JP2012157997A - Damper of liquid ejection head, inkjet head, and inkjet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a damper of a liquid ejection head that can stabilize a discharge operation of an ink with a small number of parts.SOLUTION: The damper 13 of an inkjet head 4 includes: an ink reserving recess 17; and a damper film 18 closing a recess aperture 17a and zoning a damper chamber 20. A projection 21 is formed at a bottom face 17b of the ink reserving recess 17. The damper film 18 displaces between a maximum volume position 18A by flexing to an outside of the ink reserving recess 17 and a minimum volume position 18B by flexing to an inside of thereof to thereby adjust an ink supplying pressure in the inkjet head 4. In the minimum volume position 18B, the projection 21 contacts with the damper film 18 and a space is formed between the damper film 18 and the bottom face 17b, thereby the damper film 18 is prevented from sticking to the ink reserving recess 17. As a result, the ink circles in the ink reserving recess 17, thereby a discharge fault of the ink can be avoided.

Description

  The present invention relates to a damper that reduces or absorbs fluctuations in liquid supply pressure in a liquid discharge head. The present invention also relates to an inkjet head and an inkjet printer equipped with such a damper.

  In an ink jet printer configured to supply ink via a flexible ink tube to an ink jet head mounted on a reciprocating carriage, inertia force generated in the ink in the ink tube when the carriage is accelerated or decelerated As a result, the ink supply pressure in the inkjet head varies. Since sudden fluctuations in the ink supply pressure may prevent stable ink ejection from the ink jet head, the ink jet head described in Patent Document 1 is an ink jet head between an ink tube and an ink flow path in the ink jet head. A damper for reducing or absorbing fluctuations in the ink supply pressure is mounted.

  The damper of Patent Document 1 has a rectangular concave portion including an ink inlet port communicating with an ink tube and an ink outlet port communicating with an ink flow path in the inkjet head, and a state in which the concave portion opening is diagonally crossed. A plate spring is provided, and a movable damper film is formed to block the opening of the recess from above the plate spring to form a damper chamber. The ink supply pressure in the inkjet head is adjusted by increasing or decreasing the volume of the damper chamber due to the displacement of the damper film. The leaf spring supports the damper film so that it does not displace excessively inside the recess.

JP-A-6-115092

  In order to reduce the manufacturing cost of the inkjet head, it is required to configure the damper with a small number of parts. Based on this viewpoint, it is desirable that the leaf spring can be omitted in the damper disclosed in Patent Document 1. However, if the leaf spring is reduced from the damper of Patent Document 1, there is a possibility that the damper film sticks to the bottom surface of the recess when the damper film is displaced inside the recess. If the damper film sticks to the bottom surface of the recess, the flow of ink in the recess is retarded, which causes a problem of causing ink ejection failure.

  In order to prevent the damper film from sticking to the bottom surface, it is conceivable to reduce the amount of bending of the damper film. However, when the amount of bending of the damper film is reduced, the range of pressure fluctuation that can be absorbed by the damper is reduced. Therefore, the ink ejection operation may become unstable.

  In view of this point, an object of the present invention is to provide a damper of a liquid discharge head that can stabilize the liquid discharge operation with a small number of parts. Moreover, it is providing the inkjet head and inkjet printer provided with such a damper.

In order to solve the above-described problems, the present invention provides a liquid storage recess having a liquid inlet communicating with a liquid supply path and a liquid outlet communicating with a liquid flow path in the liquid discharge head, and the liquid storage recess. A flexible damper film that blocks the recess opening of the damper and partitions the damper chamber, and adjusts the liquid supply pressure in the liquid discharge head by increasing or decreasing the volume of the damper chamber by displacement of the damper film. In the damper of the liquid discharge head that
When the damper film is bent into the liquid storage recess, the inner surface of the liquid storage recess is prevented from coming into contact with the damper film and sticking to the inner peripheral surface. A protrusion is formed.

  According to the present invention, the damper film is prevented from sticking to the inner peripheral surface of the liquid storage recess due to the protrusion formed on the inner peripheral surface of the liquid storage recess. As a result, it is possible to prevent the flow of the liquid from stagnation in the liquid storage recess, so that it is possible to avoid a liquid discharge failure from the liquid discharge head. In addition, since the damper film can be prevented from sticking to the inner peripheral surface of the liquid storage recess, the amount of deflection of the damper film can be set large, and the width of the pressure fluctuation that can be absorbed by the damper is increased. Can do. Therefore, the liquid discharge operation by the liquid discharge head is stabilized. Furthermore, since it is not necessary to arrange a leaf spring in order to prevent the damper film from sticking to the inner peripheral surface of the liquid storage recess, the number of parts can be reduced.

  In the present invention, in order to prevent the damper film from sticking to the bottom surface of the liquid storage recess, the protrusion is formed on the bottom surface of the liquid storage recess, and is formed at the center of the damper film. It is desirable that the contact is possible.

  In this case, the damper film bends to the outside of the liquid storage recess to maximize the volume of the damper chamber, and bends to the inside of the liquid storage recess to minimize the volume of the damper chamber. It is desirable that the projection is brought into contact with the central portion, and the central portion has a convex shape that rises toward the concave opening at the minimum volume position. In this way, when the damper film is bent deeply inside the liquid storage recess, the central portion of the damper film is deformed into a concave shape that is recessed toward the bottom surface of the liquid storage recess. Can be avoided. Here, if the damper film deflects inward of the liquid storage recess and the central part of the damper film changes from a convex shape to a concave shape, the damper compliance (volume per reference pressure) is generated by the reaction force generated in the damper film. (Change amount) may fluctuate rapidly and the pressure in the damper may become unstable. However, if the central part of the damper film is kept in a convex shape, such a sudden fluctuation in compliance can be avoided. The liquid supply pressure in the liquid discharge head becomes stable, and the liquid protruding operation is stabilized.

  In the present invention, a plurality of the protrusions may be formed on the bottom surface of the liquid storage recess. This makes it easy to secure a gap between the bottom surface of the liquid storage recess and the damper film when the damper film is bent deep inside the liquid storage recess. Therefore, it becomes easy to distribute the ink in the liquid storage recess.

  In the present invention, the liquid inlet is formed on the bottom surface of the liquid storage recess, the liquid outlet is formed on a peripheral wall of the liquid storage recess, and the bottom surface of the liquid storage recess It is desirable that a groove for guiding the liquid flowing into the liquid storage recess from the liquid inlet is formed. In this way, even when the damper film is bent deeply inside the liquid storage recess, the liquid can be circulated through the groove, so that it is easy to ensure the amount of liquid circulated.

  In the present invention, the recess opening is circular or elliptical, and the damper film is circular or elliptical corresponding to the recess opening, and the periphery of the damper film is closely fixed to the periphery of the recess opening. It is desirable. In this way, since the shape of the damper film is uniform or nearly uniform with respect to the displacement direction, the amount of displacement of the damper film should be increased compared to the case where the recess opening and the damper film are rectangular. Is possible. As a result, since the compliance of the damper can be increased, a large pressure fluctuation can be absorbed by the damper.

  Next, an ink jet head according to the present invention includes the above-described damper.

  According to the present invention, since the damper is configured with a small number of parts, the manufacturing cost of the inkjet head can be reduced. In addition, even when the damper film is bent deeply inside the liquid storage recess, the ink flow does not stagnate in the liquid storage recess, so that it is possible to avoid ink protrusion failure. Furthermore, since the damper film can be prevented from sticking to the inner peripheral surface of the liquid storage recess, the amount of deflection of the damper film can be set large, and the width of the pressure fluctuation that can be absorbed by the damper is increased. Can do. Therefore, the ink ejection operation of the ink jet head becomes stable.

The inkjet printer of the present invention is
A carriage that reciprocates in a predetermined scanning direction;
An inkjet head mounted on the carriage;
A flexible liquid supply path for supplying ink to the inkjet head,
The ink jet head includes the damper described above between a liquid flow path in the ink jet head and the liquid supply path.

  According to the present invention, even when the ink supply pressure in the inkjet head fluctuates due to the inertial force generated in the ink in the flexible liquid supply path when the carriage is accelerated or decelerated, the fluctuation in the ink supply pressure is reduced. Can be absorbed or relaxed. In addition, since the damper is configured with a small number of parts, the manufacturing cost of the ink jet printer can be reduced. Further, even when the damper film is bent deeply inside the liquid storage recess, the ink flow does not stagnate in the liquid storage recess, so that it is possible to avoid a poor ink protrusion. In addition, since the damper film can be prevented from sticking to the inner peripheral surface of the liquid storage recess, the amount of deflection of the damper film can be set large, and the width of the pressure fluctuation that can be absorbed by the damper is increased. Can do. Therefore, the ink ejection operation of the ink jet head becomes stable.

  According to the present invention, since the protrusion is formed on the inner peripheral surface of the liquid storage recess, when the damper film is bent inward of the liquid storage recess, the damper film is the inner peripheral surface of the liquid storage recess. It can prevent sticking to. As a result, it is possible to prevent the ink flow from stagnation in the liquid storage recess, so that it is possible to avoid ink ejection defects. In addition, since the damper film can be prevented from sticking to the inner peripheral surface of the liquid storage recess, the amount of deflection of the damper film can be set large, and the width of the pressure fluctuation that can be absorbed by the damper is increased. Can do. Therefore, the ink ejection operation by the ink jet head having such a damper becomes stable. Furthermore, since it is not necessary to arrange a leaf spring to prevent the damper film from sticking to the bottom surface of the liquid storage recess, the number of parts of the damper can be reduced, and an inkjet head including such a damper and the inkjet head The manufacturing cost of the inkjet printer equipped with can be reduced.

It is explanatory drawing which shows the principal part of the inkjet printer to which this invention is applied. It is explanatory drawing which shows schematic structure of the ink supply system of an inkjet printer. It is a perspective view of an inkjet head. It is a fragmentary sectional view of the damper formation part of an ink supply path formation part. It is a perspective view of the damper of a modification.

  Hereinafter, an inkjet printer to which the present invention is applied will be described with reference to the drawings.

(overall structure)
FIG. 1 is an explanatory view showing the main part of an ink jet printer. An ink jet printer (liquid ejecting apparatus) 1 includes a printer case 2, and a platen 3 that defines a printing area is disposed inside the printer case 2. An ink jet head (liquid ejection head) 4 and a carriage 5 on which the ink jet head (liquid ejection head) 4 is mounted are arranged on the upper side of the platen 3. The carriage 5 is shown by an imaginary line in FIG. 1 deviated to the left side of the platen 3 from the home position HP indicated by a solid line in FIG. 1 deviated to the right side from the platen 3 along the carriage guide shaft 5a spanned in the printer width direction. It moves back and forth between the indicated away position AP. The ink jet printer 1 transports recording paper along the surface of the platen 3 by a recording paper transport mechanism (not shown), and ink discharge that ejects ink from the ink jet head 4 toward the recording paper while scanning the carriage 5. Printing on recording paper is performed by alternately performing the operations.

(Ink supply system)
2A and 2B are explanatory diagrams showing a schematic configuration of an ink supply system of the ink jet printer 1. FIG. 2A shows a state where the carriage 5 is at the home position HP, and FIG. 2B shows a state where the carriage 5 is at the away position AP. Indicates the state. An ink cartridge mounting portion 6 is provided in the printer case 2, and an ink cartridge 7 is mounted on the ink cartridge mounting portion 6. The upstream end of the ink supply path 8 is connected to the ink cartridge mounting portion 6, and when the ink cartridge 7 is inserted into the mounting position of the ink cartridge mounting portion 6, the ink cartridge 7 and the ink supply path 8 communicate with each other. The downstream portion of the ink supply path 8 is configured by a flexible ink tube (liquid supply path) 9 that can be deformed in accordance with the reciprocating movement of the carriage 5.

(Inkjet head)
FIG. 3 is a perspective view of the inkjet head 4. The inkjet head 4 includes a head main body 10 and an ink supply path forming unit 11. The head main body 10 includes a nozzle surface 12 a on which a plurality of ink nozzles 12 that eject ink droplets are arranged. The inkjet head 4 is disposed with the nozzle surface 12 a facing the platen 3. An in-head flow path 10b (see FIG. 2) communicating with the ink nozzles 12 is formed inside the head main body 10, and a piezoelectric for ejecting ink from the ink nozzles 12 is formed in the in-head flow path 10b. Elements are incorporated.

  The ink supply path forming portion 11 has a rectangular parallelepiped shape, and is fixed or integrally formed with the head main body portion 10. A damper 13 for adjusting the ink supply pressure in the inkjet head 4 is provided on one end side in the longitudinal direction of the ink supply path forming portion 11. The damper 13 communicates with the downstream end of the ink tube 9. On the side of the head main body 10 in the short direction of the ink supply path forming part 11, an ink supply part 14 communicating with the in-head flow path 10b is formed. The ink supply unit 14 is provided with a filter for removing foreign matter. Between the damper 13 and the ink supply unit 14, an ink channel (liquid channel) that extends from the damper 13 toward the other end side in the longitudinal direction of the ink supply path forming unit 11 and then bends toward the head main body 10 side. 15 is connected.

  Here, the ink supply path forming unit 11 forms recesses and grooves having shapes corresponding to the damper 13, the ink supply unit 14, and the ink flow path 15 in the flow path forming member 11 a, and upper end openings of these recesses and grooves are formed. The structure is closed by a membrane member. The ink that has flowed into the damper 13 from the ink tube 9 flows into the ink supply unit 14 via the ink flow path 15 and then passes through the filter. Then, it passes through a plurality of ink supply holes 16 formed in the ink supply unit 14 and flows into the in-head flow path 10 b of the head main body unit 10.

(Damper)
A damper is demonstrated with reference to FIG. 3, FIG. FIG. 4 is a partial cross-sectional view (XX cross-sectional view in FIG. 3) of a portion where the damper 13 of the ink supply path forming portion 11 is formed. The damper 13 includes a circular ink storage recess (liquid storage recess) 17 formed in the ink supply path forming section 11 and a flexible damper film 18 attached by closing the recess opening 17a. The recess opening 17a of the ink storage recess 17 is circular, and the damper film 18 is circular corresponding to the recess opening 17a. The periphery of the damper film 18 is tightly fixed to the periphery of the recess opening 17a by welding or the like. A damper chamber 20 is defined by the ink storage recess 17 and the damper film 18.

  The damper film 18 is formed of an elastically deformable material, and the film thickness, the planar shape of the film, the Young, and the like so that the damper 13 can obtain a compliance (volume change per reference pressure) in a range assumed in advance. Characteristics such as rate have been determined. The damper film 18 is elastically deformed and bent outside the ink storage recess 17 to be the maximum volume position 18A where the damper chamber 20 has the maximum volume, and is elastically deformed and bent inside the ink storage recess 17 to be the damper chamber 20. Is displaced between the minimum volume positions 18B, where is the minimum volume.

  In the central portion of the bottom surface 17 b of the ink storage recess 17, the damper film 18 is prevented from sticking to the inner peripheral surface of the ink storage recess 17 when bent inside the ink storage recess 17. A protrusion 21 is formed. The protrusion 21 has a cylindrical shape, and when the damper film 18 is bent deep inside the ink storage recess 17, the central portion 18 a of the damper film 18 can come into contact with the flat upper end surface 21 a of the protrusion 21. It has become. In other words, when the damper film 18 is bent inward of the ink storage recess 17, the protrusion 21 first contacts the inner peripheral surface of the ink storage recess 17 (the center of the damper film). It can be brought into contact with the part 18a). As shown in FIG. 4, in this example, the height of the protrusion 21 is about ½ of the depth of the ink storage recess 17. The peripheral edge 21b of the upper end surface 21a of the protrusion 21 is chamfered and provided with a rounded shape. An ink inflow port 22 is formed at a position away from the center of the bottom surface 17b. The ink inlet 22 communicates with the ink tube 9.

  The peripheral wall 17c of the ink storage recess 17 rises vertically from the bottom surface 17b. An ink outlet 23 that communicates with the ink flow path 15 is formed in the peripheral wall 17c. The ink outlet 23 is provided by cutting out a part of the circumferential edge of the peripheral wall 17c on the concave opening 17a side. The ink inlet 22 and the ink outlet 23 are located on opposite sides of the protrusion 21.

(Adjustment operation of ink supply pressure in inkjet head)
As shown in FIG. 2, in the ink supply system of the ink jet printer 1 of this example, when the ink jet head 4 moves to the away position AP, the ink tube 9 is pulled to the ink jet head 4 side, and the ink jet head 4 moves to the home position. When moved to the HP side, the ink tube 9 is pushed back in the opposite direction. Accordingly, when the carriage 5 accelerates while moving in the direction away from the away position AP or when the carriage 5 decelerates while moving in the direction returning to the away position AP, the ink is downstream of the ink tube 9 (in the inkjet head 4). The ink supply pressure in the ink jet head 4 rises.

  When the ink supply pressure in the inkjet head 4 rises, the damper film 18 bends toward the outside of the ink storage recess 17 to increase the volume of the damper chamber 20 and relieve or absorb the pressure rise. Thereby, the ink supply pressure in the inkjet head 4 is adjusted within a predetermined pressure range.

  On the other hand, when the carriage 5 accelerates while moving in a direction away from the home position HP, or decelerates while the carriage 5 moves in a direction returning to the home position HP, the ink is upstream of the ink tube 9 (the ink cartridge 7). Therefore, the downstream side of the ink tube 9 has a negative pressure with respect to the damper 13, the ink flows out of the damper 13, and the ink supply pressure in the inkjet head 4 decreases. In addition, in order to eliminate bubbles remaining in the ink nozzles 12, the ink jet head 4 is also used when the nozzle surface 12 a is covered with a head cap (not shown) and ink is sucked from the ink nozzles 12. The ink supply pressure inside is reduced.

  When the ink supply pressure in the ink jet head 4 decreases, the damper film 18 bends toward the bottom surface 17b of the ink storage recess 17 to reduce the volume of the damper chamber 20, and relieves or absorbs the pressure drop. Thereby, the ink supply pressure in the inkjet head 4 is adjusted within a predetermined pressure range.

  Here, when the ink supply pressure in the ink jet head 4 is remarkably lowered, if the damper film 18 is bent deeply inside the ink storage recess 17, the damper film 18 is moved before the damper film 18 reaches the minimum volume position 18B. The center portion 18a of the ink and the projection 21 of the bottom surface 17b of the ink storage recess 17 abut. As shown by the dotted line in FIG. 4, when the damper film 18 reaches the minimum volume position 18B, the protrusion 21 comes into contact with the damper film 18 so that the central portion 18a of the damper film 18 is outside (recessed opening). 17a side). As a result, a region where the damper film 18 and the bottom surface 17b of the ink storage recess 17 are not in contact with each other is formed at least around the base portion of the protrusion 21. Thus, the ink can be circulated in the ink storing recess 17. Therefore, it is possible to avoid the occurrence of ink ejection failure during the printing operation. Further, in the ink suction operation, ink can be sucked through the ink nozzle 12.

  Further, when the damper film 18 reaches the minimum volume position 18B, the central portion 18a of the damper film 18 is held in a convex shape that rises outward, so that the central portion 18a of the damper film 18 is the bottom surface of the recess 17 for storing ink. It is avoided to deform into a concave shape recessed toward the side of 17b. Here, if the central portion 18a of the damper film 18 changes from a convex shape to a concave shape when the damper film 18 is bent deeply inside the ink storing concave portion 17, the reaction force generated in the damper film 18 causes the damper 13 to Although the compliance may fluctuate rapidly and the pressure in the damper 13 may become unstable, according to this example, since the central portion 18a of the damper film 18 is held in a convex shape, Abrupt fluctuations are avoided, and the ink supply pressure in the inkjet head 4 becomes stable. Therefore, the ink ejection operation is stabilized.

(Function and effect)
According to this example, since the protrusion 21 is formed on the bottom surface 17 b of the ink storage recess portion 17, the damper film 18 does not adhere to the bottom surface 17 b of the ink storage recess portion 17. As a result, it is possible to prevent the ink flow from stagnation in the ink storage recess 17, thereby avoiding ink ejection failure. Further, since the damper film 18 can be prevented from sticking to the bottom surface 17b of the ink storage recess 17, the amount of deflection of the damper film 18 can be set large, and the width of the pressure fluctuation that can be absorbed by the damper 13 can be increased. Can be bigger. Therefore, the ink ejection operation by the ink jet head 4 becomes stable. Furthermore, since it is not necessary to arrange a leaf spring or the like in order to prevent the damper film 18 from sticking to the bottom surface 17b of the ink storage recess 17, the number of parts can be suppressed. Therefore, the manufacturing cost of the inkjet head 4 and the inkjet printer 1 can be suppressed.

  Further, the protrusion 21 prevents the central portion 18a of the damper film 18 from being deformed from a convex shape to a concave shape, so that the compliance of the damper 13 fluctuates rapidly and the pressure in the damper 13 becomes unstable. You can avoid that. Therefore, the ink supply pressure in the inkjet head 4 becomes stable, and the ink protruding operation is stabilized.

  Furthermore, according to this example, since the recess opening 17a of the ink storage recess 17 and the damper film 18 are circular, the shape of the damper film 18 is uniform in the displacement direction. As a result, it is possible to increase the amount of displacement of the damper film 18 as compared with the case where the concave opening 17a and the damper film 18 are rectangular, so that the compliance of the damper 13 can be increased. Large pressure fluctuations can be absorbed. In addition, even if the recess opening 17a and the damper film 18 of the ink storage recess 17 are elliptical, the amount of displacement of the damper film 18 can be increased compared to the case where these are rectangular.

(Other embodiments)
In the above example, the protrusion 21 is formed at the center of the bottom surface 17b of the ink storage recess 17, but the protrusion 21 may be formed at a position away from the center of the bottom surface 17b. Moreover, although the upper end surface 21a of the projection 21 is flat, the upper end surface 21a may be a convex curved surface. Furthermore, a plurality of protrusions 21 having the same shape as the protrusions 21 may be provided on the bottom surface 17 b of the ink storage recess 17. Further, the protrusion 21 may be formed on the peripheral wall 17c and protrude inward from the peripheral wall 17c.

  FIG. 5 is a perspective view showing a modified damper. In the damper 13 </ b> A shown in FIG. 5A, the ink inlet 22 and the ink outlet 23 are formed on the same side with respect to the protrusion 21. According to the damper 13 </ b> A, the ink inlet 22 and the ink outlet 23 are close to each other in the ink storage recess 17, so that even if the damper film 18 is bent deep inside the ink storage recess 17, the ink flow It becomes easy to circulate ink from the inlet 22 toward the ink outlet 23 or from the ink outlet 23 toward the ink inlet 22.

  In the damper 13 </ b> B shown in FIG. 5B, a cylindrical first protrusion 211 and an annular second protrusion 212 are formed on the bottom surface 17 b of the ink storage recess 17. The second protrusion 212 is coaxially formed so as to surround the first protrusion 212. According to the damper 13 </ b> B, when the damper film 18 is bent deep inside the ink storage recess 17, the first and second protrusions 211 and 212 cause the gap between the bottom surface 17 b of the ink storage recess 17 and the damper film 18. Therefore, it is possible to reliably prevent the damper film 18 from sticking to the bottom surface 17b of the ink storage recess 17.

  In the damper 13C shown in FIG. 5C, a groove 24 is formed on the bottom surface 17b of the ink reservoir recess 17 to guide the ink that has flowed into the ink reservoir recess 17 from the ink inlet 22 to the vicinity of the ink outlet 23. Yes. According to the damper 13 </ b> C, when the damper film 18 is bent deep inside the ink storage recess 17, the ink can be circulated through the groove 24, so that it is easy to ensure the ink circulation amount. It becomes. When the ink outlet 23 is open at a position including the edge on the bottom surface 17b side of the peripheral wall 17c, that is, when the ink outlet 23 is in contact with the bottom surface 17b, the ink outlet 22 is connected to the ink outlet. A groove 24 reaching 23 can be formed.

  The above embodiment is an example in which the present invention is applied to the damper 13 of the ink jet head 4 of the ink jet printer 1, but the present invention is mounted on another liquid ejecting apparatus and a liquid ejecting head that eject liquid other than ink. It can also be applied to dampers. For example, a liquid ejection device for ejecting a reagent solution or a liquid sample from a liquid ejection head, or a damper mounted on a liquid ejection device for ejecting a liquid paint or liquid material from a liquid ejection head to apply by printing. Is also applicable.

1. Inkjet printer (liquid ejection device) 2. Printer case 3. Platen 4. Inkjet head (liquid ejection head) 5. Carriage 5. Carriage guide shaft 6. Ink cartridge mounting part 7. Ink cartridge 8, ink supply path, 9 ink tube (flexible liquid supply path), 10 head body, 10b head flow path, 11 ink supply path forming section, 11a flow path forming member, 12 -Ink nozzle, 12a-Nozzle surface, 13, 13A, 13B, 13C-Damper, 14-Ink supply section, 15-Ink flow path (liquid flow path), 16-Ink supply hole, 17-Ink storage recess, 17a・ Recess opening, 17b / bottom surface, 17c / circumferential wall, 18 / damper film, 18a / center portion, 18A / maximum volume position, 18B / minimum volume position 20 · damper chamber, 21 · projection, 21a · upper end surface, 21b · peripheral edge, 22 · ink inlet, 23 · ink outlet, 24 · groove, 211 · first projection, 212 · second projection, AP · away Position, HP / Home position

Claims (8)

A liquid storage recess having a liquid inlet communicating with the liquid supply path and a liquid outlet communicating with the liquid flow path in the liquid discharge head, and a damper chamber are defined by closing the recess opening of the liquid storage recess. In a damper of a liquid discharge head, which has a flexible damper film, and adjusts the liquid supply pressure in the liquid discharge head by increasing or decreasing the volume of the damper chamber by displacement of the damper film.
When the damper film is bent into the liquid storage recess, the inner surface of the liquid storage recess is prevented from coming into contact with the damper film and sticking to the inner peripheral surface. A liquid ejection head damper having a protrusion formed thereon. In claim 1,
The liquid ejecting head damper according to claim 1, wherein the protrusion is formed on a bottom surface of the liquid storage recess and is capable of contacting a central portion of the damper film. In claim 2,
The damper film is bent to the outside of the liquid storage recess to maximize the volume of the damper chamber, and the volume minimum position to be bent to the inside of the liquid storage recess to minimize the volume of the damper chamber. The liquid ejection head damper is characterized in that at the minimum volume position, the protrusion comes into contact with the central portion and the central portion rises toward the concave opening. In claim 1,
A plurality of the protrusions are formed on the bottom surface of the liquid storage recess. In any one of claims 1 to 4,
The liquid inlet is formed on the bottom surface of the liquid storage recess,
The liquid outlet is formed in a peripheral wall of the liquid storage recess,
A damper for a liquid discharge head, wherein a groove for guiding the liquid that has flowed into the liquid storage recess from the liquid inlet is formed on the bottom surface of the liquid storage recess. In any one of claims 1 to 5,
The recess opening is circular or elliptical;
The damper of the liquid discharge head, wherein the damper film is circular or elliptical corresponding to the opening of the recess, and the periphery of the damper film is closely fixed to the periphery of the opening of the recess.   An inkjet head comprising the damper according to any one of claims 1 to 6. A carriage that reciprocates in a predetermined scanning direction;
An inkjet head mounted on the carriage;
A flexible liquid supply path for supplying ink to the inkjet head,
The inkjet printer includes the damper according to any one of claims 1 to 6 between a liquid channel in the inkjet head and the liquid supply channel. .

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