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

Abstract

A head chip according to one aspect of the present disclosure comprises: a flow passage member in which a plurality of pressure chambers for accommodating a liquid are formed side-by-side in a first direction; an actuator plate which is disposed on the flow passage member in a state of facing the pressure chambers in a second direction intersecting the first direction; drive wiring which is formed on each flow-passage facing surface, which are surfaces that face the flow passage member, in drive portions of the actuator plate that overlap the pressure chambers when viewed from the second direction; and a sheet-like protective film which has first covering portions that cover the drive wiring on the flow-passage facing surfaces, and which divides the pressure chambers and the drive portions.

Description

Head chip, liquid jet head, liquid jet recording apparatus, and method of manufacturing head chip

[0001] This application claims priority to Japanese Patent Application No. 2023-215679, filed on December 21, 2023, the contents of which are incorporated herein by reference.

[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 overlaid on the actuator plate. Electrodes are formed on the inner surfaces of the ejection channels in the actuator plate. For example, Patent Document 1 listed below discloses a configuration in which the electrodes are protected by a deposited film. The deposited film is formed of an insulating material such as a paraxylylene-based resin material (e.g., Parylene (registered trademark)).

[0003] Japanese Patent Application Publication No. 2000-071451

[0004] However, in the above-mentioned conventional techniques, the deposited film is formed by a film formation method such as chemical vapor deposition (CVD). Therefore, if a film formation defect (e.g., a pinhole) occurs in the deposited film, a discontinuity is 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 discontinuity, which may cause a short circuit or corrosion of the electrode. In order to reduce the risk of film formation defect, it is necessary to ensure the thickness of the deposited film or strictly control the film formation state, which leads to a decrease in manufacturing efficiency and an increase in material costs.

[0005] The present disclosure provides a head chip, a liquid jet head, a liquid jet recording apparatus, and a method for manufacturing the head chip, which are capable of protecting electrodes while improving manufacturing efficiency and reducing costs.

[0006] In order to solve the above problems, the present disclosure employs the following aspects: (1) A head chip according to one aspect of the present disclosure includes a flow path member in which a plurality of pressure chambers for storing liquid are formed and aligned in a first direction, an actuator plate arranged on the flow path member while facing the pressure chambers in a second direction intersecting the first direction, drive wiring formed on a flow path facing surface facing the flow path member in a drive section of the actuator plate that overlaps with the pressure chambers when viewed from the second direction, and a sheet-like protective film that has a first covering section that covers the drive wiring on the flow path facing surface and that separates the pressure chambers from the drive section.

[0007] According to this aspect, by separating the pressure chamber and the drive unit with a sheet-like protective film, the occurrence of discontinuities such as pinholes can be suppressed, unlike conventional configurations in which a deposited film made of a paraxylylene-based resin material or the like is formed by a film-forming method such as CVD. In other words, by separating the pressure chamber and the drive unit with a continuously formed sheet-like protective film, it is possible to prevent liquid from reaching the drive wiring formed in the drive unit. This suppresses short circuits and corrosion of the drive wiring, thereby providing a highly reliable head chip. Furthermore, by employing a sheet-like protective film, a simpler and less costly protective film can be provided compared to configurations in which a deposited film is formed by a film-forming method such as CVD. As a result, the manufacturing efficiency of head chips can be improved, and the cost of head chips can be reduced.

[0008] (2) In the head chip according to the above aspect (1), it is preferable that the protective film has a protrusion that protrudes outward relative to the flow path member and the actuator plate in a direction intersecting the second direction when viewed from the second direction. According to this aspect, by providing the protective film with a protrusion, when the protective film is provided on the flow path opposing surface (drive unit), the protrusion can be used as a gripping margin in the protective film formation process or as a margin for absorbing misalignment between the actuator plate and the protective film in a direction intersecting the second direction. This improves the manufacturing efficiency of the head chip.

[0009] (3) In the head chip according to the aspect (2) above, it is preferable that the protrusion covers a side surface of the actuator plate facing the intersecting direction. According to this aspect, the protrusion covers the boundary between the first covering portion and the actuator plate. This can prevent liquid from entering the interface between the flow channel-facing surface of the actuator plate and the protective film (first covering portion) from outside the head chip. This can improve the reliability of the head chip.

[0010] (4) In the head chip according to the above aspect (3), it is preferable that the protrusion extends along the first direction on a portion of the side surface facing a third direction intersecting the first direction among the intersecting directions. According to this aspect, the protrusion is arranged on the side surface of the actuator plate along the arrangement direction of the pressure chambers. This prevents the drive wiring corresponding to different pressure chambers from being bridged by the liquid even if liquid enters the interface between the flow path member and the protective film.

[0011] (5) In the head chip according to any one of the above aspects (1) to (4), it is preferable that the protective film is provided continuously over the entire area of ​​the flow channel facing surface. According to this aspect, since the entire flow channel facing surface is covered with the protective film, it is possible to reliably prevent the liquid from reaching the drive wiring.

[0012] (6) In the head chip according to the above aspect (5), it is preferable that the drive section has a recess formed therein that is recessed in a direction away from the flow path member in the second direction, the drive wiring is formed on the inner surface of the recess, and the first covering portion is provided following the inner surface of the recess so as to cover the drive wiring. According to this aspect, by forming the drive wiring on the inner surface of the recess, the surface area of ​​the drive wiring can be secured. As a result, the electric field generated in the actuator plate can be increased, and the pressure generated in the pressure chamber during liquid ejection can be improved. Moreover, by forming a recess in the actuator plate, the rigidity of the actuator plate in the second direction can be increased.

[0013] (7) In the head chip according to any one of aspects (1) to (4), a jet plate having jet holes communicating with the pressure chambers is provided on the opposite side of the flow path member from the actuator plate in the second direction, and the protective film preferably includes a second covering portion connected to the first covering portion and covering a portion of the flow path member facing the pressure chambers, and a third covering portion connected to the second covering portion and covering a surface of the flow path member facing the jet hole plate in the second direction. According to this aspect, the interface between the actuator plate and the flow path member is covered by the second covering portion, thereby preventing liquid from entering the interface between the actuator plate and the flow path member. Furthermore, the surface of the flow path member facing the jet hole plate is covered by the third covering portion. Therefore, even if damage occurs to the third covering portion and liquid enters the interface between the flow path member and the protective film, the liquid can be prevented from reaching the interface between the actuator plate and the flow path member. As a result, peeling between the actuator plate and the flow path member can be prevented. Furthermore, by increasing the distance to the interface between the protective film and the flow path member by the thickness of the protective film, even if the second covering portion is damaged, it is possible to prevent the liquid from reaching the interface between the actuator plate and the flow path member, thereby preventing separation between the actuator plate and the flow path member.

[0014] (8) In the head chip according to any one of (1) to (4) above, a jet plate having jet holes communicating with the pressure chambers is provided on the opposite side of the flow path member from the actuator plate in the second direction. The protective film preferably includes a first protective portion continuously provided across the entire flow path facing surface and a second protective portion superimposed on the first protective portion on the drive unit. The second protective portion preferably includes a second protective portion connected to the first protective portion and covering a portion of the flow path member facing the pressure chambers, and a third protective portion connected to the second protective portion and covering a surface of the flow path member facing the jet hole plate in the second direction. According to this aspect, the entire flow path facing surface is covered by the first protective portion, thereby reliably preventing liquid from reaching the drive wiring. Furthermore, the interface between the actuator plate and the flow path member is covered by the second protective portion, thereby preventing liquid from entering the interface between the actuator plate and the flow path member. This prevents peeling between the actuator plate and the flow path member.

[0015] (9) In the head chip according to any one of the above aspects (1) to (8), the softening point of the protective film is preferably set to 120° C. or lower. According to this aspect, when the protective film is brought into close contact with the drive unit while being heated in the protective film forming process, it is possible to suppress the occurrence of polarization breakdown (for example, around 130° C.) in the actuator plate. This makes it possible to provide a head chip with excellent reliability.

[0016] (10) In the head chip according to any one of the above aspects (1) to (9), the protective film is preferably formed of a thermoplastic resin. According to this aspect, the protective film is easily deformed by heating it in the protective film forming step. This makes it easier to bring the protective film into close contact with the drive unit.

[0017] (11) A liquid jet head according to an aspect of the present disclosure preferably includes the head chip according to any one of the above aspects (1) to (10). According to this aspect, a highly reliable liquid jet head can be provided because it includes the head chip according to the above aspect.

[0018] (12) A liquid jet recording apparatus according to an aspect of the present disclosure preferably includes the liquid jet head according to aspect (11). According to this aspect, since the liquid jet recording apparatus includes the head chip according to the aspect, it is possible to provide a highly reliable liquid jet recording apparatus.

[0019] (13) A method for manufacturing a head chip according to one aspect of the present disclosure includes a flow path member in which a plurality of pressure chambers for storing liquid are formed in a line in a first direction, an actuator plate arranged on the flow path member facing the pressure chambers in a second direction intersecting the first direction and having a polarization direction in the second direction, drive wiring formed on a flow path facing surface of a drive unit of the actuator plate that overlaps with the pressure chambers when viewed from the second direction, the drive wiring facing the flow path member, and a sheet-like protective film that covers the drive wiring on the flow path facing surface of the drive unit and separates the pressure chambers and the drive unit, and includes a protective film forming step of covering the drive unit with the protective film by adhering the protective unit to the drive unit.

[0020] (14) In the head chip manufacturing method according to the aspect (13), the protective film forming step preferably includes, in a chamber in which the actuator plate and the protective film are set, creating a negative pressure in a first space located on the actuator plate side of the protective film relative to a second space located on the opposite side of the protective film from the actuator plate, thereby adhering the protective film to the drive unit. According to this aspect, creating a pressure difference between the first space and the second space makes it easier to quickly adhering the protective film to the drive unit.

[0021] According to one aspect of the present disclosure, it is possible to protect the drive wiring while improving manufacturing efficiency and reducing costs.

[0022] 1 is a schematic diagram of an inkjet printer according to a first embodiment. FIG. 2 is a schematic diagram of an inkjet head and an ink circulation mechanism according to the first embodiment. FIG. 3 is an exploded perspective view of a head chip according to the first embodiment. FIG. 4 is a cross-sectional view corresponding to line IV-IV in FIG. 3. FIG. 5 is a cross-sectional view corresponding to line V-V in FIG. 4. FIG. 6 is a plan view of a flow path member according to the first embodiment. FIG. 7 is a bottom view of an actuator plate according to the first embodiment. FIG. 8 is a plan view of an actuator plate according to the first embodiment. FIG. 9 is a plan view of a cover plate according to the first embodiment. FIG. 10 is a flowchart for explaining a method of manufacturing a head chip according to the first embodiment. FIG. 11 is a process diagram for explaining a method of manufacturing a head chip according to the first embodiment. FIG. 12 is a process diagram for explaining a method of manufacturing a head chip according to the first embodiment. FIG. 13 is a process diagram for explaining a method of manufacturing a head chip according to the first embodiment. FIG. 14 is a process diagram for explaining a method of manufacturing a head chip according to the first embodiment. FIG. 15 is a cross-sectional view of a head chip according to a second embodiment. FIG. 16 is a cross-sectional view of a head chip according to a third embodiment. FIG. 17 is a cross-sectional view of a head chip according to the third embodiment. FIG. 18 is a cross-sectional view of a head chip according to the second embodiment.

[0023] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the embodiments and modified examples described below, corresponding components may be designated by the same reference numerals and their description may be omitted. In the following description, expressions indicating relative or absolute arrangements, such as "parallel," "orthogonal," "center," and "coaxial," not only strictly refer to such arrangements, but also refer to a state in which there is a relative displacement with a tolerance or an angle or distance that provides the same function. In the following embodiment, an inkjet printer (hereinafter simply referred to as a printer) that records on a recording medium using ink (liquid) will be described as an example. In the drawings used in the following description, the scale of each component has been appropriately changed to make each component recognizable.

[0024] (First embodiment) [Printer 1] Fig. 1 is a schematic diagram of a printer 1. The printer (liquid jet recording apparatus) 1 shown in Fig. 1 includes a pair of transport mechanisms 2 and 3, an ink tank 4, an inkjet head (liquid jet head) 5, an ink circulation mechanism 6, and a scanning mechanism 7.

[0025] In the following description, an X, Y, Z Cartesian coordinate system will be used as necessary. In this case, the X direction corresponds to the transport direction (sub-scanning direction) of the recording medium P (e.g., paper, etc.). The Y direction corresponds to the scanning direction (main scanning direction) of the scanning mechanism 7. The Z direction indicates the height direction (direction of gravity) perpendicular to the X and Y directions. In the following description, of the X, Y, and Z directions, the arrows in the figures are defined as the plus (+) side, and the opposite side to the arrows is defined as the minus (-) side. In this specification, the +Z side corresponds to the upward direction in the direction of gravity, and the -Z side corresponds to the downward direction in the direction of gravity.

[0026] The transport mechanisms 2 and 3 transport the recording medium P to the +X side. Each of the transport mechanisms 2 and 3 includes a pair of rollers 11 and 12 extending in the Y direction, for example. The ink tanks 4 each contain four colors of ink, for example, yellow, magenta, cyan, and black. Each inkjet head 5 is configured to be able to eject the four colors of ink, yellow, magenta, cyan, and black, depending on the ink tank 4 connected to it.

[0027] 2 is a schematic 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.

[0028] The pressure pump 24 pressurizes the ink supply pipe 21 and sends ink through the ink supply pipe 21 to the inkjet head 5. As a result, the ink supply pipe 21 side is under positive pressure relative to the inkjet head 5. The suction pump 25 reduces the pressure inside the ink discharge pipe 22 and sucks ink from the inkjet head 5 through the ink discharge pipe 22. As a result, the ink discharge pipe 22 side is under negative pressure relative to the inkjet head 5. By driving the pressure pump 24 and the suction pump 25, the ink can be circulated between the inkjet head 5 and the ink tank 4 through the circulation flow path 23.

[0029] 1, the scanning mechanism 7 causes the inkjet head 5 to scan back and forth 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.

[0030] <Inkjet head 5> The inkjet head 5 is mounted on a 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. The inkjet head 5 includes a head chip 50 (see FIG. 3), an ink supply unit (not shown) that connects the ink circulation mechanism 6 and the head chip 50, and a control unit (not shown) that applies a drive voltage to the head chip 50.

[0031] <Head Chip 50> FIG. 3 is an exploded perspective view of the head chip 50. FIG. 4 is a cross-sectional view of the head chip 50 taken along line IV-IV in FIG. 3. FIG. 5 is a cross-sectional view of the head chip 50 taken along line V-V in FIG. 4. The head chip 50 shown in FIGS. 3 to 5 is a so-called circulation-type side-chute head chip 50. The head chip 50 circulates ink between the ink tank 4 and the head chip 50, and ejects ink from the center of the pressure chamber 61 (described later) in the extension direction (Y direction). The head chip 50 includes a nozzle plate 51, a flow path member 52, a first protective film 53, an actuator plate 54, a film 55, and a cover plate 56. In the following description, the direction from the nozzle plate 51 to the cover plate 56 in the Z direction (+Z side) is referred to as the front side, and the direction from the cover plate 56 to the nozzle plate 51 (-Z side) is referred to as the back side.

[0032] The flow path member 52 is plate-shaped with its thickness direction aligned in the Z direction. The flow path member 52 is made of a material that is resistant to ink. Examples of such materials that can be used include metals, metal oxides, glass, resins, and ceramics. The flow path member 52 is formed with flow paths 60 through which ink flows, and a plurality of pressure chambers 61 that communicate with the flow paths 60 and contain ink. The flow paths 60 and the pressure chambers 61 penetrate the flow path member 52 in the Z direction.

[0033] FIG. 6 is a plan view of the flow path member 52. As shown in FIG. 6, the pressure chambers 61 are arranged at intervals in the X direction. Portions of the flow path member 52 located between adjacent pressure chambers 61 form partition walls 62 that separate the adjacent pressure chambers 61 in the X direction. Each pressure chamber 61 is formed as a groove extending linearly in the Y direction. Each pressure chamber 61 penetrates the flow path member 52. In the first embodiment, a configuration in which the channel extension direction coincides with the Y direction will be described. However, the channel extension direction may intersect with the Y direction. Furthermore, the shape of the pressure chamber 61 in a plan view is not limited to a rectangular shape (a shape in which one of the X direction and the Y direction is the longitudinal direction and the other is the lateral direction). The shape of the pressure chamber 61 in a plan view may be a polygonal shape such as a square or a triangle, a circle, an ellipse, or the like.

[0034] The flow paths 60 include an inlet-side common flow path 64, an inlet-side communication path 65, an outlet-side common flow path 66, an outlet-side communication path 67, and a bypass path 68. The inlet-side common flow path 64 extends in the X direction through a portion of the flow path member 52 located on the +Y side of each pressure chamber 61. The -X side end of the inlet-side common flow path 64 is connected to an inlet port (not shown). The inlet port is connected directly or indirectly to the ink supply tube 21 (see FIG. 2). Ink flowing through the ink supply tube 21 is supplied to the inlet-side common flow path 64 through the inlet port. The inlet-side communication path 65 connects the inlet-side common flow path 64 to each pressure chamber 61. Each inlet-side communication path 65 branches toward the -Y side from a portion of the inlet-side common flow path 64 that overlaps with each pressure chamber 61 when viewed from the Y direction. The -Y side end of the inlet-side communication path 65 is connected to the pressure chamber 61.

[0035] The outlet-side common flow path 66 extends in the X direction through a portion of the flow path member 52 that is located on the -Y side of each pressure chamber 61. The +X side end of the outlet-side common flow path 66 is connected to an outlet port (not shown). The outlet port is directly or indirectly connected to the ink discharge tube 22 (see FIG. 2). Ink flowing through the outlet-side common flow path 66 is supplied to the ink discharge tube 22 through the outlet port. The outlet-side communication paths 67 connect the outlet-side common flow path 66 to each pressure chamber 61. Each outlet-side communication path 67 branches off toward the +Y side from a portion of the outlet-side common flow path 66 that overlaps with each pressure chamber 61 when viewed from the Y direction. The +Y side end of the outlet-side communication path 67 is connected to the pressure chamber 61.

[0036] As shown in Figures 4 and 5, the nozzle plate 51 is fixed to the back surface of the flow path member 52 by adhesive or the like. The nozzle plate 51 has the same outline as the flow path member 52 in a plan view. The nozzle plate 51 closes the -Z side openings of the flow paths 60 and the pressure chambers 61. In the first embodiment, the nozzle plate 51 is made of a resin material such as polyimide. The nozzle plate 51 is formed to have a thickness of approximately several tens to several hundred microns. However, the nozzle plate 51 may have a single layer structure or a laminated structure made of a metal material (such as SUS or Ni-Pd), glass, silicon, or the like, in addition to the resin material.

[0037] The nozzle plate 51 is formed with a plurality of nozzle holes 71 penetrating the nozzle plate 51 in the Z direction. The nozzle holes 71 are spaced apart in the X direction. Each nozzle hole 71 is connected to a corresponding pressure chamber 61 at its center in the X and Y directions. In the first embodiment, each nozzle hole 71 is formed in a tapered shape, for example, with its inner diameter gradually decreasing from the +Z side to the −Z side. In the first embodiment, a configuration in which a plurality of pressure chambers 61 and a plurality of nozzle holes 71 are aligned in a line in the X direction has been described. However, this configuration is not limited to this. If the plurality of pressure chambers 61 and the plurality of nozzle holes 71 aligned in the X direction are considered to be nozzle rows, the nozzle rows may be arranged in a plurality of rows spaced apart in the Y direction. In this case, if the number of nozzle rows is n, it is preferable that the arrangement pitch of the nozzle holes 71 (pressure chambers 61) in one nozzle row in the Y direction be shifted by 1 / n pitch from the arrangement pitch of the nozzle holes 71 in another nozzle row adjacent to the one nozzle row.

[0038] The first protective film 53 is interposed between the flow path member 52 and the actuator plate 54. Details of the first protective film 53 will be described later.

[0039] The actuator plate 54 is provided on the first protective film 53 with its thickness direction in the Z direction. The outer shape of the actuator plate 54 in a plan view is the same as the outer shape of the flow path member 52 in a plan view. The actuator plate 54 is overlaid on the entire flow path member 52 with the first protective film 53 sandwiched therebetween. The actuator plate 54 faces each pressure chamber 61 in the Z direction with the first protective film 53 sandwiched therebetween. The portions of the actuator plate 54 that overlap with the pressure chambers 61 in a plan view constitute driving sections 54a. Note that the actuator plate 54 (driving sections 54a) are not limited to a configuration in which they collectively cover all of the pressure chambers 61, and may be provided individually for each pressure chamber 61.

[0040] The actuator plate 54 is made of a piezoelectric material such as PZT (lead zirconate titanate). The polarization direction of the actuator plate 54 is set to face the +Z side. Drive wiring 75 is formed on both sides of the actuator plate 54. The actuator plate 54 is configured to be deformable in the Z direction when an electric field is generated by a voltage applied by the drive wiring 75. The actuator plate 54 expands or contracts the volume of the pressure chambers 61 by deformation in the Z direction, thereby ejecting ink from the pressure chambers 61. The configuration of the drive wiring 75 will be described later. The polarization direction of the actuator plate 54 may also face the -Z side.

[0041] The film 55 is fixed to the surface of the actuator plate 54 by adhesive or the like. In the first embodiment, the film 55 covers the entire surface of the actuator plate 54. The film 55 is made of an insulating and elastically deformable material. For example, a resin material (polyimide, epoxy, polypropylene, etc.) is selected as such a material. In the first embodiment, "elastically deformable" means that the film 55 is a member having a smaller compressive elastic modulus than adjacent members in the Z direction when multiple members are stacked. In other words, the film 55 has a smaller compressive elastic modulus than the flow path member 52 and the actuator plate 54. Note that the film 55 is not an essential component.

[0042] The cover plate 56 is fixed to the surface of the film 55 by adhesive or the like, with the thickness direction being the Z direction. The thickness of the cover plate 56 in the Z direction is greater than the actuator plate 54, the flow path member 52, the first protective film 53, and the film 55. In the first embodiment, the cover plate 56 is made of an insulating material (e.g., metal oxide, glass, resin, ceramics, etc.). The cover plate 56, the film 55, and the actuator plate 54 constitute a stacked body 100.

[0043] Next, the structure of the drive wiring 75 will be described. FIG. 7 is a bottom view of the actuator plate 54. FIG. 8 is a plan view of the actuator plate 54. The drive wiring 75 is provided corresponding to each pressure chamber 61. The drive wirings 75 corresponding to adjacent pressure chambers 61 are formed symmetrically with respect to an axis of symmetry T along the Y direction. In the following description, the drive wiring 75 provided corresponding to one of the multiple pressure chambers 61 will be described as an example, and descriptions of the drive wirings 75 corresponding to the other pressure chambers 61 will be omitted as appropriate. As shown in FIGS. 7 and 8 , the drive wiring 75 includes a common wiring 81 and individual wiring 82. The common wiring 81 includes a first common electrode 81a, a second common electrode 81b, a rear surface wiring 81c, a front surface wiring 81d, a first through wiring 81e, a second through wiring 81f, and a common pad 81g.

[0044] As shown in Figures 4 and 7, the first common electrodes 81a are formed on the back surface (channel-facing surface) of the actuator plate 54 at positions overlapping with the partition walls 62 as viewed from the Z direction. The first common electrode 81a located on the +X side of each first common electrode 81a (hereinafter referred to as the +X-side common electrode 81a1) entirely overlaps with the partition wall 62 (hereinafter referred to as the partition wall 62a) located on the +X side of the partition walls 62 that define the pressure chambers 61 as viewed from the Z direction. The first common electrode 81a located on the -X side of each first common electrode 81a (hereinafter referred to as the -X-side common electrode 81a2) entirely overlaps with the partition wall 62 (hereinafter referred to as the partition wall 62b) located on the -X side of the partition walls 62 that define the pressure chambers 61 as viewed from the Z direction. Each first common electrode 81a extends linearly in the Y direction with a length equal to that of the pressure chamber 61.

[0045] 4 and 8, the second common electrode 81b is disposed on the surface of the actuator plate 54 at a position that overlaps the corresponding pressure chamber 61 when viewed from the Z direction, but does not overlap the first common electrode 81a when viewed from the Z direction. In the example shown, the second common electrode 81b is formed in the center of the pressure chamber 61 in the X direction. The second common electrode 81b extends linearly in the Y direction with a length equal to that of the pressure chamber 61. Note that the width of the second common electrode 81b in the X direction can be changed as appropriate, as long as the second common electrode 81b is formed at a position that overlaps the pressure chamber 61 when viewed from the Z direction.

[0046] 4 and 7, the rear surface lead-out wiring 81c is connected to each of the first common electrodes 81a collectively on the rear surface of the actuator plate 54. The rear surface lead-out wiring 81c extends in the X direction while being connected to the −Y side end of each of the first common electrodes 81a.

[0047] 4 and 8, the surface wiring 81d is connected to the second common electrode 81b on the surface of the actuator plate 54. The surface wiring 81d extends in the X direction from the −Y side end of the second common electrode 81b.

[0048] As shown in FIGS. 4, 7, and 8, the first through wiring 81e connects the rear surface lead-out wiring 81c and the front surface lead-out wiring 81d. The first through wiring 81e is provided to penetrate the actuator plate 54 in the Z direction. A first common wiring hole 91 is formed in a portion of the actuator plate 54 located on the -X side with respect to the -X side common electrode 81a2. The first common wiring hole 91 is a long groove that penetrates the actuator plate 54 in the Z direction and extends in the Y direction. The first through wiring 81e is formed on the inner surface of the first common wiring hole 91. The first through wiring 81e is formed on the inner surface of the first common wiring hole 91 over at least the entire area in the Z direction. The first through wiring 81e is connected to the rear surface lead-out wiring 81c at the -Z side opening edge of the first common wiring hole 91. The first through wiring 81 e is connected to the surface lead wiring 81 d at the +Z side opening edge of the first common wiring hole 91 .

[0049] FIG. 9 is a plan view of the cover plate 56. As shown in FIGS. 4 and 9 , the second through wiring 81f routes the first through wiring 81e to the surface of the cover plate 56. The second through wiring 81f is provided to penetrate the film 55 and the cover plate 56 in the Z direction. A second common wiring hole 92 is formed in the film 55 and the cover plate 56 at a position that overlaps the first common wiring hole 91 when viewed from the Z direction. The second common wiring hole 92 penetrates the film 55 and the cover plate 56 in the Z direction. The second common wiring hole 92 is a long groove extending in the Y direction, similar to the first common wiring hole 91. The second common wiring hole 92 is connected to the first common wiring hole 91. The second through wiring 81f is formed on the inner surface of the second common wiring hole 92. The second through wiring 81f is formed on the inner surface of the second common wiring hole 92 over at least the entire area in the Z direction. The second through wiring 81f is connected to the first through wiring 81e at the −Z side opening edge of the second hole 92 for common wiring.

[0050] 9, the common pad 81g is formed on the surface of the cover plate 56. The common pad 81g extends in the X direction from a portion of the surface of the cover plate 56 that overlaps with the pressure chamber 61 when viewed from the Z direction. The −X side end of the common pad 81g is connected to the second through wiring 81f at the +Z side opening edge of the second common wiring hole 92.

[0051] As shown in Figures 7 and 8, the individual wiring 82 includes a first individual electrode 82a, a second individual electrode 82b, a back surface wiring 82c, a front surface wiring 82d, a first through wiring 82e, a second through wiring 82f, and an individual pad 82g.

[0052] As shown in Figures 4 and 7, the first individual electrodes 82a are formed on the rear surface of the actuator plate 54 between the first common electrodes 81a. The first individual electrodes 82a extend in the Y direction while being spaced apart from the first common electrodes 81a in the X direction. A potential difference is generated between the first individual electrodes 82a and the first common electrodes 81a. At least a portion of the first individual electrodes 82a overlaps with the second common electrodes 81b when viewed in the Z direction. Therefore, a potential difference is generated between the first individual electrodes 82a and the second common electrodes 81b.

[0053] 4 and 8, the second individual electrodes 82b are formed on the surface of the actuator plate 54 in portions located on both sides of the second common electrode 81b in the X direction. Each second individual electrode 82b extends in the Y direction with a gap in the X direction from the second common electrode 81b. The second individual electrodes 82b generate a potential difference between themselves and the second common electrode 81b.

[0054] 4 and 8 , the second individual electrode 82b located on the +X side of each second individual electrode 82b (hereinafter referred to as the +X-side individual electrode 82b1) generates a potential difference between itself and the +X-side common electrode 81a1. A portion of the +X-side individual electrode 82b1 overlaps with the partition wall 62a when viewed from the Z direction. The +X-side individual electrode 82b1 faces the +X-side common electrode 81a1 on the partition wall 62a in the Z direction.

[0055] Of the second individual electrodes 82b, the second individual electrode 82b located on the -X side (hereinafter referred to as the -X-side individual electrode 82b2) generates a potential difference between itself and the -X-side common electrode 81a2. A portion of the -X-side individual electrode 82b1 overlaps with the partition wall 62b when viewed from the Z direction. The -X-side individual electrode 82b2 faces the -X-side common electrode 81a2 in the Z direction on the partition wall 62b.

[0056] 7, the rear surface lead-out wiring 82c is connected to the first individual electrode 82a on the rear surface of the actuator plate 54. The rear surface lead-out wiring 82c extends in the X direction from the +Y side end of the first individual electrode 82a.

[0057] 8, the surface wiring 82d is connected to each of the second individual electrodes 82b collectively on the surface of the actuator plate 54. The surface wiring 82d extends in the X direction while being connected to the +Y side end of each of the second individual electrodes 82b.

[0058] As shown in FIGS. 4, 7, and 8, the first through wiring 82e connects the rear surface lead-out wiring 82c and the surface lead-out wiring 82d. The first through wiring 82e is provided to penetrate the actuator plate 54 in the Z direction. A first individual wiring hole 93 is formed in a portion of the actuator plate 54 located on the +X side of the +X side individual electrode 82b1. The first individual wiring hole 93 is a long groove that penetrates the actuator plate 54 in the Z direction and extends in the Y direction. The first through wirings 82e of adjacent pressure chambers 61 are formed on the inner surface of the first individual wiring hole 93 in a mutually separated state. The first through wiring 82e is connected to the rear surface lead-out wiring 82c at the -Z side opening edge of the first individual wiring hole 93. The first through wiring 82e is connected to the surface lead-out wiring 82d at the +Z side opening edge of the first individual wiring hole 93.

[0059] As shown in FIGS. 4 and 9 , the second through wires 82f route the first through wires 82e to the surface of the cover plate 56. The second through wires 82f are provided to penetrate the film 55 and the cover plate 56 in the Z direction. Second through wire holes 94 are formed in the film 55 and the cover plate 56 at positions that overlap the first through wire holes 93 when viewed from the Z direction. The second through wire holes 94 penetrate the film 55 and the cover plate 56 in the Z direction. The second through wire holes 94 are elongated grooves extending in the Y direction, similar to the first through wire holes 93. The second through wire holes 94 are connected to the first through wire holes 93. The second through wires 82f of adjacent pressure chambers 61 are formed on the inner surface of the second through wire holes 94 in a mutually separated state. The second through wires 82f are connected to the first through wires 82e at the −Z-side opening edge of the second through wire holes 94.

[0060] The individual pad 82g is formed on the surface of the cover plate 56. The individual pad 82g extends in the X direction over a portion of the surface of the cover plate 56 that overlaps with the pressure chamber 61 when viewed from the Z direction. The +X side end of the individual pad 82g is connected to the second through wiring 82f at the +Z side opening edge of the second individual wiring hole 94.

[0061] 4 , the portions of the drive wiring 75 that are formed on the surface of the actuator plate 54 are covered with the film 55. Specifically, of the drive wiring 75, the second common electrode 81 b, the second individual electrode 82 b, the surface routing wiring 81 d, 82 d, and the first through wiring 81 e, 82 e are covered with the film 55.

[0062] As shown in Figures 5 and 9, a common separation groove 96 is formed on the surface of the cover plate 56. The common separation groove 96 is formed in a portion of the surface of the cover plate 56 that is located between the common pad 81g and the individual pad 82g. The common separation groove 96 extends in the X direction so as to cross between the pressure chambers 61. A flexible printed circuit board 97 is pressure-bonded to the surface of the cover plate 56. The flexible printed circuit board 97 is mounted on the common pad 81g and the individual pads 82g on the surface of the cover plate 56. The flexible printed circuit board 97 is drawn out to the +Z side. The common wiring 81 (common pads 81g) corresponding to the multiple pressure chambers 61 are shared on the flexible printed circuit board 97.

[0063] 3 to 5, the first protective film 53 is integrally formed in a sheet (film) shape. The first protective film 53 is a so-called skin pack. The first protective film 53 is arranged so as to separate the pressure chamber 61 from the driving unit 54a. The first protective film 53 is provided on the back surface of the actuator plate 54 and on the side surfaces of the laminate 100 (a laminate of the actuator plate 54, the film 55, and the cover plate 56) via an adhesive. For example, an EVA-based adhesive is preferably used as the adhesive. However, other adhesives such as acrylic, epoxy, silicone, and urethane adhesives can also be used.

[0064] The first protective film 53 includes a rear surface protective portion (first covering portion) 53a, a +X-side protrusion 53b, a −X-side protrusion 53c, a +Y-side protrusion 53d, and a −Y-side protrusion 53e. The rear surface protective portion 53a is sandwiched between the actuator plate 54 and the flow path member 52. The rear surface protective portion 53a covers the entire rear surface of the actuator plate 54 while being in direct or indirect contact with the rear surface of the actuator plate 54. The rear surface protective portion 53a is in direct contact with the rear surface of the actuator plate 54 in a portion of the rear surface of the actuator plate 54 where the drive wiring 75 is not formed. The rear surface protective portion 53a covers the rear surface of the actuator plate 54 in a portion of the rear surface of the actuator plate 54 where the drive wiring 75 is formed while being in close contact with the drive wiring 75 (e.g., the first common electrode 81a, the first individual electrode 82a, the rear surface wiring 81c, 82c, etc.). The back surface protection portion 53a closes the -Z side opening of the first common wiring hole 91 and the -Z side opening of the first individual wiring hole 93. In the first embodiment, the back surface protection portion 53a is continuously formed over the entire back surface of the actuator plate 54, thereby preventing the drive wiring 75 from being exposed inside the pressure chamber 61. The back surface protection portion 53a is bonded to the surface of the flow path member 52 via an adhesive or the like.

[0065] The +X-side protrusion 53b is a portion of the first protective film 53 that protrudes toward the +X side relative to the actuator plate 54. The +X-side protrusion 53b is continuous over the entire length of the +X-side edge of the back surface protective portion 53a. The +X-side protrusion 53b is bent toward the +Z side relative to the back surface protective portion 53a on the +X side relative to the actuator plate 54. The +X-side protrusion 53b is in close contact with one of the side surfaces of the laminate 100 that faces the +X side. The +X-side protrusion 53b extends over the entire Y-direction on one of the side surfaces of the laminate 100 that faces the +X side. The -X-side protrusion 53c is a portion of the first protective film 53 that protrudes toward the -X side relative to the actuator plate 54. The -X-side protrusion 53c is continuous over the entire length of the -X-side edge of the back surface protective portion 53a. The -X side protrusion 53c is bent on the -X side with respect to the actuator plate 54 and on the +Z side with respect to the back surface protection portion 53a. The -X side protrusion 53c is in close contact with the side surface facing the -X side of the side surface of the laminate 100. The -X side protrusion 53c extends over the entire area in the Y direction on the side surface facing the -X side of the side surface of the laminate 100.

[0066] The +Y side protrusion 53d is a portion of the first protective film 53 that protrudes toward the +Y side relative to the actuator plate 54. The +Y side protrusion 53d is continuous over the entire length of the +Y side edge of the back surface protective portion 53a. The +Y side protrusion 53d is bent toward the +Z side relative to the back surface protective portion 53a on the +Y side relative to the actuator plate 54. The +Y side protrusion 53d is in close contact with the side surface of the laminate 100 that faces the +Y side. The +Y side protrusion 53d extends over the entire area in the X direction on the side surface of the laminate 100 that faces the +Y side. The -Y side protrusion 53e is a portion of the first protective film 53 that protrudes toward the -Y side relative to the actuator plate 54. The -Y side protrusion 53e is continuous over the entire length of the -Y side edge of the back surface protective portion 53a. The -Y side protrusion 53e is bent on the -Y side with respect to the actuator plate 54 and toward the +Z side with respect to the back surface protection portion 53a. The -Y side protrusion 53e is in close contact with the side surface of the laminate 100 that faces the -Y side. The -Y side protrusion 53e extends over the entire area in the X direction on the side surface of the laminate 100 that faces the -Y side. Therefore, the entire periphery of the side surface of the laminate 100 is covered by the protrusions 53b to 53e.

[0067] It is preferable that each of the protrusions 53b to 53e covers the boundary portion between the back surface protection portion 53a and the actuator plate 54 on the side of the laminate 100, and it is more preferable that it covers the boundary portion between the film 55 and the actuator plate 54, or the boundary portion between the film 55 and the cover plate 56.

[0068] The first protective film 53 of the first embodiment is preferably made of a thermoplastic resin material that has excellent insulating properties and ink resistance and a softening point (Vicat softening temperature according to JIS K7206) of 120°C or less, more preferably 100°C or less. In the first embodiment, the first protective film 53 is composed of a single layer film or a laminate film made of ionomer (softening point of 57°C to 80°C) or low-density polyethylene (softening point of 85°C to 97°C), etc. When a laminate film is used for the first protective film 53, it is preferable to use a material with excellent flexibility (e.g., ionomer) as a base layer and a material with excellent ink resistance (e.g., low-density polyethylene) as a surface layer. The thickness of the first protective film 53 is, for example, 10 μm to 200 μm.

[0069] [Operation Method of Printer 1] Next, a case where characters, figures, etc. are recorded on a recording medium P using the printer 1 configured as described above will be described below. In the initial state, it is assumed that the four ink tanks 4 shown in Fig. 1 are each filled with a sufficient amount of ink of a different color. The ink in the ink tanks 4 is then filled into the inkjet head 5 via the ink circulation mechanism 6.

[0070] When the printer 1 is operated in an initial state, the recording medium P is conveyed in the +X direction while being sandwiched between the rollers 11 and 12 of the conveyance mechanisms 2 and 3. Simultaneously with the conveyance of the recording medium P, the carriage 29 moves in the Y direction, causing the inkjet heads 5 mounted on the carriage 29 to move back and forth in the Y direction. While the inkjet heads 5 move back and forth, ink is ejected from each inkjet head 5 appropriately onto the recording medium P. This allows characters, images, etc. to be recorded on the recording medium P.

[0071] The operation of each inkjet head 5 will now be described in detail. In a circulation side chute type inkjet head 5 such as that of this embodiment, first, the pressure pump 24 and the suction pump 25 shown in FIG. 2 are operated to circulate ink through the circulation flow path 23. In this case, ink circulating through the ink supply pipe 21 is supplied into each pressure chamber 61 through the inlet side common flow path 64 and the inlet side communicating path 65. The ink supplied into each pressure chamber 61 circulates through each pressure chamber 61 in the Y direction. Thereafter, the ink is discharged through the outlet side communicating path 67 to the outlet side common flow path 66, and then returned to the ink tank 4 through the ink discharge pipe 22. This allows ink to circulate between the inkjet head 5 and the ink tank 4.

[0072] When the inkjet head 5 starts to move back and forth due to the movement of the carriage 29 (see FIG. 1), a drive voltage is applied between the common electrodes 81 a, 81 b and the individual electrodes 82 a, 82 b via the flexible printed circuit board 97. At this time, the drive voltage is applied with the common electrodes 81 a, 81 b at the reference potential GND and the individual electrodes 82 a, 82 b at the drive potential Vdd.

[0073] Application of a drive voltage generates a potential difference in the X direction between the first common electrode 81a and the first individual electrode 82a, and between the second common electrode 81b and the second individual electrode 82b. The potential difference in the X direction generates an electric field in the actuator plate 54 in a direction perpendicular to the polarization direction (Z direction). As a result, the actuator plate 54 undergoes thickness shear deformation in the Z direction due to shear mode. Specifically, on the back surface of the actuator plate 54, an electric field is generated between the first common electrode 81a and the first individual electrode 82a in a direction that moves them toward each other in the X direction. On the front surface of the actuator plate 54, an electric field is generated between the second common electrode 81b and the second individual electrode 82b in a direction that moves them away from each other in the X direction. As a result, the portions of the actuator plate 54 corresponding to each pressure chamber 61 shear upward from both ends in the X direction toward the center.

[0074] Meanwhile, a potential difference occurs in the Z direction between the first common electrode 81a and the second individual electrode 82b, and between the first individual electrode 82a and the second common electrode 81b. This potential difference in the Z direction generates an electric field in the actuator plate 54 in a direction parallel to the polarization direction (Z direction). As a result, the actuator plate 54 expands and contracts in the Z direction due to the bend mode. That is, in the head chip 50 of the first embodiment, the deformations of the actuator plate 54 due to the shear mode and the bend mode both extend in the Z direction. Specifically, when a drive voltage is applied, the actuator plate 54 deforms in a direction away from the pressure chamber 61. This causes the volume of the pressure chamber 61 to expand. When the drive voltage is then reduced to zero, the actuator plate 54 returns to its original state, and the volume of the pressure chamber 61 returns to its original state. During the process of the actuator plate 54's restoration, the pressure in the pressure chamber 61 increases, causing the ink in the pressure chamber 61 to be ejected to the outside through the nozzle hole 71. When the ink ejected to the outside lands on the recording medium P, print information is recorded on the recording medium P.

[0075] <Method of Manufacturing Head Chip 50> Next, a method of manufacturing the head chip 50 described above will be described. Fig. 10 is a flowchart for explaining the method of manufacturing the head chip 50. Figs. 11 to 17 are process diagrams for explaining the method of manufacturing the head chip 50. In the following explanation, for convenience, an example will be described in which the head chip 50 is manufactured at the chip level. As shown in Fig. 10, the method of manufacturing the head chip 50 includes a laminate processing step S1, a protective film forming step S2, a first flow path member processing step S3, a first bonding step S4, a second flow path member processing step S5, and a second bonding step S6.

[0076] 11 , in the laminate processing step S1, the drive wiring 75 is formed, and a laminate 100 is formed in which the actuator plate 54, the film 55, and the cover plate 56 are laminated. Specifically, some of the drive wiring 75 (common electrodes 81a, 81b, individual electrodes 82a, 82b, various routing wirings 81c, 81d, 82c, 82d, and first through wirings 81e, 82e) are formed on the actuator plate 54 by, for example, vapor deposition. The remaining drive wiring 75 (second through wirings 81f, 82f, common pad 81g, and individual pad 82g) are formed on the cover plate 56 by, for example, vapor deposition after the film 55 and the cover plate 56 are laminated on the surface of the actuator plate 54.

[0077] 12 , in the protective film forming process S2, a first protective film 53 is formed on the laminate 100. In the protective film forming process S2, an adhesive is first applied to a region of the laminate 100 where the first protective film 53 is to be formed. Next, the laminate 100 and the first protective film 53 are set in a chamber 101 while facing each other. Specifically, the laminate 100 is set on a stage 102 in the chamber 101 via an undercoat film 103, with the back surface of the actuator plate 54 facing upward. The undercoat film 103 is formed of a material that can be peeled off from both the actuator plate 54 and the first protective film 53. The first protective film 53 is set in the chamber 101 at a distance from the laminate 100. A portion of the first protective film 53 that is outside the laminate 100 in a plan view is held by a jig or the like (not shown). That is, the portion of the first protective film 53 located outside the stacked body 100 also functions as a gripping margin for gripping the first protective film 53 inside the chamber 101. Before the first protective film 53 is brought into close contact with the stacked body 100, the first protective film 53 has a thickness that is approximately two to five times that of the first protective film 53 after it has been brought into close contact with the stacked body 100. The adhesive may be applied to the first protective film 53 instead of the stacked body 100.

[0078] With the laminate 100 and the first protective film 53 set in the chamber 101, the chamber 101 is heated so that the first protective film 53 reaches or exceeds the softening point, but within a range below the Curie point (the temperature at which polarization is completely destroyed) of the actuator plate 54. Thereafter, a first space S1 (lower space) located on the actuator plate 54 side of the first protective film 53 within the chamber 101 is made to have a negative pressure relative to a second space S2 (upper space) located on the opposite side of the first protective film 53 from the actuator plate 54.

[0079] As a result, as shown in FIG. 13 , the pressure difference between the first space S1 and the second space S2 causes the first protective film 53 to approach the laminate 100. Thereafter, upon contact with the laminate 100, the first protective film 53 is stretched and deformed to conform to the outer surface shape of the laminate 100. As a result, the first protective film 53 adheres closely to the outer surface of the laminate 100, forming the skin pack body 110 shown in FIG. 14 . The chamber 101 is then cooled so that the temperature of the first protective film 53 falls below the softening point, and the skin pack body 110 is then removed from the chamber 101. Specifically, the first protective film 53 and the base film 103 are cut around the periphery of the laminate 100, and the skin pack body 110 is removed together with the base film 103. The base film 103 is then peeled off from the skin pack body 110. In the protective film forming step S2, the first protective film 53 and the stack 100 (stage 102) may be moved toward each other while a pressure difference is generated between the first space S1 and the second space S2.

[0080] 15, in the flow path member first processing step S3, the flow paths 60 (see FIG. 6) and the pressure chambers 61 are formed in the flow path member 52. The flow paths 60 and the pressure chambers 61 are formed by, for example, sandblasting the flow path member 52.

[0081] As shown in FIG. 16, in the first bonding step S4, the flow path member 52 is attached to the rear surface of the first protective film 53 (rear surface protection portion 53a) using an adhesive or the like.

[0082] 17 , in the second flow path member processing step S5, grinding is performed on the rear surface of the flow path member 52 (grinding step). At this time, the flow path member 52 is ground to the position where the flow paths 60 and the pressure chambers 61 are opened on the rear surface of the flow path member 52.

[0083] In the second bonding step S6, the nozzle plate 51 is attached to the rear surface of the flow path member 52 in a state where the nozzle holes 71 and the pressure chambers 61 are aligned. In this way, the head chip 50 is completed.

[0084] When the head chip 50 is manufactured at the wafer level, a stack of an actuator plate wafer, a film, and a cover plate wafer is formed. After that, the wafer stack is divided into individual pieces, and then the first protective film 53 may be formed on each of the individual pieces, or the first protective film 53 may be formed on the entire wafer stack, and then the wafer stack is divided into individual pieces.

[0085] As described above, the head chip 50 of the first embodiment includes a flow path member 52 in which a plurality of pressure chambers 61 are formed in a line in the X direction (first direction), an actuator plate 54 arranged facing the pressure chambers 61 in the Z direction (second direction), drive wiring 75 formed on the back surface (flow path facing surface) of each drive unit 54a of the actuator plate 54, and a sheet-like first protective film 53 having a back surface protective portion (first covering portion) 53a that covers the drive wiring 75 on the back surface of the drive unit 54a and separates the pressure chambers 61 from the drive unit 54a. According to this configuration, by covering the back surface of the drive unit 54a with the sheet-like first protective film 53, the occurrence of discontinuities such as pinholes can be suppressed, unlike conventional configurations in which a deposited film made of a paraxylylene-based resin material or the like is formed by a film formation method such as CVD. In other words, by protecting the back surface of the actuator plate 54 with the continuously formed sheet-like first protective film 53, ink can be prevented from reaching the drive wiring 75 formed on the back surface of the actuator plate 54. This makes it possible to provide a highly reliable head chip 50 by suppressing short circuits and corrosion of the drive wiring 75. Furthermore, by employing a sheet-like first protective film 53, it is possible to provide a simpler and less expensive first protective film 53 compared to a configuration in which a deposited film is formed by a film-forming method such as CVD. As a result, it is possible to improve the manufacturing efficiency of head chips and reduce the cost of head chips.

[0086] In the head chip 50 of the first embodiment, the first protective film 53 is configured to have protrusions 53b to 53e that protrude outward in the X and Y directions (intersecting directions) relative to the flow path member 52 and the actuator plate 54. With this configuration, when the first protective film 53 is provided on the back surface of the actuator plate 54, the protrusions 53b to 53e can be used as a gripping margin in the protective film forming step S2, or as a margin for absorbing misalignment between the actuator plate 54 and the first protective film 53 in the X or Y direction. This can improve the manufacturing efficiency of the head chip 50.

[0087] In the head chip 50 of the first embodiment, the protrusions 53b to 53e are configured to cover the side surfaces of the actuator plate 54. With this configuration, the boundary between the back surface protection portion 53a and the actuator plate 54 is covered by the protrusion 53b. This makes it possible to prevent liquids such as ink from entering the interface between the back surface protection portion 53a and the actuator plate 54 from outside the head chip 50. This makes it possible to improve the reliability of the head chip 50.

[0088] In the head chip 50 of the first embodiment, the Y-side protrusions 53d, 53e are configured to extend in the X direction on portions of the side surfaces of the actuator plate 54 that face the Y direction. With this configuration, the Y-side protrusions 53d, 53e are arranged along the arrangement direction of the pressure chambers 61 on the side surfaces of the actuator plate 54. This makes it possible to prevent ink from bridging between the drive wiring 75 corresponding to different pressure chambers 61, even if ink enters the interface between the flow path member 52 and the first protective film 53 (rear surface protective portion 53a).

[0089] In the head chip 50 of the first embodiment, the first protective film 53 (rear surface protective portion 53a) is configured to be provided continuously over the entire rear surface of the actuator plate 54. With this configuration, the entire rear surface of the actuator plate 54 is covered by the rear surface protective portion 53a, so that ink can be more reliably prevented from reaching the drive wiring 75.

[0090] In the head chip 50 of the first embodiment, the softening point of the first protective film 53 is set to 120° C. or lower. With this configuration, when the first protective film 53 is heated and brought into close contact with the rear surface of the actuator plate 54 (drive section 54 a) in the protective film forming step S2, it is possible to prevent polarization breakdown (for example, at about 130° C.) of the actuator plate 54. This makes it possible to provide a head chip 50 with excellent reliability.

[0091] In the head chip 50 of the first embodiment, the first protective film 53 is configured to be formed from a thermoplastic resin. With this configuration, the first protective film 53 can be easily deformed by heating the first protective film 53 in the protective film forming step S2. This makes it easy to bring the first protective film 53 into close contact with the rear surface of the actuator plate 54 (drive portion 54 a).

[0092] In the head chip 50 of the first embodiment, in the protective film forming process S2, the pressure difference between the first space S1 and the second space S2 is used to bring the first protective film 53 into close contact with the drive unit 54a. This configuration allows the protective unit 53a to quickly come into close contact with the drive unit 54a.

[0093] The printer 1 and inkjet head 5 of the first embodiment include the head chip 50 described above, and therefore can provide a printer 1 and inkjet head 5 with excellent reliability.

[0094] 18 and 19 are cross-sectional views of a head chip 50 according to a second embodiment. In the head chip 50 shown in FIGS. 18 and 19, the second protective film 253 is formed following the inner surfaces of the pressure chambers 61 and the rear surface of the flow path member 52. In the second embodiment, the flow path member 52, the actuator plate 54, the film 55, and the cover plate 56 of the head chip 50 constitute a laminated body 200. The skin pack body 210 is formed by covering the laminated body 200 with the second protective film 253.

[0095] The second protective film 253 includes an actuator protection portion (first covering portion) 253a, a flow path protection portion 253b, and protrusions 253c to 253f. The actuator protection portion 253a continuously covers the entire rear surface of the drive portion 54a. As a result, the actuator protection portion 253a separates the pressure chamber 61 from the drive portion 54a.

[0096] The flow path protection portion 253b is provided integrally with the inner surfaces of the pressure chambers 61 of the flow path member 52, the inner surfaces of the various flow paths 60, and the back surface of the flow path member 52. The flow path protection portion 253b includes a pressure chamber covering portion (second covering portion) 255, a flow path covering portion 256, and a back surface covering portion (third covering portion) 257.

[0097] The pressure chamber covering portion 255 is continuous with the entire outer periphery of the actuator protecting portion 253a. The pressure chamber covering portion 255 continuously covers the entire inner surface of the pressure chamber 61. The flow path covering portion 256 is continuous with the actuator protecting portion 253a or the pressure chamber covering portion 255. The flow path covering portion 256 is provided continuously over the entire inner surface of the various flow paths 60 (the inlet side common flow path 64, the inlet side communicating path 65, the outlet side common flow path 66, the outlet side communicating path 67, and the bypass path 68). The flow path covering portion 256 covers the inner surface of the various flow paths 60. The back surface covering portion 257 is continuous with the pressure chamber covering portion 255 or the flow path covering portion 256. The back surface covering portion 257 covers the entire back surface of the flow path member 52. The back surface covering portion 257 is sandwiched between the flow path member 52 and the nozzle plate 51. The rear surface covering portion 257 is bonded to the nozzle plate 51 via an adhesive.

[0098] Each of the protrusions 253c to 253f is connected to the outer periphery of the back surface covering portion 257. Similar to the protrusions 53b to 53e of the first embodiment, each of the protrusions 253c to 253f covers a corresponding one of the side surfaces of the laminate 200 while protruding from the flow path member 52 in a plan view. Each of the protrusions 253c to 253f preferably covers the boundary between the flow path member 52 and the actuator plate 54, and more preferably covers the boundary between the film 55 and the actuator plate 54 or the boundary between the film 55 and the cover plate 56.

[0099] The second protective film 253 of the second embodiment can be formed by performing the above-described protective film forming step S2 between the flow path member second processing step S5 and the second bonding step S6. That is, by performing the protective film forming step S2 with the flow path member 52 stacked on the actuator plate 54, the second protective film 253 is adhered to the inner surfaces of the pressure chambers 61 and the back surface of the flow path member 52. This forms the skin pack body 210. Thereafter, the nozzle plate 51 is attached to the back surface of the second protective film 253 (back surface covering portion 257), thereby completing the head chip 50.

[0100] In the head chip 50 of the second embodiment, the second protective film 253 is configured to include a pressure chamber covering portion 255 that is connected to the actuator protecting portion 253 a and covers the portion of the flow path member 52 that faces the pressure chamber 61, and a back surface covering portion 257 that is connected to the pressure chamber covering portion 255 and covers the back surface of the flow path member 52 (the surface facing the ejection port plate). With this configuration, the interface between the actuator plate 54 and the flow path member 52 is covered by the second protective film 253, thereby preventing ink from entering the interface between the actuator plate 54 and the flow path member 52. Furthermore, the back surface of the flow path member 52 is covered by the back surface covering portion 257. Therefore, even if damage occurs to the back surface covering portion 257 and ink enters the interface between the flow path member 52 and the second protective film 253, it is possible to prevent the ink from reaching the interface between the actuator plate 54 and the flow path member 52. As a result, peeling between the actuator plate 54 and the flow path member 52 can be prevented. Furthermore, the distance to the interface between the second protective film 253 and the flow path member 52 is increased by the thickness of the second protective film 253. Therefore, even if the pressure chamber covering portion 255 is damaged, it is possible to prevent ink from reaching the interface between the actuator plate 54 and the flow path member 52. As a result, it is possible to prevent the actuator plate 54 and the flow path member 52 from peeling off.

[0101] 20 and 21 are cross-sectional views of a head chip 50 according to a third embodiment. The third embodiment differs from the above-described embodiments in that both a first protective film 53 and a second protective film 253 are formed. In the head chip 50 shown in FIGS. 20 and 21, the first protective film 53 continuously covers the back surface of the actuator plate 54 and the side surfaces of the actuator plate 54, film 55, and cover plate 56. In other words, the first protective film 53 covers the first laminate 301 consisting of the actuator plate 54, film 55, and cover plate 56 from the -Z side and the sides. In the third embodiment, the back surface protective portion 53a constitutes the first protective portion according to the present disclosure.

[0102] The second protective film (second protective portion) 253 is provided so as to cover the first protective film 53 from the outside. In this case, the actuator protective portion (first covering portion) 253a is in close contact with the back surface of the back surface protective portion 53a. Corresponding protrusions 53b to 53e and 253c to 253f are in close contact with each other on their corresponding side surfaces. That is, the second protective film 253 covers the second stack 302, which is made up of the flow path member 52, the first protective film 53, the actuator plate 54, the film 55, and the cover plate 56, from the -Z side and the sides.

[0103] According to the head chip 50 of the third embodiment, the entire back surface of the actuator plate 54 is covered with the first protective film 53 (back surface protective portion 53a), which more reliably prevents ink from reaching the drive wiring 75. Furthermore, the interface between the actuator plate 54 and the flow path member 52 is covered with the second protective film 253 (pressure chamber covering portion 255), which prevents ink from entering the interface between the actuator plate 54 and the flow path member 52. This makes it possible to prevent the actuator plate 54 and the flow path member 52 from peeling off from each other.

[0104] 22 is a cross-sectional view of a head chip 50 according to a fourth embodiment. In the head chip 50 shown in FIG. 22, recesses 401 are formed in the actuator plate 54 in portions that overlap with the pressure chambers 61 in plan view. The recesses 401 are recessed upward relative to the rear surface of the actuator plate 54. Specifically, the recesses 401 extend in the Y direction along the pressure chambers 61 in plan view. The recesses 401 are formed in a rectangular shape when viewed from the Y direction.

[0105] An individual electrode 82a is formed on the inner surface of the recess 401. In the illustrated example, the individual electrode 82a is formed over the entire inner surface of the recess 401. At least a portion of the individual electrode 82a overlaps with the second common electrode 81b when viewed from the Z direction. It is sufficient that the individual electrode 82a is formed on at least a portion of the inner surface of the recess 401. In addition to the inner surface of the recess 401, the individual electrode 82a may also be connected to a portion of the back surface of the actuator plate 54 that is positioned around the recess 401.

[0106] Groove portions 402 are formed in portions of the actuator plate 54 located on both sides of the recess 401 in the X direction. The groove portions 402 overlap portions of the flow path member 52 located between adjacent pressure chambers 61 in a plan view. The groove portions 402 are recessed in the surface of the actuator plate 54. The groove portions 402 extend in the Y direction along the recess 401. In the illustrated example, the dimension of the groove portions 402 in the Z direction is larger than the dimension of the recess 401 in the Z direction. The dimension of the groove portions 402 in the X direction is smaller than the dimension of the recess 401 in the X direction.

[0107] A third common electrode 481c is formed on the inner surface of each groove 402. The third common electrode 481c is formed over the entire inner surface of each groove 402. The third common electrode 481c is disposed on both sides of the second common electrode 81b in the X direction. It is sufficient that the third common electrode 481c is formed on at least a portion of the inner surface of the groove 402.

[0108] The first protective film 53 is provided so as to cover the −Z side and the lateral sides of the laminate 100. A part of the back surface protective portion 53a is provided to follow the entire inner surface of the recess 401, thereby covering the individual electrode 82a.

[0109] According to the fourth embodiment, the surface area of ​​the individual electrodes 82a can be secured by forming the drive wiring 75 (individual electrodes 82a) following the inner surface of the recesses 401. As a result, the electric field generated in the actuator plate 54 can be increased, and the pressure generated in the pressure chambers 61 during ink ejection can be improved. Furthermore, by forming the recesses 401 in the actuator plate 54, the rigidity of the actuator plate 54 in the Z direction can be increased.

[0110] (Other Modifications) The technical scope of the present disclosure is not limited to the above-described embodiments, and various modifications may be made without departing from the spirit and scope of the present disclosure. For example, in the above-described embodiments, an inkjet printer 1 was described as an example of a liquid jet recording apparatus, but the present disclosure is not limited to a printer. For example, a fax machine, an on-demand printer, or the like may also be used. In the above-described embodiments, a configuration in which an inkjet head moves relative to a recording medium during printing (a so-called shuttle machine) was described as an example, but the present disclosure is not limited to this configuration. The configuration according to the present disclosure may also be adopted in a configuration in which the inkjet head is fixed and the recording medium moves relative to the inkjet head (a so-called fixed head machine). In the above-described embodiments, the recording medium P is described as paper, but the present disclosure is not limited to this configuration. The recording medium P is not limited to paper, but may be a metal material, a resin material, or even food. In the above-described embodiments, a configuration in which a liquid jet head is mounted on a liquid jet recording apparatus was described, but the present disclosure is not limited to this configuration. In other words, the liquid sprayed from the liquid spray head is not limited to liquid that lands on a recording medium, but may also be, for example, a medicinal liquid to be mixed into a prescription, a food additive such as a seasoning or fragrance to be added to food, or an air freshener to be sprayed into the air.

[0111] In the above-described embodiment, a configuration in which the Z direction coincides with the direction of gravity has been described, but the present invention is not limited to this configuration and the Z direction may be aligned horizontally. In the above-described embodiment, a configuration in which the protective film is formed by a so-called skin pack has been described, but the present invention is not limited to this configuration. The protective film may be formed by pressure bonding or the like. In the above-described embodiment, a configuration in which each protrusion covers the side surface of the laminate has been described, but the present invention is not limited to this configuration. The protrusions only need to protrude outward from the actuator plate 54 in a plan view. In this case, the protrusions may be configured to be used only as gripping margins for the protective film in the protective film forming step S2. In the above-described embodiment, a method in which the protective film is heated in the protective film forming step S2 has been described, but the present invention is not limited to this configuration. The protective film forming step S2 may be performed at room temperature.

[0112] In the above-described embodiment, a configuration in which the protrusion covers the entire periphery of the side surface of the stack body has been described, but the present invention is not limited to this configuration. The protrusion may cover a portion of the side surface of the stack body. It is preferable that the protrusion covers the side surface of the stack body facing the Y direction. In the above-described embodiment, a configuration in which a single protective film continuously separates each drive unit 54a from each pressure chamber 61 has been described, but the present invention is not limited to this configuration. The protective film may individually separate the corresponding drive unit 54a from each pressure chamber 61.

[0113] In addition, within the scope of the present disclosure, the components in the above-described embodiments may be replaced with well-known components as appropriate, and the above-described modified examples may be combined as appropriate.

[0114] DESCRIPTION OF SYMBOLS 1: Printer (liquid jet recording apparatus) 5: Inkjet head (liquid jet head) 50: Head chip 51: Nozzle plate (ejection hole plate) 51a: Nozzle hole (ejection hole) 52: Flow path member 53: First protective film (protective film) 53a: Back surface protective portion (first covering portion, first protective portion) 53b: +X side protrusion 53c: -X side protrusion 53d: +Y side protrusion 53e: -Y side protrusion 54: Actuator plate 54a: Drive portion 61: Pressure chamber 75: Drive wiring 101: Chamber 253: Second protective film (protective film, second protective portion) 253a: Actuator protective portion (first covering portion) 253c: +X side protrusion 253d: -X side protrusion 253e: +Y side protrusion 253f: -Y side protrusion 255: Pressure chamber covering portion (second covering portion) 257: Back surface protecting portion (third covering portion) 401: Recess

Claims

1. A head chip comprising: a flow path member in which a plurality of pressure chambers for storing liquid are formed and arranged in a first direction; an actuator plate arranged on the flow path member facing the pressure chambers in a second direction intersecting the first direction; drive wiring formed on a flow path facing surface facing the flow path member in a drive section of the actuator plate which overlaps with the pressure chambers when viewed from the second direction; and a sheet-like protective film which has a first covering section that covers the drive wiring on the flow path facing surface and which separates the pressure chambers from the drive section.

2. The head chip according to claim 1, wherein the protective film has a protruding portion that protrudes outward in a direction intersecting the second direction relative to the flow path member and the actuator plate when viewed from the second direction.

3. The head chip according to claim 2, wherein the protrusion covers a side surface of the actuator plate facing the intersecting direction.

4. The head chip according to claim 3, wherein said protrusion extends along said first direction on said side surface in a portion facing a third direction intersecting said first direction among said intersecting directions.

5. The head chip according to any one of claims 1 to 4, wherein the protective film is provided continuously over the entire area of ​​the flow path facing surface.

6. A head chip as described in claim 5, wherein the drive section is formed with a recess that is recessed in a direction away from the flow path member in the second direction, the drive wiring is formed on an inner surface of the recess, and the first covering section is provided following the inner surface of the recess so as to cover the drive wiring.

7. A head chip as claimed in any one of claims 1 to 4, wherein an injection hole plate having an injection hole communicating with the pressure chamber is provided on the opposite side of the flow path member from the actuator plate in the second direction, and the protective film comprises: a second covering portion connected to the first covering portion and covering a portion of the flow path member facing the pressure chamber; and a third covering portion connected to the second covering portion and covering a surface of the flow path member facing the injection hole plate in the second direction.

8. A head chip as claimed in any one of claims 1 to 4, wherein an injection hole plate having an injection hole communicating with the pressure chamber is provided on the opposite side of the flow path member to the actuator plate in the second direction, and the protective film includes a first protective portion provided continuously over the entire area of ​​the flow path facing surface, and a second protective portion superimposed on the first protective portion on the drive portion, and the second protective portion has: a second covering portion connected to the first covering portion and covering a portion of the flow path member facing the pressure chamber, and a third covering portion connected to the second covering portion and covering a surface of the flow path member facing the injection hole plate in the second direction.

9. The head chip according to any one of claims 1 to 8, wherein the softening point of the protective film is set to 120° C. or lower.

10. The head chip according to any one of claims 1 to 9, wherein the protective film is made of a thermoplastic resin.

11. A liquid-jet head comprising the head chip according to any one of claims 1 to 10.

12. A liquid jet recording apparatus comprising the liquid jet head according to claim 11.

13. A method for manufacturing a head chip comprising: a flow path member in which a plurality of pressure chambers for storing liquid are formed and aligned in a first direction; an actuator plate arranged on the flow path member facing the pressure chambers in a second direction intersecting the first direction and having a polarization direction in the second direction; drive wiring formed on a flow path facing surface facing the flow path member in a drive section of the actuator plate that overlaps with the pressure chambers when viewed from the second direction; and a sheet-like protective film that covers the drive wiring on the flow path facing surface of the drive section and serves as a partition between the pressure chambers and the drive section, the method comprising a protective film formation step of covering the drive section with the protective film by adhering the protective film to the drive section.

14. A method for manufacturing a head chip as described in claim 13, wherein the protective film forming process is performed by creating a negative pressure in a first space located on the actuator plate side of the protective film in a chamber in which the actuator plate and the protective film are set, relative to a second space located on the opposite side of the protective film from the actuator plate, thereby adhering the protective film to the drive section.

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