Ink cartridge and ink jet record apparatus using the ink cartridge

An ink cartridge is detachably connected to a record head and has a plurality of ink storage chambers 11 (containing third ink storage chamber 17) for containing ink whose concentration gradient occurs and an ink flow passage 18 for making the ink storage chambers communicate with each other. The ink flow passage 18 is implemented as such an ink flow passage where ink in a high-concentration ink layer a formed in a lower area in the ink storage chamber 11 and ink in a low-concentration ink layer b formed in an upper area flow and merge as ink is supplied to the record head.

BACKGROUND OF THE INVENTION

This invention relates to an ink cartridge for supplying ink to a record head, and an ink jet record apparatus using the ink cartridge.

An ink jet record apparatus generally comprises a record head mounted on a carriage and moving in the width direction of record paper, and paper feed means for moving the record paper relatively in a direction orthogonal to the move direction of the record head.

Such an ink jet record apparatus prints on record paper by ejecting ink droplets from a record head based on print data.

A record head capable of ejecting black ink, yellow ink, cyan ink, and magenta ink, for example, is mounted on a carriage, and in addition to text print in black ink, full-color print is made possible by changing the ink ejection percentage.

Thus, ink cartridges for supplying black ink, yellow ink, cyan ink, and magenta ink to the record head are placed in the main unit of the apparatus.

In the ordinary ink jet record apparatus, the ink cartridges for supplying black ink, yellow ink, cyan ink, and magenta ink are mounted on a carriage, and are moved together with the carriage.

On the other hand, in this kind of record apparatus provided for an office or business, for example, to deal with a comparatively large amount of print, the large-capacity ink cartridge storing each ink is not placed on the carriage and is placed in the apparatus main unit.

A record apparatus of the type wherein main tanks as ink cartridges are placed in the apparatus main unit (cartridge holder), and subtanks are placed on a carriage on which a record head is mounted is also provided. Ink is respectively supplied from the main tanks to the subtanks via ink supply tubes, and further from the subtanks to the record head.

In such a record apparatus, to improve throughput, such a function is required that can replenish ink from the main tanks to the subtanks in succession to stably supply ink from the subtanks to the record head, while print is executed.

By the way, nowadays, demand for high-accuracy print quality grows, and there is a tendency of using ink containing pigment (pigment ink), for example, as print ink.

Such pigment ink has a large particle diameter of color material as compared with ink containing a dye (dye ink), and pigment is likely to be collected and concentrated in the bottom portion of a cartridge (ink storage chamber), and therefore a concentration distribution (non-uniformity in concentration) easily occurs in the ink in the cartridge.

Thus, there arises a technical problem in that the ink in the cartridge is not sufficiently mixed at the use time and uniform print density and quality cannot be obtained.

It is therefore an object of the invention to provide an ink cartridge for making it possible to sufficiently mix ink in the cartridge at the use time and therefore provide uniform print density and quality. Another object of the present invention is to provide an ink jet record apparatus using the ink cartridge.

SUMMARY OF THE INVENTION

To the end, according to the invention, there is provided an ink cartridge being detachably connected to a head of a record apparatus and comprising a plurality of ink storage chambers for containing ink causing concentration gradient, and an ink flow passage for communicating the ink storage chambers with one another. In the cartridge, the ink flow passage has such an ink flow passage as to cause ink in a high-concentration ink layer formed in a lower area in the ink storage chamber and ink in a low-concentration ink layer formed in an upper area in the ink storage chamber to flow and merge with each other as ink is supplied to the record apparatus head.

Since the ink cartridge is thus configured, when ink is supplied to the record apparatus head, the ink in the high-concentration ink layer in the ink storage chamber and the ink in the low-concentration ink layer in the ink storage chamber flow and merge in the ink flow passage.

Therefore, the ink in the high-concentration ink layer and the ink in the low-concentration ink layer are mixed for supply to the record apparatus head, so that uniform print density and quality can be obtained.

Here, it is desirable that the ink storage chambers comprise a plurality of upper ink storage chambers including a head connection ink storage chamber that can be connected to the record apparatus head, and an atmosphere open lower ink storage chamber opened to the atmosphere in the connection state to the record apparatus head.

Since the ink cartridge is thus configured, ink is supplied to the record apparatus head by causing ink to flow from the lower ink storage chamber to the upper ink storage chamber.

It is desirable that the ink flow passage is formed with a first communication port opened to the inside of the high-concentration ink layer and a second communication port opened to the inside of the low-concentration ink layer.

Since the ink cartridge is thus configured, when ink is supplied to the record apparatus head, the ink in the high-concentration ink layer flows through the first communication port into the ink flow passage, the ink in the low-concentration ink layer flows through the second communication port into the ink flow passage, and the ink in the high-concentration ink layer and the ink in the low-concentration ink layer merge in the ink flow passage.

Further, it is desirable that the first-communication port is disposed at the lowest position in the gravity direction in the ink storage chamber.

Since the ink cartridge is thus configured, the ink at the lowest position in the gravity direction in the ink storage chamber flows through the first communication port into the ink flow passage.

Further, it is desirable that the flow amount ratio between the flow amount a of ink passing through the first communication port and the flow amount b of ink passing through the second communication port, a:b, is set in the range of 1:1 to 1:3.

Since the ink cartridge is thus configured, it is possible to avoid such a case that the flow-through resistance of the first communication port becomes too large as compared with that of the second communication port (the flow-through resistance ratio becomes insufficient) and the flow amount of ink passing through the first communication port is lessened.

A partition wall having both the communication ports is provided in the upper ink storage chamber.

Since the ink cartridge is thus configured, in the upper ink storage chamber, when ink is supplied to the record apparatus head, the ink in the high-concentration ink layer flows through the first communication port into the ink flow passage, the ink in the low-concentration ink layer flows through the second communication port into the ink flow passage, and the ink in the high-concentration ink layer and the ink in the low-concentration ink layer merge in the ink flow passage.

An ink guide path for causing ink to flow from a storage chamber upper part to a storage chamber lower part in an ink supply state can also be provided in the upper ink storage chamber.

Since the ink cartridge is thus configured, in the upper ink storage chamber, when ink is supplied to the record apparatus head, when ink passes through the ink guide path, it flows from the storage chamber lower part to the storage chamber upper part while it is mixed.

On the other hand, according to the invention, there is provided an ink jet record apparatus comprising a carriage for mounting a head, that can be reciprocated between a print area and a non-print area, using any of the ink cartridges described above.

According to the configuration, when ink is supplied to the record apparatus head, the ink in the high-concentration ink layer in the ink storage chamber and the ink in the low-concentration ink layer flow and merge in the ink flow passage.

Therefore, the ink in the high-concentration ink layer and the ink in the low-concentration ink layer are mixed for supply to the record apparatus head, so that there cab be provided the ink jet record apparatus that can provide uniform print density and quality.

The present disclosure relates to the subject matter contained in Japanese patent application Nos. 2001-148296 (filed on May 17, 2001), and 2001-205163 (filed on Jul. 5, 2001), which are expressly incorporated herein by reference in their entireties.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the accompanying drawings, preferred embodiments of an ink cartridge and an ink jet record apparatus using the ink cartridge incorporating the invention will be discussed.

To begin with, an ink jet record apparatus will be discussed with reference to FIG.1.FIG. 1is a perspective view to show an outline of the general configuration of the ink jet record apparatus according to an embodiment of the invention.

InFIG. 1, a carriage indicated by numeral101can be reciprocated in the axial direction of a platen105as guided by a guide member104via a timing belt103driven by a carriage motor102.

The guide member104is supported on two left and right frames131and132opposed to each other. Both the frames131and132are joined by a rear plate133and a bottom plate134.

An ink jet record head112is mounted on the lower face portion of the carriage101so that it is opposed to record paper106. A black ink cartridge107and a color ink cartridge108for supplying ink to the record head112are detachably held on the upper face portion of the carriage101.

A capping system109having a cap member109ais disposed in a non-print area (home position) in a movable area of the carriage101. When the record head112moves just above the capping system109, the capping system109can move up so as to seal the nozzle formation face of the record head112. A tube pump110as a pump unit to give a negative pressure to the internal space of the cap member109ais disposed below the capping system109.

The capping system109has a function as a lid for preventing nozzle openings of the record head112from being dried during the nonoperating period of the ink jet record apparatus. It also has a function as an ink receiver during the flushing operation of applying a drive signal not involved in print to the record head112for idly ejecting ink droplets, and a function as a cleaning system for causing a negative pressure from the tube pump110to act on the record head112for sucking ink.

A wiping system111comprising an elastic plate of rubber, etc., is disposed in the proximity of the print area side of the capping system109so that it can advance and retreat in a horizontal direction. When the carriage101reciprocates on the capping system109side, the wiping system111can advance into the moving path of the record head112.

Next, an ink cartridge used with the described ink jet record apparatus will be discussed with reference toFIGS. 2to10. FIGS.2(a) and2(b) are perspective views to show the appearance of the ink cartridge according to a first embodiment of the invention.FIGS. 3 and 4are perspective views showing the internal structure of the ink cartridge according to the first embodiment of the invention as viewed from upward and downward in a slanting direction.FIGS. 5 and 6are a front view and a rear view to show the internal structure of the ink cartridge according to the first embodiment of the invention.FIGS. 7 and 8are enlarged sectional views to show a negative pressure generation system storage chamber and a valve storage chamber of the ink cartridge according to the first embodiment of the invention.FIG. 9is a front view to show the connection state of the ink cartridge according to the first embodiment of the invention to a cartridge holder. FIGS.10(a) and10(b) are sectional views to schematically show the internal structure of the ink cartridge according to the first embodiment of the invention to describe an ink flow passage in the ink cartridge.

An ink cartridge1shown in FIGS.2(a) and2(b) (black ink cartridge107, color ink cartridge108inFIG. 1) has a container main body2having an almost flat shape rectangular in a plane view, which is opened to one side, and also has a lid body3for sealing the opening of the container main body2.

The container main body2is formed in the lower portion with an ink supply port4that can be connected to an ink supply needle72of a record head112(both are shown in FIG.9). Retention members5and6, which can be attached to and detached from a cartridge holder, are provided integrally on the upper sides of the container main body2. A memory device7is disposed below one retention member5, and a valve storage chamber8is disposed below the other retention member6.

The ink supply port4stores a valve body (not shown) therein, which is opened and closed as the ink supply needle is inserted and removed.

As shown inFIG. 8, the valve storage chamber8has an internal space opened to the cartridge insertion side (lower side), so that an identification piece73(shown inFIG. 9) and a valve operation rod70on the record apparatus matching with the ink cartridge1can advance and retreat in the internal space. The upper part of the internal space contains an operation arm66rotated as the valve operation rod70advances and retreats, and an identification convex part (s)68for determining whether or not the ink cartridge matches with a given record apparatus is formed in the lower part of the internal space. The identification convex part68is disposed at such a position as to complete the determination by the valve operation rod79(the identification piece73) of a cartridge holder71(shown inFIG. 9) before the ink supply needle72is made to communicate with the ink supply port4(before an atmospheric open valve described later is opened).

A through hole60opened and closed by the opening and closing operation of an atmospheric open valve601is formed in a chamber wall8aof the valve storage chamber8, as shown in FIG.8. The operation arm66is placed on one opening side of the through hole60, and the atmospheric open valve601is placed on the other opening side of the through hole60. The operation arm66has an operation part66bfor pressing a press member61, and is disposed to project in an upward slanting direction into the entry path of the valve operation rod70, and is fixed to the container main body2through a rotation supporting point66a.

The press member61is attached to the chamber wall8aso as to close the through hole60, and the whole of the press member61is formed of an elastic member of rubber, etc. The internal space formed between the press member61and the opening peripheral margin of the through hole60is opened to a through hole67communicating with a first ink storage chamber11(both are shown in FIG.5).

The atmospheric open valve601has a valve body65urged constantly against the opening peripheral margin of the through hole60as shown in FIG.8. The valve body65has an elastic member62, the movement of which is regulated by a projection64, and the elastic member62is fixed at a lower end part to the container main body2through a projection63.

Next, the internal space of the container main body2(inside of the ink cartridge) will be discussed. The inside of the ink cartridge is mainly constructed by an ink flow passage system and an air flow passage system, and therefore the ink flow passage system and the air flow passage system will be discussed separately. The main part of the invention is directed to the ink flow passage having a complicated structure wherein ink in a high-concentration ink layer and ink in a low-concentration ink layer flow and merge (passage where ink flows in the ink cartridge), and therefore the ink flow passage system will be discussed particularly in detail. The ink flow passage system will be discussed in the order of “ink flow operation” and “configuration of ink flow passage”.

When ink supply to the record head112(shown inFIGS. 1 and 9) is started, ink in a high-concentration ink layer a in the first ink storage chamber11flows from a communication port19avia a communication port18a(shown inFIG. 5) into a communication flow passage (flow passage connecting the first ink storage chamber11and a second ink storage chamber16)18. On the other hand, ink in a low-concentration ink layer b in the first ink storage chamber11flows from a communication port19bvia the communication port18ainto the communication flow passage18. The ink in the high-concentration ink layer a and the ink in the low-concentration ink layer b flowing into the communication flow passage18merge and further move up in the communication flow passage18to flow toward the second ink storage chamber16.

In this case, the communication ports19aand18aare disposed at the same height positions, so that the ink in the first ink storage chamber11is introduced into the second ink storage chamber16along the communication flow passage18without being left.

Next, the ink flowing from the first ink storage chamber11via the communication flow passage18into the second ink storage chamber16merges with the ink in the high-concentration ink layer a in the second ink storage chamber16, and further passes through a communication port15aof a vertical wall15, flows into a third ink storage chamber17, and passes through a communication port26aof a partition wall26, as indicated by the arrows in FIG.10(a). The ink passing through the communication port26aof the partition wall26passes through a communication port27aof a partition wall27, and further moves up in an ink flow passage28, and flows through a communication port24ainto a filter chamber34, as indicated by the arrows in FIG.10(a).

After this, the ink passes through through holes25aof a partition wall25, and flow into a differential pressure regulating valve storage chamber33, and as a differential pressure regulating valve (membrane52shown inFIG. 7) is opened, the ink passes through a through hole52cand arrives at the ink supply port4via a recess part35, as shown in FIG.10(b).

[Configuration of Ink Flow Passage]

The ink cartridge1is formed with an internal space by joining the lid body3to the container main body2and further joining an air shield film to the rear of the container main body2. The internal space is divided into upper and lower parts by a partition wall10extending slightly downward toward the ink supply port side opposed to the record head112, as shown inFIGS. 3to5. The lower area of the internal space provides the first ink storage chamber11opened to the atmosphere in the connection state to the record head112. On the other hand, the upper area of the internal space is defined by a frame14with the partition wall10as a bottom part. The internal space of the frame14is divided into left and right parts by the vertical wall15having the communication port15a. One of the areas into which the internal space is divided provides the second ink storage chamber16, and the other area provides the third ink storage chamber17.

A communication flow passage18communicating with the first ink storage chamber11is connected to the second ink storage chamber16. The communication flow passage18has communication ports18aand18bat lower and upper positions, and is defined by a vertically extending recess part18c(shown inFIG. 6) opened to the rear of the container main body2and an air shield film for closing and sealing the opening of the recess part18c. A partition wall19having two lower and upper communication ports19aand19bcommunicating with the inside of the first ink storage chamber11is provided upstream from the communication flow passage18. The communication port (first communication port)19ais disposed at a position opened to the inside of the high-concentration ink layer a (shown in FIG.10(a)) formed in the lower area in the first ink storage chamber11. The communication port (second communication port)19bis disposed at a position opened to the inside of the low-concentration ink layer b formed in the upper area in the first ink storage chamber11. Accordingly, such an ink flow passage (compartment) is formed wherein the ink passing through the communication ports19aand19bfrom the first ink storage chamber11flows into the lower communication port18aof the communication ports18aand18b.

On the other hand, the third ink storage chamber17is formed with the differential pressure regulating valve storage chamber33(shown inFIG. 6) for storing the differential pressure regulating valve52(membrane valve) and the filter chamber34(shown inFIG. 5) for storing a filter55(shown inFIG. 7) by a laterally elongating partition wall22and an annular partition wall24. The partition wall25is formed with the through holes25afor introducing ink (pigment) passed through the filter55into the differential pressure regulating valve storage chamber33from the filter chamber34.

The partition wall24is formed at a lower part with the partition wall26having the communication port26abetween the partition wall24and the partition wall101, and is formed on one side with the partition wall27having the communication port27abetween the partition wall24and the frame14. The communication passage28communicating with the communication port27aand extended in the up and down direction is provided between the partition wall27and the frame14. A through hole29communicating with the filter chamber34through the communication port24aand an area31is defined to be continuous to an upper part of the communication passage28.

The through hole29is formed by a partition wall (annular wall)30continuous to the partition wall27.

The area31is formed by the partition walls24and30and a partition wall30a(shown in FIG.6). The area31is formed deep at one end part of the container main body2(portion communicating with the through hole29) and shallow at an opposite end part (portion communicating with the filter chamber34).

The differential pressure regulating valve storage chamber33stores a spring50implemented as a helical compression spring, and the membrane valve52as a differential pressure regulating valve that can become elastically deformed, such as an elastomer, having a through hole52c, as shown in FIG.7. The membrane valve52has an outer peripheral margin fixed through an annular thick part52ato the container main body2. The spring50is supported at one end part by a spring bracket part52bof the membrane valve52, and at an opposite end part by a spring bracket part53aof the lid body53.

Numeral54denotes a frame formed integrally with the thick part52aof the membrane valve52. Numerals56and57denote air shield films disposed on the front and the rear of the container main body2.

The filter55for allowing ink to pass through and capturing dust, etc., is placed in the filter chamber34, as shown in FIG.7. The openings of the filter chamber34and the differential pressure regulating valve storage chamber33are sealed with liquid (ink, air) shield films. Accordingly, when the pressure in the ink supply port4lowers, the membrane valve52is separated from a valve sheet part25bagainst the urging force of the spring50. Thus, ink passed through the filter55passes through the through hole52c, and flows into the ink supply port4through the flow passage formed by the recess part35. When the ink pressure in the ink supply port4rises to a predetermined value, the membrane valve52sits in the valve seat part25bby the urging force of the spring50, shutting off the flow of ink. Such operation is repeated, whereby ink is supplied to the ink supply port4while a constant negative pressure is maintained.

As shown inFIG. 6, the container main body2is formed on the rear with a meander groove36for raising flow passage resistance, a wide recessed groove37opened to the atmosphere, and a recess part38(space part) almost rectangular in a plan view, which is adjacent with the second ink storage chamber16through a partition wall602. The recess part38is provided with a frame39and ribs40, onto which an air permeable film is stretched and fixed, thereby forming an atmospheric ventilation chamber. A through hole41is made in the bottom part (wall part) of the recess part38, and is made to communicate with an elongated area43defined by the partition wall42(shown inFIG. 5) of the second ink storage chamber16. The area43has a through hole44, and is made to communicate with the atmospheric open chamber501(shown inFIG. 8) through a communication groove45defined by a partition wall603and a through hole46opened to the communication groove45.

According to the configuration, when the ink cartridge1is mounted to the cartridge holder71as shown inFIG. 9, the valve operation rod70of the cartridge holder71abuts the operation arm66of the ink cartridge1shown inFIG. 8for moving the convex part66b(press member61) to the valve body side. Accordingly, the valve body65is separated from the opening peripheral margin of the through hole60, so that the first ink storage chamber11shown inFIG. 5is opened to the recess part38(atmosphere) shown in FIG.6through the through holes67,60, and46, the groove45, the through hole44, the area43, the through hole41, etc. A valve body (not shown) in the ink supply port4is opened by insertion of the ink supply needle72.

As the valve body in the ink supply port4is opened and ink (pigment ink) is consumed by the record head112, the pressure of the ink supply port4falls below a stipulated value. Thus, the membrane valve52in the differential pressure regulating valve storage chamber33shown inFIG. 7is opened (if the pressure of the ink supply port4rises above the stipulated value, the membrane valve52is closed), ink in the differential pressure regulating valve storage chamber33of the upper ink storage chamber flows into the record head112through the ink supply port4.

Further, as consumption of ink in the record head112proceeds, ink in the first ink storage chamber11, i.e. the lower ink storage chamber, flows into the second ink storage chamber16through the communication flow passage18shown in FIG.5.

In this case, ink in the high-concentration ink layer a (shown in FIG.10(a)) positioned in the lower area of the first ink storage chamber11flows into the communication flow passage18(shown inFIG. 6) through the communication port19a(shown in FIG.5), and ink in the low-concentration ink layer b (shown in FIG.10(a)) positioned in the upper area of the first ink storage chamber11flows into the communication flow passage18through the communication port19b, so that the ink in the high-concentration ink layer a and the ink in the low-concentration ink layer b merge in the communication flow passage18.

On the other hand, as ink is consumed, air flows in through the through hole67(shown inFIG. 5) communicating with the atmosphere, and the ink liquid level in the first ink storage chamber11lowers. As ink is further consumed and the ink liquid level reaches the communication port19a, ink from the first ink storage chamber11(opened to the atmosphere through the through hole67at the ink supplying time) flows into the second ink storage chamber16via the communication flow passage18together with air. Since bubbles are moved up by a buoyant force, only the ink flows into the third ink storage chamber17through the communication port15ain the lower part of the vertical wall15, passes through the communication port26aof the partition wall26from the third ink storage chamber17, moves up in the communication passage28, and flows into the upper part of the filter chamber34from the communication passage28through the area31and the communication port24a.

After this, the ink in the filter chamber34passes through the filter55shown inFIG. 7, flows into the differential pressure regulating valve storage chamber33from the through holes25a, further passes through the through hole52cof the membrane valve52separated from the valve seat part25b, and then moves down in the recess part35shown in FIG.6and flows into the ink supply port4.

The ink is thus supplied from the ink cartridge to the record head.

Therefore, in the embodiment, the ink in the high-concentration ink layer a and the ink in the low-concentration ink layer b are mixed for supply to the record head112, so that occurrence of variations in the ink concentration can be suppressed and uniform print density and quality can be provided.

If a different kind of ink cartridge1is mounted to the cartridge holder71, before the ink supply port4arrives at the ink supply needle72, the identification convex part68(shown inFIG. 8) abuts the identification piece73(shown inFIG. 9) of the cartridge holder71, thereby inhibiting entry of the valve operation rod70. Therefore, occurrence of trouble as a different kind of ink cartridge is mounted can be prevented. In this state, the valve operation rod70does not arrive at the operation arm66either, and thus the valve body65is maintained in the closed valve state, preventing evaporation of the ink solvent in the first ink storage chamber11as it is left standing.

On the other hand, if the ink cartridge1is removed from the mounting position in the cartridge holder71, the operation arm66is elastically restored because it is no longer supported by the operation rod70, and the valve body65is elastically restored accordingly to close the through hole60, so that communication between the recess part38and the first ink storage chamber11is shut off.

The ink flow passage in the embodiment has been described as such an ink flow passage where in the ink in the high-concentration ink layer a and the ink in the low-concentration ink layer b in the first ink storage chamber11flow at the ink supply time and merge in the communication flow passage18, but the invention is not limited to it. The ink flow passage may be that shown inFIG. 11(second embodiment) or shown inFIG. 12(third embodiment). In this case, the ink in the high-concentration ink layer and the ink in the low-concentration ink layer can be mixed several times and the ink mixing percentage can be raised correspondingly an increase in the number of mixing times.

Second Embodiment

As shown inFIG. 11, in a third ink storage chamber17, a vertical wall15is formed with a communication port15aopened to the inside of a high-concentration ink layer a and a communication port15bopened to the inside of a low-concentration ink layer b (the open area is about three times that of the communication port15a). The communication port15ais placed at the lowest position in the gravity direction in a second ink storage chamber16.

Accordingly, when ink is supplied to a record head112, ink flowing into the second ink storage chamber16from a first ink storage chamber11merges with ink in the high-concentration ink layer a in the second ink storage chamber16to pass through the communication port15a, and also merges with ink in the low-concentration ink layer b to pass through the communication port15b, as indicated by the arrows in FIG.11. The ink passing through the communication ports15aand15bmerges in the lower area of the third ink storage chamber17(high-concentration ink layer a) to flow toward a communication port26aof a partition wall26.

In the embodiment, the case where the flow amount ratio between the flow amount a of ink passing through the communication port15aand the flow amount b of ink passing through the communication port15b, a:b, is set to 1:3 (the open area of the communication port is about three times that of the communication port15a) has been described, but the invention is not limited to it and the flow amount ratio a:b may be set in the range of 1:1 to 1:3. In this case, if the flow amount ratio a:b is set outside the range of 1:1 to 1:3, the flow-through resistance of the communication port15abecomes too large as compared with that of the communication port15b(the flow-through resistance ratio becomes insufficient), and the flow amount of ink passing through the communication port15ais lessened.

Third Embodiment

As shown inFIG. 12, in a third ink storage chamber17, a partition wall51having a communication port51aopened to the inside of a high-concentration ink layer a and a communication port51bopened to the inside of a low-concentration ink layer b is disposed between partition walls24and27.

Accordingly, ink passing through a communication port26aof a partition wall26in the lower area of the third ink storage chamber17(high-concentration ink layer a) merges with ink in the high-concentration ink layer a on the left of the partition wall26to pass through the communication port51a, and also merges with ink in a low-concentration ink layer b on the left of the partition wall24to pass through the communication port51b, as indicated by the arrows in FIG.12. The ink passing through the communication ports51aand51bmerges in the lower area (high-concentration ink layer a) between the partition walls27and51to flow toward a communication port27aof the partition wall27.

Thus, in each of the first to third embodiments, the case where the partition walls are formed with the communication ports to mix ink has been described, but the invention is not limited to it, and an ink guide path61as shown inFIG. 13(fourth embodiment) may be provided in a filter chamber34to mix ink.

As shown inFIG. 13, the ink guide path61is formed so that it extends along the inner peripheral surface of a partition wall24, and is opened to an area31(shown inFIG. 5) and the inside of the filter chamber34. In the filter chamber34, when ink is supplied, ink from the area31(communication port24a) is made to flow from an upper part to a lower part.

Accordingly, when ink is supplied to a record head112, ink passing through the area31is guided along the ink guide path61to the lower part of the filter chamber and flows from the lower part of the filter chamber to a through hole25a(through hole made in the upper part of the filter chamber) while it is mixed, as indicated by the arrows in FIG.13.

As seen in the description made above, according to the ink cartridge and the ink jet record apparatus using the ink cartridge according to the invention, the ink in the cartridge can be sufficiently mixed at the use time, so that uniform print density and quality can be obtained.