Head chip, liquid jet head, and liquid jet recording device

Abstract

To provide a head chip, a liquid jet head and a liquid jet recording device capable of reducing the thickness of a cover plate and improving the miniaturization of through-wiring and the degree of freedom in design.SOLUTION: A head chip according to an aspect of the present disclosure includes: an actuator plate in which a liquid is stored, which is disposed to face a plurality of pressure chambers communicating with a plurality of ejection holes, respectively, and which is deformable so that the pressure chambers expand or contract; drive electrodes formed on the actuator plate; a cover plate which is superposed on a first side in a thickness direction with respect to the actuator plate and has a dimension in the thickness direction smaller than that of the actuator plate. In the cover plate, first wiring is formed which is formed in through-holes penetrating the cover plate and connects between external wiring provided on a first side in a thickness direction with respect to the cover plate and the drive electrodes. The through-holes are formed by laser processing.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present disclosure relates to a head chip, a liquid jet head, and a liquid jet recording apparatus. [Background technology]

[0002] The inkjet head ejects ink onto a recording medium through a head chip. The head chip includes an actuator plate having ejection channels formed therein, and a cover plate overlaid on the actuator plate.

[0003] The cover plate has through holes formed therein to function as ink flow paths, through holes, etc. The through holes can be formed by sandblasting (see, for example, Patent Document 1 below) or etching (see, for example, Patent Document 2 below). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2008-143072 A [Patent Document 2] JP 2006-35453 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the above-mentioned conventional technology, whether the processing method of sandblasting or etching is adopted, it is difficult to make the cover plate thin in terms of handling, processability, etc. Furthermore, since the cover plate cannot be made thin, there is still room for improvement in terms of realizing finer through holes and improving design freedom.

[0006] The present disclosure provides a head chip, a liquid jet head, and a liquid jet recording apparatus that are capable of achieving a thinner cover plate, finer through-wiring, and improved design freedom. [Means for solving the problem]

[0007] 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 comprises an actuator plate that contains liquid and has a drive unit arranged facing a plurality of pressure chambers that are each connected to a plurality of injection holes, the actuator plate being deformable to expand or contract the pressure chambers, a drive electrode formed on the actuator plate, and a cover plate that is overlaid on a first side in a thickness direction of the actuator plate and has a smaller dimension in the thickness direction than the actuator plate, wherein the cover plate has a first wiring formed in a through hole that penetrates the cover plate in the thickness direction and connects between an external wiring provided on the first side in the thickness direction of the cover plate and the drive electrode, and the through hole is formed by laser processing.

[0008] According to this aspect, by forming the first wiring on the cover plate overlapped with the actuator plate in the thickness direction, the head chip can be made smaller in the direction intersecting the thickness direction compared to the case where pads or the like are formed on the same plane as the pressure chamber. By making the head chip smaller in the direction intersecting the thickness direction, for example, when the head chips are made at the wafer level, the number of head chips that can be obtained from one wafer can be increased. In addition, by forming the first wiring as the connection wiring on the cover plate, the degree of freedom in designing the connection wiring can be improved compared to the case where both the drive electrode and the connection wiring are formed on the actuator plate. In particular, in this embodiment, the through holes are formed by laser processing, which improves the freedom of material selection for the cover plate, and thus allows the cover plate to be made thinner. In addition, the through holes can be easily made finer by adjusting the laser diameter, etc. In addition, unlike the case of forming the through holes by sandblasting, for example, there is no need to grind the actuator plate after the through holes are formed, so the through holes can be processed with the thickness dimension being equivalent to the product dimension. This allows for reduction in material costs and improvement in manufacturing efficiency.

[0009] (2) In the head chip relating to aspect (1) above, it is preferable that the through hole has an outer shape gradually smaller when viewed in the thickness direction from a first side in the thickness direction toward a second side opposite the first side. According to this aspect, when the first wiring is formed through the first side opening of the through hole, the first wiring is easily formed over the entire inner surface of the through hole in the thickness direction, which makes it possible to stabilize the conduction between the external wiring and the driving electrode.

[0010] (3) In a head chip relating to the above aspect (1) or (2), it is preferable that the pressure chamber is formed in the actuator plate and penetrates the actuator plate in the thickness direction, and the through hole is formed at a position that does not overlap the pressure chamber when viewed from the thickness direction. According to this aspect, communication between the pressure chamber and the through hole can be prevented, thereby improving reliability.

[0011] (4) In a head chip according to any one of aspects (1) to (3) above, the first wiring is formed around the entire circumference of the through hole, and for the through hole in which the first wiring corresponding to one of the driving electrodes is formed, it is preferable that the total circumference of the second-side opening edge located on the second side opposite the first side in the thickness direction is formed to be 0.25 mm or more, and for the first wiring corresponding to one of the driving electrodes, the dimension perpendicular to the thickness direction on the second-side opening edge in the thickness direction is formed to be 0.0002 mm or more. According to this aspect, by setting the circumference to 0.25 mm or more and the dimension perpendicular to the thickness direction to 0.0002 mm or more, the electrical resistance between the drive electrode and the first wiring can be sufficiently reduced, thereby enabling power savings and suppressing heat generation in the head chip.

[0012] (5) In the head chip according to any one of the above aspects (1) to (4), the cover plate is preferably made of a resin material. According to this aspect, it is easy to provide a versatile, thin, and liquid-resistant cover plate at a low cost. Even if the cover plate is made thin, there is little risk of cracking and the like, and handling is easy, so that manufacturing efficiency can be improved.

[0013] (6) In the head chip according to any one of aspects (1) to (5) above, it is preferable that the head chip further comprises a surface plate that is overlaid on a first side in the thickness direction of the cover plate and has a dimension in the thickness direction larger than that of the cover plate. According to this aspect, when liquid is ejected, the displacement of the cover plate toward the first side in the thickness direction caused by an increase in pressure in the pressure chamber, etc., can be restricted by the surface plate. This improves the pressure generated in the pressure chamber, and allows liquid to be ejected efficiently.

[0014] (7) In a head chip relating to any of the aspects of (6) above, it is preferable that a pad connected to an external wiring is formed on a surface of the surface plate facing a first side in the thickness direction, and that a second wiring is formed on the surface plate, penetrating the surface plate in the thickness direction and connecting between the first wiring and the pad. According to this aspect, by using a cover plate as an intermediate plate between the surface plate and the actuator plate, it is possible to improve design freedom compared to a case where only the cover plate is used for mounting external wiring and connecting various electrodes to each other, etc. In this case, it is possible to narrow the pitch of the pressure chambers, and it is also possible to increase the resolution of the information printed by the head chip. Furthermore, by forming a wiring pattern in cooperation with the surface plate and the cover plate, the wiring pattern can be simplified even on the upper surface of the surface plate. Therefore, when mounting each pad and external wiring, it is possible to suppress the occurrence of defects such as short circuits. In addition, by connecting the driving electrode of the actuator plate and the pad of the surface plate by the first wiring formed on the cover plate, the cover plate functions as an adapter between the actuator plate and the surface plate. This allows the wiring pattern of the surface plate to be common regardless of the ejection method, thereby reducing costs.

[0015] (8) 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 (7). According to this aspect, since the head chip according to the above aspect is included, it is possible to provide a small-sized, low-cost liquid jet head.

[0016] (9) A liquid jet recording apparatus according to an aspect of the present disclosure preferably includes the liquid jet head according to aspect (8) above. According to this aspect, since the head chip according to the above aspect is included, it is possible to provide a small-sized, low-cost liquid jet head. Effect of the Invention

[0017] According to one aspect of the present disclosure, it is possible to reduce the thickness of the cover plate, while also achieving finer through-wires and improved design freedom. [Brief description of the drawings]

[0018] [Figure 1] 1 is a schematic configuration diagram of an inkjet printer according to a first embodiment. [Diagram 2] FIG. 2 is a schematic configuration diagram of an inkjet head and an ink circulation mechanism according to the first embodiment. [Diagram 3] FIG. 2 is an exploded perspective view of the discharge unit according to the first embodiment. [Figure 4] FIG. 2 is an exploded perspective view of the head chip according to the first embodiment. [Diagram 5] FIG. 2 is a plan view of the actuator plate according to the first embodiment. [Figure 6] 6 is a cross-sectional view of the head chip taken along line VI-VI in FIG. 5. [Figure 7] 7 is a cross-sectional view of the head chip taken along line VII-VII in FIG. 5. [Figure 8] 8 is an end view of the head chip corresponding to the line VIII-VIII in FIG. 5. [Figure 9] 5 is a flowchart for explaining a manufacturing method of the discharge unit according to the first embodiment. [Figure 10] FIG. 9 is a process diagram for explaining a machining process of the actuator according to the first embodiment, and is an end view corresponding to FIG. 8. [Figure 11] FIG. 9 is a process diagram for explaining a machining process of the actuator according to the first embodiment, and is an end view corresponding to FIG. 8. [Figure 12] FIG. 9 is a process diagram for explaining a machining process of the actuator according to the first embodiment, and is an end view corresponding to FIG. 8. [Figure 13] FIG. 9 is a process diagram for explaining a machining process of the actuator according to the first embodiment, and is an end view corresponding to FIG. 8. [Figure 14] FIG. 8 is a process diagram for explaining a cover plate machining process according to the first embodiment, and is a cross-sectional view corresponding to FIG. 7. [Figure 15] FIG. 8 is a process diagram for explaining a cover plate machining process according to the first embodiment, and is a cross-sectional view corresponding to FIG. 7. [Figure 16] FIG. 8 is a process diagram for explaining a cover plate machining process according to the first embodiment, and is a cross-sectional view corresponding to FIG. 7. [Figure 17] FIG. 9 is a process diagram for explaining the grinding step according to the first embodiment, and is an end view corresponding to FIG. 8. [Figure 18] 1 is a graph showing the relationship between the circumference [mm] of a through hole and the resistance value [Ω] of a through wiring. [Figure 19] FIG. 11 is an exploded perspective view of a head chip according to a second embodiment. [Figure 20] FIG. 11 is a plan view of an actuator plate according to a third embodiment. [Figure 21] FIG. 11 is a plan view of a head chip according to a third embodiment with a flow path cover removed. [Figure 22] FIG. 13 is an exploded perspective view of a head chip according to a fourth embodiment. [Diagram 23] FIG. 13 is a plan view of an actuator plate according to a fourth embodiment. [Figure 24] 24 is a cross-sectional view of the head chip taken along line XXIV-XXIV in FIG. 23. [Diagram 25] 25 is a cross-sectional view of the head chip corresponding to the line XXV-XXV in FIG. 23. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, an embodiment according to the present disclosure will be described with reference to the drawings. In the embodiments and modified examples described below, the same reference numerals may be used to designate corresponding configurations, and the description may be omitted. In the following description, expressions indicating relative or absolute arrangements, such as "parallel," "orthogonal," "center," and "coaxial," not only strictly indicate such arrangements, but also indicate a state in which the components are relatively displaced with a tolerance or an angle or distance to the extent that the same function is obtained. In the following embodiment, an inkjet printer (hereinafter, simply referred to as a printer) that uses ink (liquid) to record on a recording medium will be taken as an example for description. In the drawings used in the following description, the scale of each component has been appropriately changed so that each component can be recognized.

[0020] (First embodiment) [Printer 1] FIG. 1 is a schematic diagram of a printer 1. A 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 .

[0021] In the following explanation, an X, Y, Z Cartesian coordinate system is used as necessary. In this case, the X direction coincides with the transport direction (sub-scanning direction) of the recording medium P (e.g., paper, etc.). 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) perpendicular to the X and Y directions. In the following explanation, the X, Y, and Z directions will be explained with the arrows on the figures as the plus (+) side and the opposite side to the arrows as the minus (-) side. In this specification, the +Z side corresponds to the upward direction of gravity, and the -Z side corresponds to the downward direction of gravity.

[0022] The transport mechanisms 2 and 3 transport the recording medium P to the +X side. The transport mechanisms 2 and 3 each include a pair of rollers 11 and 12 extending in the Y direction, for example. The ink tanks 4 each contain ink of four colors, for example, yellow, magenta, cyan, and black. Each inkjet head 5 is configured to be capable of ejecting ink of one of the four colors, yellow, magenta, cyan, or black, according to the ink tank 4 connected thereto.

[0023] FIG. 2 is a schematic diagram of the ink-jet head 5 and the ink circulation mechanism 6. As shown in FIG. 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.

[0024] 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 ink supply pipe 21 side relative to the inkjet head 5 is under positive pressure. The suction pump 25 reduces the pressure inside the ink discharge tube 22 and sucks ink from the inkjet head 5 through the ink discharge tube 22. This creates a negative pressure on the ink discharge tube 22 side 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.

[0025] 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 by the guide rail 28.

[0026] <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 discharge unit 30 (see FIG. 2), an ink supply unit (not shown) that connects the ink circulation mechanism 6 and the discharge unit 30, and a control unit (not shown) that applies a drive voltage to the discharge unit 30.

[0027] (First embodiment) [Discharge unit 30] FIG. 3 is an exploded perspective view of the discharge unit 30. As shown in FIG. 3 is a so-called circulation type side shoot type discharge unit 30 that circulates ink between the ink tank 4 and discharges ink from the center of an ejection channel 51 (described later) in the extension direction (Y direction). The discharge unit 30 includes a flow path plate 31, a head chip 32, a nozzle plate 33, a flow path cover 34, and a flexible printed circuit board 35 (see FIG. 6).

[0028] <Flow path plate 31> The flow channel plate 31 is formed in a rectangular frame shape with the thickness direction being the Z direction and the longitudinal direction being the X direction. The flow channel plate 31 defines a chip storage section 31a, an inlet common flow channel 31b, and an outlet common flow channel 31c. The chip storage section 31a, the inlet common flow channel 31b, and the outlet common flow channel 31c are in communication with each other and penetrate the flow channel plate 31 in the Z direction.

[0029] The chip receiving portion 31a is formed in the center in the Y direction of the flow path plate 31. The chip receiving portion 31a is formed in an elongated hole shape with the X direction as the longitudinal direction in a plan view. The inlet common flow channel 31b is formed in a portion of the flow channel plate 31 that is located on the +Y side of the chip storage unit 31a. The inlet common flow channel 31b is formed in an elongated hole shape with the X direction as the longitudinal direction, similar to the chip storage unit 31a. The +X side end of the inlet common flow channel 31b protrudes in the X direction with respect to the chip storage unit 31a. The outlet common flow channel 31c is formed in a portion of the flow channel plate 31 that is located on the -Y side with respect to the chip storage unit 31a. The outlet common flow channel 31c is formed in an elongated hole shape with the X direction as the longitudinal direction, similar to the inlet common flow channel 31b. The -X side end of the outlet common flow channel 31c protrudes in the X direction with respect to the chip storage unit 31a.

[0030] <Head chip 32> As shown in FIG. 3, head chip 32 is formed in a block shape with the thickness direction being the Z direction and the longitudinal direction being the X direction. Head chip 32 is fitted into chip accommodating section 31a. Specifically, head chip 32 is formed so that the thickness in the Z direction is equivalent to that of flow path plate 31 and the planar shape is equivalent to that of chip accommodating section 31a. In this case, head chip 32 has a +X side end face fixed by adhesion or the like to a surface facing the -X side among the inner surfaces of chip accommodating section 31a, and a -X side end face fixed by adhesion or the like to a surface facing the +X side among the inner surfaces of chip accommodating section 31a. Therefore, in flow path plate 31, inlet common flow path 31b and outlet common flow path 31c are blocked by head chip 32.

[0031] Fig. 4 is an exploded perspective view of head chip 32. Fig. 5 is a plan view of actuator plate 41. Fig. 6 is a cross-sectional view of head chip 32 corresponding to line VI-VI in Fig. 5. Fig. 6 is a cross-sectional view of head chip 32 corresponding to line VII-VII in Fig. 5. 4 to 7, head chip 32 includes actuator plate 41 and cover plate 42. In the following description, the direction from actuator plate 41 to cover plate 42 in the Z direction (+Z side) may be referred to as the upper side, and the direction from cover plate 42 to actuator plate 41 (-Z side) may be referred to as the lower side. In the first embodiment, the lower surface of head chip 32 is disposed flush with the lower surface of flow path plate 31. On the other hand, the upper surface of head chip 32 is disposed flush with the upper surface of flow path plate 31.

[0032] The actuator plate 41 is made of a piezoelectric material such as PZT (lead zirconate titanate). The actuator plate 41 is a so-called chevron substrate formed by laminating two piezoelectric plates whose polarization directions are different in the Z direction. However, the actuator plate 41 may be a so-called monopole substrate whose polarization direction is one direction over the entire Z direction.

[0033] A channel row 46 is formed in the actuator plate 41. The channel row 46 has ejection channels (pressure chambers) 51 filled with ink, and non-ejection channels 52 that are not filled with ink. The channels 51, 52 are arranged alternately in the actuator plate 41 with a gap therebetween in the X direction. That is, in the head chip 32 of the first embodiment, the ejection channels 51 that become pressure chambers are formed in the actuator plate 41 itself. In the first embodiment, a configuration in which the channel extension direction coincides with the Y direction will be described, but the channel extension direction may intersect with the Y direction.

[0034] The discharge channels 51 penetrate the actuator plate 41 in the Z direction and extend linearly in the Y direction over the entire length of the actuator plate 41. The +Y side opening of each discharge channel 51 communicates with the inlet common flow path 31b. Meanwhile, the -Y side opening of 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 discharge channel 51.

[0035] 4 and 7, the non-ejection channels 52 extend linearly in the Y direction in the portions of the actuator plate 41 that are located between adjacent ejection channels 51. The portions of the actuator plate 41 that are located between adjacent ejection channels 51 and non-ejection channels 52 each constitute a driving wall (driving portion) 53 that faces the ejection channel 51. Therefore, the channels 51 and 52 are surrounded on both sides in the X direction by a pair of driving walls 53.

[0036] Both ends of the non-ejection channel 52 in the Y direction terminate within the actuator plate 41. Therefore, the non-ejection channel 52 does not communicate with the inlet common flow path 31b and the outlet common flow path 31c. The non-ejection channel 52 is formed in a circular arc shape that protrudes downward when viewed from the X direction. That is, the dimension of the non-ejection channel 52 in the Y direction gradually decreases from the top to the bottom. Specifically, the non-ejection channel 52 has a through portion 52a located in the center in the Y direction and cut-up portions 52b that are continuous with both sides of the through portion 52a in the Y direction.

[0037] The through portion 52a passes through the actuator plate 41 in the Z direction. The cut-up portion 52b opens on the upper surface of the actuator plate 41, and the dimension in the Z direction gradually decreases as it moves away from the through portion 52a in the Y direction. That is, the upper end opening of the non-ejection channel 52 is formed by the through portion 52a and the cut-up portion 52b. On the other hand, the lower end opening of the non-ejection channel 52 is formed by the through portion 52a. The bottom surface of the cut-up portion 52b is formed in an arc shape with a uniform radius of curvature. A dividing groove 52c is formed in the center of the bottom surface of each cut-up portion 52b in the X direction. The dividing groove 52c is recessed over the entire length in the Y direction with respect to the bottom surface of each cut-up portion 52b. The dividing groove 52c extends concentrically with the cut-up portion 52b in a side view.

[0038] In the following description, the portion of the actuator plate 41 located between adjacent ejection channels 51 and on the -Y side of the non-ejection channels 52 is referred to as a first tail portion 41a. The portion of the actuator plate 41 located between adjacent ejection channels 51 and on the +Y side of the non-ejection channels 52 is referred to as a second tail portion 41b.

[0039] <Cover plate 42> As shown in Figs. 4, 6 and 7, the cover plate 42 is used for connecting the head chip 32 and the flexible printed circuit board (external wiring) 35. The cover plate 42 is a plate material made of, for example, a resin material (for example, PI, PE, PET, PP, PEEK, etc.). In the illustrated example, the dimension of the cover plate 42 in the Z direction is smaller than that of the actuator plate 41. The cover plate 42 may be made of a piezoelectric material such as PZT, glass, silicon, or other non-conductive material other than the resin material. The cover plate 42 may be made of a conductive material such as a metal material, and the outer surface of the base may be coated with a non-conductive material.

[0040] The cover plate 42 has the same outer shape as the actuator plate 41 in a plan view, and is overlaid on the entire upper surface of the actuator plate 41. The cover plate 42 is bonded to the upper surface of the actuator plate 41 with an adhesive or the like.

[0041] As shown in Figs. 4 and 7, the cover plate 42 is formed with a common hole (through hole) 42a, a first individual hole (through hole) 42b, and a second individual hole (through hole) 42c. Each of the holes 42a to 42c is circular in plan view and tapered so that the inner diameter gradually decreases from top to bottom. However, the inner diameter of each of the holes 42a to 42c may be uniform over the entire Z direction. In addition, the plan view shape of each of the holes 42a to 42c can be appropriately changed to an elliptical shape, a polygonal shape, or the like. The common hole 42a, the first individual hole 42b, and the second individual hole 42c may be the same shape or different shapes.

[0042] The common hole 42a 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. That is, the common hole 42a is provided between the discharge channels 51 adjacent to each other.

[0043] The first individual hole 42b and the second individual hole 42c are formed separately on both sides in the Y direction with respect to the non-ejection channel 52. Specifically, the first individual hole 42b penetrates in the Z direction a portion of the cover plate 42 that overlaps with the first tail portion 41a in a plan view and is located on the +Y side of the common hole 42a. The second individual hole 42c penetrates in the Z direction a portion of the cover plate 42 that overlaps with the second tail portion 41b in a plan view. That is, the first individual hole 42b and the second individual hole 42c are provided for each non-ejection channel 52.

[0044] Next, various wirings formed on the head chip 32 will be described. As shown in FIGS. 4 to 7, the actuator plate 41 is provided with common wiring 61 and individual wiring 62 as drive wiring.

[0045] FIG. 8 is an end view corresponding to line VIII-VIII in FIG. As shown in FIGS. 6 and 8, the common wiring 61 includes a common electrode (drive electrode) 65 and a common output wiring 66. The common electrodes 65 are formed on the inner surfaces of the ejection channel 51 that face each other in the X direction. Each common electrode 65 is formed on the inner surface of the ejection channel 51 over the entire area in the Y and Z directions. 4, the common output wiring 66 extends in a strip shape in the X direction on the upper surface of the first tail portion 41a. The common output wiring 66 connects the common electrodes 65 that face each other in the X direction with the non-ejection channel 52 therebetween at the upper end opening edges of the ejection channels 51 that face each other in the X direction with the non-ejection channel 52 therebetween.

[0046] As shown in FIGS. 7 and 8, the individual wiring 62 includes an individual electrode (drive electrode) 68 and an individual output wiring 69. The individual electrodes 68 include a first individual electrode 68a formed on at least the inner surface facing the -X side of the inner surface of the non-ejection channel 52, and a second individual electrode 68b formed on at least the inner surface facing the +X side. Each individual electrode 68 is formed over the entire area in the Y direction and the Z direction on the inner surface of the non-ejection channel 52, and is also formed on the bottom surface of the cut-up portion 52b. The first individual electrode 68a and the second individual electrode 68b formed in the same non-ejection channel 52 are separated from each other by a separating groove 52c.

[0047] As shown in FIG. 4, the individual output wiring 69 includes a first individual output wiring 69a and a second individual output wiring 69b. The first individual output wiring 69a extends in the Y direction on the upper surface of the first tail portion 41a. The first individual output wiring 69a is connected to the first individual electrode 68a at the upper opening edge of the non-ejection channel 52. The first individual output wiring 69a is separated from the common output wiring 66 on the surface of the first tail portion 41a.

[0048] The second individual output wiring 69b extends in the Y direction on the upper surface of the second tail portion 41b. The second individual output wiring 69b is connected to the second individual electrode 68b at the edge of the upper opening of the non-ejection channel 52.

[0049] As shown in FIGS. 4 and 7, the cover plate 42 is formed with a common connection wiring 71 and individual connection wiring 72 as connection wiring (first wiring). The common connection wiring 71 includes a common through wiring 75 and a common lead wiring 76 . The common through wiring 75 is formed on the inner surface of the common hole 42a. Specifically, the common through wiring 75 is formed on the entire inner surface of the common hole 42a and is formed over the entire Z direction. The common through wiring 75 is connected to the common output wiring 66 at the lower opening edge of the common hole 42a.

[0050] The common wiring 76 is formed on the upper surface of the cover plate 42. The common wiring 76 includes a strip-shaped portion 76a and a common protruding portion 76b. The strip portion 76a extends in the X direction so as to cross between the common holes 42a. The strip portion 76a is connected to the common through wiring 75 at the upper opening edge of the common hole 42a. That is, the strip portion 76a lumps together the common electrodes 65 via the common through wirings 75. It is not necessary that all the common through wirings 75 are connected to one strip portion 76a, and the common through wirings 75 may be lumped together by being shared by, for example, a plurality of strip portions 76a.

[0051] The common protrusions 76b function as a common pad on which the flexible printed circuit board 35 is mounted. The common protrusions 76b are formed on the upper surface of the cover plate 42 at positions overlapping with the respective ejection channels 51 in a plan view. The common protrusions 76b protrude from the strip portion 76a to the +Y side. In the first embodiment, the common protrusions 76b and the common through-wires 75 are arranged alternately on the upper surface of the cover plate 42.

[0052] The individual connection wiring 72 includes a first individual through wiring 81 , a second individual through wiring 82 , and an individual lead wiring 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 around the entire inner surface of the first individual hole 42b and is formed over the entire Z direction. The first individual through wiring 81 is connected to the first individual output wiring 69a at the lower end opening edge of the first individual hole 42b. The second individual through wires 82 are formed on the inner surface of the second individual hole 42c. Specifically, the second individual through wires 82 are formed on the entire inner surface of the second individual hole 42c and are formed over the entire Z direction. The second individual through wires 82 are connected to the second individual output wires 69b at the lower opening edge of the second individual hole 42c.

[0053] The individual lead-out wiring 83 is formed on the upper surface of the cover plate 42. Specifically, the individual lead-out wiring 83 includes a bridging portion 83a and an individual protruding portion 83b. The bridge portion 83a connects between a first individual through-wire 81 located on the -X side of one discharge channel 51 and a second individual through-wire 82 located on the +X side of one discharge channel 51. Specifically, the bridge portion 83a extends inclined toward the +Y side as it approaches the +X side in a plan view. A first end (-Y side end) of the bridge portion 83a is connected to the first individual through-wire 81 at the upper opening edge of the first individual hole 42b. A second end (+Y side end) of the bridge portion 83a is connected to the second individual through-wire 82 at the upper opening edge of the second individual hole 42c. This connects the individual electrodes 68a, 68b that face each other in the X direction with one ejection channel 51 in between (the second individual electrodes 68b of the non-ejection channels 52 located on the +X side of one ejection channel 51, and the first individual electrodes 68a of the non-ejection channels 52 located on the -X side of one ejection channel 51).

[0054] The individual protrusion 83b functions as an individual pad on which the flexible printed circuit board 35 is mounted. The individual protrusion 83b extends from the second end of the bridge portion 83a to the +Y side. That is, the individual protrusion 83b is provided at a position shifted in the X direction with respect to the common protrusion 76b. The common protrusion 76b and the individual protrusion 83b may be provided at the same position in the X direction. In this case, the common protrusion 76b and the individual protrusion 83b may be provided at a position overlapping the discharge channel 51 in a plan view, or may be provided at a position overlapping the tail portions 41a and 41b in a plan view.

[0055] <Nozzle plate 33> As shown in Figs. 4 and 6, the nozzle plate 33 covers the lower surface of the actuator plate 41 and the lower surface of the flow path plate 31 together. The nozzle plate 33 is bonded to the lower surface of the actuator plate 41 and the lower surface of the flow path plate 31 via an adhesive or the like. As a result, the nozzle plate 33 covers the lower end openings of the inlet common flow path 31b and the outlet common flow path 31c and the lower end openings of the channels 51 and 52 together. The nozzle plate 33 is formed of a resin material (polyimide, etc.). However, the nozzle plate 33 may have a single-layer structure or a laminated structure made of a resin material (polyimide, etc.), glass, silicon, etc., in addition to a metal material (SUS, Ni-Pd, etc.).

[0056] As shown in Figures 6 and 8, the nozzle plate 33 is formed with a plurality of nozzle holes 33a penetrating the nozzle plate 33 in the Z direction. The nozzle holes 33a are formed, for example, in a tapered shape in which the inner diameter gradually decreases from the top to the bottom. The nozzle holes 33a are arranged at intervals in the X direction. Each nozzle hole 33a is individually connected to a corresponding discharge channel 51. In the illustrated example, the upper end opening of each nozzle hole 33a opens at the center of the discharge channel 51 in the Y direction.

[0057] <Flow passage cover 34> 3 and 6, the flow path cover 34 sandwiches the flow path plate 31 and the head chip 32 between the flow path cover 34 and the nozzle plate 33. 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 whose planar outer shape is formed to be the same as that of the flow path plate 31. The cover base 95 is overlaid on the upper surfaces of the flow path plate 31 and the head chip 32. The cover base 95 is bonded to the upper 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. As a result, the cover base 95 closes the upper end openings of the inlet common flow path 31b and the outlet common flow path 31c.

[0058] A slit 95a is formed in the center of the cover base 95 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 overlapping the center of the head chip 32 (excluding the outer periphery) 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 protrusions 76b, 83b on the upper surface of the cover plate 42. In the illustrated example, the cover base 95 covers the outer periphery of the cover plate 42 with the opening edge of the slit 95a, and exposes the entirety of each of the protrusions 76b, 83b through the slit 95a.

[0059] The inlet port 96 is located at the end of the cover base 95 on the +Y side and the +X side. The inlet port 96 protrudes upward from the cover base 95. The inlet port 96 communicates with the inlet common flow channel 31b through the +X side end of the inlet common flow channel 31b (the portion protruding toward the chip accommodation section 31a). That is, the ink flowing through the ink supply tube 21 is supplied to the inlet common flow channel 31b through the inlet port 96. The outlet port 97 is located at the end of the cover base 95 on the -Y side and the -X side. The outlet port 97 protrudes upward from the cover base 95. The outlet port 97 communicates with the outlet common flow channel 31c through the -X side end of the outlet common flow channel 31c (the portion protruding toward the chip housing portion 31a). That is, the ink flowing through the outlet common flow channel 31c is discharged to the ink discharge tube 22 through the outlet port 97.

[0060] 6, the flexible printed circuit board 35 is pressure-bonded to the upper surface of the cover plate 42 through the slit 95a. The flexible printed circuit board 35 is connected to the protrusions 76b, 83b on the upper surface of the cover plate 42. The flexible printed circuit board 35 is pulled out upward and then connected to a control unit.

[0061] [Printer 1 operation method] 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. 1 are each fully filled with ink of a different color. Also, the ink in the ink tanks 4 is filled in the inkjet head 5 via the ink circulation mechanism 6.

[0062] When the printer 1 is operated in this initial state, the recording medium P is conveyed to the +X side 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, causing the inkjet head 5 mounted on the carriage 29 to move back and forth in the Y direction. While the inkjet heads 5 are moving back and forth, ink is appropriately ejected from each inkjet head 5 onto the recording medium P. In this way, characters, images, etc. can be recorded on the recording medium P.

[0063] The movement of each ink-jet head 5 will now be described in detail. In the inkjet head 5 of the circulation type side shoot type as in the first embodiment, first, the pressurizing pump 24 and the suction pump 25 shown in FIG. 2 are operated to circulate ink in the circulation flow path 23. In this case, the ink flowing in 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 ejection channel 51 through the +Y side opening of each ejection channel 51, and then flows through each ejection channel 51 to the -Y side. After that, the ink is discharged to the outlet common flow path 31c through the -Y side opening of each ejection channel 51. The ink discharged to the outlet common flow path 31c flows into the ink ejection pipe 22 through the outlet port 97, and is returned to the ink tank 4. In this way, the ink can be circulated between the inkjet head 5 and the ink tank 4.

[0064] Then, when the inkjet head 5 starts to move back and forth by the movement of the carriage 29 (see FIG. 1), a driving voltage is applied between the common electrode 65 and the individual electrodes 68 via the flexible printed circuit board 35. At this time, the driving voltage is applied with the common electrode 65 set to a reference potential GND and the individual electrodes 68 set to a driving potential Vdd. Then, a potential difference is generated in the X direction between the common electrode 65 and the individual electrodes 68, which face 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 perpendicular to the polarization direction (Z direction). As a result, the actuator plate 41 undergoes thickness slip deformation in the Z direction due to the shear mode. Specifically, thickness slip deformation occurs in the two driving walls 53 that define the ejection channel 51, and these two driving walls 53 deform so as to protrude toward the non-ejection channel 52 side. That is, since the actuator plate 41 of the first embodiment is composed of two piezoelectric substrates that are polarized in the thickness direction (Z direction) and are laminated, when a drive voltage is applied, the actuator plate 41 bends and deforms into a V shape centered on the middle position in the Z direction of the drive wall 53. This causes the ejection channel 51 to deform as if it is bulging.

[0065] Thereafter, when the driving voltage is set to zero, the actuator plate 41 returns to its original state, and the volume within the ejection channel 51 attempts to return to its original state. In the process of the actuator plate 41 returning to its original state, the pressure within the ejection channel 51 increases, and the ink within the ejection channel 51 is ejected to the outside through the nozzle hole 33a. The ink ejected to the outside lands on the recording medium P, and print information is recorded on the recording medium P.

[0066] <Method of Manufacturing Discharge Unit 30> Next, a description will be given of a method for manufacturing the above-mentioned discharge unit 30. FIG 9 is a flowchart for explaining a method for manufacturing the discharge unit 30. 8, the manufacturing method of the discharge unit 30 includes an actuator processing step S10, a cover plate processing step S20, a grinding step S30, an assembly step S40, and a second bonding step S50. Among the manufacturing steps of the discharge unit 30, the actuator processing step S10, the cover plate processing step S20, and the grinding step S30 correspond to manufacturing steps of the head chip 32. In the following description, for convenience, an example will be described in which the head chip 32 is manufactured at the chip level.

[0067] 10 to 13 are process diagrams for explaining the actuator machining step S10, and are end views corresponding to FIG. 10, a mask pattern 100 is formed on the upper surface of the actuator plate 41. Specifically, after a mask material (e.g., a laminate film) is formed on the upper surface of the actuator plate 41, the mask material is patterned using a photolithography technique. At this time, the mask pattern 100 is formed in which at least the formation regions of the common output wiring 66 and the individual output wiring 69 are opened in the mask material. Note that the dimension (pre-processing dimension) of the actuator plate 41 in the Z direction at the time of the actuator processing step S10 is larger than the dimension (post-processing dimension) of the actuator plate 41 when completed as the head chip 32.

[0068] In the channel forming step S12 shown in FIG. 11, the formation regions of the discharge channel 51 and the non-discharge channel 52 in the actuator plate 41 are processed by the first dicer 110. The first dicer 110 is formed in a disk shape when viewed from the X direction. In the channel forming step S12, the travel distance of the first dicer 110 in the Y direction is made smaller in the formation region of the non-discharge channel 52 than in the formation region of the discharge channel 51. As a result, when viewed from the X direction, the bottom surface of the non-discharge channel 52 is formed in a convex arc shape facing downward, and the bottom surface of the discharge channel 51 is formed in a straight line. In addition, the advance amount of the first dicer 110 in the Z direction is set to be larger than the post-processing dimension of the actuator plate 41 and smaller than the pre-processing dimension of the actuator plate 41. That is, after the channel forming step S12, neither the discharge channel 51 nor the non-discharge channel 52 penetrates the actuator plate 41.

[0069] 12, a common wiring 61 and individual wiring 62 are formed as drive wiring. Specifically, an electrode material (for example, TiAu, etc.) is formed by oblique deposition or the like from the upper surface side of the actuator plate 41. As a result, a common electrode 65 is formed on the inner surface of each ejection channel 51, and an individual electrode 68 is formed on the inner surface of the non-ejection channel 52. In addition, a common output wiring 66 and an individual output wiring 69 are formed on the upper surface of the actuator plate 41 through a mask pattern 100. In addition, in the first wiring formation process S13, the electrode material can be formed by sputtering, ion plating, plating, etc. in addition to oblique deposition.

[0070] 13, the individual electrodes 68a, 68b formed in one non-ejection channel 52 are separated. Specifically, the second dicer 115 is advanced into the center of the non-ejection channel 52 in the X direction. At this time, the dimension of the second dicer 115 in the X direction is smaller than the dimension of the non-ejection channel 52 in the X direction. Therefore, the individual electrodes 68a, 68b are separated at the bottom surface of the non-ejection channel 52.

[0071] 14 to 16 are process drawings for explaining the cover plate machining step S20, and are cross-sectional views corresponding to FIG. In the hole forming step S21 shown in Fig. 14, a common hole 42a and individual holes 42b, 42c are formed in the cover plate 42. Specifically, a laser beam is irradiated from the upper surface side of the cover plate 42 to penetrate the cover plate 42. That is, each of the holes 42a to 42c is formed by a laser irradiation mark caused by the laser processing. The laser used in the laser processing can be appropriately selected according to the material of the cover plate 42, such as a 266 laser, an excimer laser, a green laser, a YAG laser, or a CO2 laser.

[0072] In a first bonding step S22 shown in FIG.

[0073] 16, a common connection wiring 71 and individual connection wiring 72 are formed on the cover plate 42 as connection wiring. Specifically, an electrode material is formed by performing deposition or the like from the upper 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 hole 42a, and individual through wirings 81, 82 are formed in the individual holes 42b, 42c. In addition, a common lead-out wiring 76 and individual lead-out wiring 83 are formed on the upper surface of the cover plate 42. In the second wiring formation process S23, the electrode material can be formed by sputtering, ion plating, plating, or the like in addition to oblique deposition.

[0074] FIG. 17 is a process diagram for explaining the grinding step S30, and is an end view corresponding to FIG. 17, a grinding process is performed on the lower surface of the actuator plate 41. Specifically, the actuator plate 41 is ground until the ejection channels 51 and the non-ejection channels 52 open on the lower surface of the actuator plate 41. Through the above steps, the head chip 32 is completed.

[0075] Thereafter, in an assembly process S40, head chip 32 is attached to flow path plate 31. Specifically, head chip 32 is fitted into chip housing portion 31a so that the lower surface of flow path plate 31 and the lower surface of head chip 32 are flush with each other.

[0076] Next, in a second bonding process S50, the nozzle plate 33 is attached so as to collectively cover the lower surface of the flow path plate 31 and the lower surface of the head chip 32. Thereafter, the flow path cover 34 is attached to the upper surface of the flow path plate 31. Through the above steps, the discharge unit 30 is completed.

[0077] When the head chip 32 is manufactured at the wafer level, the actuator plate wafer and the cover plate wafer are subjected to the same processes as the actuator processing process S10, the cover plate processing process S20, and the grinding process S30 to form a wafer stack. The wafer stack is then diced into individual pieces to extract the head chips 32. The head chips 32 extracted from the wafer stack are then subjected to the assembly process S40 and subsequent processes to complete the discharge unit 30.

[0078] In this manner, head chip 32 of the first embodiment includes cover plate 42 which is overlapped above actuator plate 41 (first side in the thickness direction) and has a smaller dimension in the Z direction than actuator plate 41. In cover plate 42, common through wire 75 and individual through wires 81, 82 are formed in holes 42a to 42c which penetrate cover plate 42 in the Z direction. According to this configuration, by forming the common through wiring 75 and the individual through wirings 81, 82 in the cover plate 42, it is possible to reduce the size of the actuator plate 41 in a direction intersecting the Z direction, compared to a case where pads are formed on the same plane as the ejection channels 51 in the actuator plate 41. By reducing the size of the actuator plate 41, for example, when the head chips 32 are produced at the wafer level, it is possible to increase the number of head chips 32 that can be obtained from one wafer. In addition, by forming the connection wiring in the cover plate 42, it is possible to improve the degree of freedom in designing the connection wiring, compared to a case where both the drive electrodes and the connection wiring are formed in the actuator plate 41.

[0079] In particular, in head chip 32 of the first embodiment, holes (through holes) 42a to 42c are formed by laser processing. According to this configuration, the holes 42a to 42c are formed by laser processing, which improves the freedom of material selection for the cover plate 42, and thus allows the cover plate 42 to be made thinner. In addition, the holes 42a to 42c can be easily made fine by adjusting the laser diameter, etc. Also, unlike the case where the holes 42a to 42c are formed by sandblasting, for example, there is no need to grind the actuator plate 41 after the holes 42a to 42c are formed, so the holes 42a to 42c can be processed with the dimensions in the Z direction equivalent to the dimensions of the product. This allows for a reduction in material costs and an improvement in manufacturing efficiency.

[0080] In head chip 32 of the first embodiment, holes 42a to 42c are configured to be tapered such that the inner diameter gradually decreases from the top to the bottom. According to this configuration, for example, when the common through wiring 75 and the individual through wirings 81, 82 are formed through the upper end openings of the holes 42a to 42c, the common through wiring 75 and the individual through wirings 81, 82 can be easily formed over the entire area in the thickness direction on the inner surface of the holes 42a to 42c. Therefore, the conduction between the flexible printed circuit board 35 and the common electrode 65 and the individual electrodes 68 can be stabilized.

[0081] In head chip 32 of the first embodiment, holes 42a to 42c are formed at positions that do not overlap ejection channels 51 in a plan view. According to this configuration, communication between the discharge channel 51 and the holes 42a to 42c can be prevented, and reliability can be improved.

[0082] In the head chip 32 of the first embodiment, the cover plate 42 is configured to be made of a resin material. This configuration makes it easy to provide a versatile, thin, and ink-resistant cover plate 42 at low cost. Even if the cover plate 42 is made thinner, there is little risk of cracking and handling is easy, which improves manufacturing efficiency.

[0083] Since the inkjet head 5 and printer 1 of the first embodiment are provided with the head chip 32 described above, it is possible to achieve miniaturization and cost reduction.

[0084] 18 is a graph showing the relationship between the perimeter [mm] of the through hole and the resistance [Ω] of the through wiring. This graph shows the change in resistance when the perimeter of the lower opening edge of the common hole 42a is changed while the thickness of the common through wiring 75 is set constant at 0.00076 mm. In this case, the cross-sectional area of ​​the common through wiring 75 on the lower opening edge of the common hole 42a is calculated by the product of the perimeter of the common through wiring 75 and the thickness of the common through wiring 75.

[0085] As shown in Fig. 18, it can be seen that the resistance value decreases exponentially as the perimeter increases. Therefore, in the head chip 32 of the first embodiment, it is preferable that the common through-wire 75 is formed around the entire perimeter of the common hole 42a, and that the perimeter of the lower opening edge of the common hole 42a is formed to be, for example, 0.25 mm or more and 10.00 mm or less. The dimension (thickness) of the common through-wire 75 perpendicular to the Z direction on the lower opening edge of the common hole 42a is 0.0002 mm (0.00005 mm in cross-sectional area). 2) or more than 0.00304mm thick (0.03040mm in cross-sectional area) 2 ) is preferably formed as follows. By setting the perimeter to 0.25 mm or more and the thickness to 0.0002 mm or more, the electrical resistance between the common electrode 65 and the common through-wire 75 can be sufficiently reduced, power saving can be achieved, and heat generation of the head chip 32 can be suppressed. On the other hand, by setting the perimeter to 10.00 mm or less and the thickness to 0.00304 mm or less, the electrical resistance can be further reduced while suppressing the dimension in the X direction of the head chip 32. The above effect is similar between the individual holes 42b, 42c and the individual through-wires 81, 82. In the first embodiment, the configuration in which one common through-wire 75 is connected to one common wiring 76 has been described, but this configuration is not limited. A configuration in which multiple common through-wires 75 (common holes 42a) are connected to one common wiring 76 may also be used. In this case, it is preferable that the above-mentioned perimeter is set based on the total perimeter of the multiple common holes 42a connected to one common wiring 76.

[0086] Second embodiment FIG. 19 is an exploded perspective view of a head chip 32 according to the second embodiment. The head chip 32 shown in FIG. 19 differs from the first embodiment in the shapes of the common lead-out wiring 76 and the individual lead-out wiring 83. The common wiring 76 extends in the X direction so as to cross between the common holes 42a, similar to the strip-shaped portion 76a in the first embodiment. The common wiring 76 is connected to the common through-wire 75 at the upper opening edge of the common hole 42a. A portion of the common wiring 76 located between adjacent common holes 42a functions as a common pad on which the flexible printed circuit board 35 is mounted.

[0087] The individual lead-out wiring 83 includes a bridge portion 83a and an individual protrusion portion 83b. As in the first embodiment described above, the bridge portion 83a connects between a first individual through wiring 81 located on the −X side of one discharge channel 51 and a second individual through wiring 82 located on the +X side of one discharge channel 51, respectively. The individual protrusion 83b spreads out from a first end (the end closer to the common wiring 76) of the bridging portion 83a onto the upper surface of the cover plate 42. The individual protrusion 83b functions as an individual pad on which the flexible printed circuit board 35 is mounted.

[0088] In head chip 32 of the second embodiment, the connection portions of each of lead wirings 76, 83 and flexible printed circuit board 35 can be brought close to each other on the upper surface of cover plate 42. This makes it possible to reduce the electrostatic capacitance of head chip 32. As a result, the responsiveness of head chip 32 can be improved and heat generation in head chip 32 can be suppressed. Furthermore, by bringing the connection portions of lead wirings 76, 83 and flexible printed circuit board 35 close to each other, the work of crimping flexible printed circuit board 35 becomes easier.

[0089] Third embodiment 20 is a plan view of an actuator plate 41 according to the third embodiment. The head chip 32 of the third embodiment differs from the above-described embodiments in that the individual output wirings 69a and 69b are concentrated on one side of the actuator plate 41 with respect to the non-ejection channels 52. 20, the first individual output wiring 69a is formed on the upper surface of the second tail portion 41b on the +X side with respect to the center of the non-ejection channel 52. The first individual output wiring 69a is connected to the first individual electrode 68a at the upper opening edge of the non-ejection channel 52. The second individual output wiring 69b is formed on the upper surface of the second tail portion 41b on the -X side with respect to the center of the non-ejection channel 52. The second individual output wiring 69b is connected to the second individual electrode 68b at the upper opening edge of the non-ejection channel 52.

[0090] The first individual hole 42b and the second individual hole 42c are formed on the +Y side of the cover plate 42 with respect to the non-ejection channel 52. Specifically, the first individual hole 42b penetrates in the Z direction a portion of the cover plate 42 that overlaps with the second tail portion 41b in a plan view and is located on the +X side (more +X side than the common hole 42a) with respect to the center of the non-ejection channel 52. The second individual hole 42c penetrates in the Z direction a portion of the cover plate 42 that overlaps with the second tail portion 41b in a plan view and is located on the -X side (more -X side than the common hole 42a) with respect to the center of the non-ejection channel 52.

[0091] FIG. 21 is a plan view of the head chip 32 according to the third embodiment with the flow path cover 34 removed. As shown in FIG. 20 and FIG. 21, the bridge portion 83a of the individual lead-out wiring 83 connects between the first individual through-wire 81 located on the +X side of one discharge channel 51 and the second individual through-wire 82 located on the -X side of one discharge channel 51. Specifically, the bridge portion 83a is formed in a band shape extending in the X direction on a portion of the upper surface of the cover plate 42 located on the +Y side of the non-discharge channel 52. The +X side end of the individual lead-out wiring 83 is connected to the first individual through-wire 81 at the upper opening edge of the first individual hole 42b. The -X side end of the bridge portion 83a is connected to the second individual through-wire 82 at the upper opening edge of the second individual hole 42c.

[0092] Of the individual lead-out wiring 83, the individual protrusions 83b extend from the center of each bridge portion 83a in the X direction to the -Y side. The individual protrusions 83b are formed at positions on the upper surface of the cover plate 42 that overlap with the corresponding ejection channels 51 in a plan view. Thus, the individual protrusions 83b face the common protrusion 76b in the Y direction.

[0093] In the head chip 32 of the third embodiment, the individual output wirings 69a, 69b are concentrated on one side with respect to the non-ejection channels 52 of the actuator plate 41, so that the wiring length of the bridge portion 83a can be shortened. As a result, the electrostatic capacitance of the head chip 32 can be reduced. Also, in the head chip 32 of the third embodiment, the protruding portions 76b, 83b serving as pads protrude inward in the Y direction from the corresponding bridge portions 76a, 83a, so that they are provided at positions overlapping with the channel row 46 in a plan view. This allows the head chip 32 to be further miniaturized as compared to a configuration in which the pads protrude outward in the Y direction.

[0094] (Fourth embodiment) Fig. 22 is an exploded perspective view of head chip 32 according to the fourth embodiment. Fig. 23 is a plan view of actuator plate 41. Fig. 24 is a cross-sectional view of head chip 32 corresponding to line XXIV-XXIV in Fig. 23. Fig. 25 is a cross-sectional view of head chip 32 corresponding to line XXV-XXV in Fig. 23. 22 to 25 differs from the above-described embodiments in that a surface plate 200 is provided on the side of the cover plate 42 opposite to the actuator plate 41 (first side in the thickness direction). The surface plate 200 is used for connecting the head chip 32 and the flexible printed circuit board 35. In this case, the cover plate 42 functions as a connection board (adapter) between the various drive wirings formed on the actuator plate 41 and the various terminal wirings formed on the surface plate 200.

[0095] The surface plate 200 is a plate material made of a piezoelectric material such as PZT, a resin material such as polyimide, or other non-conductive material. The surface plate 200 may be made of a conductive material such as a metal material, and the outer surface of the base may be coated with a non-conductive material. In this case, the cover plate 42 and the surface plate 200 may be made of the same material or different materials. In the fourth embodiment, it is preferable that the surface plate 200 has a high rigidity (a high Young's modulus) relative to the cover plate 42. In the illustrated example, the dimension of the surface plate 200 in the Z direction is larger than that of the actuator plate 41. That is, the dimensions of the plates constituting the head chip 32 in the Z direction are the largest for the surface plate 200 and the smallest for the cover plate 42. The dimension of the surface plate 200 in the Z direction may be smaller than that of the cover plate 42.

[0096] The surface plate 200 has the same outer shape as the cover plate 42 in a plan view, and is overlaid on the entire upper surface of the cover plate 42. The surface plate 200 is bonded to the upper surface of the cover plate 42 with an adhesive or the like.

[0097] The surface plate 200 is formed with a surface common hole 200a and surface individual holes 200b. Each of the surface holes 200a, 200b is formed in a tapered shape in which the inner diameter gradually decreases from the top to the bottom. However, the inner diameter of each of the surface holes 200a, 200b may be uniform over the entire Z direction. The planar shape of each of the surface holes 200a, 200b can also be appropriately changed to a circular shape, a polygonal shape, or the like. The surface common hole 200a and the surface individual holes 200b may be the same shape or different shapes.

[0098] As shown in FIG. 22 and FIG. 24, the surface common hole 200a penetrates in the Z direction through a portion of the surface plate 200 that overlaps with the -Y side end of the discharge channel 51 in a plan view (a portion located between adjacent first tail portions 41a). That is, the surface common hole 200a is provided corresponding to each discharge channel 51. In a plan view, the surface common hole 200a is disposed shifted in the X direction relative to the common hole 42a. Meanwhile, in a side view, the lower end opening of the surface common hole 200a is located on the +Y side relative to the common hole 42a. However, the lower end opening of the surface common hole 200a may be provided on the -Y side relative to the common hole 42a, or may be provided at the same position in the Y direction.

[0099] The surface individual holes 200b penetrate in the Z direction through the portions of the surface plate 200 that overlap with the second tail portions 41b in a plan view. That is, the surface individual holes 200b are provided corresponding to each of the non-ejection channels 52. The surface individual holes 200b and the individual holes 42b, 42c are aligned in a straight line in the Y direction. Specifically, the lower end opening of the surface individual hole 200b is located on the +Y side with respect to the second individual hole 42c. However, the lower end opening of the surface individual hole 200b may be provided on the -Y side with respect to the second individual hole 42c, or may be formed at a position that overlaps with the first tail portion 41a in a plan view.

[0100] The surface common hole 200a and the surface individual holes 200b are arranged at both ends in the Y direction of the surface plate 200 with a shift of half a pitch with respect to the arrangement pitch of the ejection channels 51 (or non-ejection channels 52). In the fourth embodiment, the surface common hole 200a and the surface individual holes 200b are shifted from each other in the X direction when viewed from the Y direction. However, a portion of the surface common hole 200a and the surface individual holes 200b may overlap each other when viewed from the Y direction.

[0101] As shown in FIGS. 23 to 25, on the surface plate 200, a common terminal wire 211 and individual terminal wires 212 are formed as terminal wires. The common terminal wiring 211 includes a surface common wiring (second wiring) 211a and a common pad 211b.

[0102] 22 and 24, the surface common wiring 211a is formed on the inner surface of the surface common hole 200a. Specifically, the surface common wiring 211a is formed on the entire inner surface of the surface common hole 200a and is formed over the entire Z direction. The surface common wiring 211a is connected to the common protrusion 76b at the lower opening edge of the surface common hole 200a. The common pad 211b is formed on the upper surface of the surface plate 200 so as to surround the surface common hole 200a. The common pad 211b is formed in an elliptical shape with the Y direction as the major axis direction in a plan view. The -Y side end of the common pad 211b is connected to the surface common wiring 211a at the upper opening edge of the surface common hole 200a.

[0103] As shown in FIGS. 22 and 25, the individual terminal wiring (second wiring) 212 includes a surface individual wiring 212a and an individual pad 212b. The surface individual wiring 212a is formed on the inner surface of the surface individual hole 200b. Specifically, the surface individual wiring 212a is formed around the entire inner surface of the surface individual hole 200b and is formed over the entire Z direction. The surface individual wiring 212a is connected to the individual protrusion 83b at the lower opening edge of the surface individual hole 200b.

[0104] The individual pads 212b are formed on the upper surface of the surface plate 200 so as to surround the surface individual holes 200b. The individual pads 212b are formed in an elliptical shape with the Y direction as the major axis direction in a plan view. The +Y side end of the individual pads 212b is connected to the surface individual wiring 212a at the upper opening edge of the surface individual hole 200b. The common pads 211b and the individual pads 212b are arranged at both ends in the Y direction of the surface plate 200, shifted by half a pitch with respect to the arrangement pitch of the ejection channels 51 (or non-ejection channels 52).

[0105] As shown in FIGS. 24 and 25, the flexible printed circuit board 35 is connected to the pads 211b and 212b on the upper surface of the surface plate 200.

[0106] Head chip 32 of the fourth embodiment is configured to include, above cover plate 42, surface plate 200 whose dimension in the Z direction is larger than that of cover plate 42. According to this configuration, when ink is ejected, the upward displacement of the cover plate 42 caused by an increase in pressure in the ejection channel 51 or the like can be restricted by the surface plate 200. This improves the pressure generated in the ejection channel 51, and enables ink to be ejected efficiently. Note that, although the fourth embodiment has been described with respect to a configuration in which wiring is formed on the surface plate 200, this is not limiting. Wiring may not be formed on the surface plate 200. In other words, the surface plate 200 may only function as a rigid member that restricts the displacement of the cover plate 42.

[0107] In the head chip 32 of the fourth embodiment, pads 211b, 212b are formed on the upper surface of the surface plate 200. The surface plate 200 is configured to have formed thereon a surface common wiring 211a that connects the common lead-out wiring 76 and the common pad 211b, and a surface individual wiring 212a that connects the individual lead-out wiring 83 and the individual pad 212b. According to this configuration, by using the cover plate 42 as an intermediate plate between the surface plate 200 and the actuator plate 41, it is possible to improve the degree of freedom in design compared to a case where mounting to the flexible printed circuit board 35 and connecting various electrodes to each other are performed only by the cover plate 42. In this case, the pitch of the ejection channels 51 can be narrowed, and the information printed by the head chip 32 can be printed with high resolution. In addition, by forming a wiring pattern in cooperation with the surface plate 200 and the cover plate 42, the wiring pattern can be simplified even on the upper surface of the surface plate 200. Therefore, when mounting each of the pads 211b, 212b and the flexible printed circuit board 35, it is possible to suppress the occurrence of defects such as short circuits. In addition, by connecting the driving electrodes (common electrode 65 and individual electrode 68) of the actuator plate 41 to the pads 211b, 212b of the surface plate 200 by the common wiring 76 and the individual wiring 83 formed on the cover plate 42, the cover plate 42 functions as an adapter between the actuator plate 41 and the surface plate 200. As a result, the wiring pattern of the surface plate 200 can be made common regardless of the discharge method, thereby reducing costs.

[0108] (Other variations) 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 embodiment, the inkjet printer 1 has been described as an example of a liquid jet recording apparatus, but the liquid jet recording apparatus is not limited to a printer. For example, the liquid jet recording apparatus may be a fax machine, an on-demand printer, or the like. In the above-described embodiment, a configuration in which the inkjet head moves relative to the recording medium during printing (so-called shuttle machine) 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 moves relative to the inkjet head while the inkjet head is fixed (so-called fixed head machine). In the above embodiment, the recording medium P is paper, but this is not limited to the above configuration. The recording medium P is not limited to paper, and may be a metal material, a resin material, or a food product. In the above-described embodiment, the liquid ejection head is mounted on the liquid ejection recording device, but the present invention is not limited to this configuration. In other words, the liquid ejected from the liquid ejection head is not limited to the liquid that is to be landed on the recording medium, and may be, for example, a medicinal liquid to be mixed in a medicine, a food additive such as a seasoning or a fragrance to be added to food, or an aromatic to be sprayed into the air.

[0109] In the above embodiment, the configuration has been described in which the Z direction coincides with the direction of gravity, but the present invention is not limited to this configuration, and the Z direction may be aligned with the horizontal direction. In the above embodiment, the ejection channel 51 serving as the pressure chamber is formed in the actuator plate 41 itself, and the head chip 32 is of a so-called wall vent type in which the direction of pressure applied to the ink and the direction of ink ejection intersect, but the present invention is not limited to this configuration. As the head chip, a roof chute type (in which the direction of pressure applied to the ink and the direction of ink ejection are the same) may be used.

[0110] In the above-described embodiment, the head chip 32 is of a side shoot type, but the present invention is not limited to this. For example, the above-described embodiment may be appropriately adopted for a so-called edge shoot type head chip that ejects ink from the end of the ejection channel in the extension direction. In the above embodiment, the electrode material is formed only on the inner surface of the through hole, but the present invention is not limited to this configuration. The electrode material may be formed so as to fill the through hole.

[0111] 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. [Explanation of symbols]

[0112] 1: Printer (liquid jet recording device) 5: Inkjet head (liquid ejection head) 31a: Nozzle hole (injection hole) 32: Head chip 41: Actuator plate 42: Cover plate 42a: Common hole (through hole) 42b: 1st individual hole (through hole) 42c: 2nd individual hole (through hole) 51: Discharge channel (pressure chamber) 53: Drive wall (drive part) 65: Common electrode (drive electrode) 71: Common connection wiring (first wiring) 200: Surface plate 211a: Surface common wiring (second wiring) 211b: Common pad (pad)

Claims

1. an actuator plate that contains liquid and has a drive portion disposed facing a plurality of pressure chambers that are respectively in communication with a plurality of injection holes, and that is deformable so that the pressure chambers expand or contract; A driving electrode formed on the actuator plate; a cover plate that is overlapped with the actuator plate on a first side in a thickness direction and has a smaller dimension in the thickness direction than the actuator plate, a first wiring is formed in the cover plate, the first wiring being formed in a through hole penetrating the cover plate in the thickness direction and connecting between an external wiring provided on a first side of the cover plate in the thickness direction and the driving electrode; The through hole is formed by laser processing.

2. 2. The head chip according to claim 1, wherein the through hole has an outer shape that becomes gradually smaller as viewed in the thickness direction from a first side in the thickness direction toward a second side opposite to the first side.

3. the pressure chamber is formed in the actuator plate and penetrates the actuator plate in the thickness direction; 3. The head chip according to claim 1, wherein the through hole is formed at a position that does not overlap with the pressure chamber when viewed in the thickness direction.

4. the first wiring is formed around the entire periphery of the through hole, a total perimeter of a second-side opening edge located on a second side opposite to the first side in the thickness direction of the through hole in which the first wiring corresponding to one of the driving electrodes is formed is set to 0.25 mm or more; 3. The head chip according to claim 1, wherein the dimension perpendicular to the thickness direction on the second side opening edge in the thickness direction of the first wiring corresponding to one of the driving electrodes is 0.0002 mm or more.

5. 3. The head chip according to claim 1, wherein the cover plate is made of a resin material.

6. 3. The head chip according to claim 1, further comprising a surface plate overlapping said cover plate on a first side in said thickness direction and having a dimension in said thickness direction larger than that of said cover plate.

7. a pad connected to an external wiring is formed on a surface of the surface plate facing the first side in the thickness direction; 7. The head chip according to claim 6, wherein a second wiring is formed on the surface plate, the second wiring penetrating the surface plate in the thickness direction and connecting between the first wiring and the pads.

8. A liquid jet head comprising the head chip according to claim 1 or 2.

9. A liquid jet recording apparatus comprising the liquid jet head according to claim 8.

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