Liquid discharge head and liquid discharge device

Abstract

To provide a liquid discharge head with high mountability and a liquid discharge device.SOLUTION: A liquid discharge head comprises a substrate, a piezoelectric member, a diaphragm, and electrode wiring. The substrate has a wiring surface. The piezoelectric member is provided on the wiring surface of the substrate. In the piezoelectric member, one lateral surface part has an inclined surface inclining at an angle larger than 90° but smaller than 180°relative to the wiring surface. The diaphragm is opposingly arranged on an opposite side of the substrate of the piezoelectric member. The electrode wiring is formed on the inclined surface of the piezoelectric member.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] An embodiment of the present invention relates to a liquid ejection head and a liquid ejection apparatus. [Background technology]

[0002] Piezoelectric actuators using piezoelectric materials such as PZT are used as the driving source for liquid ejection devices such as inkjet printer heads. Inkjet printer heads and the like have actuators arranged at very close intervals, with many grooves formed in one piezoelectric material, and the structure has multiple pillars divided by the grooves, each of which serves as an actuator. To drive the actuator, electrodes are provided on the surface of the pillar that is perpendicular to the surface that expands and contracts, and a flexible cable is directly connected to the electrodes on the surface of the actuator by soldering.

[0003] In such a configuration, the joining strength between the actuator and the flexible cable is low, so the joining portion is easily damaged, and the electrical connection is easily opened. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2011-56730 A Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a liquid ejection head and a liquid ejection apparatus that are easy to mount. [Means for solving the problem]

[0006] A liquid ejection head according to one embodiment includes a substrate, a piezoelectric member, a vibration plate, and electrode wiring. The substrate has a wiring surface. The piezoelectric member is provided on the wiring surface of the substrate. One side portion of the piezoelectric member has an inclined surface that is inclined at an angle greater than 90° and less than 180° with respect to the wiring surface. A vibration plate is disposed opposite the piezoelectric member on the opposite side to the substrate. Electrode wiring is formed on the inclined surface of the piezoelectric member. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a cross-sectional view showing a configuration of an inkjet head according to an embodiment. [Diagram 2] FIG. 2 is a cross-sectional view showing the configuration of the inkjet head. [Diagram 3] FIG. 2 is a perspective view showing the configuration of the inkjet head. [Figure 4] 3A to 3C are explanatory diagrams showing a method of manufacturing the inkjet head. [Diagram 5] FIG. 11 is an explanatory diagram showing an inkjet head according to another embodiment. [Figure 6] FIG. 1 is an explanatory diagram showing a schematic configuration of an inkjet recording apparatus according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] An actuator 20 according to an embodiment, an inkjet head 1 which is a liquid ejection head, and an inkjet recording apparatus 100 which is a liquid ejection apparatus will be described below with reference to Figs. 1 to 6. Figs. 1 and 2 are cross-sectional views showing a schematic configuration of the inkjet head 1. Fig. 2 shows a cross-section taken along line II-II in Fig. 1. Fig. 3 is a perspective view showing a part of the inkjet head 1, Fig. 4 is an explanatory diagram showing a manufacturing method of the inkjet head, and Fig. 6 is an explanatory diagram showing a schematic configuration of the inkjet recording apparatus 100. In the figures, arrows X, Y, and Z respectively indicate three directions which are orthogonal to one another. In each figure, the configuration is enlarged, reduced, or omitted as appropriate for the purpose of explanation.

[0009] As shown in FIGS. 1 and 2, the inkjet head 1 includes a substrate 10, a pair of actuators 20, a flow path portion 40, a nozzle plate 50 having a plurality of nozzles 51, a frame portion 60, and a drive circuit .

[0010] As an example, the inkjet head 1 includes two actuators 20, and has two nozzle rows in which a plurality of nozzles 51 are aligned in a row direction (X direction), two pressure chamber rows in which a plurality of pressure chambers 31 are aligned in the row direction, and two element rows in which a plurality of piezoelectric elements 21, 22 are aligned in the row direction. In this embodiment, an example is shown in which the stacking direction of the plurality of piezoelectric layers 211 in the actuator 20, the vibration direction of the driving piezoelectric element 21, and the vibration direction of the vibration plate 30 are all along the Z direction.

[0011] The substrate 10 is a circuit board that supports the pair of actuators 20. The substrate 10 is formed in a plate shape from, for example, alumina, and has a mounting surface 101 that is a surface along the extending direction and the parallel direction. The mounting surface 101 of the substrate 10 on which the actuators 20 are mounted has substrate electrode layers 11 and 12 formed thereon. The mounting surface 101 is also called a wiring surface. For example, on the mounting surface 101 of the substrate 10, substrate electrode layers 11 that form individual electrodes are formed in outer regions on both sides of the pair of actuators 20 in the direction in which the pair of actuators 20 face each other, and substrate electrode layer 12 that forms a common electrode is formed in an inner region between the pair of actuators 20. The facing surfaces of the pair of actuators 20 are the inner region, and the surface opposite to the facing surfaces of the pair of actuators 20 is the outer region.

[0012] For example, on the mounting surface 101 of the substrate 10, a predetermined wiring pattern having individual wirings 102 that are a plurality of substrate wirings is formed by separating the substrate electrode layer 11 in the column direction in the outer region of the pair of actuators 20. For example, the individual wirings 102 are continuous with an external electrode 223 (electrode) formed on one side portion that is the outer side of the surface of the actuator 20, and form an individual electrode.

[0013] As an example, in a region near the actuator 20 on the mounting surface 101, at least within a range of reflected light from the inclined surface, the individual wiring 102 extends in the same direction as the external electrode 223 on the side surface of the actuator 20.

[0014] In the outer region of the mounting surface 101 of the substrate 10, a mounting section 76 is provided on which an FPC 71 is mounted as a component via an ACF 75.

[0015] The individual wirings 102 are formed by forming a conductive material by a method such as vacuum deposition or electroless plating, and then patterning the conductive material into a predetermined shape by a patterning process such as photolithography.

[0016] Furthermore, on the mounting surface 101 of the substrate 10, the substrate electrode layer 12 formed in the inner region between the pair of actuators 20 constitutes a common wiring 103 (wiring). The common wiring 103 is continuous with an external electrode 224 (electrode) formed on the other side surface of the actuators 20, which is the inner side, and constitutes a common electrode.

[0017] The actuator 20 is bonded to a mounting surface 101, which is one side of the substrate 10. For example, two actuators 20 are arranged side by side in the Y direction.

[0018] As shown in Figures 1 to 3, the actuator 20 comprises a plurality of driving piezoelectric elements 21 and a plurality of non-driven piezoelectric elements 22 which serve as actuators arranged alternately along the column direction, and a connecting portion 26 which connects these plurality of piezoelectric elements 21, 22 together on the substrate 10 side.

[0019] The actuator 20 is a laminated piezoelectric member in which a plurality of piezoelectric layers 211 and a plurality of internal electrodes 221, 222 are laminated.

[0020] In the actuator 20, a plurality of driving piezoelectric elements 21 and a plurality of non-driving piezoelectric elements 22 are arranged in one direction at regular intervals.

[0021] The actuator 20 is divided into several parts by grooves 23 formed to a predetermined depth from the top side on the vibration plate 30 side, and the multiple driving piezoelectric elements 21 and non-driving piezoelectric elements 22 are arranged in a row direction at the same pitch, for example. The grooves 23 are formed over the entire length of the actuator 20 in the extension direction.

[0022] The pair of actuators 20 are configured such that a side portion 203 on one outer side in the Y direction, which is the opposing direction of the pair of actuators 20, is trapezoidally expanded obliquely toward the substrate 10. For example, the width of the actuator 20 in the short side direction gradually increases on one side from the top side toward the substrate 10. The cross-sectional shape of the cross section of the actuator 20 along the short side direction is formed into a trapezoid. That is, the actuator 20 has an inclined surface that is inclined on the side portion 203 on one side in the short side direction. For example, one side portion 203 of the piezoelectric member 202 of the actuator 20 has an inclined surface with an angle between it and the mounting surface 101 of the substrate 10 that is greater than 90° and less than 180°.

[0023] In each piezoelectric member 202, the other side surface portion 204, which is the inner side where the pair of actuators 20 face each other, is configured so that the angle with the mounting surface 101 of the substrate 10 is smaller than the angle between one side surface portion 203 and the mounting surface 101. As an example, the side surface portion 204 extends along the Z direction, and the angle with the mounting surface 101 of the substrate 10 is 90°.

[0024] In the actuator 20, for example, the multiple driving piezoelectric elements 21 and the multiple non-driven piezoelectric elements 22 are each configured in a rectangular shape when viewed in a planar view from the Z direction, with the short side direction aligned with the row direction of the element row and the long side direction aligned with an extension direction perpendicular to the row direction and the Z direction.

[0025] The multiple driving piezoelectric elements 21 and the multiple non-driving piezoelectric elements 22 have one side on which an individual electrode is formed forming an inclined surface that expands toward the substrate, and the other side on which a common electrode is formed extends along the Z direction, and are configured in a trapezoidal shape with one side inclined when viewed in cross section.

[0026] The driving piezoelectric elements 21 are arranged in positions in the Z direction facing the multiple pressure chambers 31 formed in the flow path portion 40. As an example, the center positions in the row direction and extension direction of the driving piezoelectric elements 21 and the center positions in the row direction and extension direction of the pressure chambers 31 are arranged side by side in the Z direction.

[0027] The non-driven piezoelectric elements 22 are arranged in the Z direction at positions facing the multiple partition walls 42 formed in the flow path section 40. The multiple driven piezoelectric elements 21 and the multiple non-driven piezoelectric elements 22 are arranged in parallel and alternately with the grooves 23 in between in the column direction.

[0028] For example, the piezoelectric member 202 constituting the actuator 20 is a laminated piezoelectric member made of a laminated piezoelectric body, and is formed by stacking and sintering sheet-shaped piezoelectric materials.

[0029] The piezoelectric member 202 includes a plurality of laminated piezoelectric layers 211, internal electrodes 221, 222 formed on the main surface of each piezoelectric layer 211, an external electrode 223 formed on a side surface portion 203 on one side, and an external electrode 224 formed on a side surface portion 204 on the other side. An outer region side, which is the surface opposite to the opposing surfaces of the pair of actuators 20, is the side surface portion 203 on one side of the piezoelectric member 202. An inner region side, which is the opposing surfaces of the pair of actuators 20, is the side surface portion 204 on the other side of the piezoelectric member 202. Note that, as an example, the driving piezoelectric element 21 and the non-driving piezoelectric element 22 have the same laminated structure.

[0030] The piezoelectric layer 211 is formed in a thin plate shape from a piezoelectric ceramic material such as PZT (lead zirconate titanate) or lead-free KNN (potassium sodium niobate). The multiple piezoelectric layers 211 are laminated with their thickness direction aligned with the lamination direction and are bonded to each other. For example, in this embodiment, the thickness direction and lamination direction of the piezoelectric layers 211 are arranged along the vibration direction (Z direction).

[0031] The internal electrodes 221 and 222 are conductive films formed into a predetermined shape using a sinterable conductive material such as silver palladium. The internal electrodes 221 and 222 are formed in a predetermined region on the main surface of each piezoelectric layer 211. The internal electrodes 221 and 222 have different polarities. For example, one internal electrode 221 is formed in a region that reaches one end of the piezoelectric layer 211 but does not reach the other end of the piezoelectric layer 211 in the extension direction (Y direction) that is perpendicular to both the row direction (X direction) in which the multiple driving piezoelectric elements 21 and the multiple non-driving piezoelectric elements 22 are arranged and the vibration direction (Z direction). The other internal electrode 222 is formed in a region that does not reach one end of the piezoelectric layer 211 but reaches the other end of the piezoelectric layer 211 in the extension direction. The internal electrodes 221 and 222 are connected to external electrodes 223 and 224 formed on the side surfaces of the piezoelectric elements 21 and 22, respectively.

[0032] Furthermore, the piezoelectric members 202 constituting the driving piezoelectric elements 21 and the non-driving piezoelectric elements 22 may further include a dummy layer, which is not deformed by being not subjected to an electric field, on either or both of the ends on the substrate 10 side and the nozzle plate 50 side. The dummy layer is made of the same material as the piezoelectric layer 211, does not function as a piezoelectric body, and serves as a base for fixing, or as a polishing allowance for polishing to achieve precision during or after assembly.

[0033] The external electrodes 223 and 224 are formed on the surfaces of the plurality of driving piezoelectric elements 21 and the plurality of non-driving piezoelectric elements 22 , and are connected to the ends of the internal electrodes 221 and 222 .

[0034] For example, the external electrode 223 is formed on an inclined surface of one side surface portion 203 in the extension direction of the piezoelectric member 202. The external electrodes 223 are separated for each element to form individual wiring. Each external electrode 223 is continuous with the individual wiring 102 formed by the substrate electrode layer 11 on the substrate 10.

[0035] For example, each external electrode 223 extends in the same direction as each individual wiring 102 at least in the region near the actuator 20 when viewed from the direction of light irradiation in the photolithography process.

[0036] In this embodiment, the individual wiring 102 of the board wiring portion is formed along the mounting surface 101 and extends in the same direction as the external electrode 223, which is the wiring of the inclined surface of the actuator 20, at least within the reflected light range where the reflected light reaches. Specifically, in a plan view seen from the third direction (Z direction) which is the exposure direction, for example, the individual wiring 102 extends on the same straight line toward the second direction (Y direction) which is the short-side direction of the piezoelectric member 202. That is, the individual wiring 102 extends in a direction perpendicular to the upper and lower sides which are the edges of the side surface portion 203 which is an inclined surface, on a straight line perpendicular to the first direction (X direction) which is the arrangement direction of the multiple nozzles 51, at least within the reflected light range where the distance from the piezoelectric member 202 is equal to or less than a predetermined distance. The individual wiring 102 of the board 10 extends in the second direction (Y direction) which is the short-side direction of the actuator 20 along the mounting surface 101.

[0037] The external electrode 224 is formed on the other side surface portion 204 in the extending direction of the piezoelectric member 202. The external electrode 224 is continuous with the common wiring 103 constituted by the substrate electrode layer 12 on the substrate 10.

[0038] The external electrodes 223 and 224 are formed by plating, sputtering, or other methods using Ni, Cr, Au, etc. The external electrodes 223 and 224 have different polarities.

[0039] In this embodiment, as an example, the external electrode 223 is an individual electrode separated for each piezoelectric element 21, and the external electrode 224 is a common electrode. The external electrodes 223 serving as individual electrodes for the multiple driving piezoelectric elements 21 and the multiple non-driven piezoelectric elements 22 are formed by dividing an electrode layer formed on one side surface of the piezoelectric member 202 in the manufacturing process, and are arranged independently for each piezoelectric element 21. In other words, the electrode layers are separated and independent from each other in the parallel direction, constituting the external electrodes 223 as multiple individual electrodes. The external electrodes 223 are disposed at intervals from one another by grooves 23, and are connected to the drive circuit 70, for example, via individual wiring 102 on the substrate 10, and via an FPC 71 serving as a flexible substrate, which is an example of a wiring substrate. For example, each external electrode 223 is connected to the control unit 116 serving as a drive unit, via a drive IC 72 of the drive circuit 70, by the FPC 71 connected by ACF mounting using ACF 75, and is configured to be driveable and controllable by the control of the control circuit 1161. The external electrode 224 may be routed around the side surface on the external electrode 223 side, and connected to the drive circuit 70 via the FPC 71.

[0040] The external electrode 224 is a common electrode in which the electrode layer is continuous in a region closer to the substrate 10 than the bottom of the groove 23. The external electrodes 224 are connected to each other on the other side of the piezoelectric member 202 and are connected to a common wiring 103 on the substrate 10, and are, for example, grounded.

[0041] The vibration direction of each of the piezoelectric elements 21 and 22 is along the stacking direction, and when an electric field is applied, they are displaced in the d33 direction.

[0042] As an example, each of the piezoelectric elements 21, 22 has 3 to 50 layers, each layer has a thickness of 10 to 40 μm, and the product of the thickness and the total number of layers is less than 1000 μm.

[0043] The driving piezoelectric element 21 vibrates when a voltage is applied to the internal electrodes 221, 222 via the external electrodes 223, 224. In this embodiment, the driving piezoelectric element 21 vibrates longitudinally along the stacking direction of the piezoelectric layer 211. The longitudinal vibration here means, for example, "vibration in the thickness direction defined by the piezoelectric constant d33." The driving piezoelectric element 21 displaces the vibration plate 30 and deforms the pressure chamber 31 by the longitudinal vibration.

[0044] The flow path section 40 includes a vibration plate 30 disposed opposite one side of the actuator 20 in the deformation direction, and a plurality of flow path substrates 405 and 406 stacked on one side of the vibration plate 30.

[0045] The diaphragm 30 is provided between the flow path substrate 405 and the actuator 20 in the vibration direction. The diaphragm 30, together with the flow path substrate 405, constitutes the flow path portion 40. The diaphragm 30 extends in a direction intersecting with the side surface on which the individual electrodes and the common electrode of the piezoelectric member 202 are formed.

[0046] The vibration plate 30 extends along a plane perpendicular to the Z direction, which is the vibration direction, and is bonded to one side in the vibration direction of the multiple piezoelectric elements 21, 22, i.e., the surface on the nozzle plate 50 side. The vibration plate 30 is configured to be deformable, for example. The vibration plate 30 is bonded to the driving piezoelectric element 21 and the non-driving piezoelectric element 22 of the actuator 20, and to a frame portion 60. For example, the vibration plate 30 has a vibration region 301 facing the piezoelectric elements 21, 22, and a support region 302 facing the frame portion 60.

[0047] The vibration region 301 is, for example, in the form of a flat plate arranged such that the thickness direction coincides with the vibration direction of the piezoelectric layer 211. The vibration plate 30 has a surface direction extending in the arrangement direction of the multiple driving piezoelectric elements 21 and the multiple non-driving piezoelectric elements 22. The vibration plate 30 is, for example, a metal plate. The vibration plate 30 has multiple vibration parts that face each pressure chamber 31 and are individually displaceable. The vibration plate 30 is formed by integrally connecting the multiple vibration parts.

[0048] As an example, the vibration plate 30 is made of a nickel or SUS plate, and the thickness dimension along the vibration direction is set to about 5 μm to 15 μm. Note that the vibration region 301 may have folds or steps formed in the regions adjacent to the vibration regions or between adjacent vibration regions so that the multiple vibration regions can be easily displaced. The vibration region 301 is deformed by the displacement of the region disposed opposite the driving piezoelectric element 21 due to the expansion and compression of the driving piezoelectric element 21. For example, the vibration plate 30 is formed by electroforming or the like. The vibration plate 30 is joined to the upper end surface of the actuator 20 by adhesive or the like.

[0049] The support region 302 is a plate-like member disposed between the frame portion 60 and the flow path substrate 405. The support region 302 has a communication portion 33 having a through hole communicating with the common chamber 32.

[0050] For example, the communication portion 33 includes a filter member having a large number of pores as through holes through which liquid can pass.

[0051] The flow path substrates 405 and 406 are disposed between the nozzle plate 50 and the diaphragm 30 in the vibration direction. For example, the flow path substrate 405 is bonded to one side in the vibration direction of the diaphragm 30. The flow path substrate 406 is bonded to one side of the flow path substrate 405 in the vibration direction.

[0052] The flow path substrates 405 and 406 form a predetermined ink flow path having a plurality of pressure chambers 31 and a plurality of individual flow paths that connect the pressure chambers 31 and the common chamber 32 .

[0053] For example, the flow path substrate 405 has a partition portion 41 , a partition portion 42 , and a peripheral wall portion 43 .

[0054] For example, the partition portion 41 is a wall member that separates the rows of pressure chambers 31 that face a pair of actuators 20 .

[0055] The partitions 42 are wall members that separate the multiple pressure chambers 31 lined up in the parallel direction and that form both side portions of the pressure chambers 31. The partitions 42 are disposed opposite the non-driven piezoelectric elements 22 via the vibration plate 30 and are supported by the non-driven piezoelectric elements 22. A plurality of partitions 42 are provided at the same pitch as the pitch at which the multiple pressure chambers 31 are lined up.

[0056] The peripheral wall portion 43 is a wall member that surrounds the outer periphery of the ink flow passage including a plurality of individual flow passages and a common flow passage.

[0057] The flow path substrate 406 has a frame portion 44 that forms a flow path that communicates from each pressure chamber 31 to the nozzle 51 .

[0058] In the flow path section 40, two rows of pressure chambers 31 aligned in the X direction are formed in each actuator 20. In each row, the pressure chambers 31 aligned in the X direction are separated by partitions 42. That is, both sides of the parallel direction of the pressure chambers 31 are formed by the partitions 42. In addition, the row of pressure chambers 31 arranged opposite one actuator 20 is separated from the row of pressure chambers 31 opposite the other actuator 20 by partitions 41. Each pressure chamber 31 communicates with a nozzle 51 formed in a nozzle plate 50 arranged on one side. In addition, the pressure chambers 31 are closed on the opposite side of the nozzle plate 50 by the vibration plate 30.

[0059] The multiple pressure chambers 31 are spaces formed on one side of the vibration region 301 of the vibration plate 30, and communicate with the common chamber 32 via individual flow paths and communication parts 33. The multiple pressure chambers 31 communicate with nozzles 51 formed in the nozzle plate 50. In addition, the pressure chambers 31 are closed on the side opposite to the nozzle plate 50 by the vibration plate 30.

[0060] The pressure chambers 31 hold liquid supplied from a common chamber 32 , and are deformed by vibration of a vibration plate 30 that forms a part of the pressure chambers 31 , thereby ejecting the liquid from a nozzle 51 .

[0061] The nozzle plate 50 is configured as a rectangular plate having a thickness of about 10 μm to 100 μm and made of a metal such as SUS or Ni or a resin material such as polyimide. The nozzle plate 50 is disposed on one side of the flow path substrate 405 so as to cover the openings of the pressure chambers 31 on one side.

[0062] A plurality of nozzles 51 are arranged in a first direction, which is the same as the arrangement direction of the pressure chambers 31, to form a nozzle row. For example, the nozzles 51 are provided in two rows, and each nozzle 51 is provided at a position corresponding to the plurality of pressure chambers 31 arranged in the two rows. In this embodiment, the nozzles 51 are provided at the end positions of the pressure chambers 31 in the extension direction.

[0063] The frame portion 60 is a structure that is bonded to the vibration plate 30 together with the piezoelectric elements 21, 22. The frame portion 60 is provided on the side of the vibration plate 30 opposite the flow path substrate 405 of the piezoelectric elements 21, 22, and for example, is disposed adjacent to the actuator 20 in this embodiment. The frame portion 60 is bonded to the other side of the vibration plate 30 and is provided between the vibration plate 30 and the substrate 10, and constitutes the outer shell of the inkjet head 1. The frame portion 60 also forms a flow path for liquid therein. In this embodiment, the frame portion 60 forms the common chamber 32.

[0064] The common chamber 32 is formed inside the frame portion 60, and communicates with the pressure chambers 31 through the communication portions 33 provided in the diaphragm 30 and the individual flow paths.

[0065] The drive circuit 70 includes an FPC 71 (Flexible printed circuits) connected to the actuator 20 via individual wiring 102 and common wiring 103 on the mounting surface 101 of the substrate 10, a drive IC 72 mounted on the FPC 71, and a printed wiring board 73 mounted on the other end of the FPC 71.

[0066] The drive circuit 70 applies a drive voltage to the external electrodes 223 and 224 via the drive IC 72 to drive the drive piezoelectric element 21 , thereby increasing or decreasing the volume of the pressure chamber 31 and causing droplets to be ejected from the nozzle 51 .

[0067] The FPC 71 is connected to the mounting surface 101 of the substrate 10, and is connected to a plurality of external electrodes 223, 224 of the actuator 20 via individual wiring 102 and common wiring 103. As the FPC 71, a COF (Chip on Film) on which a driving IC 72 is mounted as an electronic component is used.

[0068] The driving IC 72 is connected to external electrodes 223 and 224 via the FPC 71. The driving IC 72 is an electronic component used for ejection control.

[0069] The driving IC 72 generates a control signal and a driving signal for operating each driving piezoelectric element 21. The driving IC 72 generates a control signal for controlling the timing of ink ejection and the selection of the driving piezoelectric element 21 for ejecting ink according to an image signal input from the control unit 116 of the inkjet recording device 100 on which the inkjet head 1 is mounted. The driving IC 72 also generates a voltage to be applied to the driving piezoelectric element 21, i.e., a driving signal, according to a control signal from the control unit 116. When the driving IC 72 applies a driving signal to the driving piezoelectric element 21, the driving piezoelectric element 21 is driven to displace the vibration plate 30 and change the volume of the pressure chamber 31. This causes the ink filled in the pressure chamber 31 to generate pressure vibration. The pressure vibration causes ink to be ejected from the nozzle 51 communicating with the pressure chamber 31. The inkjet head 1 may be configured to realize gradation expression by changing the amount of ink droplets that land on one pixel. The inkjet head 1 may also be configured to change the amount of ink droplets that land on one pixel by changing the number of times ink is ejected. In this manner, the driving IC 72 is an example of an application unit that applies a driving signal to the driving piezoelectric element 21.

[0070] For example, the drive IC 72 includes a data buffer, a decoder, and a driver. The data buffer stores print data for each drive piezoelectric element 21 in chronological order. The decoder controls the driver for each drive piezoelectric element 21 based on the print data stored in the data buffer. The driver outputs a drive signal that operates each drive piezoelectric element 21 based on the control of the decoder. The drive signal is, for example, a voltage applied to each drive piezoelectric element 21.

[0071] The printed wiring board 73 is a PWA (Printing Wiring Assembly) on which various electronic components and connectors are mounted, and has a head control circuit 731. The printed wiring board 73 is connected to the control unit 116 of the inkjet recording apparatus 100.

[0072] In the inkjet head 1 configured as above, the nozzle plate 50, the frame section 60, and the flow path section 40 form an ink flow path having a plurality of pressure chambers 31 communicating with the nozzle 51 and a common chamber 32 communicating with each of the pressure chambers 31. For example, the common chamber 32 communicates with a cartridge, and ink is supplied to each pressure chamber 31 through the common chamber 32. All the driving piezoelectric elements 21 are connected to each other by wiring so that a voltage can be applied thereto. In the inkjet head 1, when the control section 116 of the inkjet recording device 100 applies a driving voltage to the electrodes 221 and 222 by the driving IC 72, the driving piezoelectric element 21 to be driven vibrates, for example, in the stacking direction, that is, in the thickness direction of each piezoelectric layer 211. In other words, the driving piezoelectric element 21 vibrates vertically.

[0073] Specifically, the control unit 116 applies a driving voltage to the internal electrodes 221, 222 of the driving piezoelectric element 21 to be driven, selectively driving the driving piezoelectric element 21 to be driven. Then, the vibration plate 30 is deformed by combining the deformation in the tensile direction and the deformation in the compressive direction by the driving piezoelectric element 21 to be driven, and the volume of the pressure chamber 31 is changed, so that liquid is guided from the common chamber 32 and ejected from the nozzle 51.

[0074] An example of a manufacturing method for the inkjet head 1 according to this embodiment will be described with reference to Fig. 4. First, the internal electrodes 221, 222 are formed by printing on the surface of a sheet-like piezoelectric layer 211 made of a piezoelectric material. Then, a plurality of piezoelectric layers 211 on which the internal electrodes 221, 222 are formed are laminated, and a firing process and a polarization process are performed to form the piezoelectric member 202, which is a laminated piezoelectric member.

[0075] Then, the piezoelectric element 21 of the piezoelectric member 202 on which the internal electrodes 221, 222 have been formed in advance is subjected to a polarization process, and the piezoelectric element 21 is attached to the mounting surface 101 of the substrate 10 with an adhesive or the like.

[0076] Then, with the piezoelectric member 202 placed on the substrate 10, the surfaces of the substrate 10 and the piezoelectric member 202 are processed to form the mounting surface 101 and the outer surface of the piezoelectric member 202. At this time, a continuous surface without steps is formed from one side surface of the piezoelectric member 202 to the mounting surface 101 of the substrate 10 by mechanical processing such as grinding using a grindstone. Note that if burrs are formed when a grindstone capable of processing the substrate 10 or the piezoelectric body is used, it is preferable to perform surface processing such as buffing or sandblasting as a finishing process.

[0077] Next, a metal film is formed by plating on the surface of the piezoelectric member 202 including the top surface and both side surfaces 203, 204, and on the mounting surface 101 of the substrate 10. For example, electrodes are formed by Ni electroless plating on the surface of the piezoelectric member 202 including the surface and both side surfaces, and on the entire mounting surface 101 around the actuator 20, to form electrode layers that become the external electrodes 223, 224, and to form substrate electrode layers 11, 12 on the mounting surface 101 of the substrate 10. Then, a polishing process is performed on the top surface of the piezoelectric member 202 to remove the electrodes on the top surface and to form a bonding surface for the top surface. The polishing process ensures the flatness of the top surface of the piezoelectric member 202 to which the vibration plate 30 is bonded in a later process.

[0078] Next, a tool such as a diamond cutter is moved in the Z direction to perform dicing, thereby forming multiple grooves 23 in the actuator 20. For example, the piezoelectric member 202 bonded to the substrate 10 is separated by forming grooves 23 to a predetermined depth from the top side, which is the side opposite to the substrate 10, by dicing, thereby separating the piezoelectric member 202. As a result, multiple driving piezoelectric elements 21 and non-driving piezoelectric elements 22 are formed, which are separated by the grooves 23 and arranged at a predetermined pitch.

[0079] Then, the electrode layer on the surface of the piezoelectric member 202 and the substrate 10 is patterned by photolithography, PEP, or the like to form a predetermined wiring pattern. In the patterning process by photolithography, for example, after applying a photosensitive resist material, an exposure process is performed in a predetermined pattern by irradiating ultraviolet light from an irradiation head S through a photomask as shown in Fig. 4, and the wiring layer is patterned through a development process and an etching process.

[0080] That is, for the wiring layer formed on the entire surfaces of the piezoelectric member 202 and the substrate 10, one side region constituting the individual electrodes, i.e., the outer region where the pair of actuators 20 face each other, is exposed to light in a predetermined pattern to remove predetermined portions, and patterning is performed to divide the substrate electrode layer 11 on one end side, which is the individual wiring 102 side, into a plurality of parts. At this time, since the side portion 203 on the individual wiring 102 side is tapered relative to the mounting surface 101, the side portion 203 and the mounting surface 101 of the substrate 10, which form a continuous surface, can be irradiated with light at the same time, and can be patterned at the same time. That is, the electrode layer of the side portion 203 of the piezoelectric member 202 having a tapered inclined surface and the substrate electrode layer 11 formed on the mounting surface 101 of the substrate 10 are divided for each element, whereby the external electrodes 223 and the individual wiring 102 are patterned.

[0081] The external electrode 223 is separated by the groove 23 at the nozzle plate 50 side of the piezoelectric member 202, and is separated by patterning at the substrate 10 side.

[0082] On the other hand, the substrate electrode layer 12 on the other side is not divided by patterning, but remains continuous to form the common wiring 103. As a result, a plurality of individual wirings 102 divided for each element are formed on one side of the piezoelectric member 202, and a continuous common wiring 103 is formed on the other side.

[0083] An FPC 71, on which electronic components such as a driver IC 72 are mounted as a control component, is connected to a wiring pattern such as individual wiring 102 and common wiring 103 formed into a predetermined shape on the substrate 10 by an ACF (anisotropic conductive film) 75. Furthermore, a printed wiring board 73 having a head control circuit 731 is connected to the FPC 71. As a result, a mounting section 76 using the ACF 75 is formed on the substrate 10.

[0084] Furthermore, the vibration plate 30, the flow path substrates 405, 406 and the nozzle plate 50 are stacked on the actuator 20 with bonding material between them to determine their position, and a frame portion 60 is placed on the outer periphery of the actuator 20. By bonding these multiple components together, the inkjet head 1 is completed.

[0085] An example of an inkjet recording device 100 including an inkjet head 1 will be described below with reference to Fig. 6. The inkjet recording device 100 includes a housing 111, a medium supply unit 112, an image forming unit 113, a medium discharge unit 114, a conveying device 115, and a control unit 116.

[0086] The inkjet recording device 100 is a liquid ejection device that performs an image formation process on paper P by ejecting liquid such as ink while transporting the paper P as a printing medium, which is the ejection target, along a predetermined transport path R from a medium supply section 112 through an image forming section 113 to a medium ejection section 114.

[0087] The housing 111 constitutes the outer shell of the inkjet recording apparatus 100. The housing 111 is provided at a predetermined location with an outlet for discharging the paper P to the outside.

[0088] The medium supply unit 112 includes a plurality of paper feed cassettes, and is configured to be able to hold a plurality of sheets of paper P of various sizes in a stack.

[0089] The medium discharge unit 114 includes a paper discharge tray configured to be able to hold the paper P discharged from the discharge opening.

[0090] The image forming section 113 includes a support section 117 that supports the paper P, and a plurality of head units 130 that are disposed above the support section 117 so as to face the support section 117.

[0091] The support section 117 includes a conveyor belt 118 provided in a loop shape in a predetermined area where image formation is performed, a support plate 119 supporting the conveyor belt 118 from the back side, and a plurality of belt rollers 120 provided on the back side of the conveyor belt 118.

[0092] During image formation, the support section 117 supports the paper P on a holding surface, which is the upper surface of the conveyor belt 118, and conveys the paper P downstream by feeding the conveyor belt 118 at a predetermined timing by the rotation of the belt roller 120.

[0093] The head unit 130 includes multiple (four colors) inkjet heads 1, ink tanks 132 as liquid tanks mounted on each inkjet head 1, a connection flow path 133 connecting the inkjet heads 1 and the ink tanks 132, and a supply pump 134.

[0094] In this embodiment, the inkjet heads 1 are provided with four colors, cyan, magenta, yellow, and black, and ink tanks 132 that respectively contain ink of each color. The ink tanks 132 are connected to the inkjet heads 1 by connection channels 133.

[0095] In addition, a negative pressure control device such as a pump (not shown) is connected to the ink tank 132. Then, by controlling the negative pressure inside the ink tank 132 by the negative pressure control device according to the water head value between the inkjet head 1 and the ink tank 132, the ink supplied to each nozzle 51 of the inkjet head 1 is caused to form a meniscus of a predetermined shape.

[0096] The supply pump 134 is a liquid delivery pump constituted by, for example, a piezoelectric pump. The supply pump 134 is provided in a supply flow path. The supply pump 134 is connected to a control circuit 1161 of the control unit 116 by wiring and is configured to be controllable by the control unit 116. The supply pump 134 supplies liquid to the inkjet head 1.

[0097] The conveying device 115 conveys the paper P along a conveying path R that runs from the medium supply unit 112 through the image forming unit 113 to the medium discharge unit 114. The conveying device 115 includes a plurality of guide plate pairs 121 and a plurality of conveying rollers 122 that are arranged along the conveying path R.

[0098] Each of the guide plate pairs 121 includes a pair of plate members disposed opposite each other with the paper P being transported therebetween, and guides the paper P along the transport path R.

[0099] The conveying rollers 122 are driven to rotate under the control of the control unit 116, thereby sending the paper P downstream along the conveying path R. Sensors for detecting the conveying status of the paper are disposed at various points along the conveying path R.

[0100] The control unit 116 includes a control circuit 1161 such as a CPU (Central Processing Unit) which serves as a controller, a ROM (Read Only Memory) which stores various programs, a RAM (Random Access Memory) which temporarily stores various variable data, image data, and the like, and an interface unit which inputs data from the outside and outputs data to the outside.

[0101] In the inkjet recording device 100 configured as above, when the control unit 116 detects a print instruction by a user operating an operation input unit, for example, in an interface, the control unit 116 drives the conveying device 115 to convey the paper P and outputs a print signal to the head unit 130 at a predetermined timing, thereby driving the inkjet head 1. As a discharge operation, the inkjet head 1 sends a drive signal to the driving IC 72 by an image signal corresponding to image data, applies a drive voltage to the internal electrodes 221 and 222, and selectively drives the driving piezoelectric element 21 to be discharged, for example, to vibrate vertically in the stacking direction, and changes the volume of the pressure chamber 31 to discharge ink from the nozzle 51, thereby forming an image on the paper P held on the conveying belt 118. As a liquid discharge operation, the control unit 116 drives the supply pump 134 to supply ink from the ink tank 132 to the common chamber 32 of the inkjet head 1.

[0102] Here, the driving operation for driving the inkjet head 1 will be described. The inkjet head 1 according to this embodiment includes driving piezoelectric elements 21 arranged to face the pressure chambers 31, and these driving piezoelectric elements 21 are connected by wiring so that a voltage can be applied thereto. The control unit 116 sends a driving signal to the driving IC 72 based on an image signal corresponding to image data, and applies a driving voltage to the internal electrodes 221, 222 of the driving piezoelectric elements 21 to be driven, thereby selectively deforming the driving piezoelectric elements 21 to be driven. Then, the volume of the pressure chambers 31 is changed by combining the deformation in the tensile direction and the deformation in the compressive direction of the vibration plate 30, thereby discharging liquid.

[0103] For example, the control unit 116 alternates between a pulling operation and a compression operation. In the inkjet head 1, during pulling to increase the internal volume of the target pressure chamber 31, the driving piezoelectric element 21 to be driven is contracted, and the driving piezoelectric element 21 that is not the driving target is not deformed. Also, during compression to decrease the internal volume of the target pressure chamber 31 in the inkjet head 1, the target driving piezoelectric element 21 is expanded. Note that the non-driven piezoelectric element 22 is not deformed.

[0104] According to the inkjet head 1 and the inkjet recording device 100 of the above-described embodiment, one side of the actuator 20 is formed in a trapezoidal shape having an inclined surface, thereby improving the workability of the pattern processing by light irradiation such as exposure. Furthermore, by making the side surface 203 of the actuator 20 continuous with the mounting surface 101, it becomes easy to lead out the electrodes, and the mountability can be further improved. For example, when light is irradiated from one direction in the pattern processing by exposure processing such as photolithography processing, if the electrode wiring of the side surface of the actuator and the wiring part of the mounting surface 101 are perpendicular to each other, it is not possible to form a wiring pattern on the side surface. However, by making the angle with the side surface larger than 90° and smaller than 180°, the mounting surface 101 and the side surface 203 can be patterned simultaneously.

[0105] Furthermore, defects due to solder joints can be avoided by mounting components using ACF75 on mounting surface 101. That is, when solder joints are used, the adhesive strength between the piezoelectric member and the electrode and the adhesive strength of the solder joints are low, so the solder joints are prone to damage when stress is applied to the flexible cable, but by using ACF mounting, the adhesive strength is ensured and damage can be prevented.

[0106] Also, compared to solder mounting, in which a piezoelectric body is heated by sandwiching a flexible cable, the load due to pressure and heat can be reduced. In addition, insufficient pressure in solder mounting can lead to open circuits due to poor bonding, but ACF mounting can improve bonding properties. Furthermore, for example, when solder bonding is performed on the surface of a piezoelectric component, the bonding surface is constrained by the solder, and the piezoelectric component may not deform easily, but ACF mounting can avoid the constraint of the solder and improve deformation characteristics. In addition, when solder bonding is performed on the surface of a piezoelectric component, the mounting part may be damaged due to deformation of the piezoelectric component, but ACF mounting can achieve a configuration that is less susceptible to damage.

[0107] For example, in the case of a share mode structure, it is necessary to provide an inclination on both sides of the piezoelectric member because it is necessary to pattern the electrode wiring on both sides (one side and the opposite side), but in the actuator 20 according to this embodiment, one side is a common electrode and does not need to be patterned, so there is no need to provide an inclination on the common electrode. In other words, since it is necessary to provide an inclination only on one side of the actuator 20, the width of the inkjet head 1 can be reduced, making it possible to make the inkjet head more compact.

[0108] The present invention is not limited to the above-described embodiment, and in the implementation stage, the components can be modified and embodied without departing from the spirit of the invention.

[0109] The specific materials and configurations of the piezoelectric elements 21 and 22 in the above embodiment are not limited to those described above, and may be changed as appropriate.

[0110] For example, laser patterning can also be used to form the wiring pattern. In this case, the laser light can be irradiated simultaneously onto the front surface and the inclined surface, and the same effects as those of the above embodiment can be obtained.

[0111] The specific shape of the wiring is not limited to the above. For example, the wiring pattern on the mounting surface 101 of the substrate 10 and the wiring pattern on the side surface 203, which is an inclined surface, are aligned in the same direction, but the wiring pattern is not limited to this. For example, the wiring pattern may be an inverted pattern corresponding to the light reflected from the inclined surface to the substrate. Or the wiring pattern may be in a different direction.

[0112] For example, when the directions of the wiring patterns near the piezoelectric member 202 are not aligned, the angle of the inclined surface can be adjusted to eliminate the influence of reflected light between the side surface 203 and the mounting surface 101 during exposure. In this case, it is desirable to set the angle at which the side surface 203, which forms the inclined surface, intersects with the mounting surface 101 to be greater than 135°. That is, as shown in Fig. 5 as another embodiment, by setting the inclination angle θ to an angle greater than 135°, it is possible to achieve a configuration with fewer restrictions on the extension direction of each wire of the wiring pattern and a high degree of freedom in wiring.

[0113] The patterning of the individual wirings 102 may be performed simultaneously with the patterning of the external electrodes 223 on the slanted surfaces, or may be performed in a separate process.

[0114] In the above embodiment, a plurality of piezoelectric layers 211 are laminated, and the driving piezoelectric element 21 is driven by longitudinal vibration (d33) in the lamination direction, but the present invention is not limited to this. For example, the present invention can be applied to a configuration in which the driving piezoelectric element 21 is composed of a single layer of piezoelectric material, or to a configuration in which the driving element 21 is driven by lateral vibration displacing in the d31 direction.

[0115] The arrangement of the nozzles 51 and the pressure chambers 31 is not limited to the above embodiment. For example, the nozzles 51 may be arranged in two or more rows. Also, air chambers serving as dummy chambers may be formed between a plurality of pressure chambers 31. The inkjet head is not limited to a circulation type, and may be a non-circulation type.

[0116] In addition, the configurations and positional relationships of various components including the flow path section 40, the nozzle plate 50, and the frame section 60 are not limited to the above-mentioned examples, and can be changed as appropriate.

[0117] Further, in the above embodiment, an example was shown in which two actuators 20 were arranged in parallel on the substrate 10, but this is not limited thereto, and the number of actuators 20 may be one, or three or more.

[0118] Furthermore, the liquid to be ejected is not limited to ink for printing, but may be, for example, a device that ejects liquid containing conductive particles for forming a wiring pattern on a printed wiring board.

[0119] In addition, in the above embodiment, the inkjet head 1 is used in a liquid ejection device such as an inkjet recording device, but the present invention is not limited to this and can also be used in, for example, 3D printers, industrial manufacturing machines, and medical applications, enabling reduction in size, weight, and cost.

[0120] According to at least one of the embodiments described above, it is possible to provide a liquid ejection head and a liquid ejection apparatus that can improve mountability.

[0121] Although several other embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0122] 1...inkjet head, 10...substrate, 20...actuator, 202...piezoelectric member, 21...driven piezoelectric element, 22...non-driven piezoelectric element, 23...groove, 30...vibration plate, 31...pressure chamber, 32...common chamber, 33...communicating portion, 40...flow path portion, 42...partition wall portion, 50...nozzle plate, 51...nozzle, 60...frame portion, 70...drive circuit, 71...FPC, 72...drive IC, 73...printed wiring board, 731...head control circuit, 100...inkjet recording device, 111...housing, 112...medium supply portion, 113...image form forming section, 114...medium discharge section, 115...transport device, 117...support section, 118...transport belt, 119...support plate, 120...belt roller, 121...pair of guide plates, 122...transport roller, 130...head unit, 132...ink tank, 133...connecting flow path, 134...supply pump, 116...control section, 1161...control circuit, 211...piezoelectric layer, 221...internal electrode, 222...internal electrode, 223...external electrode, 224...external electrode, 301...vibration area, 302...support area, 405, 406...flow path substrate.

Claims

1. A substrate having a wiring surface; a piezoelectric member provided on a wiring surface of the substrate, the piezoelectric member having an inclined surface, one side portion of which is inclined at an angle of more than 90° and less than 180° with respect to the wiring surface; a vibration plate disposed opposite the piezoelectric member to the substrate; An electrode wiring formed on the inclined surface of the piezoelectric member; A liquid ejection head comprising:

2. a flow path portion forming a pressure chamber disposed opposite the vibration plate; The liquid ejection head according to claim 1 , further comprising: substrate wiring formed on a wiring surface of the substrate and connected to electrode wiring formed on the side surface portion.

3. 3. The liquid ejection head according to claim 2, wherein an angle between the one side portion of the piezoelectric member and the wiring surface of the substrate is greater than 135° and greater than an angle between the other side portion of the piezoelectric member and the wiring surface of the substrate.

4. The liquid ejection head according to claim 2 , wherein the substrate is provided on the wiring surface with a mounting section where components are mounted on the substrate wiring via an anisotropic conductive film.

5. A liquid ejection apparatus comprising the liquid ejection head according to any one of claims 1 to 4.

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