Head chip, liquid jet head, liquid jet recording device and method for manufacturing head chip

Abstract

To provide a head chip, a liquid jet head, a liquid jet recording device and a method for manufacturing the head chip, which improve manufacturing efficiency and reduce a cost, and can protect an electrode.SOLUTION: A head chip includes: pressure chambers which are formed so as to be aligned side by side in a first direction and store liquid; a chip body having driving parts arranged in for each part facing the pressure chambers; a first driving electrode formed on the driving parts; and a sheet-like protective film formed following the driving parts, in a state of coating the first driving electrode. On the chip body, an air vent passage is formed which connects between the inside of the pressure chamber and the outside of the chip body, in which communication between the inside of the pressure chambers and the outside of the chip body is blocked by the protective film.SELECTED DRAWING: Figure 12

Description

Technical Field

[0001] The present disclosure relates to a head chip, a liquid ejection head, a liquid ejection recording apparatus, and a method for manufacturing a head chip.

Background Art

[0002] An inkjet head ejects ink onto a recording medium through a head chip. The head chip includes an actuator plate in which ejection channels are formed, and a cover plate superposed on the actuator plate. In the actuator plate, electrodes are formed on the inner surfaces of the ejection channels. For example, Patent Document 1 below discloses a configuration in which electrodes are protected by a deposited film made of an insulating material such as a parylene-based resin material (e.g., parylene (registered trademark)).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above-described conventional technology, since the deposited film is formed by a film-forming method such as chemical vapor deposition (CVD), when film-forming defects (e.g., pinholes, etc.) occur, discontinuous portions are formed in the deposited film. In this case, ink may enter between the deposited film and the inner surface of the ejection channel through the discontinuous portion, which may cause short circuits or corrosion of the electrodes. In order to reduce the risk of film-forming defects, ensuring the thickness of the deposited film or strictly managing the film-forming state is required, which leads to a decrease in manufacturing efficiency and an increase in material costs.

[0005] The present disclosure provides a head chip, a liquid ejection head, a liquid ejection recording apparatus, and a method for manufacturing a head chip that can protect electrodes while improving manufacturing efficiency and reducing costs.

Means for Solving the Problems

[0006] In order to solve the above problems, the present disclosure adopts the following aspects. (1) A head chip according to one aspect of the present disclosure includes a chip body having a plurality of pressure chambers formed side by side in a first direction and accommodating liquid, and drive portions separately disposed on portions facing the pressure chambers, a first drive electrode formed on the drive portion, and a sheet-like protective film formed following the drive portion while covering the first drive electrode. An air vent passage is formed in the chip body to connect between the inside of the pressure chamber and the outside of the chip body, and the communication between the inside of the pressure chamber and the outside of the chip body is blocked by the protective film.

[0007] According to this aspect, by covering the drive portion with a sheet-like protective film, unlike a configuration in which a deposition film made of a parylene-based resin material (for example, parylene (registered trademark)) is formed by a film-forming method such as CVD as in the prior art, the occurrence of discontinuous portions such as pinholes can be suppressed. Therefore, it is possible to suppress the liquid from reaching the first drive electrode formed on the drive portion. As a result, short circuits, corrosion, etc. of the first drive electrode can be suppressed, and a head chip with excellent reliability can be provided. In addition, by adopting a sheet-like protective film, a simple and low-cost protective film can be provided compared to a configuration in which a deposited film is formed by CVD or the like. As a result, the manufacturing efficiency of the head chip can be improved, and the cost of the head chip 32 can be reduced.

[0008] By the way, if there is a portion where the adhesion between the protective film and the drive portion is poor, the deformation of the drive portion at the adhesion poor portion is difficult to be transmitted to the liquid through the protective film. On the other hand, in the head chip of this aspect, an air vent passage is formed in the chip body to connect between the pressure chamber and the outside of the chip body, and the communication between the pressure chamber and the outside of the chip body is blocked by a protective film. According to this configuration, since the air vent passage connects between the pressure chamber and the outside of the chip body, in the protective film forming process, the air remaining in the pressure chamber can be efficiently discharged to the outside of the chip body. As a result, it becomes easier to generate a negative pressure in the pressure chamber, and it becomes easier to draw the protective film into the pressure chamber. As a result, it becomes easier to closely attach the protective film to a desired position (driving portion) in the pressure chamber. In this case, since the deformation of the driving portion is easily transmitted to the liquid through the protective film, a desired generated pressure can be ensured in the pressure chamber, and a decrease in discharge performance accompanying the formation of the protective film can be suppressed.

[0009] (2) In the head chip according to the aspect (1) above, it is preferable that the air vent passage extends so as to straddle a plurality of the pressure chambers. According to this aspect, the air in each pressure chamber can be efficiently discharged through the air vent passage. As a result, it becomes easier to closely attach the protective film to a desired position (driving portion) in the pressure chamber.

[0010] (3) In the head chip according to the aspect (2) above, in the chip body, an air chamber in which no liquid is stored is formed in a portion located between adjacent pressure chambers in the first direction, the protective film is provided so as to straddle each of the pressure chamber and the air chamber in the first direction, and it is preferable that the air vent passage extends so as to straddle between the pressure chamber and the air chamber. According to this aspect, the air in each pressure chamber and air chamber can be efficiently discharged through the air vent passage. As a result, it becomes easier to attract the protective film to the chip body, and the protective film can be provided at a desired position with high precision.

[0011] (4) In the head chip according to the aspect of (3) above, a second drive electrode that generates a potential difference with the first drive electrode is formed on the inner surface of the air chamber, and a through wiring that is formed on the inner surface of a wiring hole that opens into the air chamber in the chip body and is connected to the second drive electrode is preferably formed. According to this aspect, the inside of the pressure chamber is connected to the outside of the chip body even through the air vent passage, the air chamber, and the wiring hole. That is, in the protective film forming process, the air in the pressure chamber and the air chamber can also be discharged through the wiring hole. As a result, while simplifying the air vent passage, the protective film can be provided at a desired position with high precision.

[0012] (5) In the head chip according to any one of the aspects of (1) to (4) above, the pressure chamber extends in the chip body with a second direction intersecting the first direction as the longitudinal direction, and the air vent passage is preferably connected to the central portion of the pressure chamber in the second direction. According to this aspect, in the protective film forming process, air can be exhausted from the central portion in the second direction of the pressure chamber. As a result, air can be effectively discharged over the entire area of the pressure chamber, so that poor adhesion of the protective film can be suppressed.

[0013] (6) In the head chip according to the aspect of (5) above, the pressure chamber opens on an opening surface facing a third direction that intersects the second direction when viewed from the first direction in the chip body, and an injection hole plate that closes the opening of the pressure chamber and has injection holes communicating with the pressure chamber is provided on the opening surface of the chip body, and the air vent passage is preferably provided at a position overlapping the injection holes when viewed from the third direction in the pressure chamber. According to this aspect, since the air vent passage is provided at a position overlapping the injection holes when viewed from the third direction, the portion of the protective film covering the air vent passage elastically displaces in response to the pressure fluctuation in the pressure chamber during liquid injection. Therefore, during liquid injection, the pressure fluctuation in the pressure chamber can be alleviated, and the variation in the generated pressure between the pressure chambers can be easily reduced.

[0014] (7) In the head chip according to any one of the above aspects (1) to (6), the chip body includes an actuator plate having the pressure chamber and the drive unit, and a cover plate superposed on the actuator plate, and it is preferable that the air vent passage is formed in the actuator plate. According to this aspect, by forming the air vent passage in the actuator plate, the degree of freedom in the design of the cover plate can be improved.

[0015] (8) In the head chip according to any one of the above aspects (1) to (7), the chip body includes an actuator plate having the pressure chamber and the drive unit, and a cover plate superposed on the actuator plate, and it is preferable that the air vent passage is formed in the cover plate. According to this aspect, since the air vent passage is formed in the cover plate, the degree of freedom in the design of the actuator plate can be improved. Also, unlike the case where the air vent passage is formed in the actuator plate, it is possible to suppress a reduction in the surface area of the drive unit due to the formation of the air vent passage. Therefore, it becomes possible to provide an air vent passage while maintaining the injection performance.

[0016] (9) In the head chip according to any one of the above aspects (1) to (7), the chip body includes a flow path member in which the pressure chamber is formed, and an actuator plate superposed on the pressure chamber and having the drive unit. A first recess that opens toward the flow path member is formed in the drive unit. A second recess that opens toward the side opposite to the flow path member is formed in a portion of the actuator plate that is located between the pressure chambers adjacent to each other in the first direction. The first drive electrode is formed on the inner surface of the first recess, the protective film is provided following the inner surface of the first recess in the drive unit, and it is preferable that the air vent passage is formed so as to connect the first recess and the second recess. According to this aspect, by forming the first drive electrode following the inner surface of the first recess, the surface area of the first drive electrode can be ensured. As a result, the electric field generated in the actuator plate can be increased, and the pressure generated in the pressure chamber during liquid injection can be improved. Further, by forming the first recess in the actuator plate, the rigidity of the actuator plate in the Z direction can be enhanced. Furthermore, since the second recess is formed in the actuator plate, when the actuator plate deforms, the second recess functions as a relief portion that allows the deformation of the actuator plate. Thereby, it becomes easier to ensure the amount of deformation of the actuator plate. Moreover, since the air vent passage is formed so as to connect the first recess and the second recess, in the protective film forming process, the air inside the first recess can be effectively discharged. Thereby, it becomes easy to adhere the protective film to the inner surface of the first recess.

[0017] (10) The liquid ejection head according to one aspect of the present disclosure preferably includes the head chip according to any one of the above (1) to (9). According to this aspect, since the head chip according to the above aspect is provided, a liquid ejection head having excellent reliability can be provided.

[0018] (11) The liquid ejection recording apparatus according to one aspect of the present disclosure preferably includes the liquid ejection head according to the aspect of the above (10). According to this aspect, since the head chip according to the above aspect is provided, a liquid ejection recording apparatus having excellent reliability can be provided.

[0019] (12)A method for manufacturing a head chip according to an aspect of the present disclosure includes a chip body having a plurality of pressure chambers formed side by side in a first direction and accommodating a liquid, and drive units respectively disposed in portions facing the pressure chambers, a first drive electrode formed on the drive unit, and a sheet-like protective film formed following the drive unit while covering the first drive electrode. The chip body is provided with an air vent passage that connects between the inside of the pressure chamber and the outside of the chip body and blocks communication between the inside of the pressure chamber and the outside of the chip body on the drive unit by the protective film. The method for manufacturing a head chip is characterized in that a protective film forming step is provided in which a negative pressure is applied to the inside of the pressure chamber through the air vent passage to the space on the side opposite to the pressure chamber with respect to the protective film, thereby bringing the protective film into close contact with the drive unit.

Advantages of the Invention

[0020] According to an aspect of the present disclosure, it is possible to protect the first drive wiring while improving manufacturing efficiency and reducing costs.

Brief Description of the Drawings

[0021]

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Best Mode for Carrying Out the Invention

[0022] Hereinafter, embodiments according to the present disclosure will be described with reference to the drawings. In the embodiments and modifications described below, corresponding components may be denoted by the same reference numerals and the description thereof may be omitted. In the following description, expressions indicating relative or absolute arrangements such as "parallel", "orthogonal", "center", "coaxial", etc. not only strictly represent such arrangements, but also include states where there are tolerances or relative displacements with angles and distances that provide the same function. In the following embodiments, an inkjet printer (hereinafter simply referred to as a printer) that performs recording on a recording medium using ink (liquid) will be described as an example. In the drawings used in the following description, the scales of the respective members are appropriately changed in order to make the respective members recognizable in size.

[0023] (First Embodiment) [Printer 1] FIG. 1 is a schematic configuration diagram of the printer 1. The printer (liquid ejection recording apparatus) 1 shown in FIG. 1 includes a pair of conveyance mechanisms 2 and 3, an ink tank 4, an inkjet head (liquid ejection head) 5, an ink circulation mechanism 6, and a scanning mechanism 7.

[0024] In the following description, the orthogonal coordinate system of X, Y, and Z will be used for explanation as necessary. In this case, the X direction coincides with the conveyance direction (sub-scanning direction) of the recording medium P (for example, paper or the like). The Y direction coincides with the scanning direction (main scanning direction) of the scanning mechanism 7. The Z direction indicates the height direction (gravity direction) orthogonal to the X direction and the Y direction. In the following description, among the X direction, the Y direction, and the Z direction, the side of the arrow in the figure is defined as the plus (+) side, and the side opposite to the arrow is defined as the minus (-) side for explanation. In this specification, the +Z side corresponds to the upper side in the gravity direction, and the -Z side corresponds to the lower side in the gravity direction.

[0025] The conveyance mechanisms 2 and 3 convey the recording medium P to the +X side. The conveyance mechanisms 2 and 3 each include, for example, a pair of rollers 11 and 12 extending in the Y direction. The ink tank 4 separately stores, for example, four colors of ink: yellow, magenta, cyan, and black. Each inkjet head 5 is configured to be able to eject the four colors of ink, namely yellow, magenta, cyan, and black, according to the connected ink tank 4.

[0026] FIG. 2 is a schematic configuration diagram of the inkjet head 5 and the ink circulation mechanism 6. As shown in FIGS. 1 and 2, the ink circulation mechanism 6 circulates ink between the ink tank 4 and the inkjet head 5. Specifically, the ink circulation mechanism 6 includes a circulation flow path 23 having an ink supply pipe 21 and an ink discharge pipe 22, a pressure pump 24 connected to the ink supply pipe 21, and a suction pump 25 connected to the ink discharge pipe 22.

[0027] The pressure pump 24 pressurizes the inside of the ink supply pipe 21 and sends ink to the inkjet head 5 through the ink supply pipe 21. As a result, the side of the ink supply pipe 21 with respect to the inkjet head 5 is at a positive pressure. The suction pump 25 depressurizes the inside of the ink discharge pipe 22 and sucks ink from the inkjet head 5 through the ink discharge pipe 22. As a result, the side of the ink discharge pipe 22 with respect to the inkjet head 5 is at a negative pressure. The ink can circulate between the inkjet head 5 and the ink tank 4 through the circulation flow path 23 by driving the pressure pump 24 and the suction pump 25.

[0028] As shown in FIG. 1, the scanning mechanism 7 reciprocally scans the inkjet head 5 in the Y direction. The scanning mechanism 7 includes a guide rail 28 extending in the Y direction and a carriage 29 movably supported on the guide rail 28.

[0029] <Inkjet head 5> The inkjet head 5 is mounted on the carriage 29. In the illustrated example, a plurality of inkjet heads 5 are mounted side by side in the Y direction on one carriage 29. It includes a discharge unit 30 (see FIG. 2), an ink supply section (not shown) that connects between the ink circulation mechanism 6 and the discharge unit 30, and a control section (not shown) that applies a drive voltage to the discharge unit 30.

[0030] [Discharge unit 30] FIG. 3 is an exploded perspective view of the discharge unit 30. The discharge unit 30 shown in FIG. 3 is a so-called circulation type side shoot type discharge unit 30 that circulates ink with the ink tank 4 and discharges ink from the central portion in the extending direction (Y direction) of the discharge channel 51 described later. The discharge unit 30 includes a flow path plate 31, a head chip 32, a flow path cover 34, and a flexible printed circuit board 35 (see FIG. 7).

[0031] [Flow path plate 31] The flow path plate 31 is formed in a rectangular frame shape with the Z direction as the thickness direction and the X direction as the longitudinal direction. The flow path plate 31 partitions a chip accommodation portion 31a, an inlet common flow path 31b, and an outlet common flow path 31c. The chip accommodation portion 31a, the inlet common flow path 31b, and the outlet common flow path 31c penetrate the flow path plate 31 in the Z direction in a state of being in communication with each other.

[0032] The chip accommodation portion 31a is formed at the central portion in the Y direction of the flow path plate 31. The chip accommodation portion 31a is formed in a long hole shape with the X direction as the longitudinal direction in plan view. The inlet common flow path 31b is formed in a portion of the flow path plate 31 that is located on the +Y side with respect to the chip accommodation portion 31a. The inlet common flow path 31b is formed in a long hole shape with the X direction as the longitudinal direction, similar to the chip accommodation portion 31a. The +X side end portion in the inlet common flow path 31b protrudes in the X direction with respect to the chip accommodation portion 31a. The common outlet flow path 31c is formed in a portion of the flow path plate 31 that is located on the -Y side with respect to the chip accommodation portion 31a. The common outlet flow path 31c is formed in a long hole shape with the X direction as the longitudinal direction, similar to the common inlet flow path 31b. The -X side end portion of the common outlet flow path 31c protrudes in the X direction with respect to the chip accommodation portion 31a.

[0033] <Head chip 32> FIG. 4 is an exploded perspective view of the head chip 32. FIG. 5 is a bottom view of the actuator plate 41. FIG. 6 is a plan view of the actuator plate 41. FIG. 7 is a cross-sectional view of the discharge unit 30 corresponding to line VII-VII in FIG. 5. FIG. 8 is a cross-sectional view of the discharge unit 30 corresponding to line VIII-VIII in FIG. 5. As shown in FIGS. 4 to 8, the head chip 32 includes a drive head 37 and a nozzle plate 44.

[0034] <Drive head 37> The drive head 37 is formed in a block shape with the Z direction as the thickness direction and the X direction as the longitudinal direction. The drive head 37 is fitted into the chip accommodation portion 31a. Specifically, the thickness of the drive head 37 in the Z direction is the same as that of the flow path plate 31, and the planar shape is formed to be the same as that of the chip accommodation portion 31a. In this case, the +X side end face of the drive head 37 is fixed to the surface of the inner face of the chip accommodation portion 31a that faces the -X side by adhesion or the like, and the -X side end face is fixed to the surface of the inner face of the chip accommodation portion 31a that faces the +X side by adhesion or the like. Therefore, in the flow path plate 31, the common inlet flow path 31b and the common outlet flow path 31c are blocked by the drive head 37. In the first embodiment, the back surface of the drive head 37 is arranged flush with the back surface of the flow path plate 31. On the other hand, the front surface of the drive head 37 is arranged flush with the front surface of the flow path plate 31.

[0035] The drive head 37 includes an actuator plate 41, a cover plate 42, and a protective film 43. In the following description, in the Z direction, the direction from the actuator plate 41 toward the cover plate 42 (+Z side) may be described as the front side, and the direction from the cover plate 42 toward the actuator plate 41 (−Z side) may be described as the back side. In the first embodiment, the actuator plate 41 and the cover plate 42 constitute the chip body 40.

[0036] <Actuator plate 41> The actuator plate 41 is formed of a piezoelectric material such as PZT (lead zirconate titanate). The actuator plate 41 is, for example, a so-called Chevron substrate formed by laminating two piezoelectric plates with different polarization directions in the Z direction. However, the actuator plate 41 may be a so-called monopole substrate in which the polarization direction is unidirectional throughout the Z direction.

[0037] A channel row 46 is formed in the actuator plate 41. The channel row 46 has a discharge channel 51 filled with ink and a non-discharge channel 52 not filled with ink. Each of the channels 51 and 52 is alternately arranged at intervals in the X direction in the actuator plate 41. That is, in the head chip 32 of the first embodiment, the discharge channel 51 serving as a pressure chamber and the non-discharge channel 52 serving as an air chamber are formed in the actuator plate 41 itself. In the first embodiment, a configuration in which the channel extending direction coincides with the Y direction will be described, but the channel extending direction may intersect the Y direction.

[0038] As shown in FIGS. 5 to 7, the discharge channel 51 penetrates the actuator plate 41 in the Z direction and linearly extends in the Y direction over the entire length of the actuator plate 41. The +Y side opening in each discharge channel 51 communicates with the inlet common flow path 31b. On the other hand, the -Y side opening in each discharge channel 51 communicates with the outlet common flow path 31c. That is, the inlet common flow path 31b and the outlet common flow path 31c communicate with each other through each discharge channel 51.

[0039] As shown in FIGS. 4 and 8, the non-discharge channel 52 linearly extends in the Y direction in the portion of the actuator plate 41 located between adjacent discharge channels 51. The portions of the actuator plate 41 located between adjacent discharge channels 51 and non-discharge channels 52 respectively constitute drive walls (drive portions) 53 facing the discharge channels 51. Therefore, the channels 51 and 52 are surrounded on both sides in the X direction by a pair of drive walls 53.

[0040] Both ends in the Y direction of the non-discharge channel 52 terminate within the actuator plate 41. Therefore, the non-discharge channel 52 does not communicate with the inlet common flow path 31b and the outlet common flow path 31c. The non-discharge channel 52 is formed in a downwardly convex arc shape when viewed from the X direction. That is, the dimension in the Y direction of the non-discharge channel 52 gradually decreases from the +Z side to the -Z side. Specifically, the non-discharge channel 52 includes a through portion 52a located at the central portion in the Y direction and upwardly inclined portions 52b continuous with both sides in the Y direction with respect to the through portion 52a.

[0041] The through portion 52a penetrates the actuator plate 41 in the Z direction. The rising portion 52b opens on the surface of the actuator plate 41, and the dimension in the Z direction gradually decreases as it moves away from the through-hole portion 52a in the Y direction. That is, the +Z side opening of the non-discharge channel 52 is formed by the through-hole portion 52a and the rising portion 52b. On the other hand, the -Z side opening of the non-discharge channel 52 is formed by the through-hole portion 52a. The bottom surface of the rising portion 52b is formed in an arc shape with a uniform radius of curvature. At the center portion in the X direction on the bottom surface of each rising portion 52b, a dividing groove 52c is formed. The dividing groove 52c is recessed over the entire length in the Y direction with respect to the bottom surface of each rising portion 52b. The dividing groove 52c extends concentrically with the rising portion 52b in a side view.

[0042] In the following description, among the actuator plate 41, the portion located between adjacent discharge channels 51 and located on the +Y side with respect to the non-discharge channel 52 is referred to as the first tail portion 41a. Among the actuator plate 41, the portion located between adjacent discharge channels 51 and located on the -Y side with respect to the non-discharge channel 52 is referred to as the second tail portion 41b.

[0043] <Cover plate 42> As shown in FIGS. 4, 7, and 8, the cover plate 42 is used for connecting the head chip 32 and the flexible printed circuit board (external wiring) 35. In the illustrated example, the dimension of the cover plate 42 in the Z direction is larger than that of the actuator plate 41. The cover plate 42 is formed of a piezoelectric material such as PZT, glass, silicon, a resin material, or other non-conductive materials. Further, as the cover plate 42, a conductive material such as a metal material may be used as a base, and a non-conductive material may be coated on the outer surface of the base.

[0044] The cover plate 42 has an outer shape in a plan view equivalent to that of the actuator plate 41 and is superposed on the entire surface of the actuator plate 41. The cover plate 42 is joined to the surface of the actuator plate 41 by an adhesive or the like.

[0045] FIG. 9 is a bottom view of the cover plate 42. FIG. 10 is a plan view of the cover plate 42. As shown in FIGS. 4, 8 to 10, the cover plate 42 is formed with a common through hole 42a, a first individual hole 42b, and a second individual hole 42c. Each of the holes 42a to 42c is formed in a tapered shape in which the inner diameter gradually decreases from the +Z side toward the -Z side. However, the inner diameters of the holes 42a to 42c may be uniform throughout the Z direction. Note that the planar view shapes of the holes 42a to 42c can be appropriately changed, such as rectangular, circular, oval, polygonal, etc. The common through hole 42a, the first individual hole 42b, and the second individual hole 42c may have the same shape or different shapes from each other.

[0046] The common through hole 42a penetrates in the Z direction through a portion of the cover plate 42 that overlaps with the second tail portion 41b in a plan view. That is, the common through hole 42a is provided between adjacent discharge channels 51 in the X direction.

[0047] The first individual hole 42b and the second individual hole 42c are provided on the +Y side with respect to the non-discharge channel 52. Specifically, the first individual hole 42b penetrates in the Z direction through a portion of the cover plate 42 that overlaps with the first tail portion 41a in a plan view and is located on the +X side with respect to the dividing groove 52c. The second individual hole 42c penetrates in the Z direction through a portion of the cover plate 42 that overlaps with the first tail portion 41a in a plan view and is located on the -X side with respect to the dividing groove 52c. That is, the first individual hole 42b and the second individual hole 42c are provided for each non-discharge channel 52 in a portion of the cover plate 42 that overlaps with the first tail portion 41a in a plan view.

[0048] FIG. 11 is a cross-sectional view corresponding to the line XI-XI in FIG. 6. As shown in FIG. 11, each of the individual holes 42b, 42c overlaps with a part of the non-discharge channel 52 in a plan view. Therefore, the inside of the non-discharge channel 52 communicates with the outside of the chip body 40 through the individual holes 42b, 42c.

[0049] Next, various wirings formed on the head chip 32 will be described. As shown in FIGS. 4 to 8, a common wiring 61 and individual wirings 62 as drive wirings are formed on the actuator plate 41.

[0050] As shown in FIGS. 5 to 7, the common wiring 61 includes a common electrode 65, a common extraction wiring 66, and a common back surface wiring 67. The common electrodes 65 are respectively formed on the inner surfaces of the discharge channel 51 that face each other in the X direction. Each common electrode 65 is formed over the entire area in the Y direction and Z direction on the inner surface of the discharge channel 51. As shown in FIG. 6, the common extraction wiring 66 extends in a strip shape in the X direction on the surface of the second tail portion 41b. The common extraction wiring 66 connects the common electrodes 65 that face each other in the X direction with the non-discharge channel 52 interposed therebetween at the +Z side opening edges of the discharge channels 51 that face each other in the X direction with the non-discharge channel 52 interposed therebetween. As shown in FIG. 5, the common back surface wiring 67 extends in the X direction on the back surfaces of the respective tail portions 41a and 41b. Each common back surface wiring 67 connects the common electrodes 65 that face each other in the X direction with the non-discharge channel 52 interposed therebetween at the -Z side opening edges of the discharge channels 51 that face each other in the X direction with the non-discharge channel 52 interposed therebetween.

[0051] As shown in FIGS. 5, 6, and 8, the individual wiring 62 includes an individual electrode 68 and an individual extraction wiring 69. The individual electrode 68 includes a first individual electrode 68a formed on the inner surface of the non-discharge channel 52 that faces at least the -X side and a second individual electrode 68b formed on the inner surface of the non-discharge channel 52 that faces at least the +X side. Each individual electrode 68 is formed over the entire area in the Y direction on the inner surface of the non-discharge channel 52 and is also formed on the bottom surface of the rising portion 52b. The first individual electrode 68a and the second individual electrode 68b formed in the same non-discharge channel 52 are separated by a separation groove 52c.

[0052] FIG. 12 is a cross-sectional view corresponding to line XII-XII in FIG. 6. As shown in FIGS. 8 and 12, the individual electrode 68 is formed over the entire inner surface of the non-discharge channel 52 in the Z direction, excluding the -Z side end portion. That is, the -Z side edge of the individual electrode 68 is retracted to the +Z side with respect to the -Z side opening edge of the non-discharge channel 52. Among the inner surfaces of the non-discharge channel 52, the -Z side end portion constitutes a non-formation region Q where the individual electrode 68 is not formed. The dimension of the non-formation region Q in the Z direction is preferably 2% or more and 10% or less with respect to the dimension of the non-discharge channel 52 in the Z direction.

[0053] As shown in FIG. 6, the individual extraction wiring 69 includes a first individual extraction wiring 69a and a second individual extraction wiring 69b. The first individual extraction wiring 69a is formed on the surface of the first tail portion 41a at a portion located on the +X side with respect to the division groove 52c. The first individual extraction wiring 69a is connected to the first individual electrode 68a at the +Z side opening edge of the non-discharge channel 52. The second individual extraction wiring 69b is formed on the surface of the first tail portion 41a at a portion located on the -X side with respect to the division groove 52c. The second individual extraction wiring 69b is connected to the second individual electrode 68b at the +Z side opening edge of the non-discharge channel 52.

[0054] As shown in FIGS. 4, 9, and 10, a common connection wiring 71 and an individual connection wiring 72 are formed on the cover plate 42 as connection wirings. The common connection wiring 71 includes a common through wiring 75 and a common pad 76. The common through wiring 75 is formed on the inner surface of the common through hole 42a. Specifically, the common through wiring 75 is formed over the entire inner circumference of the common through hole 42a and is formed over the entire Z direction. The common through wiring 75 is connected to the common extraction wiring 66 at the -Z side opening edge of the common through hole 42a.

[0055] The common pad 76 is formed on the surface of the cover plate 42. The common pad 76 is formed at a portion of the surface of the cover plate 42 that is located between adjacent common through-wiring 75. The common pad 76 is connected to the adjacent common through-wiring 75 at the +Z side opening edge of the common through-hole 42a, and protrudes toward the -Y side with respect to the common through-hole 42a. That is, the common pad 76 is arranged alternately with the common through-wiring 75 on the surface of the cover plate 42.

[0056] The individual connection wiring 72 includes a first individual through-wiring 81, a second individual through-wiring 82, and an individual pad 83. The first individual through-wiring 81 is formed on the inner surface of the first individual hole 42b. Specifically, the first individual through-wiring 81 is formed along the entire circumference of the inner surface of the first individual hole 42b and extends throughout the Z direction. The first individual through-wiring 81 is connected to the first individual extraction wiring 69a at the -Z side opening edge of the first individual hole 42b. The second individual through-wiring 82 is formed on the inner surface of the second individual hole 42c. Specifically, the second individual through-wiring 82 is formed along the entire circumference of the inner surface of the second individual hole 42c and extends throughout the Z direction. The second individual through-wiring 82 is connected to the second individual extraction wiring 69b at the -Z side opening edge of the second individual hole 42c.

[0057] The individual pads 83 are formed in a portion of the surface of the cover plate 42 that is located on the -Y side with respect to the individual holes 42b and 42c. Specifically, the individual pads 83 are respectively connected between a first individual through-wiring 81 located on the -X side with respect to one discharge channel 51 and a second individual through-wiring 82 located on the +X side with respect to one discharge channel 51. Specifically, the -X side end portion of the individual pad 83 is connected to the first individual through-wiring 81 at the +Z side opening edge of the first individual hole 42b. The +X side end portion of the individual pad 83 is connected to the second individual through-wiring 82 at the +Z side opening edge of the second individual hole 42c. Thereby, the individual electrodes 68a and 68b facing each other in the X direction with one discharge channel 51 interposed therebetween (the second individual electrodes 68b of the non-discharge channels 52 located on the +X side with respect to one discharge channel 51 and the first individual electrodes 68a of the non-discharge channels 52 located on the -X side with respect to one discharge channel 51) are connected. In the illustrated example, the common pad 76 and the individual pad 83 are provided at the same position in the X direction.

[0058] <Protective film 43> As shown in FIGS. 7, 8, 11, and 12, the protective film 43 is integrally formed in a sheet shape (film shape) and is adhered to the outer surface of the chip body 40 via an adhesive 45 (see FIG. 12) by a so-called skin pack. Specifically, the protective film 43 includes a discharge channel covering portion 43a, a back surface covering portion 43b, a non-discharge channel covering portion 43c, and a side surface covering portion 43d.

[0059] The discharge channel covering portion 43a is provided in the discharge channel 51 in a state of being folded back in the Z direction when viewed from the Y direction. The discharge channel covering portion 43a covers the entire inner surface of the discharge channel 51 in a state of being in direct or indirect contact with the inner surface of the discharge channel 51. That is, the top surface of the discharge channel 51 (the portion of the back surface of the cover plate 42 that is exposed in the discharge channel 51) is in direct contact with the discharge channel covering portion 43a. The inner side surface of the discharge channel 51 (the portion of the drive wall 53 that is exposed in the discharge channel 51) is in indirect contact with the discharge channel covering portion 43a via the common electrode 65. Thereby, the discharge channel covering portion 43a continuously covers the top surface and the inner side surface of the discharge channel 51. In FIG. 7, a part of the laminated structure on the drive wall 53 is shown broken. Specifically, the inside of the broken line shows the discharge channel covering portion 43a formed on the outermost layer, and the outside of the broken line shows the common electrode 65 covered by the discharge channel covering portion 43.

[0060] The back surface covering portion 43b covers the entire portion of the back surface of the actuator plate 41 where the channels 51 and 52 are not open. That is, the back surface covering portion 43b covers the common back surface wiring 67 from the -Z side. The back surface covering portion 43b is in direct or indirect contact with the portion of the back surface of the actuator plate 41 where the channels 51 and 52 are not open. The back surface covering portion 43b is integrally continuous with the discharge channel covering portion 43a at the -Z side opening edge of the discharge channel 51.

[0061] As shown in FIGS. 8 and 12, the non-ejection channel covering portion 43c closes the -Z side opening of the non-ejection channel 52. Specifically, the non-ejection channel covering portion 43c is provided so as to straddle the entire -Z side opening of the non-ejection channel 52. The outer peripheral edge of the non-ejection channel covering portion 43c is integrally continuous with the back surface covering portion 43b. Note that a part of the non-ejection channel covering portion 43c may enter the non-ejection channel 52 through the -Z side opening of the non-ejection channel 52. Even if the non-ejection channel covering portion 43c enters the non-ejection channel 52, it is preferable that the non-ejection channel covering portion 43c does not contact the individual electrode 68 (is located within the range of the non-formation region Q in the Z direction).

[0062] As shown in FIGS. 7 and 8, the side surface covering portion 43d is integrally continuous with the outer peripheral edges of the ejection channel covering portion 43a and the back surface covering portion 43b. The side surface covering portion 43d covers the side surface of the chip body 40 (the surface facing the X direction or the Y direction). Specifically, the side surface covering portion 43d covers the entire circumference of the side surface of the chip body 40 except for the +Y side opening and the -Y side opening of the ejection channel 51. The side surface covering portion 43d is integrally continuous with the outer peripheral edge of the back surface covering portion 43b at the -Z side edge of the side surface of the chip body 40. The side surface covering portion 43d is integrally continuous with the ejection channel covering portion 43a at the +Y side opening edge and the -Y side opening edge of the ejection channel 51. Note that the side surface covering portion 43d is preferably formed to extend in the X direction on at least the side surface of the chip body 40 facing the Y direction. However, the side surface covering portion 43d is not an essential configuration.

[0063] As shown in FIG. 12, the protective film 43 is adhered to the chip body 40 while being stretched in the protective film forming step S50 described later, so that it is thinner than the original thickness of the protective film 43 (for example, 30 μm to 300 μm). In particular, since the discharge channel covering portion 43a is deformed in a state where the displacement of the protective film 43 is restricted by the back surface of the actuator plate 41, it has the minimum thickness in the protective film 43. In this case, the thickness of the discharge channel covering portion 43a is, for example, 10 μm to 60 μm, and the thickness of portions other than the discharge channel covering portion 43a (the back surface covering portion 43b, the non-discharge channel covering portion 43c, and the side surface covering portion 43d) is about 10 μm to 200 μm. Furthermore, the width of the discharge channel 51 in the X direction is preferably 2 times or more and 20 times or less the original thickness of the protective film 43. On the other hand, the width of the non-discharge channel 52 in the X direction is preferably less than 2 times the original thickness of the protective film 43, and more preferably less than 2 times the minimum thickness. Further, the width of the discharge channel 51 in the X direction is preferably 2 times or more the width of the non-discharge channel 52 in the X direction. In this case, the width of the discharge channel 51 in the X direction is set to about 100 μm, and the width of the non-discharge channel 52 in the X direction is set to about 40 μm.

[0064] The protective film 43 of the first embodiment preferably uses a thermoplastic resin material that is excellent in insulation and ink resistance and has a softening point (Vicat softening temperature conforming to JIS K7206) of 120° C. or lower, preferably 100° C. or lower. In the first embodiment, the protective film 43 is composed of a single-layer film or a laminated film such as an ionomer (softening point of 57° C. to 80° C.) or low-density polyethylene (softening point of 85° C. to 97° C.). When a laminated film is adopted for the protective film 43, it is preferable to use a material excellent in flexibility (for example, ionomer, etc.) as the base layer and a material excellent in ink resistance (for example, low-density polyethylene, etc.) as the upper layer.

[0065] As shown in FIGS. 7 to 9, an air vent passage 70 is formed in the cover plate 42 described above. The air vent passage 70 is a groove that opens on the back surface of the cover plate 42 and extends along the X direction. The air vent passage 70 extends over the entire length of the cover plate 42 in the X direction. Therefore, the air vent passage 70 opens on the side surface of the cover plate 42 facing the X direction. The air vent passage 70 is formed at a position overlapping the central portion in the Y direction in each of the channels 51 and 52 when viewed from the Z direction. The central portion in the Y direction is, for example, a region of 1 / 3 located at the center with respect to the entire length of the discharge channel 51. In the illustrated example, the air vent passage 70 is formed at a position including the center in the Y direction in each of the channels 51 and 52. However, the air vent passage 70 may be formed in a region other than the central portion in the Y direction in each of the channels 51 and 52 when viewed from the Z direction.

[0066] The air vent passage 70 crosses between the adjacent discharge channel 51 and the non-discharge channel 52 in the X direction. Therefore, the air vent passage 70 connects each of the channels 51 and 52 to the outside of the chip body 40. Then, of the air vent passage 70, the portion overlapping the discharge channel 51 when viewed from the Z direction is covered by the discharge channel covering portion 43a, so that the communication between the inside of the discharge channel 51 through the air vent passage 70 and the outside of the chip body 40 is blocked. Therefore, when the air vent passage 70 is blocked by the discharge channel covering portion 43a, the communication between the inside of the discharge channel 51 and the inside of the non-discharge channel 52 through the air vent passage 70 is also blocked. On the other hand, of the air vent passage 70, the portion overlapping the non-discharge channel 52 when viewed from the Z direction allows the inside of the non-discharge channel 52 and the outside of the chip body 40 to communicate through the air vent passage 70. In the first embodiment, connecting the discharge channel 51 to the outside of the chip body 40 means that, in a state where the communication between the inside of the discharge channel 51 and the inside of the air vent passage 70 is blocked, it is indirectly connected to the discharge channel 51, for example, with the discharge channel covering portion 43a interposed therebetween.

[0067] Incidentally, the position and number of the air vent passages 70 can be changed as appropriate. In the first embodiment, the configuration in which the air vent passages 70 are formed linearly has been described, but the present invention is not limited to this configuration. The air vent passages 70 may be formed in a curved shape or the like. Further, as long as the air vent passages 70 are configured to connect between the channels 51 and 52, they may terminate within the cover plate 42 (they do not have to open on the side surface of the cover plate 42).

[0068] <Nozzle plate 44> As shown in FIGS. 4 and 7, the nozzle plate 44 closes the -Z side openings of the discharge channel 51 and the non-discharge channel 52. The nozzle plate 44 collectively covers the back surface of the actuator plate 41 and the back surface of the flow path plate 31. The nozzle plate 44 is joined to the back surface covering portion 43b via an adhesive to cover the back surface of the actuator plate 41, and is joined to the back surface of the flow path plate 31 via an adhesive or the like to cover the back surface of the flow path plate 31. Thereby, the nozzle plate 44 collectively closes the -Z side openings of the inlet common flow path 31b and the outlet common flow path 31c, and the -Z side openings of the respective channels 51 and 52. The nozzle plate 44 is formed of a resin material (such as polyimide). However, the nozzle plate 44 may have a single-layer structure or a laminated structure made of a resin material (such as polyimide), glass, silicon, etc., in addition to a metal material (such as SUS or Ni-Pd).

[0069] As shown in FIGS. 7 and 12, the nozzle plate 44 is formed with a plurality of nozzle holes 44a penetrating the nozzle plate 44 in the Z direction. The nozzle holes 44a are formed, for example, in a tapered shape with a gradually decreasing inner diameter from the +Z side toward the -Z side. The nozzle holes 44a are arranged at intervals in the X direction. Each nozzle hole 44a communicates separately with a corresponding discharge channel 51. In the illustrated example, the +Z side openings of the respective nozzle holes 44a overlap, as viewed in the Z direction, with the portion of the air vent passage 70 exposed in the discharge channel 51 at the central portion in the Y direction in the discharge channel 51. However, the nozzle holes 44a may be provided at positions shifted in the Y direction with respect to the air vent passage 70.

[0070] <Flow path cover 34> As shown in FIGS. 3 and 7, the flow path cover 34 sandwiches the flow path plate 31 and the head chip 32 between itself and the nozzle plate 44. The flow path cover 34 includes a cover base 95, an inlet port 96, and an outlet port 97. The cover base 95 is a rectangular plate-shaped member having an outer shape in plan view equivalent to that of the flow path plate 31. The cover base 95 is superimposed on the surfaces of the flow path plate 31 and the head chip 32, respectively. The cover base 95 is joined to the surfaces of the flow path plate 31 and the head chip 32 via an adhesive or the like and is fastened to the flow path plate 31 with screws or the like. Thereby, the cover base 95 closes the upper end openings of the inlet common flow path 31b and the outlet common flow path 31c.

[0071] Among the cover base 95, a slit 95a is formed at the central portion in the Y direction. The slit 95a penetrates the cover base 95 in the Z direction and extends in the X direction. The slit 95a is formed at a position that overlaps with the central portion (excluding the outer peripheral portion) of the head chip 32 in a plan view. That is, the dimension of the slit 95a in the Y direction is smaller than the dimension of the head chip 32 in the Y direction. The dimension of the slit 95a in the X direction is smaller than the dimension of the head chip 32 in the X direction. The slit 95a exposes at least a part of each of the pads 76, 83 on the surface of the cover plate 42.

[0072] The inlet port 96 is located at the +Y side and +X side end of the cover base 95. The inlet port 96 protrudes from the cover base 95 to the +Z side. The inlet port 96 communicates with the inlet common flow path 31b through the +X side end portion (the portion protruding with respect to the chip accommodating portion 31a) in the inlet common flow path 31b. That is, the ink flowing through the ink supply pipe 21 is supplied to the inlet common flow path 31b through the inlet port 96. The outlet port 97 is located at the -Y side and -X side end of the cover base 95. The outlet port 97 protrudes from the cover base 95 to the +Z side. The outlet port 97 communicates with the outlet common flow path 31c through the -X side end portion (the portion protruding with respect to the chip accommodating portion 31a) in the outlet common flow path 31c. That is, the ink flowing through the outlet common flow path 31c is discharged to the ink discharge pipe 22 through the outlet port 97.

[0073] As shown in FIG. 7, the flexible printed circuit board 35 is pressure-bonded to the surface of the cover plate 42 through the slit 95a. The flexible printed circuit board 35 is connected to each of the pads 76, 83 on the surface of the cover plate 42. After being drawn out to the +Z side, the flexible printed circuit board 35 is connected to the control unit.

[0074] [Operation Method of Printer 1] Next, the case of recording characters, figures, etc. on the recording medium P using the printer 1 configured as described above will be described below. As an initial state, it is assumed that the four ink tanks 4 shown in FIG. 1 are each sufficiently filled with ink of a different color. Also, the ink in the ink tank 4 is in a state of being filled into the inkjet head 5 via the ink circulation mechanism 6.

[0075] In such an initial state, when the printer 1 is operated, the recording medium P is conveyed in the +X direction while being sandwiched between the rollers 11 and 12 of the conveying mechanisms 2 and 3. At the same time, the carriage 29 moves in the Y direction, so that the inkjet head 5 mounted on the carriage 29 reciprocates in the Y direction. While the inkjet head 5 is reciprocating, ink is appropriately ejected from each inkjet head 5 onto the recording medium P. Thereby, recording of characters, images, etc. can be performed on the recording medium P.

[0076] Here, the movement of each inkjet head 5 will be described in detail below. In the case of the circulation type side shoot type inkjet head 5 as in the first embodiment, first, the pressurizing pump 24 and the suction pump 25 shown in FIG. 2 are operated to circulate the ink in the circulation flow path 23. In this case, the ink flowing through the ink supply pipe 21 is supplied into the inlet common flow path 31b through the inlet port 96. The ink supplied to the inlet common flow path 31b is distributed to each discharge channel 51 through the +Y side opening in each discharge channel 51, and then flows through each discharge channel 51 in the -Y side direction. Thereafter, the ink is discharged into the outlet common flow path 31c through the -Y side opening of each discharge channel 51. The ink discharged into the outlet common flow path 31c flows into the ink discharge pipe 22 through the outlet port 97 and is thereby returned to the ink tank 4. Thereby, the ink can be circulated between the inkjet head 5 and the ink tank 4.

[0077] Then, when the reciprocating movement of the inkjet head 5 is started by the movement of the carriage 29 (see FIG. 1), a driving voltage is applied between the common electrode 65 and the individual electrode 68 through the flexible printed circuit board 35. At this time, the driving voltage is applied with the common electrode 65 as the reference potential GND and the individual electrode 68 as the driving potential Vdd. Then, a potential difference is generated in the X direction between the common electrode 65 and the individual electrode 68 facing each other across the driving wall 53. Due to the potential difference generated in the X direction, an electric field is generated in the actuator plate 41 in a direction orthogonal to the polarization direction (Z direction). As a result, the actuator plate 41 undergoes thickness-shear deformation in the Z direction in the shear mode. Specifically, thickness-shear deformation occurs in the two driving walls 53 that define the discharge channel 51, and these two driving walls 53 are deformed so as to protrude toward the non-discharge channel 52 side. That is, since the actuator plate 41 of the first embodiment is formed by laminating two piezoelectric substrates polarized in the thickness direction (Z direction), by applying a driving voltage, it bends and deforms in a V shape centered on the intermediate position in the Z direction of the driving wall 53. As a result, the discharge channel 51 deforms as if it swells.

[0078] Thereafter, when the driving voltage is set to zero, the actuator plate 41 is restored, and the volume in the discharge channel 51 tries to return to its original state. In the process of the actuator plate 41 being restored, the pressure in the discharge channel 51 increases, and the ink in the discharge channel 51 is discharged to the outside through the nozzle hole 44a. When the ink discharged to the outside lands on the recording medium P, print information is recorded on the recording medium P.

[0079] <Manufacturing method of the discharge unit 30> Next, the manufacturing method of the discharge unit 30 described above will be explained. FIG. 13 is a flowchart for explaining the manufacturing method of the discharge unit 30. FIGS. 14 to 25 are process diagrams for explaining the manufacturing method of the discharge unit 30. As shown in FIG. 13, the manufacturing method of the ejection unit 30 includes an actuator processing step S10, a cover plate processing step S20, a grinding step S30, an electrode removal step S40, a protective film forming step S50, an assembly step S60, and a nozzle joining step S70. Among the manufacturing steps of the ejection unit 30, the actuator processing step S10, the cover plate processing step S20, the grinding step S30, the electrode removal step S40, the protective film forming step S50, and the nozzle joining step S70 correspond to the manufacturing steps of the head chip 32. In the following description, for convenience, the case of manufacturing the head chip 32 at the chip level will be described as an example.

[0080] As shown in FIG. 14, in the actuator processing step S10, first, in the actuator plate 41, the formation regions of the ejection channel 51 and the non-ejection channel 52 are processed by the first dicing machine 110 (channel formation step). The first dicing machine 110 is formed in a disc shape when viewed from the X direction. In the channel formation step, the formation region of the non-ejection channel 52 reduces the traveling amount of the first dicing machine 110 in the Y direction with respect to the formation region of the ejection channel 51. Thereby, when viewed from the X direction, the bottom surface of the non-ejection channel 52 is formed in a convex arc shape facing the -Z side (see FIG. 19), and the bottom surface of the ejection channel 51 is formed in a straight line shape. Also, the entering amount of the first dicing machine 110 in the Z direction is set to be larger than the processed dimension of the actuator plate 41 and smaller than the unprocessed dimension of the actuator plate 41. That is, after the channel formation step, both the ejection channel 51 and the non-ejection channel 52 do not penetrate the actuator plate 41.

[0081] Next, as shown in FIG. 15, a common wiring 61 and individual wirings 62 as drive wirings are formed on the actuator plate 41 (first wiring forming step). Specifically, by performing oblique vapor deposition or the like from the surface side of the actuator plate 41, an electrode material (for example, TiAu or the like) is formed into a film. As a result, a common electrode 65 is formed on the inner surface of each discharge channel 51, and an individual electrode 68 is formed on the inner surface of the non-discharge channel 52. In addition, a common extraction wiring 66 and an individual extraction wiring 69 are formed on the surface of the actuator plate 41. In the first wiring forming step, the electrode material can be formed by sputtering, ion plating, plating, or the like in addition to oblique vapor deposition.

[0082] Next, as shown in FIG. 16, the individual electrodes 68a and 68b formed in one non-discharge channel 52 are divided (division step). Specifically, the second dicing machine 115 is made to enter the central portion in the X direction of the non-discharge channel 52. At this time, the dimension in the X direction of the second dicing machine 115 is smaller than the dimension in the X direction of the non-discharge channel 52. Therefore, the individual electrodes 68a and 68b are divided at the bottom surface of the non-discharge channel 52.

[0083] As shown in FIG. 17, in the cover plate processing step S20, an air vent passage 70 is formed on the back surface of the cover plate 42 (air vent passage forming step). The air vent passage 70 can be formed by dicing, sandblasting, or the like. Next, as shown in FIG. 18, a common hole 42a and individual holes 42b and 42c are formed in the cover plate 42 (hole forming step). Specifically, the cover plate 42 is penetrated by irradiating laser light from the surface side of the cover plate 42. Note that the order of the air vent passage forming step and the hole forming step may be reversed.

[0084] Subsequently, as shown in FIG. 19, the cover plate 42 is attached to the surface of the actuator plate 41 (bonding step).

[0085] Thereafter, as shown in FIG. 20, a common connection wiring 71 and individual connection wirings 72 as connection wirings are formed on the cover plate 42 (second wiring formation step). Specifically, a film of an electrode material is formed by performing vapor deposition or the like from the surface side of the cover plate 42 through a mask pattern (not shown). As a result, a common through-wiring 75 is formed in the common through-hole 42a, and individual through-wirings 81 and 82 are formed in the individual holes 42b and 42c. Further, a common pad 76 and individual pads 83 are formed on the surface of the cover plate 42.

[0086] Next, as shown in FIG. 21, grinding is performed on the back surface of the actuator plate 41 (grinding step S30). Specifically, the actuator plate 41 is ground until the discharge channel 51 and the non-discharge channel 52 open on the back surface of the actuator plate 41.

[0087] Then, as shown in FIG. 22, a non-formation region Q is formed on the inner surface of the non-discharge channel 52 (electrode removal step S40). Specifically, the -Z side end portion of the individual electrode 68 is removed by laser processing, dicing, or the like through the -Z side opening of the non-discharge channel 52. In order to form the non-formation region Q, for example, the -Z side end portion of the non-discharge channel 52 may be formed in a stepped shape in advance. In this case, the non-formation region Q can be formed by removing the individual electrode 68 formed in the stepped portion. Thus, the chip body 40 is completed.

[0088] As shown in FIG. 23, in the protective film formation step S50, a protective film 43 is formed on the chip body 40. In the protective film formation step S50, the chip body 40 and the protective film 43 are set in the chamber 120 in a facing state. Specifically, first, an adhesive 45 (see FIG. 12) is applied to the formation region of the protective film 43 of the chip body 40.

[0089] Subsequently, with the back surface of the actuator plate 41 facing upward, the chip body 40 is set on the stage 121 in the chamber 120 via the base film 122. The base film 122 is formed of a material that can be peeled off from both the actuator plate 41 and the protective film 43. On the other hand, the protective film 43 is set at a distance from the chip body 40 in the chamber 120. Among the protective film 43, the portion outside the chip body 40 in plan view is held by a holder or the like (not shown). That is, the portion of the protective film 43 located outside the chip body 40 also functions as a gripping margin for gripping the protective film 43 in the chamber 120.

[0090] With the chip body 40 and the protective film 43 set in the chamber 120, the inside of the chamber 120 is heated so that the protective film 43 is at or above its softening point within the range below the Curie point (the temperature at which polarization breakdown occurs) of the actuator plate 41. Thereafter, the first space S1 (lower space) located on the chip body 40 side with respect to the protective film 43 in the chamber 120 is made to have a negative pressure with respect to the second space S2 (upper space) located on the side opposite to the chip body 40 with respect to the protective film 43. Then, the air present in the chip body 40 is discharged through the openings that open on the outer surface of the chip body 40 among the channels 51, 52, the air vent passage 70, and the individual holes 42b, 42c. In particular, in the first embodiment, since the air vent passage 70 communicates with the central portion in the Y direction in each of the channels 51, 52, the air in each of the channels 51, 52 is discharged directly from the air vent passage 70 or indirectly from the non-discharge channel 52 and the individual holes 42b, 42c through the air vent passage 70.

[0091] Then, as shown in FIG. 24, due to the pressure difference between the first space S1 and the second space S2, the protective film 43 approaches the chip body 40. Thereafter, the protective film 43 contacts the chip body 40 and deforms while being stretched so as to follow the outer surface shape of the chip body 40. Specifically, the protective film 43 contacts the back surface of the chip body 40, and the downward displacement is restricted. Thereafter, a part of the protective film 43 enters the discharge channel 51 while being stretched and adheres to the inner surface of the discharge channel 51. Therefore, the portion of the air vent passage 70 exposed in the discharge channel 51 is blocked by the protective film 43 (discharge channel covering portion 43a). Also, a part of the protective film 43 enters the side surface of the chip body 40 while being stretched and adheres to the side surface of the chip body 40. Note that the width of the non-discharge channel 52 in the X direction is set to be less than twice the original thickness of the protective film 43. Therefore, in the protective film forming step S50, it is difficult for the protective film 43 to enter the non-discharge channel 52. Thus, the non-discharge channel covering portion 43c closes the -Z side opening of the non-discharge channel 52 on the back surface of the chip body 40. Thereby, the protective film 43 is formed on the chip body 40.

[0092] As shown in FIG. 25, after the formation of the protective film 43, the inside of the chamber 120 is cooled so that the protective film 43 becomes below the softening point, and then the head chip 32 is taken out from the chamber 120. Specifically, around the chip body 40, the protective film 43 and the base film 122 are cut, and the head chip 32 is taken out together with the base film 122. Thereafter, the base film 122 is peeled off from the head chip 32.

[0093] In addition, when the chip body 40 is manufactured at the wafer level, a laminate of a wafer for an actuator plate and a wafer for a cover plate is formed. Thereafter, the protective film 43 may be formed on each chip body 40 after the laminate of the wafers is singulated for each chip body 40, or may be formed on the entire laminate of the wafers and then the laminate of the wafers may be singulated for each head chip 32.

[0094] Thereafter, in the assembly step S60, the head chip 32 is assembled to the flow path plate 31. Specifically, the head chip 32 is fitted into the chip housing portion 31a such that the back surface of the flow path plate 31 and the back surface of the head chip 32 are flush with each other.

[0095] Subsequently, in the nozzle joining step S70, the nozzle plate 44 is attached so as to collectively cover the back surfaces of the flow path plate 31 and the head chip 32. Thereafter, the flow path cover 34 is attached to the front surface of the flow path plate 31. Thus, the discharge unit 30 is completed.

[0096] As described above, the head chip 32 of the first embodiment includes a chip body 40 having a discharge channel (pressure chamber) 51 in which ink is stored and drive walls (drive portions) 53 separately disposed in portions facing the discharge channel 51, a common electrode (first drive electrode) 65 formed on the drive walls, and a sheet-like protective film formed following the drive walls 53 while covering the common electrode 65. According to this configuration, by covering the drive walls 53 with the sheet-like protective film 43, unlike a configuration in which a deposition film made of a parylene-based resin material (e.g., parylene (registered trademark)) or the like is formed by a film formation method such as CVD, it is possible to suppress the occurrence of discontinuous portions such as pinholes. Therefore, it is possible to suppress ink from reaching the common electrode 65 formed on the drive walls 53. As a result, short circuits, corrosion, etc. of the common electrode 65 can be suppressed, and a head chip 32 with excellent reliability can be provided. In addition, by adopting the sheet-like protective film 43, a simple and low-cost protective film 43 can be provided as compared with a configuration in which a deposition film is formed by CVD or the like. As a result, the manufacturing efficiency of the head chip 32 can be improved, and the cost of the head chip 32 can be reduced.

[0097] By the way, if there is a portion with poor adhesion between the protective film 43 and the drive walls 53, deformation of the drive walls 53 at the portion with poor adhesion is difficult to be transmitted to the ink through the protective film 43. On the other hand, in the head chip 32 of the first embodiment, the chip body 40 is configured to form an air vent passage 70 that connects between the inside of the discharge channel 51 and the outside of the chip body 40, and the communication between the inside of the discharge channel 51 and the outside of the chip body 40 is blocked by the protective film 43. According to this configuration, since the air vent passage 70 connects between the inside of the discharge channel 51 and the outside of the chip body 40, in the protective film forming step S50, the air remaining in the discharge channel 51 can be efficiently discharged to the outside of the chip body 40. As a result, it becomes easier to generate a negative pressure in the discharge channel 51, and it becomes easier to draw the protective film 43 into the discharge channel 51. As a result, it becomes easier to closely adhere the protective film 43 to the entire inner surface (driving wall 53) of the discharge channel 51. In this case, since the deformation of the driving wall 53 is easily transmitted to the ink through the protective film 43, a desired generation pressure can be ensured in the discharge channel 51, and a decrease in discharge performance due to the formation of the protective film 43 can be suppressed.

[0098] In the head chip 32 of the first embodiment, the air vent passage 70 is configured to extend so as to straddle between a plurality of discharge channels 51. According to this configuration, the air in each discharge channel 51 can be efficiently discharged through the air vent passage 70. As a result, it becomes easier to closely adhere the protective film 43 to the entire inner surface (driving wall 53) of the discharge channel 51.

[0099] In the head chip 32 of the first embodiment, in the chip body 40, a non-discharge channel (air chamber) in which ink is not stored is formed in a portion located between adjacent discharge channels 51 in the X direction. The protective film 43 is provided so as to straddle the discharge channel 51 and the non-discharge channel 52 in the X direction, and the air vent passage 70 is configured to extend so as to straddle between the discharge channel 51 and the non-discharge channel 52 chambers. According to this configuration, the air in each discharge channel 51 and non-discharge channel 52 can be efficiently discharged through the air vent passage 70. As a result, it becomes easier to draw the protective film 43 to the chip body 40, and the protective film 43 can be provided at a desired position with high precision.

[0100] In the head chip 32 of the first embodiment, an individual electrode (second drive electrode) 68 that generates a potential difference with the common electrode 65 is formed on the inner surface of the non-discharge channel 52, and individual through wirings (through wirings) 81 and 82 that are formed on the inner surfaces of individual holes (wiring holes) 42b and 42c that open into the non-discharge channel 52 in the chip body 40 and are connected to the individual electrode 68 are formed. According to this configuration, the inside of the discharge channel 51 is connected to the outside of the chip body 40 even through the air vent passage 70, the non-discharge channel 52, and the individual holes 42b and 42c. That is, in the protective film forming step S50, the air in the discharge channel 51 and the non-discharge channel 52 can also be discharged through the individual holes 42b and 42c. Thereby, while simplifying the air vent passage 70, the protective film 43 can be provided at a desired position with high precision.

[0101] In the head chip 32 of the first embodiment, the discharge channel 51 extends in the chip body 40 with the Y direction (second direction) as the longitudinal direction, and the air vent passage 70 is connected to the central portion in the Y direction of the discharge channel 51. According to this configuration, in the protective film forming step S50, air can be extracted from the central portion in the Y direction of the discharge channel 51. Thereby, since air can be effectively discharged over the entire area within the discharge channel 51, poor adhesion of the protective film 43 can be suppressed.

[0102] In the head chip 32 of the first embodiment, the discharge channel 51 opens on the back surface (opening surface facing the third direction) of the chip body 40, and a nozzle plate (injection hole plate) 44 that closes the opening of the discharge channel 51 and has a nozzle hole (injection hole) 44a communicating with the discharge channel 51 is provided on the back surface of the chip body 40, and the air vent passage 70 is provided at a position overlapping the nozzle hole 44a when viewed from the Z direction of the discharge channel 51. According to this configuration, since the air vent passage 70 is provided at a position overlapping the nozzle hole 44a when viewed from the Z direction, the portion of the protective film 43 covering the air vent passage 70 elastically displaces in response to the pressure fluctuations in the discharge channel 51 during ink discharge. Therefore, during ink discharge, the pressure fluctuations in the discharge channel 51 can be alleviated, and it is easy to reduce the variation in the generated pressure among the respective discharge channels 51.

[0103] In the head chip 32 of the first embodiment, the chip body 40 includes an actuator plate 41 having a discharge channel 51 and a drive wall 53, and a cover plate 42 superposed on the actuator plate 41, and the air vent passage 70 is configured to be formed in the cover plate 42. According to this configuration, since the air vent passage 70 is formed in the cover plate 42, the degree of freedom in the design of the actuator plate 41 can be improved. Also, unlike the case where the air vent passage 70 is formed in the actuator plate 41, it is possible to suppress a reduction in the surface area of the drive wall 53 due to the formation of the air vent passage 70. Therefore, it becomes possible to provide the air vent passage 70 while maintaining the discharge performance.

[0104] Since the printer 1 and the inkjet head 5 of the first embodiment include the above-described head chip 32, it is possible to provide a printer 1 and an inkjet head 5 with excellent reliability.

[0105] In the above-described first embodiment, the configuration in which the protective film 43 includes the discharge channel covering portion 43a, the back surface covering portion 43b, the non-discharge channel covering portion 43c, and the side surface covering portion 43d has been described, but the configuration is not limited to this. The protective film 43 may have a configuration having at least the discharge channel covering portion 43a, for example, a configuration not having the non-discharge channel covering portion 43c, or a configuration not having at least any one of the back surface covering portion 43b, the non-discharge channel covering portion 43c, and the side surface covering portion 43d.

[0106] In the above-described first embodiment, the configuration for forming the non-formation region Q of the individual electrode 68 on the inner surface of the non-discharge channel 52 has been described, but the present invention is not limited to this configuration. The individual electrode 68 may be formed over the entire Z direction on the inner surface of the non-discharge channel 52.

[0107] (Modification example) In the above-described embodiment, the configuration in which the air vent passage 70 is formed in the cover plate 42 has been described, but the present invention is not limited to this configuration. For example, as shown in FIG. 26, the air vent passage 70 may be formed in the actuator plate 41. Specifically, the air vent passage 70 is a groove that opens on the surface of the actuator plate 41 and extends along the X direction. The air vent passage 70 extends over the entire length of the actuator plate 41 in the X direction. Therefore, the air vent passage 70 opens on the side surface of the actuator plate 41 facing the X direction. The air vent passage 70 is formed at a position overlapping the central portion in the Y direction in each of the channels 51 and 52 when viewed from the Z direction.

[0108] The air vent passage 70 crosses between the adjacent discharge channel 51 and the non-discharge channel 52 in the X direction. The air vent passage 70 overlaps a part of the channels 51 and 52 when viewed from the Y direction. That is, in the air vent passage 70, the portion overlapping the channels 51 and 52 when viewed from the Z direction is exposed in each of the channels 51 and 52. The air vent passage 70 connects each of the channels 51 and 52 to the outside of the chip body 40. Then, in the air vent passage 70, the portion overlapping the discharge channel 51 when viewed from the Z direction is covered by the discharge channel covering portion 43a, so that the communication between the inside of the discharge channel 51 through the air vent passage 70 and the outside of the chip body 40 is blocked. On the other hand, in the air vent passage 70, the portion overlapping the non-discharge channel 52 when viewed from the Z direction allows the communication between the inside of the non-discharge channel 52 and the outside of the chip body 40 through the air vent passage 70.

[0109] By forming the air vent passage 70 in the actuator plate 41 as in this modification example, the degree of freedom in the design of the cover plate 42 can be improved.

[0110] In the first embodiment and the modification example described above, the configuration in which the air vent passage is formed in either the actuator plate 41 or the cover plate 42 has been described, but the configuration is not limited to this. The air vent passage may be formed in both the actuator plate 41 and the cover plate 42. In the above-described embodiment, the configuration in which the discharge channels 51 and the non-discharge channels 52 are arranged alternately has been described, but the configuration is not limited to this. For example, the present disclosure may be applied to a so-called 3-cycle type head chip 32 that sequentially ejects ink from all the channels.

[0111] (Second Embodiment) The head chip 32 according to the second embodiment is different from the first embodiment in that the discharge channel 51 does not penetrate the actuator plate 41 in the Z direction. FIG. 27 is a cross-sectional view of the head chip 32 according to the second embodiment. FIG. 28 is a cross-sectional view corresponding to the line XXVIII-XXVIII in FIG. 27.

[0112] As shown in FIGS. 27 and 28, the discharge channel 51 opens on the back surface of the actuator plate 41 and penetrates the actuator plate 41 in the Y direction. The depth of the discharge channel 51 in the Z direction is shallower than the thickness of the actuator plate 41 in the Z direction. Therefore, the top surface of the discharge channel 51 is formed by the actuator plate 41. In this case, the common electrode 65 is formed over the entire inner surface (inner side surface and top surface) of the discharge channel 51. Therefore, the discharge channel covering portion 43a continuously covers the entire area of the discharge channel 51 via the common electrode 65 by directly or indirectly adhering to the top surface and the inner side surface of the discharge channel 51.

[0113] FIG. 29 is a cross-sectional view corresponding to line XXIX-XXIX of FIG. 27. FIG. 30 is a plan view of the actuator plate 41. FIG. 31 is a bottom view of the actuator plate 41. As shown in FIGS. 29 to 31, in the actuator plate 41, common through-holes 200 are formed in portions located on both sides in the Y direction with respect to the non-discharge channel 52. The common through-holes 200 penetrate the actuator plate 41 in the Z direction.

[0114] As shown in FIGS. 27 and 30, the common wiring 61 includes a common surface wiring 210 and a common lead wiring 211. The common surface wiring 210 extends in the X direction in portions located on both sides in the Y direction with respect to the non-discharge channel 52 on the surface of the actuator plate 41. Each common surface wiring 210 crosses the common through-hole 200 in the X direction. The common lead wiring 211 is formed on the inner surface of the common through-hole 200. Specifically, the common lead wiring 211 is formed over the entire inner circumference of the common through-hole 200 and is formed over the entire Z direction. The common lead wiring 211 is connected to the common back surface wiring 67 at the -Z side opening edge of the common through-hole 200 and is connected to the common surface wiring 210 at the +Z side opening edge of the common through-hole 200.

[0115] As shown in FIGS. 28 and 30, the individual wiring 62 includes an individual surface electrode 220 and a connection wiring 221. The individual surface electrode 220 is formed in a portion of the surface of the actuator plate 41 that overlaps the discharge channel 51 when viewed from the Z direction. The individual surface electrode 220 has the same width as the discharge channel 51 and is formed in a strip shape extending in the Y direction. The connection wiring 221 extends in the X direction at the central portion in the Y direction on the surface of the actuator plate 41. The connection wiring 221 connects the individual electrodes 68 facing each other in the X direction with one discharge channel 51 interposed therebetween at the +Z side opening edge of the non-discharge channel 52 and is connected to the individual surface electrode 220 on the surface of the actuator plate 41.

[0116] Here, as shown in FIGS. 27, 28, and 29, the air vent passage 230 is a groove that opens on the surface of the actuator plate 41 and extends along the X direction. The air vent passage 230 extends over the entire length of the actuator plate 41 in the X direction. Therefore, the air vent passage 230 opens on the side surface of the actuator plate 41 facing the X direction. The air vent passage 230 is formed at a position overlapping the central portion in the Y direction in each of the channels 51 and 52 when viewed from the Z direction. Therefore, the air vent passage 230 divides the individual surface electrodes 220 and the connection wiring 221 at their central portions in the Y direction, respectively.

[0117] The air vent passage 230 traverses in the X direction between the adjacent discharge channel 51 and the non-discharge channel 52. The air vent passage 230 overlaps a part of the channels 51 and 52 when viewed from the Y direction. That is, in the air vent passage 230, the portion overlapping the channels 51 and 52 when viewed from the Z direction is exposed within each of the channels 51 and 52. The air vent passage 230 connects each of the channels 51 and 52 to the outside of the chip body 40. Then, the portion of the air vent passage 230 overlapping the discharge channel 51 when viewed from the Z direction is covered by the discharge channel covering portion 43a, so that the communication between the inside of the discharge channel 51 through the air vent passage 230 and the outside of the chip body 40 is blocked. Therefore, when the air vent passage 230 is blocked by the discharge channel covering portion 43a, the communication between the inside of the discharge channel 51 and the inside of the non-discharge channel 52 through the air vent passage 230 is also blocked. On the other hand, in the air vent passage 230, the portion overlapping the non-discharge channel 52 when viewed from the Z direction allows the communication between the inside of the non-discharge channel 52 and the outside of the chip body 40 through the air vent passage 230.

[0118] Note that the overlapping amount in the Z direction between the air vent passage 230 and the discharge channel 51 (the distance between the bottom surface of the air vent passage 230 and the top surface of the discharge channel 51 in the Z direction) is preferably as small as possible, and is preferably 2% or more and 15% or less with respect to the dimension of the discharge channel 51 in the Z direction. By setting the overlapping amount in the Z direction between the air vent passage 230 and the discharge channel 51 to be 2% or more with respect to the dimension of the discharge channel 51 in the Z direction, the inside of the discharge channel 51 and the inside of the air vent passage 70 can be more reliably connected. On the other hand, by setting the overlapping amount in the Z direction between the air vent passage 230 and the discharge channel 51 to be 15% or less with respect to the dimension of the discharge channel 51 in the Z direction, a decrease in the area of the common electrode 65 due to the formation of the air vent passage 230 can be suppressed.

[0119] In the head chip 32 according to the second embodiment, the individual hole 231 is formed at the central portion in the Y direction of the individual surface electrode 220 when viewed from the Z direction in the cover plate 42 and at a position overlapping the air vent passage 230. Therefore, the air vent passage 230 communicates with the outside of the chip body 40 through the individual hole 231. An individual through-wiring 232 is formed on the inner surface of the individual hole 231. The individual through-wiring 232 is formed over the entire inner circumference of the individual hole 231 and over the entire Z direction. The individual through-wiring 232 is connected to portions of the individual surface electrode 220 that are located on both sides in the Y direction with respect to the air vent passage 230 at the -Z side opening edge of the individual hole 231. On the other hand, the individual through-wiring 232 is connected to the individual pad 83 at the +Z side opening edge of the individual hole 231.

[0120] In the head chip 32 according to the second embodiment, when ink is ejected, a potential difference is generated in the X direction between a portion of the common electrode 65 formed on the inner surface of the ejection channel 51 and the individual electrode 68, so that the actuator plate 41 (driving wall 53) can be deformed in the X direction in the shear mode. Further, a potential difference in the Z direction is generated between a portion of the common electrode 65 formed on the top surface of the ejection channel 51 and the individual surface electrode 220, so that a portion (top driving wall 240) of the actuator plate 41 located between the top surface of the ejection channel 51 and the surface of the actuator plate 41 can be deformed in the Z direction in the bend mode. That is, in the second embodiment, the driving wall 53 and the top driving wall 240 constitute the driving portion according to the present disclosure. Furthermore, a potential difference can be generated in the Z direction between a portion of the individual electrode 68 located on the +Z side of the top surface of the ejection channel 51 and a portion of the common electrode 65 formed on the top surface of the ejection channel 51. Therefore, the actuator plate 41 can be deformed in the direction in which the volume of the ejection channel 51 expands by the shear mode and the bend mode. In this way, by deforming the actuator plate 41 in both the X direction and the Z direction, it is easy to secure the elastic energy of the actuator plate 41 when a voltage is applied. Therefore, it is easy to secure the pressure generated in the ejection channel 51 when ink is ejected, and desired ejection performance can be obtained.

[0121] In the head chip 32 according to the second embodiment, since the air bleeding passage 230 is formed in the actuator plate 41, the cover plate 42 does not need to be processed with respect to the air bleeding passage 230. Therefore, the degree of freedom in design of the cover plate 42 can be improved. Furthermore, in the head chip 32 according to the second embodiment, by deforming the actuator plate 41 by the shear mode and the bend mode as described above, it is possible to suppress a decrease in the generated pressure due to a decrease in the areas of the common electrode 65 and the individual electrode 68 caused by forming the air bleeding passage 230 in the actuator plate 41.

[0122] (Third Embodiment) The head chip 300 of the third embodiment is different from each of the above-described embodiments in that it adopts a so-called roof shoot type. FIG. 32 is an exploded perspective view of the head chip 300. FIG. 33 is a cross-sectional view corresponding to line XXXIII-XXXIII of FIG. 32. FIG. 34 is a cross-sectional view corresponding to line XXXIV-XXXIV of FIG. 33. As shown in FIGS. 32 to 34, the head chip 300 includes a nozzle plate 301, a flow path member 302, a protective film 303, an actuator plate 304, a film 305, and a cover plate 306. The actuator plate 304, the film 305, and the cover plate 306 constitute the chip body 308 in the third embodiment.

[0123] The flow path member 302 is plate-shaped with the Z direction as the thickness direction. The flow path member 302 is formed of a material having ink resistance. As such a material, for example, metal, metal oxide, glass, resin, ceramics, etc. can be adopted. In the flow path member 302, a flow path 310 through which ink flows and a plurality of pressure chambers 311 that communicate with the flow path 310 and in which ink is stored are formed. The flow path 310 and the pressure chambers 311 penetrate the flow path member 302 in the Z direction.

[0124] As shown in FIG. 32, the pressure chambers 311 are arranged at intervals in the X direction. Each pressure chamber 311 is formed in a groove shape extending linearly in the Y direction. Each pressure chamber 311 penetrates the flow path member 302 over the entire Y direction. However, the pressure chamber 311 may penetrate the flow path member 302 in a part of the Y direction. In plan view, each pressure chamber 311 is partitioned by a partition wall 312.

[0125] The flow path 310 includes an inlet-side common flow path 314, an inlet-side communication path 315, an outlet-side common flow path 316, and an outlet-side communication path 317. The inlet-side common flow path 314 extends in the X direction in a portion of the flow path member 302 that is located on the +Y side with respect to each pressure chamber 311. The inlet-side connecting passages 315 branch from portions of the inlet-side common flow path 314 that overlap with each pressure chamber 311 when viewed from each Y direction toward the -Y side, thereby connecting the inlet-side common flow path 314 and each pressure chamber 311 respectively.

[0126] The outlet-side common flow path 316 extends in the X direction in a portion of the flow path member 302 that is located on the -Y side with respect to each pressure chamber 311. The outlet-side connecting passages 317 branch from portions of the outlet-side common flow path 316 that overlap with each pressure chamber 311 when viewed from the Y direction toward the +Y side, thereby connecting the outlet-side common flow path 316 and each pressure chamber 311 respectively.

[0127] As shown in FIGS. 32 and 33, the nozzle plate 301 is fixed to the back surface of the flow path member 302 by adhesion or the like. The nozzle plate 301 closes the -Z side openings of the flow path 310 and the pressure chambers 311. A plurality of nozzle holes 301a that penetrate the nozzle plate 301 in the Z direction are formed in the nozzle plate 301. The respective nozzle holes 301a are arranged at intervals in the X direction. Each nozzle hole 301a communicates with the corresponding pressure chamber 311 at the central portions in the X and Y directions.

[0128] The protective film 303 is interposed between the flow path member 302 and the actuator plate 304. Details of the protective film 303 will be described later.

[0129] The actuator plate 304 is provided on the protective film 303 with the Z direction being the thickness direction. The outer shape of the actuator plate 304 in plan view is equivalent to the outer shape of the flow path member 302 in plan view. The actuator plate 304 is overlapped with the entire flow path member 302 with the protective film 303 interposed therebetween. The actuator plate 304 faces each pressure chamber 311 in the Z direction with the protective film 303 interposed therebetween. Among the actuator plate 304, the portion facing the pressure chamber 311 constitutes the drive unit in the third embodiment. Note that the actuator plate 304 (drive unit) is not limited to the configuration of covering all the pressure chambers 311 together, and may be provided individually for each pressure chamber 311.

[0130] As shown in FIG. 33, the actuator plate 304 is set such that the polarization direction faces one direction on the +Z side. Drive wirings 325 are formed on both surfaces of the actuator plate 304. The actuator plate 304 is configured to be deformable in the Z direction by generating an electric field due to the voltage applied by the drive wirings 325. The actuator plate 304 discharges ink from the pressure chamber 311 by expanding or contracting the volume in the pressure chamber 311 by the deformation in the Z direction. Note that the configuration of the drive wirings will be described later.

[0131] Among the actuator plate 304, first recesses 326 are formed in the portions facing the respective pressure chambers 311. The first recesses 326 are recessed on the +Z side with respect to the back surface of the actuator plate 304. Specifically, the first recesses 326 are formed in the portions located at the center in the X direction in the pressure chambers 311 in plan view. The first recesses 326 are formed in a rectangular shape when viewed from the Y direction.

[0132] Of the actuator plate 304, portions located on both sides in the X direction with respect to the first recess 326 have second recesses (air chambers) 327 formed therein. The second recesses 327 overlap in plan view with portions of the flow path member 302 located between adjacent pressure chambers 311. The second recesses 327 are recessed with respect to the surface of the actuator plate 304. The second recesses 327 extend in the Y direction along the first recesses 326. In the illustrated example, the bottom surface (-Z side surface) of the second recesses 327 is located on the -Z side with respect to the top surface (+Z side surface) of the first recesses 326.

[0133] The film 305 is fixed to the surface of the actuator plate 304 by adhesion or the like. In the third embodiment, the film 305 covers the entire surface of the actuator plate 304. The film 305 is made of an insulating and elastically deformable material. Note that the second film 55 is not an essential component.

[0134] The cover plate 306 is fixed to the surface of the film 305 by adhesion or the like with the Z direction as the thickness direction.

[0135] Next, the structure of the drive wiring 325 will be described. FIG. 35 is a bottom view of the actuator plate 304. FIG. 36 is a plan view of the actuator plate 304. The drive wiring 325 is provided corresponding to each pressure chamber 311. The drive wirings 325 corresponding to adjacent pressure chambers 311 have the same configuration as each other. In the following description, the drive wiring 325 provided corresponding to one of the plurality of pressure chambers 311 will be described as an example, and the description of the drive wirings 325 corresponding to the other pressure chambers 311 will be omitted as appropriate. As shown in FIGS. 33, 35, and 36, the drive wiring 325 includes a common wiring 331 and an individual wiring 332.

[0136] The common wiring 331 includes a first common electrode 331a, a second common electrode 331b, a third common electrode 331c, a -Y side connection wiring 331d, a central connection wiring 331e, a +Y side connection wiring 331f, a common pad 331g, and a common through-wiring 331h. As shown in FIGS. 33 to 35, the first common electrodes 331a are respectively formed at positions overlapping with the partition walls 312 when viewed in the Z direction on the back surface of the actuator plate 304. Each first common electrode 331a extends linearly in the Y direction with a length equivalent to that of the pressure chamber 311.

[0137] As shown in FIGS. 33 and 36, the second common electrodes 331b are arranged on the front surface of the actuator plate 304 at positions overlapping with the corresponding pressure chambers 311 when viewed in the Z direction and not overlapping with the first common electrodes 331a when viewed in the Z direction. In the illustrated example, the second common electrodes 331b are formed in a region including the central portion in the X direction in the pressure chambers 311. The second common electrodes 331b extend linearly in the Y direction with a length equivalent to that of the pressure chamber 311. The third common electrodes 331c are formed over the entire inner surface of each second recess 327. That is, the third common electrodes 331c are arranged on both sides of the second common electrodes 331b in the X direction. Note that the third common electrodes 331c may be formed on at least a part of the inner surface of the second recesses 327.

[0138] As shown in FIG. 36, the -Y side connection wiring 331d connects the -Y side end portions of the second common electrodes 331b and the third common electrodes 331c on the front surface of the actuator plate 304. The central connection wiring 331e connects the central portions in the Y direction of the second common electrodes 331b and the third common electrodes 331c on the front surface of the actuator plate 304. The +Y side connection wiring 331f connects the +Y side end portions of the second common electrodes 331b and the third common electrodes 331c on the front surface of the actuator plate 304.

[0139] FIG. 37 is a plan view of the cover plate 306. As shown in FIG. 37, the common pad 331g is formed at a portion of the surface of the cover plate 306 that overlaps with the pressure chamber 311 when viewed from the Z direction.

[0140] The through wiring 331h connects the first common electrode 331a, the -Y side connection wiring 331d, and the common pad 331g. The common through wiring 331h is provided so as to penetrate the actuator plate 304, the film 305, and the cover plate 306 in the Z direction. Specifically, a common wiring hole 341 is formed in a portion of the actuator plate 304, the film 305, and the cover plate 306 that is located on the -Y side with respect to the second recess 327. The common wiring holes 341 are formed individually for each partition wall 312. The common wiring holes 341 communicate with the inside of the second recess 327. The common through wiring 331h is formed over the entire region in the Z direction on the inner surface of the common wiring hole 341. The -Y side edge portions of the first common electrode 331a, the -Y side connection wiring 331d, and the common pad 331g are connected to the common through wiring 331h at the opening edge of the common wiring hole 341.

[0141] As shown in FIGS. 33 to 35, the individual wiring 332 includes an individual electrode (first drive electrode) 332a, an individual pad 332b, and an individual through wiring 332c. The individual electrode 332a generates a potential difference with the first common electrode 331a, and also generates potential differences with the second common electrode 331b and the third common electrode 331c. At least a part of the individual electrode 332a overlaps with the second common electrode 331b when viewed from the Z direction. The individual electrode 332a extends in the Y direction with a gap in the X direction with respect to each first common electrode 331a. The individual electrode 332a is formed on the inner surface of the first recess 326. In the illustrated example, the individual electrode 332a is formed over the entire length of the first recess 326 and over the entire top surface and inner side surface of the first recess 326. However, the individual electrode 332a only needs to be formed on at least a part of the inner surface of the first recess 326.

[0142] As shown in FIG. 37, the individual pads 332b are formed on the surface of the cover plate 306. The individual pads 332b extend in the Y direction in a portion of the surface of the cover plate 306 that overlaps with the pressure chamber 311 when viewed from the Z direction.

[0143] As shown in FIGS. 34, 35, and 37, the individual through-wiring 332c connects the corresponding individual electrodes 332a and individual pads 332b. The individual through-wiring 332c is provided to penetrate the actuator plate 304 in the Z direction. Specifically, individual wiring holes 343 are formed in portions of the actuator plate 304, the film 305, and the cover plate 306 that are located on the +Y side with respect to the individual electrodes 332a. The individual wiring holes 343 are individually formed at positions shifted from the common wiring holes 341 in the X direction for each pressure chamber 311. The individual through-wiring 332c is formed over the entire inner surface of the individual wiring holes 343 in the Z direction. The +Y side edge portions of the corresponding individual electrodes 332a and individual pads 332b are connected to the individual through-wiring 332c at the opening edge of the individual wiring holes 343.

[0144] As shown in FIGS. 32 to 34, the protective film 303 is adhered to the outer surface of the chip body 308 via an adhesive 309. The protective film 303 includes a recess covering portion 303a, a back surface covering portion 303b, and a side surface covering portion 303c. The recess covering portion 303a is provided to follow the inner surface shape of the first recess 326. The recess covering portion 303a continuously covers the inner surface of the first recess 326 in a state of being in close contact with the individual electrodes 332a. The back surface covering portion 303b continuously covers the entire back surface of the actuator plate 304 including the first common electrode 331a. The back surface covering portion 303b is integrally continuous with the recess covering portion 303a at the -Z side opening edge of the first recess 326. The side surface covering portion 303c is integrally continuous with the outer peripheral edge of the back surface covering portion 303b. The side surface covering portion 303c continuously covers the entire side surface (the surface facing the X direction or the Y direction) of the chip body 308.

[0145] As shown in FIG. 33, the portion of the drive wiring formed on the surface of the actuator plate 304 is covered with a film 305. Specifically, among the drive wiring, the second common electrode 331b, the third common electrode 331c, the -Y side connection wiring 331d, the central connection wiring 331e, and the +Y side connection wiring 331f are covered with the film 305.

[0146] Here, as shown in FIGS. 33, 34, and 36, an air vent passage 350 is formed in the actuator plate 304. The air vent passage 350 is a groove that opens on the surface of the actuator plate 304 and extends in the X direction. The air vent passage 350 extends over the entire length of the actuator plate 304 in the X direction so as to cross between adjacent pressure chambers 311 when viewed from the Z direction. Therefore, the air vent passage 350 opens on the side surface of the actuator plate 304 facing the X direction. Note that the opening of the air vent passage 350 on the side surface of the actuator plate 304 is blocked by a side covering portion 303c.

[0147] The air vent passage 350 is formed at a position overlapping the central portion in the Y direction in the pressure chamber 311 when viewed from the Z direction. Therefore, the air vent passage 350 overlaps the nozzle hole 301a when viewed from the Z direction. Also, the air vent passage 350 divides the central connection wiring 331e in the Y direction.

[0148] The bottom surface of the air vent passage 350 is located between the top surface of the first recess 326 and the bottom surface of the second recess 327 in the Z direction. Therefore, the air vent passage 350 communicates with the outside of the chip body 308 through the second recess 327 while being connected to the inside of the pressure chamber 311 through the first recess 326. Then, the portion of the air vent passage 350 exposed in the first recess 326 is blocked by a recess covering portion 303a, thereby blocking the communication between the outside of the chip body 308 and the inside of the pressure chamber 311 through the air vent passage 350.

[0149] The air vent passage 350 is formed by performing dicing or sandblasting on the surface of the actuator plate 304 after forming drive wirings on both surfaces of the actuator plate 304 and before laminating the film 305 and the cover plate 306. Then, the protective film 303 is formed on the chip body 308 obtained by laminating the actuator plate 304, the film 305, and the cover plate 306 through a protective film forming step S50. In this case, the air in the first recess 326 is discharged to the outside of the chip body 308 directly from the air vent passage 350 or through the second recess 327, the common wiring hole 341, etc. from the air vent passage 350. Thereby, the protective film 303 (recess covering portion 303a) can be adhered also to the inner surface of the first recess 326.

[0150] In the head chip 300 of the third embodiment, a potential difference is generated in the X direction between the first common electrode 331a and the individual electrode 332a by applying a drive voltage. Due to the potential difference generated in the X direction, the actuator plate 304 undergoes a thickness shear deformation in the Z direction in a shear mode. On the other hand, a potential difference is generated in the Z direction between the second common electrode 331b and the individual electrode 332a, and between the third common electrode 331c and the individual electrode 332a. Due to the potential difference generated in the Z direction, the actuator plate 304 undergoes an expansion and contraction deformation in the Z direction in a bend mode. That is, in the head chip 300 of the third embodiment, the deformations caused by the shear mode and the bend mode of the actuator plate 304 both extend in the Z direction. That is, by applying a drive voltage, the actuator plate 304 deforms in a direction away from the pressure chamber 311. Thereby, the volume inside the pressure chamber 311 expands. Then, when the drive voltage is set to zero, as the actuator plate 304 restores, the volume inside the pressure chamber 311 tries to return to its original state. In the process of the actuator plate 304 restoring, the pressure inside the pressure chamber 311 increases, and the ink inside the pressure chamber 311 is discharged to the outside through the nozzle hole 301a.

[0151] In the head chip 300 of the third embodiment, a first recess 326 that opens toward the flow path member 302 is formed in the actuator plate 304. A second recess 327 that opens toward the side opposite to the flow path member 302 is formed in a portion of the actuator plate 304 that is located between adjacent pressure chambers 311. The individual electrode (first drive electrode) 322a is formed on the inner surface of the first recess 326. The protective film 303 is provided following the inner surface of the first recess 326. The air vent passage 350 is formed so as to connect the first recess 326 and the second recess 327. According to this configuration, by forming the individual electrode 332a following the inner surface of the first recess 326, the surface area of the individual electrode 332a can be ensured. As a result, the electric field generated in the actuator plate 304 can be increased, and the generated pressure in the pressure chamber 311 during ink ejection can be improved. Further, by forming the first recess 326 in the actuator plate 304, the rigidity of the actuator plate 304 in the Z direction can be increased. Furthermore, since the second recess 327 is formed in the actuator plate 304, when the actuator plate 304 deforms in the Z direction, the second recess 327 functions as a relief portion that allows the deformation of the actuator plate 304. Thereby, it becomes easier to ensure the amount of deformation of the actuator plate 304. Moreover, since the air vent passage 350 is formed so as to connect the first recess 326 and the second recess 327, in the protective film forming step S50, the air in the first recess 326 can be effectively discharged. Thereby, it becomes easy to adhere the protective film 303 to the inner surface of the first recess 326.

[0152] In the third embodiment, the case where one air vent passage 350 is provided at the central portion in the Y direction has been described, but the present invention is not limited to this configuration. For example, as shown in FIG. 38, the air vent passages 350 may be provided on both sides of the central connection wiring 331e in the Y direction. Further, for example, as shown in FIG. 39, three or more air vent passages 350 may be provided at intervals in the Y direction.

[0153] Also, in the third embodiment, the configuration in which the air vent passage 350 is formed only in the actuator plate 41 has been described, but the configuration is not limited to this. For example, as shown in FIG. 40, the air vent passage 350 may penetrate the film 305 and the cover plate 306 and be formed so as to be recessed with respect to the surface of the actuator plate 304. In this case, the air vent passage 350 can be formed after the formation of the chip body 308 and before the protective film forming step S50.

[0154] (Fourth Embodiment) The head chip 300 of the fourth embodiment is different from the third embodiment in that the air vent passage 350 is formed on the back surface of the actuator plate 304. FIG. 41 is a cross-sectional view of the head chip 400 according to the fourth embodiment. FIG. 42 is a bottom view of the actuator plate 304. FIG. 43 is a plan view of the actuator plate 304. In the head chip 400 shown in FIGS. 41 to 43, the common wiring 331 includes a first common electrode 331a, a second common electrode 331b, a third common electrode 331c, a -Y side connection wiring 331d, a central connection wiring 331e, a +Y side connection wiring 331f, a common pad 331g, a common through wiring 331h, a back surface routing wiring 331j, a front surface routing wiring 331k, and a side surface routing wiring 331m.

[0155] The back surface routing wiring 331j extends in the X direction along the +Y side edge on the back surface of the actuator plate 304. The back surface routing wiring 331j connects adjacent first common electrodes 331a to each other. The front surface routing wiring 331k extends in the Y direction at a portion located between adjacent individual wiring holes 343 on the front surface of the actuator plate 304. The -Y side end portion of the front surface routing wiring 331k is connected to the third common electrode 331c at the +Z side opening edge in the second recess 327. The +Y side end portion of the front surface routing wiring 331k reaches the +Y side edge on the front surface of the actuator plate 304.

[0156] The side routing wiring 331m is formed on the side surface of the actuator plate 304 that faces the +Y side. The side routing wiring 331m connects between the backside routing wiring 331j and the frontside routing wiring 331k. Note that the side routing wiring 331m is preferably covered by the side covering portion 303c.

[0157] The air vent passage 402 is a groove that opens on the back surface of the actuator plate 304 and extends in the X direction. The air vent passage 402 extends over the entire length of the actuator plate 304 in the X direction so as to cross between adjacent pressure chambers 311 when viewed from the Z direction. Therefore, the air vent passage 402 opens on the side surface of the actuator plate 304 that faces the X direction.

[0158] The air vent passage 402 is formed at a position that overlaps the central portion of the pressure chamber 311 in the Y direction when viewed from the Z direction. The top surface (the surface located on the +Z side) of the air vent passage 402 is located on the -Z side of the top surface of the first recess 326 and on the +Z side of the bottom surface of the second recess 327 in the Z direction. Therefore, the air vent passage 402 communicates with the outside of the chip body 308 through the second recess 327 while being connected to the inside of the pressure chamber 311 through the first recess 326. Moreover, the portion of the air vent passage 350 that is exposed in the first recess 326 is blocked by the recess covering portion 303a, thereby blocking the communication between the outside of the chip body 308 and the inside of the pressure chamber 311 through the air vent passage 350.

[0159] In the fourth embodiment, the first common electrode 331a is divided in the Y direction by the air vent passage 402. However, the portion of the first common electrode 331a that is located on the -Y side with respect to the air vent passage 402 is connected to the -Y side connection wiring 331d through the common through-wiring 331h. On the other hand, the portion of the first common electrode 331a that is located on the +Y side with respect to the air vent passage 402 is connected to the frontside routing wiring 331k through the backside routing wiring 331j and the side routing wiring 331m. Therefore, the common wiring 331 is integrally continuous on the front and back surfaces of the actuator plate 304. Of the individual electrodes 332a, at least a part of the portion located on the inner surface of the first recess 326 is divided in the Y direction by the air vent passage 402. On the other hand, the portion of the individual electrode 332a located on the top surface of the first recess 326 is located on the +Z side of the air vent passage 402, and thus continuously extends along the entire length in the Y direction on the top surface of the recess 326.

[0160] According to the configuration of the fourth embodiment, after forming various wirings on the front and back surfaces of the actuator plate 304, the air vent passage 402 can be formed. As a result, with the front and back surfaces of the actuator plate 304 communicating through the air vent passage 402 and the second recess 327, there is no need to form various wirings on the back surface of the actuator plate 304. Therefore, it is possible to suppress the various wirings formed on the front and back surfaces of the actuator plate 304 from being connected through the air vent passage 402. As a result, a head chip 400 with excellent reliability can be provided.

[0161] In the fourth embodiment described above, the configuration in which the dimension of the first recess 326 in the Y direction is equivalent to that of the pressure chamber 311 has been described, but the present invention is not limited to this configuration. As shown in FIG. 44, the first recess 326 may extend to a position overlapping the common flow paths 314 and 316 when viewed from the Z direction.

[0162] (Other Modification Examples) Note that the technical scope of the present disclosure is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present disclosure. For example, in the above-described embodiments, as an example of the liquid ejection recording apparatus, the inkjet printer 1 has been described as an example, but the present invention is not limited to printers. For example, a facsimile machine, an on-demand printer, or the like may be used. In the above-described embodiments, the configuration in which the inkjet head moves relative to the recording medium during printing (so-called shuttle mechanism) has been described as an example, but the present disclosure is not limited to this configuration. The configuration according to the present disclosure may be adopted in a configuration in which the recording medium is moved relative to the inkjet head with the inkjet head fixed (so-called fixed head mechanism). In the above-described embodiments, the case where the recording medium P is paper has been described, but the present disclosure is not limited to this configuration. The recording medium P is not limited to paper, and may be a metal material, a resin material, or food, etc. In the above-described embodiments, the configuration in which the liquid ejection head is mounted on the liquid ejection recording apparatus has been described, but the present disclosure is not limited to this configuration. That is, the liquid ejected from the liquid ejection head is not limited to that which lands on the recording medium, and may be, for example, a chemical solution to be blended in a preparation, a food additive such as a seasoning or a fragrance to be added to food, an aromatic agent ejected into the air, etc.

[0163] In the above-described embodiments, the configuration in which the Z direction coincides with the gravitational direction has been described, but the present disclosure is not limited to this configuration only, and the Z direction may be along the horizontal direction. In the above-described embodiments, the method of heating the protective film in the protective film forming step S50 has been described, but the present disclosure is not limited to this configuration. The protective film forming step S50 may be performed at room temperature.

[0164] In the above-described embodiments, the side shoot type head chip has been described as an example, but the present disclosure is not limited to this configuration. For example, the configuration according to the present disclosure may be adopted in a so-called edge shoot type head chip that ejects ink from an end portion in the extending direction of the discharge channel. In the above-described embodiments, the configuration in which the air vent passage extends across a plurality of pressure chambers has been described, but the present disclosure is not limited to this configuration. The air vent passage may be individually connected to each pressure chamber. In the above-described embodiments, the configuration in which the air vent passage extends across the pressure chamber and the air chamber has been described, but the present disclosure is not limited to this configuration. The air vent passage may be connected only to the pressure chamber or only to the air chamber.

[0165] In addition, without departing from the gist of the present disclosure, it is possible to appropriately replace the components in the above-described embodiments with well-known components, and the above-described modification examples may be appropriately combined.

Explanation of Signs

[0166] 1: Printer (Liquid Jet Recording Device) 5: Inkjet Head (Liquid Jet Head) 32: Head Chip 40: Chip Body 41: Actuator Plate 42: Cover Plate 42b: First Individual Hole (Wiring Hole) 42c: Second Individual Hole (Wiring Hole) 43: Protective Film 44: Nozzle Plate (Jet Hole Plate) 51: Discharge Channel (Pressure Chamber) 52: Non-Discharge Channel (Air Chamber) 53: Driving Wall (Driving Portion) 65: Common Electrode (First Driving Electrode) 68: Individual Electrode (Second Driving Electrode) 70: Air Bleeding Passage 81: First Individual Through-Wiring (Through-Wiring) 82: Second Individual Through-Wiring (Through-Wiring) 120: Chamber 230: Air Bleeding Passage 231: Individual Hole (Wiring Hole) 240: Top Driving Wall (Driving Portion) 300: Head Chip 302: Flow Path Member 303: Protective Film 304: Actuator Plate 308: Chip Body 311: Pressure Chamber 326: First Recess 327: Second Recess (Second Recess) 332a: Individual Electrode (First Driving Electrode) 350: Air Bleeding Passage 400: Head Chip 402: Air vent passage S50: Protective film forming process

Claims

1. A chip body having a plurality of pressure chambers formed side by side in a first direction and accommodating a liquid, and drive units respectively disposed on portions facing the pressure chambers, a first drive electrode formed on the drive unit, and a sheet-like protective film formed following the drive unit while covering the first drive electrode, wherein the chip body is provided with a head chip in which an air vent passage that connects between the inside of the pressure chamber and the outside of the chip body and whose communication between the inside of the pressure chamber and the outside of the chip body is blocked by the protective film is formed.

2. The head chip according to claim 1, wherein the air vent passage extends across a plurality of the pressure chambers.

3. In the chip body, an air chamber in which no liquid is accommodated is formed in a portion located between adjacent pressure chambers in the first direction, the protective film is provided so as to straddle the pressure chamber and the air chamber in the first direction, and the head chip according to claim 2, wherein the air vent passage extends across the pressure chamber and the air chamber.

4. A second drive electrode that generates a potential difference with the first drive electrode is formed on the inner surface of the air chamber, and the head chip according to claim 3, wherein the chip body is formed on the inner surface of a wiring hole that opens into the air chamber and is connected to the second drive electrode.

5. The pressure chamber extends in the chip body with a second direction intersecting the first direction as a longitudinal direction, and the head chip according to any one of claims 1 to 4, wherein the air vent passage is connected to a central portion of the pressure chamber in the second direction.

6. The pressure chamber opens on an opening surface facing a third direction intersecting the second direction when viewed from the first direction of the chip body, and an injection hole plate that closes the opening of the pressure chamber and has injection holes communicating with the pressure chamber is provided on the opening surface of the chip body, and the head chip according to claim 5, wherein the air vent passage is provided at a position overlapping the injection hole when viewed from the third direction of the pressure chamber.

7. The chip body includes an actuator plate having the pressure chamber and the drive unit, and a cover plate superimposed on the actuator plate. The air vent passage is formed in the actuator plate, the head chip according to any one of claims 1 to 4.

8. The chip body An actuator plate having the pressure chamber and the drive unit, A cover plate superposed on the actuator plate, and comprises, The air vent passage is formed in the cover plate, the head chip according to any one of claims 1 to 4.

9. The chip body A flow path member in which the pressure chamber is formed, An actuator plate superposed on the pressure chamber and having the drive unit, and comprises, A first recess is formed in the drive unit and opens toward the flow path member, A second recess is formed in a portion of the actuator plate located between the pressure chambers adjacent to each other in the first direction and opens toward the side opposite to the flow path member, The first drive electrode is formed on the inner surface of the first recess, The protective film is provided following the inner surface of the first recess in the drive unit, The air vent passage is formed so as to connect between the first recess and the second recess, the head chip according to any one of claims 1 to 4.

10. A liquid ejection head including the head chip according to claim 1 or claim 2.

11. A liquid ejection recording apparatus including the liquid ejection head according to claim 10.

12. A chip body having a plurality of pressure chambers formed side by side in a first direction and accommodating liquid, and drive units respectively disposed in portions facing the pressure chambers, A first drive electrode formed in the drive unit, A sheet-like protective film formed following the drive unit while covering the first drive electrode, and comprises, A method of manufacturing a head chip in which an air vent passage is formed in the chip body to connect between the inside of the pressure chamber and the outside of the chip body, and the communication between the inside of the pressure chamber and the outside of the chip body on the drive unit is blocked by the protective film, A method of manufacturing a head chip, comprising a protective film forming step of bringing the protective film into close contact with the drive unit by applying a negative pressure to the inside of the pressure chamber through the air vent passage in a space on the side opposite to the pressure chamber with respect to the protective film.

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