JP2004001564A - Ink cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an ink cartridge which can supply ink surely to a recording head by responding surely to a micro differential pressure between the cartridge and a recording head thereby sustaining a negative pressure suitable for printing between them regardless of rolling of ink, and can prevent leakage of ink regardless of pressure rise on the ink supply port side or leakage of ink from the recording head. <P>SOLUTION: The ink cartridge having the ink supply port 2 for supplying ink to the ink jet recording head, and an ink chamber 4 communicating with the ink supply port 2 is further provided with a membrane valve seat 3, i.e. an elastically deformable body, interposed between the ink chamber 4 and the ink supply port 2 while having a central through hole 6 for conducting ink, and a valve element 8 disposed movable to face the through hole 6 and becoming a sealing member. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to an ink cartridge suitable for mounting on a carriage on which an inkjet recording head is mounted.

Inkjet printers have a carriage with an inkjet printhead that applies pressure to a pressure generation chamber that communicates with a common ink chamber and a nozzle opening to eject ink droplets from the nozzle opening, and an ink cartridge that supplies ink to the printhead. The ink droplets are ejected onto recording paper in accordance with the print data while the carriage is reciprocated.

By the way, since the nozzle opening of the recording head is located at a position lower than the ink liquid level of the ink cartridge, a water head pressure acts on the nozzle opening. The pressure of the ink cartridge is configured to be slightly lower than that of the nozzle opening due to the surface tension of the body, and measures are taken to prevent the ink from seeping out from the nozzle opening.

However, as the consumption of ink progresses and the amount of ink absorbed by the porous body decreases, the surface tension of the porous body increases, and the supply of ink to the recording head tends to be delayed, and the ink in the cartridge is reduced. There is a problem that it cannot be completely consumed.
Further, since the amount of ink that can be stored in the cartridge is reduced by the substantial volume of the porous body, there is a problem that the ink cartridge becomes large.

In order to solve such a problem, for example, as shown in Patent Documents 1 and 2, an ink reservoir and a cavity are separated by a wall provided with a through hole at a lower portion of an ink tank. Ink for an ink jet print head, wherein the valve is movably provided, and when the ink pressure of the print head drops, the valve is opened to discharge the ink in the tank reservoir into the cavity and supply it to the print head. Cartridges have been proposed.
U.S. Pat. No. 4,677,447 JP-A-62-231759

According to this, since it is not necessary to store the porous body in the cartridge, it is possible to increase the substantial ink storage amount of the tank.However, the umbrella check valve generally supplies the ink to the recording head. To precisely adjust the supply, the offset amount is too large, and there is a big problem that the ink supply amount fluctuates and the print quality is reduced.

On the other hand, when the umbrella check valve is closed, the ink reservoir and the recording head are completely shut off. Therefore, when the volume of the ink in the cavity expands by 2 to 5% due to a change in environmental temperature, the pressure in the cavity is reduced. Rises and breaks the seal at the connection port with the print head, causing ink to leak.In the state where the print head is mounted, this pressure acts on the print head and causes There is a problem that the negative pressure cannot be maintained between the recording heads and ink leaks from the recording head.

Further, the umbrella check valve has a weak valve closing force at a pressure difference of about several tens mmAq to be maintained in order to supply a stable ink to the recording head, so that the umbrella check valve responds to the ink swing due to the movement of the carriage. There is a problem that the valve is opened and stable printing is impossible.

The present invention has been made in view of such a problem, and an object of the present invention is to reliably respond to a minute differential pressure between the recording head and the ink, and to cope with ink swing caused by movement of a carriage. Ink can be reliably supplied to the recording head by maintaining a negative pressure suitable for printing with the recording head without being influenced by the recording head. An object of the present invention is to provide an ink cartridge that prevents ink leakage and ink leakage from a recording head.

In order to solve such a problem, according to the present invention, in an ink cartridge including an ink supply port for supplying ink to an ink jet recording head and an ink storage area communicating with the ink supply port, the ink cartridge is provided at a central portion. An elastic body having an ink circulation through-hole, elastically deformable disposed between the ink storage area and the ink supply port, and movably disposed to face the through-hole of the elastic body; The sealing member is provided.

The membrane valve seat receives a differential pressure over a large area and opens a flow path from the ink storage area to the ink supply port in response to the slight consumption of ink, and applies a negative pressure to the print head without applying excessive negative pressure to the print head. Even when the ink is supplied and the pressure between the ink supply port and the membrane valve rises due to a rise in temperature or the like, the sealing member is pushed back by the membrane valve and retreats between the ink supply port and the membrane valve. By absorbing the pressure, the rise in the pressure is released to the ink storage chamber, thereby preventing the ink from leaking from the recording head.

Therefore, the details of the present invention will be described below based on illustrated embodiments.
FIG. 1 shows an embodiment of the present invention, wherein reference numeral 1 denotes 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 is provided on a bottom surface 1a. Is formed, and the space in the container is divided into an ink chamber 4 and an ink supply chamber 5 by a membrane valve seat 3 described later.

Reference numeral 3 denotes the above-mentioned membrane valve seat, which is formed by forming a through hole 6 at the center in an elastic film such as a rubber film or a polymer elastomer film having durability against ink, and formed at the lower part of the container 1. It is stretched over the stepped portion 7.

Reference numeral 8 denotes a valve body which is vertically movably inserted into a through hole 10 provided in the valve assembly 9 and has a thickness sufficient to secure a gap enough to allow ink to flow down and has a long length. Is configured to be slightly longer than the thickness of the valve assembly 9. Are in contact. In the valve assembly 9, an ink flow path 15 for guiding ink is formed.

Reference numeral 11 denotes the above-described valve body support member, which is stretched on the surface of the valve assembly 9 and always makes the valve body 8 elastically contact the membrane valve seat 3 while preventing the valve body 8 from falling below a certain position. The through hole 12 is formed in the elastic membrane made of the same material as the membrane valve seat 3, and the top of the valve body 8 is held by the through hole.

The upper surface of the container 1 is sealed by a lid member 13 having an air communication hole 14. On the ink chamber side of the lid member 13, a concave portion 30 surrounding the communication hole 14, a communication port 32 located at a predetermined distance from the concave portion 30, and a narrow groove 31 forming a capillary connecting these are formed. ing. On the upper surfaces of the concave portion 30 and the groove 31, a flexible film 33 that is slackened so as to be separated from the through hole when the lid member 13 is located above is provided.

The membrane valve seat 3, the valve body support 11, and the valve body 8 are preferably integrally assembled to a valve assembly 9, and are recessed into the step 7 of the container 1 and incorporated into the container 1. .

In this embodiment, when the container 1 is tilted and the ink in the ink chamber 4 comes into contact with the lid member 13, the flexible film 33 receives the pressure of the ink and comes into contact with the convex portion 14a around the through hole 14. The through hole 14 is sealed to prevent the ink from leaking from the atmosphere communication hole 14.

(4) When the ink supply port 2 is inserted into the ink supply needle of the recording head on which the carriage is mounted, the ink supply chamber 5 and the recording head are connected. In this state, since the flexible film 33 of the lid member 13 hangs down due to gravity and the through hole 14 is opened, the ink chamber 4 communicates with the atmosphere via the concave portion 30, the groove 31, and the communication hole 32.

In this state, when printing is executed and ink droplets are ejected from the recording head, the ink in the ink supply chamber 5 flows into the recording head from the ink supply port 2 and the pressure in the ink supply chamber 5 gradually decreases. In response to the pressure drop in the ink supply chamber 5, the membrane valve seat 3 receives the pressure from the ink chamber 4 and expands into a spherical shape having a radius R due to its elasticity, and descends. At this point, since the valve element 8 follows the membrane valve seat 3 (FIG. 2A), the pressure from the ink chamber 4 to the ink supply chamber 5 is reduced while preventing the pressure in the ink supply chamber 5 from excessively decreasing. The flow of ink is prevented, and the pressure in the ink supply chamber 5 is prevented from excessively increasing. As a result, the pressure of the recording head is maintained at a constant negative pressure with respect to the ink chamber 4.

Further, when the ink consumption in the recording head further proceeds and the membrane valve seat 3 descends further, the valve body 8 is prevented from descending below a certain position by the valve body support member 11, so that the valve body 8 is moved to the membrane valve seat. 3 slightly (Fig. 2 (b)). Thereby, the ink in the ink chamber 4 flows into the ink supply chamber 5 from the through hole 6 via the narrow gap formed between the valve element 8 and the membrane valve seat 3.

When the pressure of the ink supply chamber 5 slightly increases due to the inflow of ink, the membrane valve seat 3 moves toward the valve body 8 due to its own elasticity and elastically contacts the valve body 8, and the through hole 6 is closed by the lower surface of the valve body 8. It comes off. Thus, the flow of the ink from the ink chamber 4 to the ink supply chamber 5 is stopped. As a result, regardless of the amount of ink in the ink chamber 3, the pressure of the ink supply port 2 is kept constant.

Thereafter, each time the pressure in the ink supply chamber 6 slightly decreases, the membrane valve seat 3 expands slightly downward to form a gap between the valve body 8 and the ink in the ink chamber 3 through the gap. Let it flow into Since the membrane valve seat 3 formed of the elastic membrane comes in contact with and separates from the valve body 8 in accordance with the consumption of ink, if the elasticity of the membrane valve seat 3 is set to an appropriate size, the pressure at the start of ink supply is reduced. Not only the pressure difference at the time when the ink supply is stopped, that is, the offset, can be made extremely small, but also all the ink in the ink chamber 4 can be discharged to the recording head.

On the other hand, if the ambient temperature rises while printing is interrupted, the pressure in the ink supply chamber 5 rises, but the ink valve chamber 3 is opened to the atmosphere in response to this pressure. Move to 4 side. This prevents the pressure in the ink supply chamber 5 from increasing, and maintains an optimal negative pressure between the recording head and the recording head irrespective of the temperature increase. Therefore, leakage of ink from the recording head due to the pressure increase is prevented. Will be prevented.

FIG. 3 shows that the membrane valve seat 3 is made of a rubber membrane having a thickness of 0.04 mm and an effective diameter, that is, an elastically deformable region having a diameter of 20 mm. FIG. 2A shows the change in the water head value of the ink cartridge of the present invention in which the lower limit position of the valve body 8 is set so that the radius R of the spherical surface is 26 mm. It can be seen that even when the ink is supplied, the increase in the water head value is small, and even when a large amount of ink is consumed by the recording head, the ink can be supplied smoothly without applying an excessive negative pressure to the recording head.

On the other hand, in the manufacturing process, when the ink supply port 2 is sealed with a seal 16 and a negative pressure is applied to the ink chamber 4 to eliminate air in the cartridge, the pressure of the ink chamber 4 is higher than that of the ink supply chamber 5. As shown in FIG. 2C, the valve body 8 moves toward the ink chamber against the elastic force of the valve body support member 11 and moves between the membrane valve seat 3 and the valve body 8 as shown in FIG. Since the space is formed, the air in the entire cartridge can be eliminated regardless of the presence of the membrane valve seat 3 and the valve element 8, and the entire cartridge including the ink supply chamber 5 can be filled with ink. It becomes.

FIG. 4 shows another embodiment of the valve element 8. In this embodiment, when the lower surface of the valve element 8 contacts the membrane valve seat 3, the flat plate contacts the upper surface of the valve assembly 9. A positioning piece 35 is provided.

According to this embodiment, when the valve element 8 is in contact with the membrane valve seat 3, the positioning piece 35 contacts the upper surface of the valve assembly 9, and the valve element 3 is supported by the valve assembly 9. Since the vertical posture is maintained as much as possible, it is possible to reliably seal the through hole 6 of the membrane valve seat 3 against vibration due to the movement of the carriage and the like.

FIG. 5 shows another embodiment of the present invention. In the figure, reference numeral 20 denotes a valve body, which is constantly pressed downward by a spring 21 into a valve body accommodating chamber 9 a formed in the valve assembly 9. The lower end position is defined by the positioning piece 36 formed on the valve body 20 abutting on the convex portion 9b at the lower part of the valve body accommodating chamber 9a. Reference numerals 22 and 23 in the drawing indicate through holes for connecting the ink chamber 4 and the ink supply chamber 5, respectively.

In this embodiment, in response to the pressure drop of the ink supply chamber 5, the membrane valve seat 3 receives the pressure from the ink chamber 4 and expands into a spherical shape having a radius R due to its elasticity, and descends. At this time, the valve element 20 follows the membrane valve seat 3 by the elasticity of the spring 21 and the positioning piece 36 abuts on the convex portion 9b to hold the valve element 20 in a vertical position (FIG. 6A). 3) Inflow of ink from the ink chamber 4 into the ink supply chamber 5 is prevented while preventing the pressure in the ink supply chamber 5 from excessively decreasing. Accordingly, the membrane valve seat 3 abuts on the valve body 20 irrespective of the swing caused by the movement of the carriage, so that the ink pressure of the recording head is maintained at a constant negative pressure with respect to the ink chamber 4.

When the ink consumption in the recording head progresses and the membrane valve seat 3 descends further, the valve body 20 is prevented from descending below a certain position by the projection 9b of the valve body accommodating chamber 9a. Very slightly away from the valve seat 3 (FIG. 6 (b)). Thereby, the ink in the ink chamber 4 flows into the ink supply chamber 5 from the through hole 6 via the narrow gap formed between the valve element 8 and the membrane valve seat 3.

When the pressure of the ink supply chamber 5 rises slightly due to the inflow of ink, the membrane valve seat 3 moves toward the valve body 20 due to its own elasticity and elastically contacts the valve body 20, and the through hole 6 is closed by the lower surface of the valve body 8. It comes off. Thus, the flow of the ink from the ink chamber 4 to the ink supply chamber 5 is stopped. As a result, regardless of the amount of ink in the ink chamber 3, the pressure of the ink supply port 2 is kept constant.

On the other hand, in the manufacturing process, when the ink supply port 2 is sealed with a seal 16 and a negative pressure is applied to the ink chamber 4 to eliminate air in the cartridge, the pressure of the ink chamber 4 is higher than that of the ink supply chamber 5. 6C, the valve body 8 moves toward the ink chamber against the spring 21 to form a gap between the membrane valve seat 3 and the valve body 20 as shown in FIG. Irrespective of the presence of the membrane valve seat 3 and the valve element 20, the air in the entire cartridge can be eliminated, and the entire cartridge including the ink supply chamber can be filled with ink.

In the above-described embodiment, the elastic member for bringing the valve body 20 into contact with the membrane valve seat 3 is incorporated in the valve assembly 9. However, as shown in FIG. It may be formed in a mold, and the cap portion 37a may function as a positioning piece and a stopper, and the vertex may be elastically pressed toward the membrane valve seat 3 by the spring 38.

According to this embodiment, since the valve element 37 and the spring 38 can be attached from outside the valve assembly 9, the assembly operation can be simplified.

In the above-described embodiment, a spring is provided above the valve body. However, as shown in FIG. 8, the container 40 is divided into an ink chamber 42 and an ink supply chamber by a partition plate 41 having a through hole 41a. 43, a membrane valve seat 44, a spherical surface 46a sealing the through hole 45 of the membrane valve seat 44 on the lower surface, and a through hole 45 of the membrane valve seat 44 which extends vertically from the spherical surface 46a. It is apparent that a similar effect can be obtained even if the valve body 46 including the supporting portion 46b penetrating through the housing is accommodated and the supporting portion 46b is supported via the spring 47 which constantly presses downward. In the drawing, reference numeral 48 denotes a positioning guide hole which is fitted to the lower end of the support portion 46b to position the valve body 46 in a vertical posture, and reference numeral 49 denotes an ink supply port.

According to this embodiment, since the lower part of the valve body 46 is pulled downward by the spring 47, the posture is stabilized irrespective of the buoyancy due to the ink. Can be supplied stably.

FIG. 9 shows another embodiment of the present invention. In the drawing, reference numeral 50 denotes a liquid level stabilizing film, which is a film of a soft porous material that can follow the movement of the membrane valve seat 3. The valve body 8 is formed of a lattice-like membrane, and a through hole 51 is formed in a region facing the valve body 8 so as to fit into the valve body 8. Fixed.

In this embodiment, when the pressure in the ink supply chamber 5 decreases due to consumption of ink, the membrane valve seat 3 separates from the valve body 8 and the ink in the ink chamber 4 passes through the liquid level stabilizing film 50 to supply the ink. It flows into the room 5.

Further, when the ink consumption further proceeds and the liquid level of the ink chamber 4 drops to the vicinity of the assembly 9, the ink vibrates violently near the valve element 8 due to the movement of the carriage. After the pressure fluctuation is suppressed as much as possible, the ink passes through the through hole 6 of the membrane valve seat 3, and the ink pressure of the recording head is kept constant irrespective of the decrease in the amount of ink in the ink chamber 4.

In the above-described embodiment, the valve element is resiliently contacted with the membrane valve seat 3 by using elastic means. An elastic member that makes elastic contact with the seat 3 can be eliminated.
FIG. 10 shows an embodiment in which an elastic member for resiliently pressing a valve body against a membrane valve seat is not required. Is formed, and its periphery is fixed by the valve assembly 27. Reference numeral 28 denotes a valve body which is immovably fixed so as to take a posture perpendicular to the valve assembly 27. Reference numeral 29 in the drawing indicates a through hole that connects the ink chamber 4 and the ink supply chamber 5.

In this embodiment, when the pressure difference between the ink chamber 4 and the ink supply chamber 5 is equal to or less than a predetermined value, the membrane valve seat 24 elastically contacts the through hole 25 with the valve body 28 by its own elasticity. Then, the flow of ink from the ink supply chamber 5 to the ink supply chamber 5 stops.

On the other hand, when the pressure in the ink supply chamber 5 decreases, the membrane valve seat 24 descends while expanding in a spherical shape, so that the through hole 25 separates from the valve body 28, and ink flows from the ink chamber 4 into the ink supply chamber 5, When the supply of ink proceeds and the pressure in the ink supply chamber 5 rises, the membrane valve seat 24 overcomes the differential pressure and resiliently contacts the valve body 28 to stop the outflow of ink.

By the way, when air enters the recording head, the pressure for ejecting ink droplets is absorbed by air bubbles generated in the flow path of the recording head due to the air, causing a printing failure. It is necessary to prevent the recording head from sucking air at the end of ink.

FIG. 11 shows an embodiment of an ink cartridge in which air is prevented from entering the recording head when the recording head has finished ink. Is formed, a conical valve seat 54 that expands, a spherical floating valve 55 that floats by buoyancy is accommodated therein, and a valve holding plate 56 such as a net that allows ink to pass therethrough is provided on the upper portion to form a shielding valve. It is composed. Reference numeral 57 in the figure denotes a membrane valve seat that contacts the valve body 58 and controls the flow of ink from the ink chamber.

In this embodiment, when the ink cartridge is mounted on the recording head, the floating valve 55 is stuck to the valve holding plate 56 by buoyancy, the ink supply port 52 is opened, and ink is supplied to the recording head. Is supplied.

On the other hand, when the consumption of the ink in the cartridge progresses and the water level of the ink drops to the vicinity of the ink supply port 52, the floating valve 55 loses the buoyancy due to the ink and comes into contact with the valve seat 54 (the state shown by a dotted line in the figure). I do. Therefore, even if the printing is further advanced, the ink supply port 52 is sealed, so that the infiltration of air into the recording head is prevented, and the occurrence of printing trouble can be prevented.

イ ン ク Furthermore, when the ink cartridge is mounted on the recording head, it is not normally inserted or removed until the ink in the ink chamber is consumed, but the ink cartridge may still be removed from the recording head by an erroneous operation. As described above, once the mounted cartridge is removed from the recording head, the ink supply port 2 is opened to the atmosphere, and air enters the ink supply chamber or the ink chamber, which adversely affects the recording operation.

FIG. 12 shows an embodiment for preventing the above-mentioned inconvenience caused by the attachment / detachment of the ink cartridge. In the figure, reference numeral 60 denotes an extensible valve provided at an ink supply port 61, Is provided with an ink supply needle fitting hole 62 into which the ink supply needle 70 fits. Further, a through hole 64 for connecting the ink supply chamber 63 and the ink supply needle fitting hole 62 when moved to the upper limit position is provided.

In this embodiment, the valve body 60 always elastically contacts the bottom 63a of the ink supply chamber 63 due to elasticity as shown in FIG. 12A, thereby reliably preventing the ink from flowing out of the ink supply chamber 63.

When the ink supply needle 70 is inserted into the fitting hole 62, the valve body 60 extends to the upper limit position and separates from the bottom surface 63a of the ink supply chamber 63, and the communication hole 64 is exposed to the ink supply chamber 63 (see FIG. (B). As a result, the ink supply chamber 63 and the ink flow path 70a of the ink supply needle 70 are connected through the communication holes 64 and 70b, and the ink in the ink supply chamber 63 flows into the ink supply needle 70, and the ink is supplied to the recording head. Will be.

When the ink cartridge mounted on the recording head is removed, the valve body 60 moves downward to shut off the ink supply chamber 63 and the ink supply port 61 (FIG. 10A). And the inflow of air into the ink supply chamber 63 is prevented.

It is sectional drawing which shows one Example of this invention. FIGS. 7A and 7B are diagrams showing the operation of the membrane valve seat and the valve body in a state of being attached to the recording head, respectively, and FIG. 7C is a diagram when the ink cartridge is filled with ink. It is a figure showing a state of a valve element. FIG. 4 is a diagram illustrating a relationship between an ink discharge amount and a water head value of the ink cartridge of the present invention. FIG. 7 is a diagram illustrating another embodiment of the present invention in which the vicinity of an ink supply chamber is enlarged. FIG. 6 is a cross-sectional view illustrating another embodiment of the present invention. FIGS. 6A and 6B are diagrams showing the operation of the membrane valve seat and the valve body when mounted on the recording head, and FIG. 6C is a diagram showing the valve when the ink cartridge is filled with ink. It is a figure showing a state of a body. FIG. 7 is a diagram illustrating another embodiment of the present invention in which the vicinity of an ink supply chamber is enlarged. FIG. 7 is a diagram illustrating another embodiment of the present invention in which the vicinity of an ink supply chamber is enlarged. FIG. 7 is a diagram illustrating another embodiment of the present invention in which the vicinity of an ink supply chamber is enlarged. FIG. 7 is a diagram illustrating another embodiment of the present invention in which the vicinity of an ink supply chamber is enlarged. FIG. 4 is a diagram illustrating an example of an ink supply port. FIGS. 7A and 7B are diagrams showing other embodiments of the ink supply port in a state where the ink supply port is not mounted on the recording head and a state where the ink supply port is mounted on the recording head, respectively.

Explanation of reference numerals

{Circle around (1)} container {2} ink supply port {3} membrane valve seat {4} ink chamber # 5 ink supply chamber # 6 through hole {7} stepped part {8} valve body {9} valve assembly {25} soft porous body membrane

Claims (1)

In an ink cartridge having an ink supply port for supplying ink to an inkjet recording head and an ink storage area communicating with the ink supply port,
An elastic body that has a through hole for ink circulation at the center thereof and that is elastically deformable and disposed between the ink storage area and the ink supply port, and moves to face the through hole of the elastic body; An ink cartridge for an ink jet printer, comprising: a sealing member arranged so as to be capable of being mounted.

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