc. A liquid remaining-amount sensor (sensor unit) 31 (see FIG. 3 or FIG. 4) for detecting the amount of ink remaining in the ink cartridge 1 by utilizing residual vibration is provided behind the circuit substrate 34. In the following description, the unit including the liquid remaining-amount sensor 31 and the circuit substrate 34 is sometimes called an ink end sensor 30.
As shown in FIG. 1, a label 60a indicating the content of the ink cartridge is adhered to the top face 1a of the ink cartridge 1. The label 60a is formed as an end portion of an outer surface film 60 that extends so as to cover both a broad face 1f and the top face 1a. 
As shown in FIGS. 1 and 2, broad faces 1e and 1f that are respectively adjacent to the two long sides of the top face 1a of the ink cartridge 1 are both flat. In the following description, for convenience of explanation, the broad face 1e, the broad face 1f, the narrow face 1c, and the narrow face 1d will be called front, back, right, and left sides, respectively.
Next, each component of the ink cartridge 1 will be described below with reference to FIGS. 3 and 4.
The ink cartridge 1 includes a cartridge main body 10 that functions as a container main body and a lid member 20 that covers the front side of the cartridge main body 10.
The cartridge main body 10 includes ribs 10a having various shapes on the front side thereof. The ribs 10a function as partition walls for dividing the inner space into a plurality of ink storage chambers (liquid storage chambers) that are filled with ink I, an ink-free chamber that is free from the ink I, and air chambers disposed at intermediate positions of an atmosphere communicating path 150, which will be described below.
A film 80 that covers the front side of the cartridge main body 10 is disposed between the cartridge main body 10 and the lid member 20. The film 80 seals the top sides of the ribs, recesses, and grooves so as to define a plurality of flow paths, the ink storage chambers, the ink-free chamber, and the air chambers.
A differential-pressure-regulating-valve storage chamber 40a, which functions as a recess for receiving a differential pressure regulating valve 40, and a gas-liquid separation chamber 70a, which functions as a recess for receiving a gas-liquid separation filter 70, are formed at the back side of the cartridge main body 10.
The differential-pressure-regulating-valve storage chamber 40a receive the differential pressure regulating valve 40 which includes a valve member 41, a spring 42, and a spring washer 43. The differential pressure regulating valve 40 is positioned between the ink-supplying unit 50 disposed at a downstream position and the ink storage chambers disposed at upstream positions. The differential pressure regulating valve 40 reduces a downstream pressure relative to an upstream pressure, so that the ink I supplied to the ink-supplying unit 50 has a negative pressure.
A bank 70b is provided at a central region of the gas-liquid separation chamber 70a so as to extend along the outer periphery thereof, and a gas-liquid separation film 71 is adhered to the top side of the gas-liquid separation chamber 70a along the bank 70b. The gas-liquid separation film 71 blocks liquid while allowing gas to pass therethrough, and the overall structure functions as the gas-liquid separation filter 70. The gas-liquid separation filter 70 is disposed in the atmosphere communicating path 150 that connects the atmospheric vent 100 to the ink storage chambers and prevents the ink I in the ink storage chambers from flowing out of the atmospheric vent 100 through the atmosphere communicating path 150.
In addition to the differential-pressure-regulating-valve storage chamber 40a and the gas-liquid separation chamber 70a, a plurality of grooves 10b are formed in the back side of the cartridge main body 10. The outer surface film 60 covers the grooves 10b in a state such that the differential pressure regulating valve 40 and the gas-liquid separation filter 70 are installed. Accordingly, the open sides of the grooves 10b are closed so as to form the atmosphere communicating path 150 and ink guide paths.
As shown in FIG. 4, a sensor chamber 30a which functions as a recess for receiving members included in the ink end sensor 30 is formed in the right side of the cartridge main body 10. The sensor chamber 30a receives the liquid remaining-amount sensor 31 and a compression spring 32 that fixes the liquid remaining-amount sensor 31 by pressing the liquid remaining-amount sensor 31 against an inner wall of the sensor chamber 30a. The open side of the sensor chamber 30a is covered with a cover member 33, and the circuit substrate 34 is fixed to an outer surface 33a of the cover member 33. Sensing elements included in the liquid remaining-amount sensor 31 are connected to the circuit substrate 34.
The liquid remaining-amount sensor 31 includes a cavity that functions as a portion of an ink guide path extending between the ink-supplying unit 50 and the ink storage chambers, a vibration plate that defines a portion of a wall surface of the cavity, and a piezoelectric element (piezoelectric actuator) for causing the vibration plate to vibrate. The liquid remaining-amount sensor 31 detects the presence/absence of the ink I in the ink guide path on the basis of residual vibration obtained when the vibration plate is vibrated. The liquid remaining-amount sensor 31 detects a difference in the amplitude, frequency, etc., of the residual vibration between the ink I and gas (air bubbles B mixed in the ink), thereby determining the presence/absence of the ink I in the cartridge main body 10.
More specifically, when the ink contained in the ink storage chambers of the cartridge main body 10 runs out and the atmospheric air that flows into the ink storage chambers travels through the ink guide path and enters the cavity of the liquid remaining-amount sensor 31, such a state is detected from a change in the amplitude or the frequency of the residual vibration. Accordingly, an electrical signal indicating that the ink has run out is output.
In addition to the above-described ink-supplying unit 50 and the atmospheric vent 100, as shown in FIG. 4, a pressure reducing hole 110, a recess 95a, and a buffer chamber 30b are formed in the bottom side of the cartridge main body 10. The pressure reducing hole 110 is used for reducing the pressure by sucking out the air from the ink cartridge 1 using vacuuming means when the ink is injected. The recess 95a defines the ink guide path that extends from the ink storage chambers to the ink-supplying unit 50. The buffer chamber 30b is disposed under the ink end sensor 30.
Open sides of the ink-supplying unit 50, the atmospheric vent 100, the pressure reducing hole 110, the recess 95a, and the buffer chamber 30b are sealed by sealing films 54, 90, 98, 95, and 35, respectively, immediately after the ink cartridge is manufactured. The sealing film 90 that seals the atmospheric vent 100 is removed by the user when the ink cartridge is attached to the ink jet recording apparatus for use. Accordingly, the atmospheric vent 100 is exposed and the ink storage chambers in the ink cartridge 1 communicate with the atmosphere via the atmosphere communicating path 150.
As shown in FIGS. 6 and 7, when the ink cartridge is attached to the ink jet recording apparatus, an ink supply needle 240 provided in the ink jet recording apparatus breaks the sealing film 35 adhered to the outer surface of the ink-supplying unit 50.
As shown in FIGS. 6 and 7, the ink-supplying unit 50 includes an annular seal member 51 that is pressed against the outer surface of the ink supply needle 240 when the ink cartridge is attached, a spring washer 52 that is in contact with the seal member 51 so as to close the ink-supplying unit 50 while the ink cartridge is not attached to the printer, and a compression spring 53 for urging the spring washer 52 toward the seal member 51.
As shown in FIGS. 6 and 7, when the ink supply needle 240 is inserted into the ink-supplying unit 50, the space between the inner periphery of the seal member 51 and the outer periphery of the ink supply needle 240 are sealed so that the gap between the ink-supplying unit 50 and the ink supply needle 240 are sealed liquid-tight. In addition, a tip portion of the ink supply needle 51 comes into contact with the spring washer 52 and pushes the spring washer 52 upward, so that the spring washer 52 is removed from the seal member 51. Accordingly, the ink can be supplied from the ink-supplying unit 50 to the ink supply needle 240.
The inner structure of the ink cartridge 1 according to the present embodiment will be described below with reference to FIGS. 8 to 12.
FIG. 8 is a front view of the cartridge main body 10 of the ink cartridge 1 according to the present embodiment. FIG. 9 is a rear view of the cartridge main body 10 of the ink cartridge 1 according to the present embodiment. FIG. 10(a) is a simplified diagram of the structure shown in FIG. 8, and FIG. 10(b) is a simplified diagram of the structure shown in FIG. 9. FIG. 11 is a sectional view of FIG. 8 taken along line A-A. FIG. 12 is an enlarged perspective view of a flow path shown in FIG. 8.
In the ink cartridge 11 according to the present embodiment, three ink storage chambers in which the ink I is contained are provided at the front side of the cartridge main body 10. The three ink storage chambers include the upper ink storage chamber 370 and a lower ink storage chamber 390 that are separated from each other in the vertical direction, and a buffer chamber 430 that is positioned between the upper and lower ink storage chambers (see FIG. 10).
In addition, the atmosphere communicating path 150 for allowing the atmospheric air to flow into the upper ink storage chamber 370, which is at the most upstream position, in accordance with the amount of consumption of the ink I is provided at the back side of the cartridge main body 10.
The ink storage chambers 370 and 390 and the buffer chamber 430 are sectioned from each other by the ribs 10a. In the present embodiment, these ink storage chambers have concavities 374, 394, and 434 formed so as to dent downward in the ribs 10a that extend horizontally to define the bottom walls of the storage chambers.
The concavity 374 is formed by denting a portion of the rib 10a that forms a bottom wall 375 of the upper ink storage chamber 370 downward. The concavity 394 is formed so as to dent in the thickness direction of the cartridge by the rib 10a that forms a bottom wall 395 of the lower ink storage chamber 390 and a swelling portion of a wall surface. The concavity 434 is formed by denting a portion of the rib 10a that forms a bottom wall 435 of the buffer chamber 430 downward.
Ink outlets 371, 311, and 432 that communicate with an ink guide path 380, an upstream ink-end-sensor connecting flow path 400, and an ink guide path 440, respectively, are provided at or near the concavities 374, 394, and 434, respectively.
The ink outlets 371 and 432 are through holes that extend through the walls of the corresponding ink storage chambers in the thickness direction of the cartridge main body 10. The ink outlet 311 is a through hole that extends downward through the bottom wall 395.
The ink guide path 380 communicates with the ink outlet 371 of the upper ink storage chamber 370 at one end thereof and with an ink inlet 391 formed in the lower ink storage chamber 390 at the other end thereof. The ink guide path 380 functions as a liquid guide path that guides the ink I from the upper ink storage chamber 370 to the lower ink storage chamber 390. The ink guide path 380 is formed so as to extend vertically downward from the ink outlet 371 of the upper ink storage chamber 370, and thereby provides a descending connection between the liquid storage chambers 370 and 390 so that the ink I descends downward through the liquid guide path.
An ink guide path 420 is connected to an ink outlet 312 provided in the cavity of the liquid remaining-amount sensor 31 disposed downstream of the lower ink storage chamber 390 at one end thereof, and to an ink inlet 431 provided in the buffer chamber 430 at the other end thereof. The ink guide path 420 guides the ink I from the lower ink storage chamber 390 to the buffer chamber 430. The guide path 420 extends obliquely upward from the ink outlet 312 formed in the cavity of the liquid remaining-amount sensor 31, and thereby provides an ascending connection between the ink storage chambers 390 and 430 so that the ink I ascends upward through the liquid guide path.
Thus, in the cartridge main body 10 according to the present invention, the descending connection and the ascending connection are alternately provided to connect the three ink storage chambers 370, 390, and 430.
The ink guide path 440 guides the ink from the ink outlet 432 of the buffer chamber 430 to the differential pressure regulating valve 40.
According to the present embodiment, the ink inlets 391 and 431 of the ink storage chambers are respectively positioned above the ink outlets 371 and 311 formed in the corresponding storage chambers and near the bottom walls 375, 395, and 435 of the corresponding ink storage chambers.
The ink guide paths for guiding the ink from the upper ink storage chamber 370, which is a main ink storage chamber, to the ink-supplying unit 50 will be described below with reference to FIGS. 8 to 12.
The upper ink storage chamber 370 is positioned at the most upstream (uppermost) position in the cartridge main body 10, and is disposed at the front side of the cartridge main body 10, as shown in FIG. 8. The upper ink storage chamber 370 has a capacity of about half of the total capacity of the ink storage chambers, and occupies substantially an upper half section of the cartridge main body 10.
The ink outlet 371 that communicates with the ink guide path 380 is formed in the concavity 374 of the bottom wall 375 of the upper ink storage chamber 370. The ink outlet 371 is positioned below the bottom wall 375 of the upper ink storage chamber 370. Therefore, even when the ink surface F in the upper ink storage chamber 370 becomes lower and reaches the bottom wall 375, the ink outlet 371 is still below the ink surface F and continues to stably eject the ink I.
As shown in FIG. 9, the ink guide path 380 is disposed at the back side of the cartridge main body 10 and guides the ink I downward to the lower ink storage chamber 390.
The ink I contained in the upper ink storage chamber 370 is guided to the lower ink storage chamber 390. As shown in FIG. 8, the lower ink storage chamber 390 is disposed at the front side of the cartridge main body 10 and has a capacity of about half of the total capacity of the ink storage chambers. The lower ink storage chamber 390 occupies a lower half section of the cartridge main body 10.
The ink inlet 391, which communicates with the ink guide path 380, opens into a communicating flow path disposed under the bottom wall 395 of the lower ink storage chamber 390. The ink I from the upper ink storage chamber 370 flows into the lower ink storage chamber 390 through the communicating flow path.
The lower ink storage chamber 390 communicates with the upstream ink-end-sensor connecting flow path 400 through the ink outlet 311 that extends through the bottom wall 395. The upstream ink-end-sensor connecting flow path 400 includes a maze-like flow path having a three-dimensional structure for catching the air bubbles B and the like that flow into the maze-like flow path before the ink runs out so as to prevent the air bubbles B and the like from flowing downstream.
The upstream ink-end-sensor liquid-guide-path connecting flow path 400 communicates with a downstream ink-end-sensor liquid-guide-path connecting flow path 410 via a through hole (not shown), and the ink I is guided to the liquid remaining-amount sensor 31 through the downstream ink-end-sensor connecting flow path 410.
The ink I guided to the liquid remaining-amount sensor 31 passes through the cavity (flow path) in the liquid remaining-amount sensor 31, and is guided to the ink guide path 420, which is disposed at the back side of the cartridge main body 10, through the ink outlet 312 formed in the cavity.
The ink guide path 420 is formed so as to guide the ink I obliquely upward from the liquid remaining-amount sensor 31, and is connected to the ink inlet 431 that communicates with the buffer chamber 430. Accordingly, the ink I from the liquid remaining-amount sensor 31 is guided to the buffer chamber 430 through the ink guide path 420.
The buffer chamber 430 is a small cell defined by the ribs 10a at a position between the upper ink storage chamber 370 and the lower ink storage chamber 390. The buffer chamber 430 functions as a space in which the ink is stored immediately before reaching the differential pressure regulating valve 40. The buffer chamber 430 is formed so as to face the back side of the differential pressure regulating valve 40. The ink I flows into the differential pressure regulating valve 40 through the ink guide path 440 that communicates with the ink outlet 432 formed in the concavity 434 of the buffer chamber 430.
The ink I that flows into the differential pressure regulating valve 40 is guided downstream by the differential pressure regulating valve 40 to an outlet flow path 450 through a through hole 451. The outlet flow path 450 communicates with the ink-supplying unit 50. The ink I is supplied to the ink jet recording apparatus through the ink supply needle 240 inserted into the ink-supplying unit 50.
Next, the atmosphere communicating path 150 extending from the atmospheric vent 100 to the upper ink storage chamber 370 will be described below with reference to FIGS. 8 to 12.
When the ink I contained in the ink cartridge 11 is consumed and the pressure in the ink cartridge 11 is reduced, the atmospheric air (air) flows into the upper ink storage chamber 370 through the atmospheric vent 100 by an amount corresponding to the amount of reduction of the ink I.
The small hole 102 formed in the atmospheric vent 100 communicates with a meandering path 310 provided at the back side of the cartridge main body 10 at one end thereof. The meandering path 310 is formed so as to increase the distance from the atmospheric vent 100 to the upper ink storage chamber 370 and has an elongate shape so as to suppress the evaporation of moisture in the ink. The other end of the meandering path 310 is connected to the gas-liquid separation filter 70.
The gas-liquid separation chamber 70a included in the gas-liquid separation filter 70 has a through hole 322 in the bottom surface thereof, and communicates with a space 320 provided at the front side of the cartridge main body 10 through the through hole 322.
In the gas-liquid separation filter 70, the gas-liquid separation film 71 is disposed between the through hole 322 and the other end of the meandering path 310. The gas-liquid separation film 71 is made of a mesh webbing made of a textile material having high water repellency and oil repellency.
The space 320 is provided at an upper right section of the upper ink storage chamber 370 when viewed from the front of the cartridge main body 10. In the space 320, a through hole 321 is formed above the through hole 322. The space 320 communicates with an upper connecting flow path 330 formed at the back side through the through hole 321.
The upper connecting flow path 330 extends through a section adjacent to the top surface of the ink cartridge 11, that is, through an uppermost section in the direction of gravity when the ink cartridge 11 is in the attached state. The upper connecting flow path 330 includes flow-path portions 333 and 337. The flow-path portion 333 extends rightward from the through hole 321 along the long side when viewed from the back side. The flow-path portion 337 extends above the flow-path portion 333 from a bent portion 335 positioned near a short side to a through hole 341 formed at a position near the through hole 321. The through hole 341 communicates with an ink trap chamber 340 formed at the front side.
When the upper connecting flow path 330 is viewed from the back, the flow-path portion 337, which extends from the bent portion 335 to the through hole 341, has a position 336 at which the through hole 341 is formed and a recess 332 that is deeper than the position 336 in the cartridge thickness direction. A plurality of ribs 331 are formed so as to divide the recess 332. The flow-path portion 333 that extends from the through hole 321 to the bent portion 335 is shallower than the flow-path portion 337 that extends from the bent portion 335 to the through hole 341.
According to the present embodiment, the upper connecting flow path 330 is provided at the uppermost section in the direction of gravity. Therefore, basically, the ink I is prevented from reaching the atmospheric vent 100 through the upper connecting flow path 330. In addition, the upper connecting flow path 330 is thick enough to prevent the backflow of the ink I caused by the capillary phenomenon. In addition, since the recess 332 is formed in the flow-path portion 337, the ink I that flows backward can be easily caught.
The ink trap chamber 340 is a rectangular parallelepiped space formed at an upper right corner of the cartridge main body 10 when viewed from the front. As shown in FIG. 12, the through hole 341 is formed at a position near the upper left back corner of the ink trap chamber 340 when viewed from the front. In addition, a notch portion 342 is formed in the rib 10a that functions as a separation wall at the lower right front corner of the ink trap chamber 340. Thus, the ink trap chamber 340 communicates with a connecting buffer chamber 350 through the notch portion 342.
The ink trap chamber 340 and the connecting buffer chamber 350 are air chambers obtained by partially increasing the volume of the atmosphere communicating path 150 at intermediate positions thereof. Even if the ink I flows backward from the upper ink storage chamber 370 for some reason, the ink I can be trapped in the ink trap chamber 340 and the connecting buffer chamber 350 and be prevented from flowing further toward the atmospheric vent 100. The detailed roles of the ink trap chamber 340 and the connecting buffer chamber 350 will be described below.
The connecting buffer chamber 350 is a space provided below the ink trap chamber 340. The pressure reducing hole 110 for removing the air in the process of injecting the ink is provided in a bottom surface 352 of the connecting buffer chamber 350. In addition, a through hole 351 that extends in the thickness direction is formed at a position near the bottom surface 352, that is, at a lowermost position in the direction of gravity in the state in which the ink cartridge is attached to the ink jet recording apparatus. The connecting buffer chamber 350 communicates with a connecting flow path 360 provided at the back side through the through hole 351.
The connecting flow path 360 extends upward in a central area when viewed from the back, and communicates with the upper ink storage chamber 370 through a through hole 372 that opens at a position near the bottom surface of the upper ink storage chamber 370. Accordingly, the structure from the atmospheric vent 100 to the connecting flow path 360 forms the atmosphere communicating path 150 according to the present embodiment. The connecting flow path 360 has a meniscus structure, and the thickness thereof is determined such that the ink I is prevented from flowing backward.
In the ink cartridge 1 according to the present embodiment, as shown in FIG. 8, in addition to the above-described ink storage chambers (the upper ink storage chamber 370, the lower ink storage chamber 390, and the buffer chamber 430), the air chambers (the ink trap chamber 340 and the connecting buffer chamber 350), and the ink guide paths (the upstream ink-end-sensor connecting flow path 400 and the downstream ink-end-sensor connecting flow path 410), an ink-free chamber 501 that is free from the ink I is also provided at the front side of the cartridge main body 10.
The ink-free chamber 501 is shown as a hatched area near the left side, and is formed between the upper ink storage chamber 370 and the lower ink storage chamber 390 at the front side of the cartridge main body 10.
The ink-free chamber 501 has an atmospheric vent 502 that extends through a back wall thereof at an upper left corner of the inner space, and communicates with the atmosphere through the atmospheric vent 502.
The ink-free chamber 501 functions as a deaerating chamber that accumulates negative pressure for deaerating in the process of vacuum-packaging the cartridge 1. Before use, the pressure in the cartridge main body 10 is maintained equal to or below a predetermined pressure due to the ink-free chamber 501 and the negative-pressure suction force applied in the vacuum packaging process. Accordingly, the ink I with a small amount of dissolved air can be provided.
In the above-described ink cartridge 1, there is a possibility that the ink cartridge 1 will be detached form the carriage 200 while in use and fall over. In addition, even when the ink cartridge 1 is attached to the carriage 200, there is a possibility that the ink surfaces F in the ink storage chambers 370, 390, and 430 will shake due to external vibrations or the like. In such a case, if the amount of ink remaining in any of the ink storage chamber is small, there is a risk that the air layer in the storage chamber will come into contact with the corresponding ink outlet and air bubbles will enter the ink guide path that communicates with the ink outlet.
However, according to the structure of the present embodiment, the descending connection and the ascending connection are alternately provided to connect the three ink storage chambers 370, 390, and 430. Therefore, the liquid guide path that extends to the liquid remaining-amount sensor 31 is provided as a meandering flow path that is bent upward and downward.
Therefore, even if the air bubbles B are included in the ink I that flows into the liquid guide path extending from the upper ink storage chamber 370 disposed at the upstream position to the ink-supplying unit 50, when the air bubbles B pass through the ink guide path 380, which provides the descending connection, the air bubbles B receive buoyancy from the ink I existing in the ink guide path 380, which provides the descending connection. Therefore, the air bubbles B that enter the liquid guide path cannot easily flow downstream.
In addition, if the ink cartridge 1 is detached from the carriage 200 and is turned upside down, the ink guide path 420, which usually provides the ascending connection, provides a descending connection so as to stop the downstream movement of the air bubbles B. In other words, even when the ink cartridge 1 is turned upside down, the downstream movement of the air bubbles B can be prevented since the ink guide path 420 provides a descending connection.
In addition, the lower ink storage chamber 390 and the buffer chamber 430, which are located at the second and the following stages, function as trap spaces for catching the air bubbles B that flow from the upper ink storage chamber 370 disposed at the upstream position. More specifically, if the ink cartridge 1 falls over on its side so that the ink guide paths 380 and 420, which originally extend vertically, extend in the horizontal direction, the descending connection between the ink storage chambers cannot provide a function of preventing the movement of the air bubbles B. However, in such a case, upper spaces of the lower ink storage chamber 390 and the buffer chamber 430 effectively function as trap spaces for catching the air bubbles B. Accordingly, the ink I remaining in the lower ink storage chamber 390 and the buffer chamber 430 reliably prevents the downstream movement of the air bubbles B.
Therefore, even when the air bubbles B enter the ink guide paths 380 and 420 from the upstream upper ink storage chamber 370 disposed at the upstream position and the lower ink storage chamber 390, respectively, as long as a usable amount of ink is remaining in the zigzag ink guide paths connecting the ink storage chambers to each other, the lower ink storage chamber 390, and the buffer chamber 430, the air bubbles B that enter the ink guide paths can be prevented from reaching the detection position of the liquid remaining-amount sensor 31. As a result, the liquid remaining-amount sensor 31 can be prevented from making a false detection due to the air bubbles B.
In the above-described embodiment, three ink storage chambers are provided in a single cartridge main body. However, the number of ink storage chambers to be provided in the cartridge main body may be set to an arbitrary number selected from three or more. As the number of ink storage chambers is increased, the number stages of the traps for catching the air bubbles is increased and the performance of preventing the downstream movement of the air bubbles can be increased.
The application of the liquid storage container according to the present invention is not limited to the ink cartridge explained in the above-described embodiment. In addition, the liquid-consuming apparatus having a container-receiving unit to which the liquid storage container according to the present invention is attached is also not limited to the ink jet recording apparatus explained in the above-described embodiment.
The liquid-consuming apparatus may be any kind of apparatus which includes a container-receiving unit for receiving the liquid storage container in a detachable manner and to which the liquid contained in the liquid storage container is supplied. For example, the present invention may be applied to an apparatus including a color-material ejecting head used for manufacturing a color filter of a liquid crystal display or the like, an apparatus including an electrode-material (conductive paste) ejecting head used for forming electrodes of an organic EL display, a field emitting display (FED), etc., an apparatus including a living-organic-material ejecting head used for manufacturing biochips, an apparatus including a sample-ejecting head that functions as a precision pipette, etc.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an external perspective view illustrating an ink cartridge as a liquid storage container according to an embodiment of the present invention.
FIG. 2 is an external perspective view of the ink cartridge according to the embodiment of the present invention shown in FIG. 1 as viewed from the opposite angle.
FIG. 3 is an exploded perspective view of the ink cartridge according to the embodiment of the present invention.
FIG. 4 is an exploded perspective view of the ink cartridge according to the embodiment of the present invention shown in FIG. 3 as viewed from the opposite angle.
FIG. 5 is a diagram illustrating the state in which the ink cartridge according to the embodiment of the present invention is attached to a carriage of an inkjet recording apparatus.
FIG. 6 is a sectional view illustrating the state immediately before the ink cartridge according to the embodiment of the present invention is attached to the carriage.
FIG. 7 is a sectional view illustrating the state immediately before the ink cartridge according to the embodiment of the present invention is attached to the carriage.
FIG. 8 is a front view of a cartridge main body of the ink cartridge according to the embodiment of the present invention.
FIG. 9 is a rear view of a cartridge main body of the ink cartridge according to the embodiment of the present invention.
FIG. 10(a) is a simplified diagram of the structure shown in FIG. 8, and FIG. 10(b) is a simplified diagram of the structure shown in FIG. 9.
FIG. 11 is a sectional view of FIG. 8 taken along line A-A.
FIG. 12 is an enlarged perspective view of a portion of a flow path structure in the cartridge main body shown in FIG. 8.



REFERENCE NUMERALS
1 . . . ink cartridge (liquid storage container), 10 . . . cartridge main body (container main body), 20 . . . lid member, 30 . . . ink end sensor, 31 . . . liquid remaining-amount sensor, 40 . . . differential pressure regulating valve, 50 . . . ink-supplying unit (liquid-supplying unit), 70 . . . gas-liquid separation filter, 80 . . . film, 100 . . . atmospheric vent, 150 . . . atmosphere communicating path, 200 . . . carriage, 330 . . . upper connecting flow path, 340 . . . ink trap chamber (air chamber), 350 . . . connecting buffer chamber (air chamber), 370 . . . upper ink storage chamber (liquid storage chamber), 371, 311, 432 . . . ink outlets (liquid outlet), 374, 394, 434 . . . concavities, 375, 395, 435 . . . bottom wall of liquid storage chamber, 380 . . . ink guide path (liquid guide path), 390 . . . lower ink storage chamber (liquid storage chamber), 391, 431 . . . ink inlet (liquid inlet), 400 . . . upstream ink-end-sensor connecting flow path (liquid guide path), 410 . . . downstream ink-end-sensor connecting flow path (liquid guide path), 420 . . . ink guide path (liquid guide path), 430 . . . buffer chamber (liquid storage chamber), 501 . . . ink-free chamber (deaerating chamber), B . . . air bubbles, I . . . ink (liquid)

## Claims

1. A liquid storage container opened to the atmosphere and attachable to and detachable from a liquid-consuming apparatus, the liquid storage container comprising:
liquid storage chambers that store liquid;
a liquid-supplying unit connectable to the liquid-consuming apparatus;
liquid guide paths for guiding the liquid contained in the liquid storage chambers to the liquid-supplying unit;
an atmosphere communicating path that allows atmospheric air to flow into one of the liquid storage chambers from the outside as the liquid in the liquid storage chambers is consumed; and
a liquid remaining-amount sensor disposed at an intermediate position of one of the liquid guide paths and determining that the liquid in the liquid storage chambers has run out when a flow of gas into the one of the liquid guide paths is detected,
wherein the number of the liquid storage chambers provided in the liquid storage container is three or more,
wherein a descending connection that connects a pair of the liquid storage chambers to each other with one of the liquid guide paths such that the liquid descends downward therethrough and an ascending connection that connects a pair of the liquid storage chambers to each other with another one of the liquid guide paths such that the liquid ascends upward are alternately provided to connect the liquid storage chambers in series, and
wherein the one of the liquid guide paths at which the liquid remaining-amount sensor is disposed connects a pair of the liquid storage chambers provided downstream from the one of the liquid storage chambers communicating with the atmosphere.

2. The liquid storage container according to claim 1, wherein the atmosphere communicating path is provided with an air chamber for preventing a leakage of the liquid from the liquid storage chambers.

3. The liquid storage container according to claim 1 or 2, wherein at least a portion of the atmosphere communicating path passes through an uppermost section in the direction of gravity in the liquid container.

4. The liquid storage container according to one of claims 1 to 3, wherein the atmosphere communicating path is provided with a gas-liquid separation filter that blocks liquid while allowing gas to pass therethrough.

5. The liquid storage container according to one of claims 1 to 4, wherein the liquid storage container is packed in a vacuum package in which the pressure is reduced to the atmospheric pressure or less.

6. A liquid storage container opened to the atmosphere and attachable to and detachable from a liquid-consuming apparatus, the liquid storage container comprising:
liquid storage chambers that store liquid;
a liquid-supplying unit connectable to the liquid-consuming apparatus;
liquid guide paths for guiding the liquid contained in the liquid storage chambers to the liquid-supplying unit;
an atmosphere communicating path that allows atmospheric air to flow into one of the liquid storage chambers from the outside as the liquid in the liquid storage chambers is consumed; and
a liquid sensor disposed in one of the liquid guide paths,
wherein the number of the liquid storage chambers provided in the liquid storage container is three or more,
wherein a descending connection that connects a pair of the liquid storage chambers to each other with one of the liquid guide paths such that the liquid descends downward therethrough and an ascending connection that connects a pair of the liquid storage chambers to each other with another one of the liquid guide paths such that the liquid ascends upward are alternately provided to connect the liquid storage chambers in series, and
wherein the one of the liquid guide paths at which the liquid sensor is disposed connects a pair of the liquid storage chambers provided downstream from the one of the liquid storage chambers communicating with the atmosphere.