JP3414583B2 - Ink cartridge for inkjet printer - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink cartridge suitable for mounting on a carriage carrying an ink jet recording head.

[0002]

2. Description of the Related Art An ink jet printer supplies an ink to an ink jet type recording head for applying a pressure to a pressure generating chamber communicating with a common ink chamber and a nozzle opening to eject an ink droplet from the nozzle opening, and to the recording head. An ink cartridge and an ink cartridge are mounted on the carriage, and the ink droplets are ejected onto the recording paper in conformity with the print data while reciprocating the carriage.

In such a recording head, the nozzle opening is usually arranged so as to be lower than the ink surface of the ink cartridge, so that the head pressure acts on the nozzle opening, and the ink leaks from the nozzle opening. There is a problem that occurs. In order to solve this problem, a porous body is usually housed in the ink cartridge, and the capillary force of the porous body causes the ink pressure of the ink cartridge to be slightly lower than that of the recording head.

However, when the consumption of ink progresses and the amount of ink absorbed in the porous body decreases, the supply of the ink to the recording head is delayed due to the capillary force of the porous body, and the cartridge is lost. There are problems that the ink inside cannot be completely consumed and that the ink that can be accommodated in the cartridge is reduced due to the substantial volume of the porous body and the ink cartridge becomes large.

In order to solve such a problem, for example, as disclosed in Japanese Patent Laid-Open No. 62-231759, a wall provided with a through hole at the bottom of an ink tank separates an ink reservoir and a cavity. An ink for an inkjet recording head that is provided with an umbrella check valve, and when the ink pressure in the recording head drops, the valve is opened to discharge the ink in the ink reservoir into the cavity and supply it to the recording head. Cartridges have been proposed.

[0006]

According to this, since the porous body is not required, it is possible to increase the amount of ink stored. However, in general, an umbrella check valve is used as an ink for a recording head. There is a big problem that the offset amount is too large to precisely adjust the supply of the ink, and the ink supply amount and the differential pressure between the recording head and the ink supply largely fluctuate, resulting in deterioration of print quality.

Further, when the umbrella check valve is closed, the flow path connecting the connection port with the recording head and the ink reservoir is completely closed, so that the ink in the cavity is removed due to the change in the environmental temperature. If it expands by 2 to 5%,
The ink in the cavity loses its escape and breaks the seal at the connection port with the recording head and leaks to the outside, or when mounted on the recording head, this pressure acts on the recording head as it is and the nozzle of the recording head In addition to the problem of leaking from the opening, when the operation of forcibly discharging the ink from the recording head by applying a negative pressure to the recording head via the capping means in order to recover the ink droplet ejection capability is also performed. There is a problem that it is difficult to remove the air bubbles that have stagnated near the umbrella check valve.

The present invention has been made in view of the above problems, and an object of the present invention is to reliably print in response to a minute differential pressure between the recording head and the recording head. Ink cartridge that can reliably supply ink to the recording head while maintaining a negative pressure suitable for the ink, prevents leakage due to temperature change, and reliably removes air bubbles stagnant at the ink supply port side to the outside. Is to provide.

[0009]

In order to solve such a problem, in the present invention, an ink chamber for containing ink is used.
A flow path connecting the i ink supply port is disposed so as to divide vertically and, communicating with the ink chamber and the ink supply port
The ink chamber and the ink supply port having a through hole in the center
It includes a membrane valve seat made of elastic membrane responsive to the pressure differential, the valve body the through hole of the membrane valve seat you contact between the ink supply
Set the area near the outflow area to the inlet as the highest level,
The membrane valve seat is provided so as to be inclined with respect to the horizontal plane .

[0010]

Operation: The membrane valve seat receives a differential pressure over a wide area, and in response to a slight ink consumption, the flow path from the ink chamber to the ink supply port is opened to perform recording without applying an excessive negative pressure to the recording head. When ink is supplied to the head and the pressure of the ink supply port rises due to temperature rise or the like, the membrane valve seat responds to release the increased pressure into the ink chamber to prevent ink leakage from the recording head. Further, the bubbles are collected in a communication passage extending from the ink supply port, and are put on the ink flow and discharged to the outside when the ink is sucked from the recording head.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below based on the illustrated embodiments. 1 shows an embodiment of the present invention, in which reference numeral 1 is a container constituting an ink cartridge main body, and an ink supply port 2 into which an ink supply needle of a recording head is inserted on a bottom surface 1a. Is formed, and the space between the ink chamber 3 and the ink supply port 2 is separated by a membrane valve seat 4 and a valve body 6 described later.

Reference numeral 4 denotes the above-mentioned membrane valve seat, which is provided so as to be inclined with respect to the horizontal plane of the ink so that the region on the ink supply port 2 side becomes the highest position, and the ink is supplied in the vicinity of this highest position region. The upper end 5a of the communication passage 5 extending from the mouth 2 is connected.

The membrane valve seat 4 is made of an elastic membrane such as rubber or polymer elastomer having durability against ink,
A through hole 4 through which ink passes is provided in a region where the valve body 6 abuts.
It is constructed by punching a and is attached to the container 1 by being sandwiched between the valve body support 7 and the container bottom surface 1a.

Reference numeral 6 denotes a valve element, which is made of a material having a larger specific gravity than ink, and a lower end 6a of which is normally a membrane valve seat 4
The through hole 4a is attached to the guide hole 7a of the valve body support 7 so as to be vertically movable in accordance with the inclination of the membrane valve seat 4. The valve body support 7 is provided with an ink flow path 7b for guiding the ink in the ink chamber 3 to the upper region A of the membrane valve seat 4. Note that reference numeral 8 in the drawing denotes a lid member that includes the atmosphere communication passage 8a and seals the upper opening of the container 1.

In this embodiment, the ink supply port 2 is
When the ink is fed through the ink supply needle of the recording head equipped with the carriage, the recording head passes through the communication passage 5 and the membrane valve seat 4
To the lower region B of the.

In this state, when printing is performed and ink droplets are ejected from the recording head, the ink in the lower area B of the membrane valve seat 4 flows into the recording head from the ink supply port 2 and the lower area B of the membrane valve seat 4 is printed. Pressure gradually decreases. Corresponding to this pressure drop, the membrane valve seat 4 expands into a hemispherical shape having a convex downward side due to its elasticity, and the position of the through hole 4a drops. At this point in time, the valve body 8 follows the membrane valve seat 4 by its own weight and the suction force due to the pressure difference, and therefore the pressure of the ink supply port 2 is not excessively lowered, and the membrane valve seat 4 expands to lower region B. Ink is supplied to the recording head. As a result, the pressure of the ink on the recording head is maintained at a constant negative pressure state suitable for printing.

When the ink consumption in the recording head further progresses and the membrane valve seat 4 expands and the position of the through hole 4a further lowers, the valve body 8 is lowered by the valve body supporting member 7 to a certain position or less. Since it is blocked, the through hole 4a of the membrane valve seat 4 is not
Is slightly separated from the lower end 6a (Fig. 2). This allows
The ink in the upper area A of the membrane valve seat 4 moves to the lower area B of the membrane valve seat 4 through the through hole 4a and replenishes the ink to the ink supply port 2.

The lower region B of the membrane valve seat 4 due to the inflow of ink
When the pressure of (1) slightly rises, the membrane valve seat 4 moves toward the valve body 6 side by its elasticity and makes elastic contact with the valve body 6, so that the through hole 4a is closed by the lower end 6a of the valve body 6. As a result, the inflow of ink from the ink chamber 3 is stopped. As a result, the pressure of the ink supply port 2 is maintained substantially constant regardless of the amount of ink in the ink chamber 3.

Hereinafter, each time the pressure of the ink supply port 2 is slightly lowered, the membrane valve seat 4 expands to a position below the lower limit position of the valve body 6 so that a gap is formed between it and the lower end 6a of the valve body 6. Then, the ink in the ink chamber 3 is caused to flow in through this gap.

Since the membrane valve seat 4 formed of the elastic membrane comes into contact with and separates from the valve body 6 in accordance with the consumption of ink, when the elasticity of the membrane valve seat 4 is set to an appropriate size, ink supply starts. Not only the difference between the pressure at the time and the pressure at the time of stopping the ink supply, that is, the offset can be made extremely small
It is possible to supply all the ink in the ink chamber 3 to the recording head.

On the other hand, when the environmental temperature rises while printing is suspended, the pressure in the lower region B of the membrane valve seat 4 rises, but the membrane valve seat 4 moves upward in response to this pressure. Since the pressure in the lower region B that contracts and communicates with the recording head is released to the ink chamber 3, the pressure increase in the recording head due to the temperature change is alleviated and the leakage of ink from the recording head is prevented.

By the way, the ink flowing from the ink chamber 3 into the lower region B of the membrane valve seat 4 receives the action of the negative pressure thereof and releases the dissolved gas as bubbles E. Due to its buoyancy, the bubbles E move along the spherical surface formed by the membrane valve seat 4 and gather in the uppermost region, that is, in the vicinity of the upper end 5a of the communication hole 5.

In this state, when the recording head is sucked and the ink is forcibly ejected in order to recover the ink ejection capacity of the recording head, the vicinity of the upper end 5a of the communication hole 5 is narrowed more than other places and the ink is not ejected. Since a fast flow is generated, the air bubbles collected here are sucked into the through holes 5 along with the flow of ink, and are discharged to the outside from the nozzle opening of the recording head together with the ink.

FIG. 3 shows another embodiment of the present invention. In this embodiment, the recess 1b is formed in the region of the container 1 where the valve mechanism does not exist, and the valve body support 7 is formed. An opening 7c is provided so as to communicate with the upper area A defined by the membrane valve seat 4, and the opening 7c and the bottom surface 1c of the recess 1b are connected by a flow path 1d.

In this embodiment, when the ink in the lower region B of the membrane valve seat 4 is consumed and the membrane valve seat 4 expands downward,
The ink on the bottom 1c of the container 1 is sucked up by the siphon phenomenon and passes through the through hole 4a of the membrane valve seat 4 and the ink supply port 2
Flow into. According to this embodiment, the ink storage volume of the container 1 can be expanded.

In the above-described embodiment, the valve body 10 is brought into contact with the membrane valve seat 4 by its own weight, but when the valve body is made of a material having a smaller specific gravity of ink. It is apparent that the same effect can be obtained by elastically contacting with an elasticity imparting means such as a spring, as in the embodiment described later.

4 and 5 show another embodiment of the present invention, in which reference numeral 10 is a valve element, which is a valve element support 1.
1, the spring 1 is constantly installed in the valve body accommodating chamber 11a formed in FIG.
It is inserted in the state of being pressed downward by 2. The valve body 10 is formed with a flange 10a guided on the inner surface of the valve body storage chamber 11a on its side surface and a convex portion 10b for restricting the lowering limit of the valve body 10 to cause the valve body storage chamber 11a to exert a piston effect on the flange 10a. It is configured to leave enough space for it. The collar 10a includes an ink chamber 3 and a valve body accommodating chamber 11a.
Through, that is, between the upper and lower sides of the collar 10a, a through hole 10d having a fluid resistance when the valve body 10 is moved.
Is provided.

On the other hand, the valve body support 11 has a through hole 11b for connecting the upper region A of the membrane valve seat 4 and the ink chamber 3 in addition to the above-mentioned valve body accommodating chamber 11a. The membrane valve seat 4 is fixed to the bottom of the container 1 so that the upper end 5a side becomes the uppermost position.

In this embodiment, when the pressure of the ink supply port 2 is lowered, the membrane valve seat 4 is expanded into a hemispherical shape so as to be convex downward due to the pressure difference with the ink chamber 3, and its through hole 4a.
Lower the position of.

On the other hand, the valve body 10 tends to move downward due to the urging force of the spring 12, but since the collar 10 needs to remove the ink of the valve accommodating chamber 11a from the through hole 10d to the ink chamber 3, it is a little. I will descend with a time delay,
A gap is created between the tip 10a of the valve body 10 and the through hole 4a of the membrane valve seat 4 so that the ink in the ink chamber 3 is absorbed in the lower region B of the membrane valve seat 4.
Flow into.

After a lapse of a predetermined time, the valve body 10 is lowered to seal the through hole 4a of the membrane valve seat 4 with the tip 10e thereof to prevent the pressure of the ink supply port 2 from excessively rising. ,
The ink in the region B is sent to the ink supply port 2 by the downward expansion of the membrane valve seat 4.

As a result, not only the ink can be supplied immediately in response to a slight decrease in the pressure of the ink supply port 2, but also the excessive supply is reliably prevented and the ink in the ink chamber 3 is supplied to the ink supply port 2. can do.

When acceleration is applied to the valve body 10 due to the movement of the carriage, the collar 10 and the through hole 10 are formed.
Since d and the valve body accommodating chamber 11a function as a fluid damper, the valve body 10 is prevented from swinging.

When the ink consumption in the recording head is further advanced and the membrane valve seat 4 is further lowered, the valve body 10 is moved to the convex portion 1 thereof.
Since it is prevented from falling below a certain position by 0b, a gap is created between the valve body 10 and the membrane valve seat 4. The ink in the ink chamber 3 replenishes the shortage in the lower region B of the membrane valve seat 4 via the through hole 4a of the membrane valve seat 4.

The lower region B of the membrane valve seat 4 due to the inflow of ink
When the pressure is slightly increased, the membrane valve seat 4 contracts upward due to its elasticity and elastically contacts the valve body 10 to push it up, closing the through hole 4a at the lower end 10e of the valve body 10. As a result, the inflow of ink to the lower region B of the membrane valve seat 4 is stopped, and a constant negative pressure is maintained between the ink and the recording head.

By the way, the ink flowing from the ink chamber 3 into the lower region B of the membrane valve seat 4 receives the action of the negative pressure thereof and releases the dissolved gas as bubbles E. Due to its buoyancy, the bubbles E move along the spherical surface formed by the membrane valve seat 4 and gather in the uppermost region, that is, in the vicinity of the upper end 5a of the communication hole 5.

In this state, when the recording head is sucked and the ink is forcibly ejected in order to recover the ink ejection capacity of the recording head, the vicinity of the upper end 5a of the communication hole 5 is narrower than other portions, and the ink is not ejected. Since a fast flow is generated, the air bubbles collected here are sucked into the through holes 5 along with the flow of ink, and are discharged to the outside from the nozzle opening of the recording head together with the ink.

Although the valve body 10 is elastically contacted with the membrane valve seat 4 by the spring 12 in the above-described embodiment,
When the material is made of a material having a larger specific gravity than the ink, the spring 12 can be eliminated by providing a means for preventing the valve body 10 from coming off.

FIG. 6 shows another embodiment of the present invention, in which reference numeral 20 is a container body, which is an ink supply port 2.
It is configured as an ink container by sealing with a lid member 22 provided with 1. The lid member 22 has an ink supply port 21.
A membrane valve seat 24, which will be described later, for separating the ink chamber 23 from the ink chamber 23 is provided.

The membrane valve seat 24 is made of an elastic membrane such as rubber or polymer elastomer having durability against ink, and has a through hole 24a through which ink passes in a region where a valve body 25 described later abuts. The valve body support 2 is formed by drilling.
It is sandwiched and fixed between 6 and the lid member 22.

A valve element 25 is movably attached to the guide hole 26a of the valve element support 26, and is constantly urged upward by the spring 27. This valve body support 26 has a through hole 2
6b is provided, and the upper end of the ink absorbing string 28 whose lower end reaches the bottom portion 20a of the ink container is inserted therein.

In this embodiment, the ink in the ink chamber 23 is sucked up to the lower region D of the membrane valve seat 24 by the capillary force of the ink absorbing string 28 until it balances with the elastic force of the membrane valve seat 24.

In this state, the ink supply port 2 is mounted on the recording head so that the ink supply port 2 faces upward. When the recording head consumes the ink, the ink in the upper region C of the membrane valve seat 24 is discharged from the ink supply port 21. Flowing into the recording head, the pressure in the upper region C of the membrane valve seat 24 gradually decreases. Corresponding to this pressure drop, the membrane valve seat 24 expands in a hemispherical shape so as to be convex upward due to its elasticity, and raises the position of the through hole 24a.

At this time, the valve body 28 follows the membrane valve seat 24 by the urging force of the spring 27, so that the upper region C is expanded by the expansion of the membrane valve seat 24 without excessively reducing the pressure of the ink supply port 21. The ink is compressed and supplied to the recording head. As a result, the pressure of the ink on the recording head is maintained at a constant negative pressure state suitable for printing.

When the ink consumption in the recording head further progresses and the membrane valve seat 24 further expands, the valve body 25 is prevented from rising above a certain position by the valve body supporting member 26. It slightly separates from the tip 25a of the valve body 25. Thereby, the ink in the ink chamber 23 is sucked up to the lower region D of the membrane valve seat 24 by the capillary force of the ink absorption string 28, and passes through the through hole 24a to the upper region C of the membrane valve seat 24.
Ink is supplied to the ink supply port 21 side.

When the pressure in the upper region C of the membrane valve seat 24 slightly rises due to the inflow of ink, the membrane valve seat 24 moves to the valve body 25 side by its elasticity and elastically contacts the tip 25a of the valve body 25 to pass therethrough. The hole 24a is closed. As a result, the ink absorption string 2
Ink absorption by 8 stops. As a result, the pressure of the ink supply port 21 is maintained substantially constant regardless of the amount of ink in the ink chamber 23.

In this embodiment, ink bubbles gather on the top of the membrane valve seat 24. Therefore, when a negative pressure is applied to the recording head to forcibly eject the ink, the membrane valve seat 2
After passing through the through hole 4a of No. 4, the ink is easily discharged to the outside through the recording head.

[0048]

As described above, according to the present invention ,
Since the membrane valve seat receives a differential pressure in a large area and flows out from the ink chamber in response to a slight ink consumption, the ink can be supplied to the recording head without applying an excessive negative pressure to the recording head. Not only can the ink in the chamber be discharged to the recording head without waste, but if the temperature rises significantly while printing is stopped, the membrane valve seat is displaced toward the ink chamber and communicates with the recording head. It is possible to release the increased pressure of the ink supply port that is being discharged to the ink chamber, and to prevent the leakage of ink when not in use.

Further, since the elasticity of the membrane valve seat can enhance the close contact with the valve body, the valve function can be surely exhibited regardless of the ink swing in the ink chamber caused by the movement of the carriage. As a result, the pressure difference with the recording head can be maintained constant regardless of the movement of the carriage, and the printing quality can be improved.

Furthermore, since the membrane valve seat is inclined so that the region in the vicinity of the communication passage extending from the ink supply port becomes the highest in the peripheral edge thereof, air bubbles in the region communicating with the ink supply port are eliminated. The ink can be positively collected in the communication path and easily discharged to the outside by suction of ink from the recording head.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view showing the vicinity of a membrane valve seat in a state where ink is flowing from an ink chamber to an ink supply port.

FIG. 3 is a sectional view showing another embodiment of the present invention.

FIG. 4 is a sectional view showing another embodiment of the present invention.

FIG. 5 is an enlarged sectional view showing the vicinity of a membrane valve seat.

FIG. 6 is a sectional view showing another embodiment of the present invention.

[Explanation of symbols]

1 container 2 Ink supply port 3 ink chamber 4 membrane valve seat 4a through hole 5 passages 6 valve body 7 Valve support

Continuation of the front page (56) Reference JP-A-5-50609 (JP, A) JP-A-6-64183 (JP, A) JP-A-7-314705 (JP, A) JP-A-8-174860 (JP , A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) B41J 2/175

Claims (10)

(57) [Claims] 1. A through hole is provided in a central portion, which is arranged so as to vertically divide a flow path connecting an ink chamber containing ink and an ink supply port, and which connects the ink chamber and the ink supply port. And a valve body made of an elastic film that responds to the pressure difference between the ink chamber and the ink supply port, and a valve body with which the through hole of the film valve seat abuts, and an outflow region to the ink supply port An ink cartridge for an ink jet printer in which the membrane valve seat is provided so as to be inclined with respect to a horizontal plane so that a region near the position is the highest. 2. The membrane valve seat expands so as to be convex downward when the pressure on the downstream side of the membrane valve seat is lower than a pressure on the upstream side of the membrane valve seat by a predetermined value or more. 1. An ink cartridge for an inkjet printer according to 1. 3. The ink cartridge for an ink jet printer according to claim 1, wherein the valve body is constantly elastically pressed to the membrane valve seat to a certain lower limit position by elasticity imparting means. 4. The valve body is attached to the bottom surface of a container forming the ink chamber via a support, and the ink chamber is provided in the lowest area of the support in the upstream area of the membrane valve seat. The ink cartridge for an ink jet printer according to claim 1, wherein a through hole that allows communication is formed in the support. 5. The valve body is mounted above the bottom surface of a container forming the ink chamber via the support body,
The ink cartridge for an ink jet printer according to claim 1, wherein the ink chamber is connected to the upstream side of the membrane valve seat via a communication passage extending from the bottom surface of the container. 6. A through hole is provided in a central portion, which is arranged so as to vertically divide a flow path connecting an ink chamber containing ink and an ink supply port, and connects the ink chamber with the ink supply port. Then, a membrane valve seat made of an elastic membrane that responds to a pressure difference between the ink chamber and the ink supply port, a valve body in which the through hole of the membrane valve seat is in contact, and a collar is formed, and the collar. While accommodating and restricting the moving direction of the valve element, the valve element accommodating chamber that gives a piston effect to the collar is provided, and the area near the outflow area to the ink supply port is set to the highest level. An ink cartridge for an inkjet printer, in which a membrane valve seat is provided so as to be inclined with respect to a horizontal plane. 7. The ink jet printer according to claim 6, wherein when the pressure of the ink supply port is lower than the pressure of the ink chamber by a predetermined value or more, the membrane valve seat expands so that the downward direction is convex. ink cartridge. 8. The ink cartridge for an ink jet printer according to claim 6, wherein the valve body is constantly elastically pressed against the membrane valve seat by the elasticity imparting means. 9. The ink cartridge for an ink jet printer according to claim 6, wherein the collar is formed with a through hole that generates a fluid resistance to the extent that a damper effect is produced. 10. A through hole is provided at a central portion, which is arranged so as to vertically divide a flow path connecting an ink chamber containing ink and an ink supply port, and which connects the ink chamber and the ink supply port. Then, a membrane valve seat made of an elastic membrane that responds to the pressure difference between the ink chamber and the ink supply port, a valve body with which the through hole of the membrane valve seat abuts, and the valve body is elastically contacted with the through hole. And an absorbing member for ink supply arranged between the ink chamber and the upstream side of the membrane valve seat, and a region near the outflow region to the ink supply port is set as the highest position. Ink cartridge for an inkjet printer, wherein the membrane valve seat is provided so as to be inclined with respect to a horizontal plane.