JP2003312002A - Ink cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink cartridge which prevents ink from leaking to the outside of the ink cartridge from an atmosphere communication hole by setting a check valve at the atmosphere communication hole formed for introducing the atmosphere into the ink cartridge. <P>SOLUTION: A peripheral wall of the atmosphere communication hole 18 opened in an outer wall of the ink cartridge 1 is projected upward like a cylinder with its closed upper end. A communication hole for making the inside and the outside of the ink cartridge 1 communicate with each other through the atmosphere is opened in an outer periphery of the peripheral wall. The communication hole is shut by a cylindrical elastic member which covers the peripheral wall in a tightening state. The check valve 20 constituted as above prevents the ink stored in the ink cartridge 1 from leaking to the outside. When the ink is consumed and the interior of the ink cartridge becomes a negative pressure, a gap is generated between the elastic member and the peripheral wall by the pressure of the atmosphere, whereby the atmosphere is introduced into the ink cartridge 1. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink cartridge that contains ink to be supplied to a recording head in an image forming apparatus.

[0002]

2. Description of the Related Art Conventionally, an image forming apparatus such as an ink jet type printer records an image on a recording medium by ejecting ink droplets from nozzles of a recording head mounted on a carriage. The liquid is ejected by driving a piezoelectric actuator or the like arranged in the recording head to generate a pressure wave. The ink is supplied from an ink cartridge that is detachably mounted on the recording head. The ink cartridge has an ink supply port for supplying the ink to the recording head and an atmosphere having a volume of the supplied ink. An atmosphere communication hole for introduction is provided.

For example, as shown in FIG. 9, in a conventional ink cartridge 100, a first ink chamber 109 for accommodating a porous material such as polyurethane foam that has absorbed ink and a communication hole 115 are provided. First ink chamber 1
09, and a second ink chamber 110 connected to an ink supply port 117 for supplying ink to the recording head,
An air communication hole 118 for taking in air from the outside of the ink cartridge 100 is provided, and a buffer chamber 111 for introducing air into the first ink chamber 109 via a passage 116.
And are provided. The peripheral wall of the atmosphere communication hole 118 of the buffer chamber 111 is provided in a cylindrical shape so as to protrude upward, and a wall surface is formed in a labyrinth shape around the first ink chamber 1 by ribs or the like.
Even if the ink leaks from the buffer chamber 111 from 09, the ink is not easily leaked to the outside of the ink cartridge 100.

[0004]

However, even if such a labyrinthine wall structure, that is, a rib having a so-called labyrinth structure, is provided, the ink leaked into the buffer chamber 111 due to overturning when carrying the ink cartridge. Ink may leak to the outside of the ink cartridge 100 depending on the amount, and since ribs are provided,
The structure of that part was complicated.

The present invention has been made to solve the above problems, and a check valve is provided in an atmosphere communication hole for introducing the atmosphere into the ink cartridge, and the check valve is provided outside the ink cartridge through the atmosphere communication hole. An object is to provide an ink cartridge capable of preventing ink from leaking.

[0006]

In order to achieve the above-mentioned object, an ink cartridge according to a first aspect of the invention is an ink cartridge for containing ink to be supplied to a recording head, and a housing of the ink cartridge. A cylindrical projection that is provided in a cylindrical shape inside the ink cartridge from the inner edge of the opening portion that is open to the outer wall surface, and has a closed end, and an opening on the outer peripheral surface of the cylindrical projection. And an outer peripheral hole communicating with the atmosphere, and a cylindrical plug member made of a cylindrical elastic member mounted on the outer peripheral surface of the cylindrical projection so as to cover the outer peripheral hole with the outer peripheral surface being clamped.

In the ink cartridge having this structure, the outside and the inside of the ink cartridge can be communicated with the atmosphere via the cylindrical protrusion.

In addition to the structure of the invention according to claim 1, the ink cartridge of the invention according to claim 2 is characterized in that when the pressure inside the ink cartridge becomes lower than the pressure outside the ink cartridge, The cylindrical plug member is expanded by the pressure of the atmospheric air flowing in from the outer peripheral hole of the cylindrical protrusion, and a gap is formed between the cylindrical plug member and the cylindrical protrusion.

In the ink cartridge of this structure, in addition to the action of the invention according to claim 1, the inside and the outside of the ink cartridge are separated from each other only when the pressure inside the ink cartridge becomes lower than the pressure outside the ink cartridge. Can communicate with the atmosphere.

In addition to the structure of the invention described in claim 1 or 2, the ink cartridge of the invention according to claim 3 supplies ink to the recording head on the outer wall surface of the housing of the ink cartridge. And the cylindrical protrusion is provided on the inner wall surface of the casing of the ink cartridge upstream of the supply hole in the ink supply direction inside the ink cartridge.

In the ink cartridge of this structure, in addition to the operation of the invention according to claim 1 or 2, an ink flow path can be formed between the cylindrical projection communicating with the atmosphere and the ink supply hole.

In addition to the configuration of the invention described in any one of claims 1 to 3, the ink cartridge of the invention according to claim 4 stores ink at least inside and supplies the ink to the recording head. And a buffer chamber communicating with the ink chamber for supplying the atmosphere to the ink chamber, wherein the tubular protrusion is a portion forming an outer wall of the buffer chamber. The projection is provided on the inner wall surface of the casing of the ink cartridge.

In the ink cartridge of this structure, in addition to the effect of the invention according to any one of claims 1 to 3, the inside of the ink chamber and the outside of the ink cartridge can be communicated with the atmosphere via the buffer chamber.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of an ink cartridge according to the present invention will be described below with reference to the drawings. First, the structure of the ink cartridge 1 of the present embodiment will be described with reference to FIGS. FIG. 1 is a sectional view showing a state in which the ink cartridge 1 is mounted on the recording head 72. FIG. 2 is a perspective view of the ink cartridge 1. FIG. 3 is a cross-sectional view of the ink cartridge 1 taken along the double-dotted chain line AA ′ shown in FIG. FIG. 4 is a cross-sectional view of the ink cartridge 1 taken along the chain double-dashed line BB ′ shown in FIG.
FIG. 5 is an exploded cross-sectional view of the ink cartridge 1 taken along the chain double-dashed line AA ′ shown in FIG. FIG. 6 is a partial cross-sectional view of the check valve 20. FIG. 7 is a diagram for explaining the shape of the elastic member 19 when the atmosphere flows into the buffer chamber 11 via the check valve 20.

As shown in FIG. 1, in an image forming apparatus such as an ink jet printer, a head holder 50 that supports a recording head 72 is mounted on a carriage 52 that scans and moves along a recording medium. The ink cartridge 1 is detachably attached to the. The ink cartridge 1 has an ink supply port 1 provided on the lower surface thereof.
7 is fitted into a joint member 74 on the head holder 50 side, and ink is distributed to a large number of ink ejection channels (not shown) of the recording head 72 through the manifold member 73. As is well known, the recording head 72 ejects ink from each ink ejection channel by driving an actuator composed of a piezoelectric element or a heating element. The ink supply port 17 is the "supply hole" in the present invention.

Next, as shown in FIG. 2, the ink cartridge 1 in this embodiment has a case 2 formed of a transparent or translucent resin material in a rectangular shape, an upper lid member 3, and a lower lid member 4. It consists of and. Case 2 is
A pair of first side walls 2a and 2b facing each other and a pair of second side walls 2c and 2d connecting the pair of side walls,
It has a rectangular tubular shape with open upper and lower end surfaces. The upper and lower lid members 3 and 4 are heat-welded so as to cover both upper and lower open surfaces of the case 2.

Further, as shown in FIG. 3, the case 2 is
Partition wall 5, which extends substantially parallel to the first side walls 2a, 2b
6. The inside is partitioned by a bottom partition wall 7 that is connected to the lower ends of both the partition walls and extends substantially parallel to the bottom open surface, and partition walls 7a and 7b that extend vertically from the bottom partition wall 7 toward the bottom open surface. Has been done. The partition walls 5, 6, the bottom partition wall 7, and the partition walls 7a, 7b are the second side walls 2c, 2
It extends in the direction of connecting d (see FIG. 2) (the front and back sides of the page).

Partition walls 5, 6, bottom partition wall 7, and second partition wall
The first ink chamber 9 whose upper surface is opened at the upper end of the case 2 is formed in a place surrounded by the side walls 2c and 2d of
Porous material such as polyurethane foam that has absorbed ink 8
Are housed. A second ink chamber 10 is formed in a portion surrounded by the first side wall 2a, the partition wall 5, and the second side walls 2c and 2d, and the other first side wall 2b and the partition wall 6 are formed.
A buffer chamber 11 is formed in the portion surrounded by the second side walls 2c and 2d. The second ink chamber 10 has an upper end opened on the upper surface of the case 2, a lower end bent along the lower surface of the bottom partition wall 7, and a lower end opened on the lower surface of the case 2. The upper and lower ends of the buffer chamber 11 are open at the upper and lower surfaces of the case 2, respectively. The first and second ink chambers 9 and 10
Is the "ink chamber" in the present invention.

The upper lid member 3 includes the first and second ink chambers 9 and 1.
0 and the buffer chamber 11 are respectively covered and fixed to the upper ends of the side walls 2a to 2d and the partition walls 5 and 6 by thermal welding, so that the first and second ink chambers 9 and 10 and the buffer chamber 11 are independent. . The lower lid member 4 covers the lower ends of the second ink chamber 10 and the buffer chamber 11, respectively, and is fixed to the lower ends of the side walls 2a to 2d and the partition walls 7a and 7b by heat welding.
1 is independent. As a result, the second ink chamber 10
A vertical portion 10a along the side wall 2a and a horizontal portion 10b located below the first ink chamber 9 form a substantially L shape.

A portion between the second ink chamber 10 and the buffer chamber 11, that is, the partition walls 7a and 7b and the bottom partition wall 7 is formed.
The space 33 surrounded by the lower lid member 4 and the lower lid member 4 does not communicate with the first and second ink chambers 9 and 10 and the buffer chamber 11, and an opening 34 (see FIG. 2) to communicate with the outside of the ink cartridge 1. The ink cartridge 1 filled with ink is hermetically housed in a packaging bag (not shown) in a depressurized state at the time of shipping. When the packaging bag is depressurized, the space 33 is also depressurized. Therefore, the packaging bag can be maintained in a reduced pressure state for a long period of time due to its volume.

The bottom partition wall 7 has a first ink chamber 9 and a second ink chamber 9.
A communication hole 15 that connects the ink chamber 10 is formed. Ink is stored in the first and second ink chambers 9 and 10, and ink chambers are formed by both chambers. Second ink chamber 10
Serves as a passage when ink is filled and also serves as a relay chamber when ink is supplied from the first ink chamber 9 to the recording head 72. The first ink chamber 9 is formed sufficiently larger than the second ink chamber 10. The buffer chamber 11 supplies air to the first ink chamber 9 when the ink in the first ink chamber 9 is consumed. As described above, the partition walls 5 and 6 are provided at both ends of the case 2 substantially in parallel with the side walls 2a and 2b, so that the side portions have a substantially double-walled structure and the case strength is increased. In addition, the case 2 having such a shape
Can be easily resin-molded by a mold that is separated into upper and lower parts.

An ink filling port 13 is formed in the upper lid member 3 so as to correspond to the upper end open surface of the second ink chamber 10, and
A depressurizing port 14 for depressurizing the inside of the case 2 at the time of ink filling is formed corresponding to the upper end open surface of the first ink chamber 9. The communication hole 15 that connects the second ink chamber 10 and the first ink chamber 9 to each other is arranged at the end far from the side where the ink filling port 13 and the pressure reducing port 14 are arranged, that is, on the lower lid member 4 side. Therefore, it is effective in increasing the ink filling efficiency and the ink consumption efficiency.

The first ink chamber 9 and the buffer chamber 11 are communicated with the upper lid member 3 by a passage 16 formed so as to straddle the upper end of the partition wall 6. That is,
The passage 16 is formed in a concave shape on the upper surface of the upper lid member 3, and one end of the passage 16 communicates with the first ink chamber 9 via the pressure reducing port 14.
The other end communicates with the buffer chamber 11 through the through hole 16a. Further, the upper lid member 3 has a wall 27 that projects into the first ink chamber 9 and contacts the upper surface of the porous material 8. That is, the upper lid member 3 is formed thick at a portion corresponding to the first ink chamber 9 and slightly compresses the porous material 8.

An ink supply port 17 for supplying the ink in the second ink chamber 10 to the recording head 72 is formed in the lower lid member 4 so as to correspond to the lower end open surface of the second ink chamber 10, and the buffer chamber is formed. Atmosphere communication holes 18 are respectively formed corresponding to the lower end open surfaces of 11. Case 2 of lower lid member 4
The check valve 2 is provided on a portion of the inner surface corresponding to the atmosphere communication hole 18.
0 is provided. Further, as shown in FIG. 4, the communication hole 15 and the ink supply port 17 are positioned so as to be offset from each other when seen from a plane, and the communication hole 15 and the ink supply port 17 are connected to the second ink chamber 10. A rib-shaped barrier 31 on the shortest road
Are formed. The barrier 31 is preferably formed by integrally projecting from the bottom partition wall 7 of the case 2 and joined to the inner wall surface of the lower lid member 4. However, the barrier 31 may be integrally projected from the lower lid member 4. It doesn't matter. The lower surface 7d of the bottom partition wall 7 is an inclined surface so as to rise from the lower end of the communication hole 15 toward the vertical portion 10a of the second ink chamber 10. One end of the barrier 31 has a communication hole 1
5 is located on the side of the second ink chamber 10, and the other end extends to a position close to the vertical portion 10a of the second ink chamber 10. As a result, when the ink is drawn from the second ink chamber 10 by the negative pressure generated by the ink ejection from the recording head 72, the ink that has exited the communication hole 15 from the first ink chamber 9 is a barrier as indicated by arrow C. Bypassing 31 and entering the horizontal portion 10b of the second ink chamber 10 to reach the ink supply port 17. The atmosphere communication hole 18 is the "opening portion opened on the outer wall surface of the housing of the ink cartridge" in the present invention.

Next, as shown in FIG. 5, the ink filling port 1
3 and the depressurizing port 14 are the first sealing material 21, which is attached to the outer surface of the upper lid member 3 by heat welding or the like after the ink is filled.
Each is closed at 22. The sealing material 22 is the passage 16
Ensure that it covers its upper surface. The ink supply port 17 and the atmosphere communication hole 18 are closed by a second seal material 23 that is detachably attached by heat welding or the like. Since the ink filling port 13 and the ink supplying port 17 are separate from each other, the surroundings of the ink supplying port 17 are not wet with the ink at the time of filling unlike the conventional one which also serves as the ink filling port before ink filling. Therefore, the second sealing material 23
Is capable of exerting a sufficient sealing effect even if the heat welding is so weak that the ink supply port 17 is not deformed. Since it is not necessary to peel off the sealing materials 21 and 22, the sealing materials 21 and 22 may be firmly heat-welded to such an extent that the upper lid member 3 is slightly deformed.
Each of the sealing materials 21 to 23 is made of an air-opaque resin or metal foil or a laminated material thereof.

The second ink chamber 1 of the ink supply port 17
A mesh filter 24 made of stainless steel is attached to the 0-side surface. The filter 24 has an eye size such that the ink in the second ink chamber 10 does not leak in a natural state due to surface tension.

Next, as shown in FIG. 6, the atmosphere communication hole 18
Has a peripheral wall 18a protruding upward in a cylindrical shape, and a closing portion 18b for closing the upper end thereof. A communication hole 18c for communicating the inside and the outside of the cylinder is provided in a portion slightly above the middle position of the peripheral wall 18a in the projecting direction of the peripheral wall 18a, and the buffer chamber is connected via the communication hole 18c. Reference numeral 11 is in communication with the outside of the ink cartridge 1. Then, on the outer periphery of the peripheral wall 18a, a cylindrical elastic member 1 having an inner diameter smaller than the outer diameter of the peripheral wall 18a.
9, the peripheral wall 18a is tightly fitted and fitted,
The check valve 20 is configured by closing the communication hole 18c.
The elastic member 19 is a member having elasticity, for example, made of rubber or the like, and may have a length enough to close the communication hole 18c, but it is provided longer than the height of the peripheral wall 18a protruding. Is desirable. The peripheral wall 18a and the closed portion 1
8b is the "cylindrical protrusion" in the present invention, and the communication hole 18c is the "outer peripheral hole" in the present invention. The elastic member 19 is the "cylindrical plug member" of the present invention.

Further, as shown in FIG. 7, the buffer chamber 11
When the inside of the ink cartridge becomes negative pressure than the outside of the ink cartridge 1 and the atmospheric pressure becomes larger than the tightening force (elastic force) of the elastic member 19 against the peripheral wall 18a, the communication hole 18
At the portion where c and the elastic member 19 are opposed to each other, the atmospheric pressure spreads the elastic member 19 by the pressure, so that a gap is created between the peripheral wall 18a and the elastic member 19, and the buffer chamber 11 and the outside of the ink cartridge 1 are exposed to the atmospheric air. It is designed to communicate.

Next, the flow of ink filled in the ink cartridge 1 when the image forming apparatus in which the ink cartridge 1 of this embodiment is mounted performs a recording operation on a recording medium will be described with reference to FIG. This will be described with reference to FIGS. 4 and 7.

As shown in FIG. 1, when the user uses the ink cartridge 1, the user has a sealing material attached so as to close the ink supply port 17 and the atmosphere communication hole 18 of the ink cartridge 1. 23 (see FIG. 5) is peeled off, and the ink supply port 17 is connected to the manifold member 73 of the recording head 72 via the joint member 74.
Then, as is known, suction means (not shown) is connected to the recording head 72, and ink is filled from the ink cartridge 1 to the recording head 72.

During the recording operation, a negative pressure acts on the ink supplied from the second ink chamber 10 to the recording head 72 due to the absorbing power of the porous material 8 in the first ink chamber 9, that is, the capillary phenomenon. I am letting you. An actuator (not shown) of the recording head 72 performs an ink ejection operation to generate a negative pressure in the ejection direction, and the ink cartridge 1
Aspirate ink from. When the ink in the second ink chamber 10 flows out from the ink supply port 17, the ink is replenished in the second ink chamber 10 from the porous material 8 in the first ink chamber 9 and is consumed in the first ink chamber 9. Along with that, buffer room 1
Air flows from 1 to the first ink chamber 9. Then, the buffer chamber 11 also has a negative pressure, and the atmosphere tends to be introduced into the buffer chamber 11 through the atmosphere communication hole 18. In this case, as shown in FIG. 7, the pressure inside the buffer chamber 11 and the check valve 2
When the atmospheric pressure becomes larger than the combined force with the elastic force of the elastic member 19 of 0, the portion of the elastic member 19 facing the communication hole 18c is pushed to the atmosphere, and the elastic member 19 and the peripheral wall 18 are pushed.
A gap is formed between a and a. Then, the atmosphere is introduced into the buffer chamber 11 from the atmosphere communication hole 18 through the communication hole 18c through the gap between the elastic member 19 and the peripheral wall 18a.

Further, as shown in FIG. 1, the second ink chamber 1
Since the upper end of 0 is sealed by the sealing material 21,
In the state where the second ink chamber 10 is fully filled with ink, the atmospheric pressure does not work on the ink in the second ink chamber 10, so after the ink in the first ink chamber 9 is almost consumed,
The ink in the second ink chamber 10 is consumed.
That is, when the ink in the first ink chamber 9 is exhausted, the ink in the second ink chamber 10 is consumed due to the pressure at which the recording head 72 absorbs the ink, and the first ink chamber 9 is also consumed.
Air enters the second ink chamber 10 from the second ink chamber 1
A void is generated from the upper part of the vertical portion 10a of 0, and the ink surface is lowered.

As described above, since the air is introduced from the side far from the communication hole 15 in the first ink chamber 9, the ink in the first ink chamber 9 is effectively used and the ink in the second ink chamber 10 is also used. The entire ink including the ink is effectively used. Also, the work of peeling off the sealing material 23 is easy because it is only on one surface of the ink cartridge 1.

Further, as described above, since the barrier 31 is provided between the communication hole 15 and the ink supply port 17, the pressure at which the recording head 72 absorbs the ink causes the ink to communicate from the first ink chamber 9 to the communication hole. 15 through the second ink chamber 1
When air bubbles are mixed in the ink when it is drawn into 0, or when the ink in the first ink chamber 9 is consumed and air is drawn into the second ink chamber 10, the air bubbles and air are It can be prevented from flowing into the recording head 72. That is, when the ink flow bypasses the barrier 31 as shown by the arrow C in FIG.
Bubbles and air at the location corresponding to the vertical portion 10a of the ink chamber 10 escapes above the vertical portion 10a by buoyancy and does not reach the ink supply port 17. In addition, the ceiling surface of the horizontal portion 10b of the second ink chamber 10, that is, the lower surface 7d of the bottom partition wall 7, extends from the lower end of the communication hole 15 to the second ink chamber 1.
By being inclined so as to rise toward the vertical portion 10a of 0, bubbles and air do not remain on the lower surface of the bottom partition wall 7 but flow above the vertical portion 10a. Therefore,
It is possible to prevent bubbles or air from entering the recording head 72 and causing ink ejection failure.

Further, for example, the ink that has flowed out of the first ink chamber 9 into the buffer chamber 11 through the passage 16 due to the ink cartridge 1 falling over or the user pressing the second side walls 2c and 2d. The check valve 20 provided in the atmosphere communication hole 18 prevents the ink from leaking to the outside of the ink cartridge 1. As described above, there is a gap between the elastic member 19 of the check valve 20 and the peripheral wall 18a when the internal pressure of the buffer chamber 11 is a negative pressure with respect to the external pressure of the ink cartridge 1,
At this time, since the atmosphere is introduced into the buffer chamber 11 through the communication hole 18c, the ink does not leak to the outside against the flow path of the atmosphere.

As described above, in the ink cartridge 1 of this embodiment, the ink supplied to the recording head 72 is filled in the first and second ink chambers 9 and 10, and when the ink is consumed, Air is introduced from the buffer chamber 11 via the passage 16. Then, when the inside of the buffer chamber 11 becomes a negative pressure, the atmosphere spreads the elastic member 19 from the atmosphere communication hole 18 through the communication hole 18c, and the buffer chamber 11 is generated from the gap formed between the elastic member 19 and the peripheral wall 18a. Atmosphere is introduced inside. Even when ink flows from the first ink chamber 9 into the buffer chamber 11, the atmosphere communication hole 1
The check valve 20 provided on the valve 8 prevents the leakage from the outside.

Needless to say, the present invention can be modified in various ways. For example, as shown in FIG. 8, the buffer chamber 11 is eliminated, and the wall surface of the case 2 at the end far from the position where the communication hole 15 in the first ink chamber 9 is provided communicates with the outside of the ink cartridge 1. The atmosphere communication hole 18 may be opened, and the check valve 20 may be provided in the atmosphere communication hole 18 as described above. In this case, the check valve 20 is provided in the first ink chamber 9.
Since the check valve 20 is arranged, the space around the check valve 20 is filled with the ink. However, the condition that a gap is formed between the elastic member 19 of the check valve 20 and the peripheral wall 18a is as described above, that is, the ink. Ink does not leak to the outside against the flow of the air drawn from the outside of the cartridge 1. Further, since the check valve 20 is provided at the end far from the communication hole 15 in the first ink chamber 9, there is an effect of increasing the ink consumption efficiency. Furthermore, by eliminating the buffer chamber 11, the space can be used as the first ink chamber 9, and the capacity of the ink filled in the ink cartridge 1 can be increased.

Alternatively, the check valve may be constructed by using a polymer film or the like that passes through the air and does not pass through the ink.

[0039]

As described above, in the ink cartridge of the invention according to the first aspect, the outside and the inside of the ink cartridge can be communicated with the atmosphere through the cylindrical protrusion. Therefore, it is possible to maintain the same pressure inside and outside the ink cartridge.

Further, in the ink cartridge of the invention according to claim 2, in addition to the effect of the invention according to claim 1, only when the pressure inside the ink cartridge becomes lower than the pressure outside the ink cartridge, The inside and the outside can communicate with the atmosphere. Therefore,
It is possible to reliably prevent ink leakage from the ink cartridge.

Further, in the ink cartridge of the invention according to claim 3, in addition to the effect of the invention according to claim 1 or 2, an ink flow path is formed between the cylindrical projection communicating with the atmosphere and the ink supply hole. can do. Therefore, it is possible to smoothly supply the ink without mixing bubbles in the ink supplied to the recording head.

Further, in the ink cartridge of the invention according to claim 4, in addition to the effect of the invention according to any one of claims 1 to 3, the inside of the ink chamber and the outside of the ink cartridge are exposed to the atmosphere through the buffer chamber. Can communicate.
Therefore, the ink leakage from the ink cartridge can be reliably prevented only by changing a part of the configuration of the existing ink cartridge.

[Brief description of drawings]

FIG. 1 shows an ink cartridge 1 with a recording head 7.
It is sectional drawing which shows the state mounted in 2.

FIG. 2 is a perspective view of the ink cartridge 1.

FIG. 3 is a cross-sectional view of the ink cartridge 1 taken along the double-dotted chain line AA ′ shown in FIG.

FIG. 4 is a cross-sectional view of the ink cartridge 1 taken along the double-dotted chain line BB ′ shown in FIG.

5 is an exploded cross-sectional view of the ink cartridge 1 as seen from the direction of the arrow along the two-dot chain line AA ′ shown in FIG.

FIG. 6 is a partial cross-sectional view of the check valve 20.

FIG. 7 is a diagram for explaining the shape of the elastic member 19 when the atmosphere flows into the buffer chamber 11 via the check valve 20.

FIG. 8 is a cross-sectional view showing a modified example of the ink cartridge 1.

FIG. 9 is a cross-sectional view of a conventional ink cartridge 100.

[Explanation of symbols]

1 ink cartridge 2 cases 9 First ink chamber 10 Second ink chamber 11 buffer room 17 Ink supply port 18 atmosphere communication hole 18a peripheral wall 18b blockage 18c communication hole 19 Elastic member 72 recording head

Claims (4)

[Claims] 1. An ink cartridge for containing ink to be supplied to a recording head, wherein the ink cartridge has a cylindrical shape protruding from an inner edge of an opening portion opened on an outer wall surface of a casing of the ink cartridge. , A cylindrical projection whose end is closed, an outer peripheral hole which is opened in the outer peripheral surface of the cylindrical projection and communicates with the inside of the ink cartridge to the atmosphere, and a state in which the outer peripheral surface is tightened on the outer peripheral surface of the cylindrical projection. And a cylindrical plug member made of a cylindrical elastic member mounted so as to cover the outer peripheral hole. 2. When the internal pressure of the ink cartridge becomes lower than the external pressure of the ink cartridge, the pressure of the atmospheric air flowing from the outer peripheral hole of the cylindrical projection causes the cylindrical plug member to expand, The ink cartridge according to claim 1, wherein a gap is formed between the cylindrical plug member and the cylindrical protrusion. 3. A supply hole for supplying ink to the recording head is opened in an outer wall surface of a housing of the ink cartridge, and the cylindrical protrusion is formed in the ink supply direction inside the ink cartridge. The ink cartridge according to claim 1 or 2, wherein the ink cartridge is projected on an inner wall surface of a casing of the ink cartridge on an upstream side of the supply hole. 4. An ink chamber containing at least an ink therein and having a supply hole for supplying the ink to the recording head, the chamber being in communication with the ink chamber and supplying the atmosphere to the ink chamber. 4. The buffer chamber according to claim 1, wherein the cylindrical protrusion is provided so as to project from an inner wall surface of the casing of the ink cartridge in a portion that forms an outer wall of the buffer chamber. The ink cartridge described in Crab.