Liquid dispensing head

Abstract

To provide a liquid discharge head which can suppress an electrode film from being peeled off even when decreasing resistance value of a common electrode.SOLUTION: A liquid discharge head comprises: an actuator; a substrate; and an electrode. The actuator includes: a plurality of pressure chambers arranged in one direction; and a plurality of air chambers with resin walls which are alternatively arranged relative to the plurality of pressure chambers. The actuator is arranged on the substrate. The electrode is formed by a metal film which includes: a plurality of individual electrodes driving the plurality of respective pressure chambers; and a common electrode driving the plurality of air chambers. Film thickness of the common electrode is thicker than that of the individual electrode.SELECTED DRAWING: Figure 7

Description

Technical Field

[0005]

[0001] Embodiments of the present invention relate to a liquid ejection head.

Background Art

[0002] Conventionally, a liquid ejection head such as an inkjet head is known, in which a plurality of partition walls are formed on a substrate made of ceramic at a predetermined interval, and a piezoelectric ceramics having ink flow paths between the partition walls is provided. In the liquid ejection head, drive electrodes are formed on side surfaces of each partition wall, and an end surface of the partition wall has an inclined surface that extends outward from its top to bottom. Patterns as lead lines are formed on the inclined surface of the partition wall and the substrate for the electrodes of the liquid ejection head.

[0003] For example, in order to increase the speed of ink ejection, the liquid ejection head uses an independent drive structure having a groove for liquid ejection (hereinafter referred to as a discharge groove) and a groove for not ejecting liquid (hereinafter referred to as an air groove).

[0004] As such a liquid ejection head with an independent drive structure, there is an example in which electrodes of grooves for not ejecting liquid are bundled at the center of the substrate and commonly grounded, and electrodes of grooves for liquid ejection are led out to the driver IC side. However, when the common electrode resistance is large, there is a problem that the driver IC breaks due to latch-up. However, when the electrode film is thickened to reduce the resistance of the common electrode, the thickened electrode film is likely to peel off.

Prior Art Documents

Patent Documents

[0005] [[ID=​​​​​​​​​​​​The problem that this invention aims to solve is to provide a liquid dispensing head that can suppress the peeling of the electrode film even when the resistance value of the common electrode is reduced. [Means for solving the problem]

[0007] The liquid discharge head of the embodiment comprises an actuator, a substrate, and electrodes. The actuator has a plurality of pressure chambers arranged in one direction and a plurality of air chambers having resin walls, which are arranged alternately with the plurality of pressure chambers. The substrate is on which the actuator is provided. The electrodes are formed of a metal film and include a plurality of individual electrodes that drive each of the plurality of pressure chambers and a common electrode that drives the plurality of air chambers. The film thickness of the common electrode is thicker than the film thickness of the individual electrodes. The resin wall is positioned on the common electrode within the air chamber and is provided on the primary and secondary sides of the air chamber, thereby closing the primary and secondary sides of the air chamber, respectively. The individual electrodes and the common electrode are formed from a multilayer film including a Ni sputtered film, an electroless Ni plating film, and an electrolytic metal plating film of a dissimilar metal to the Ni sputtered film and the electroless Ni plating film. [Brief explanation of the drawing]

[0008] [Figure 1] A perspective view showing the configuration of a liquid dispensing head according to an embodiment. [Figure 2] A bottom view showing the configuration of the liquid dispensing head according to the embodiment. [Figure 3] A bottom view showing the configuration of the liquid discharge head according to the embodiment, with some parts omitted. [Figure 4] A perspective view showing the configuration of the head body of the liquid dispensing head according to the embodiment. [Figure 5] A cross-sectional view showing the configuration of the head body according to the embodiment. [Figure 6] A plan view showing the configuration of the head body according to the embodiment. [Figure 7] A cross-sectional view showing the configuration of the head body according to the embodiment, with some parts omitted. [Figure 8] A schematic plan view showing the configuration of the head body according to the embodiment. [Figure 9] A cross-sectional view showing the configuration of individual electrodes and common electrodes of the head body according to the embodiment. [Figure 10] A flowchart showing an example of a method for manufacturing a liquid dispensing head according to the embodiment. [Figure 11]A plan view showing an example of the manufacturing process for the head body according to the embodiment. [Figure 12] An explanatory diagram showing the configuration of a liquid dispensing device using a liquid dispensing head according to the embodiment. [Figure 13] An explanatory diagram showing the configuration of a modified example of the head body according to the embodiment. [Modes for carrying out the invention]

[0009] Below, a liquid discharge head 1 and a liquid discharge device 2 using the liquid discharge head 1 according to an embodiment will be described with reference to Figures 1 to 12. Figure 1 is a perspective view showing the configuration of the liquid discharge head 1 according to the first embodiment, and Figure 2 is a bottom view showing the configuration of the liquid discharge head 1. Figure 3 is a bottom view showing the configuration of the liquid discharge head 1 with the nozzle plate 114 omitted. Figure 4 is a perspective view showing the configuration of the head body 11 of the liquid discharge head 1 with a part of the nozzle plate 114 cut out, and Figure 5 is a cross-sectional view showing the configuration of the head body 11. Figure 6 is a plan view showing the configuration of the substrate 111, actuator 113 and electrode 117 of the head body 11. Figure 7 is a cross-sectional view showing the configuration of the substrate 111, actuator 113 and electrode 117 of the head body 11. Figure 8 is a schematic plan view showing the configuration of the pressure chamber 1131 and air chamber 1132 of the actuator 113.

[0010] Figure 9 is a cross-sectional view showing the configuration of the individual electrodes 118 and common electrode 119 of the head body 11. Figure 10 is a flowchart showing an example of forming the electrodes 117 of the head body 11 as an example of a manufacturing method for the liquid dispensing head 1. Figure 11 is a plan view showing an intermediate molded product in the manufacturing of the head body 11. Figure 12 is an explanatory diagram showing the configuration of the liquid dispensing device 2 using the liquid dispensing head 1. Note that in each figure, the configuration is enlarged, reduced, or omitted as appropriate for explanatory purposes.

[0011] The liquid ejection head 1 is, for example, an inkjet head in a share mode provided in a liquid ejection device 2 such as an inkjet recording apparatus shown in FIG. 12. The liquid ejection head 1 is provided in a head unit 2130 including a supply tank 2132 as a liquid storage unit provided in the liquid ejection device 2.

[0012] Ink as the liquid stored in the supply tank 2132 is supplied to the liquid ejection head 1. Note that the liquid ejection head 1 may be a non-circulating head that does not circulate the ink, or may be a circulating head that circulates the ink. In the present embodiment, the liquid ejection head 1 will be described using an example of a non-circulating head. Further, the liquid ejection head 1 is connected to a temperature control device 2116 provided in the liquid ejection device 2, and temperature control liquid (temperature control water) for controlling the temperature of the ink is supplied.

[0013] As shown in FIGS. 1 to 4, the liquid ejection head 1 includes a head body 11, a manifold unit 12, a circuit board 13, and a cover 14. For example, the liquid ejection head 1 is a side shooter type 4-column integrated structure head having two sets of head bodies 11 each having a pair of actuators 113.

[0014] The head body 11 ejects liquid. As shown in FIGS. 3 to 6, the head body 11 includes a substrate 111, a frame member 112, an actuator 113 having a plurality of pressure chambers 1131 and a plurality of air chambers 1132, and a nozzle plate 114. The head body 11 has a common liquid chamber 116 communicating with the plurality of pressure chambers 1131 of the actuator 113.

[0015] Further, the head body 11 has electrodes 117 for driving the plurality of pressure chambers 1131 of the actuator 113 on the substrate 111 and the actuator 113.

[0016] In the example of this embodiment, the head body 11 has two actuators 113, and an example in which the common liquid chamber 116 has one first common liquid chamber 1161 and two second common liquid chambers 1162 will be used for explanation. The common liquid chamber 116 includes, for example, a first common liquid chamber 1161 communicating with one opening of a plurality of pressure chambers 1131 of the actuator 113, a second common liquid chamber 1162 communicating with the other opening of the plurality of pressure chambers 1131 of the actuator 113, and a third common liquid chamber 1163 connecting both ends of the first common liquid chamber 1161 and both ends of the two second common liquid chambers 1162.

[0017] The substrate 111 is formed in a rectangular plate shape, for example, from a ceramic material. The substrate 111 is formed, for example, in a rectangular shape that is long in one direction. On one surface of the substrate 111, a wiring pattern that forms part of the electrode 117 is formed. As a specific example, on one surface of the substrate 111, a wiring pattern that forms part of a plurality of individual electrodes 118 (described later) of the electrode 117 and a wiring pattern that forms part of a single common electrode 119 are formed. On one surface of the substrate 111, a pair of actuators 113 are provided side by side in the short side direction of the substrate 111. One surface of the substrate 111 refers to one surface of the substrate 111. The substrate 111 has, for example, a single supply port 1111 and a plurality of discharge ports 1112. The supply port 1111 and the discharge ports 1112 are through holes that penetrate between both main surfaces of the substrate 111.

[0018] The supply port 1111 is an inlet for supplying ink to the first common liquid chamber 1161. The supply port 1111 is a through hole formed at the center in the short side direction of the substrate 111. The supply port 1111 extends along the long side direction of the substrate 111. In other words, the supply port 1111 is, for example, an elongated hole that is long in one direction along the long side direction of the actuator 113 and the long side direction of the first common liquid chamber 1161. The supply port 1111 is provided between the pair of actuators 113 and opens at a position facing the first common liquid chamber 1161.

[0019] The discharge port 1112 is an outlet for discharging ink from the second common liquid chamber 1162. Multiple discharge ports 1112 are provided, for example, four. Each discharge port 1112 is provided in, for example, two third common liquid chambers 1163. Note that multiple discharge ports 1112 may also be provided in the second common liquid chamber 1162.

[0020] The frame member 112 is fixed to one main surface of the substrate 111 with adhesive or the like. The frame member 112 surrounds the supply port 1111, the multiple discharge ports 1112, and the actuator 113 provided on the substrate 111. For example, the frame member 112 has a stepped structure.

[0021] For example, the frame member 112 is formed in a rectangular frame shape, thereby forming a long opening in one direction along the longitudinal direction of the frame member 112. A pair of actuators 113, a supply port 1111, and four discharge ports 1112 are arranged in the opening of the frame member 112.

[0022] A pair of actuators 113 are bonded to the mounting surface of the substrate 111. The pair of actuators 113 are arranged in two rows on the substrate 111, with the supply port 111 in between. The actuators 113 are formed in a plate shape that is long in one direction. The actuators 113 are placed within the opening of the frame member 112 and bonded to the main surface of the substrate 111.

[0023] As shown in Figures 3, 4, and 6, the actuator 113 has a plurality of pressure chambers 1131 arranged at equal intervals in the longitudinal direction, and a plurality of air chambers 1132 arranged at equal intervals in the longitudinal direction and positioned between adjacent pressure chambers 1131. In other words, the actuator 113 has a plurality of pressure chambers 1131 and a plurality of air chambers 1132 arranged alternately along the longitudinal direction.

[0024] The side of the actuator 113 opposite to the substrate 111 is bonded to the nozzle plate 114. The actuators 113 are arranged at equal intervals in the longitudinal direction, and multiple grooves are formed along a direction perpendicular to the longitudinal direction. The multiple grooves form multiple pressure chambers 1131 and multiple air chambers 1132. That is, the multiple grooves include multiple pressure grooves that constitute multiple pressure chambers 1131 and multiple air grooves that constitute multiple air chambers 1132. In other words, the actuator 113 has multiple piezoelectric elements 1133 which are driving elements that form walls that form grooves between them, arranged at equal intervals in the longitudinal direction. The multiple piezoelectric elements 1133 form multiple pressure chambers 1131 and multiple air chambers 1132 between adjacent piezoelectric elements 1133, and the volume of the pressure chambers 1131 is changed when a driving voltage is applied.

[0025] The actuator 113 has a width in the shorter direction that gradually increases from the top side toward the substrate 111 side. The cross-sectional shape of the actuator 113 along the direction perpendicular to the longitudinal direction (shorter direction) is formed as a trapezoid. That is, the actuator 113 has an inclined surface 1134 that slopes toward the side surface in the shorter direction. The side surface (inclined surface 1134) is positioned opposite the first common liquid chamber 1161 and the second common liquid chamber 1162.

[0026] As a specific example, the actuator 113 is formed from a laminated piezoelectric member, which consists of two rectangular plates of piezoelectric material, each elongated in one direction, bonded together facing each other so that their polarization directions are opposite. Here, the piezoelectric material is, for example, PZT (lead zirconate titanate). The actuator 113 is bonded to the mounting surface of the substrate 111, for example, by a thermosetting epoxy adhesive. The actuator 113 is then formed into an inclined surface 1134 by, for example, machining. In addition, the substrate 111 and the actuator 113 are polished, for example, by polishing, so that the surfaces on which the multiple individual electrodes 118 and the common electrode 119 of the electrode 117 are patterned are polished, forming a polished surface. For example, the polished surface is formed on the inclined surface 1134 of the actuator 113 and on the substrate 111 at the base of the inclined surface 1134. Furthermore, the actuator 113 is formed by, for example, machining, which creates multiple grooves that form multiple pressure chambers 1131 and multiple air chambers 1132, and piezoelectric elements (driving elements) 1133 that serve as side walls separating adjacent grooves.

[0027] Furthermore, the actuator 113 has wiring patterns that become part of a plurality of individual electrodes 118, and wiring patterns that become part of one or more common electrodes 119.

[0028] The pressure chamber 1131 deforms during printing or other operations by the liquid ejection head 1, thereby ejecting ink from the nozzle 1141. The pressure chamber 1131 has an inlet that opens into the first common liquid chamber 1161 and an outlet that opens into the second common liquid chamber 1162. Ink flows into the pressure chamber 1131 from the inlet and flows out from the outlet. The pressure chamber 1131 may also be configured so that ink flows in from both openings described as the inlet and outlet.

[0029] As shown by the dashed line in Figure 7 and the solid line in Figure 8, the air chamber 1132 is separated from the first common liquid chamber 1161 and the second common liquid chamber 1162 by a liquid-blocking wall 1135, which is a resin wall made of photosensitive resin or the like, that seals both sides of the longitudinal direction of the air groove formed in the actuator 113. Specifically, the liquid-blocking wall 1135 of the air chamber 1132 is formed by injecting ultraviolet-curable resin into the groove forming the air chamber 1132, and then using a mask plate or the like to irradiate the necessary parts, for example, both ends of the groove adjacent to the first common liquid chamber 1161 and adjacent to the second common liquid chamber 1162, with ultraviolet light. Such a liquid-blocking wall 1135 prevents ink from entering the air chamber 1132. The liquid-blocking wall 1135 is also formed on the common electrode 119 formed inside the air chamber 1132 of the actuator 113. Furthermore, the air chamber 1132 is blocked by the nozzle plate 114, and the nozzle 1141 is not positioned there. Therefore, ink does not flow into the air chamber 1132.

[0030] The nozzle plate 114 is formed in a plate shape. The nozzle plate 114 is fixed to the main surface of the frame member 112 opposite to the substrate 111 with an adhesive or the like. The nozzle plate 114 has a plurality of nozzles 1141 formed at positions facing the plurality of pressure chambers 1131. In this embodiment, the nozzle plate 114 has two rows of nozzle rows 1142 in which the plurality of nozzles 1141 are arranged in one direction.

[0031] The first common liquid chamber 1161 is formed between the central sides of a pair of actuators 113, excluding both ends, and constitutes a flow path for ink from the supply port 1111 to one opening of the multiple pressure chambers 1131 of each actuator 113. The first common liquid chamber 1161 extends along the longitudinal direction of the actuators 113.

[0032] The second common liquid chamber 1162 is formed between each actuator 113 and the frame member 112. The second common liquid chamber 1162 forms a flow path for ink from the third common liquid chamber 1163 to the other opening of the plurality of pressure chambers 1131. The second common liquid chamber 1162 extends along the longitudinal direction of the actuator 113.

[0033] The third common liquid chamber 1163 is adjacent to, for example, both longitudinal ends of the actuator 113. The third common liquid chamber 1163 connects the first common liquid chamber 1161 and the two second common liquid chambers 1162 at both longitudinal ends of the pair of actuators 113. The third common liquid chamber 1163 forms a flow path for some ink from the first common liquid chamber 1161 to the second common liquid chambers 1162 without passing through the multiple pressure chambers 1131 of each actuator 113. The third common liquid chamber 1163 also forms a flow path for ink from the first common liquid chamber 1161 and the two second common liquid chambers 1162 to the outlet 1112.

[0034] The electrode 117 is an electrode film (metal film) formed in a film shape from a metallic material. The electrode 117 includes, for example, a plurality of individual electrodes 118 that drive each of the plurality of pressure chambers 1131, and one or more common electrodes 119 that drive the plurality of pressure chambers 1131 simultaneously.

[0035] As shown in Figure 7, the electrode 117 has a first electrode portion 1171 which is a conductive portion formed on the upper surface of the substrate 111 and the inclined surface 1134 of the actuator 113, and a second electrode portion 1172 which is a conductive portion formed on the bottom and side surfaces of the plurality of pressure chambers 1131 and plurality of air chambers 1132 of the actuator 113.

[0036] The first electrode portion 1171 is a wiring pattern (leader wire). The first electrode portion 1171 is formed of a multilayer film. The second electrode portion 1172 is formed on the bottom surface of the grooves that form the pressure chamber 1131 and the air chamber 1132. The second electrode portion 1172 is formed of a multilayer film of the same layer as the first electrode portion 1171.

[0037] As shown in Figures 7 and 9, the electrode 117 includes a Ni sputtered film 11731, an electroless Ni plating film 11732, and an electrolytic metal plating film 11733 formed of a different metal (dissimilar metal) from the Ni sputtered film 11731 and the electroless Ni plating film 11732. The electrode 117 may also have an electrolytic Ni plating film between the electroless Ni plating film 11732 and the electrolytic metal plating film 11733.

[0038] The electrolytic metal plating film 11733 is, for example, an Au plating film. In the following description, the electrolytic metal plating film 11733 will be described as an electrolytic Au plating film 11733. However, the electrolytic metal plating film 11733 may be made of a metal material other than Au.

[0039] As shown in Figure 9, the common electrode 119 has a thicker electrolytic Au plating film 11733 (plating film thickness t2) than the individual electrode 118 (plating film thickness t1). The thickness of the Ni sputtered film 11731 and the electroless Ni plating film 11732 are the same for both the individual electrode 118 and the common electrode 119. Therefore, the common electrode 119 has a thicker film and lower resistance than the individual electrode 118. The thicknesses of the Ni sputtered film 11731 and the electroless Ni plating film 11732 are different, but they may be the same thickness.

[0040] Multiple individual electrodes 118 apply individual drive voltages to multiple piezoelectric elements 1133, which are driving elements. Multiple individual electrodes 118 individually deform each pressure chamber 1131. The individual electrodes 118 are formed by wiring patterns formed on the substrate 111 and wiring patterns formed on the actuator 113. The individual electrodes 118 are wiring patterns formed by a first electrode portion 1171 and a second electrode portion 1172. Multiple individual electrodes 118 are connected to the circuit board 13.

[0041] As a specific example, as shown in Figure 7, multiple individual electrodes 118 are formed on the inner surface of each pressure chamber 1131, the inclined surface 1134 of the actuator 113, and the substrate 111. Specifically, the individual electrodes 118 are formed by the second electrode portion 1172 on the side surface of the piezoelectric element 1133 that forms the pressure chamber 1131, and on the bottom surface of the pressure chamber 1131 (pressure groove). In addition, the individual electrodes 118 are formed by the first electrode portion 1171 on the inclined surface 1134 and the polished surface of the substrate 111. The individual electrodes 118 extend from inside the pressure chamber 1131 to the short-side end of the substrate 111, and their ends are positioned at the connection portion 1116 to which the circuit board 13 of the substrate 111 is connected. The individual electrodes 118 are provided so as to be in close contact with the bottom of the pressure chamber 1131 and the surface of the piezoelectric element that forms the piezoelectric element 1133. For example, the individual electrodes 118 on the substrate 111 are covered on the lower side of the frame member 112 with an adhesive that adheres the frame member 112 to the substrate 111.

[0042] The common electrode 119 applies a driving voltage to multiple piezoelectric elements 1133. For example, the common electrode 119 applies the same driving voltage to all of the multiple piezoelectric elements 1133. The common electrode 119 deforms multiple pressure chambers 1131 simultaneously. The common electrode 119 is formed by a wiring pattern formed on the substrate 111 and a wiring pattern formed on the actuator 113. The common electrode 119 is a wiring pattern provided from the inner circumferential surface of the supply port 1111 of the substrate 111 across the piezoelectric elements 1133 that form multiple air chambers 1132. The common electrode 119 is connected to the circuit board 13.

[0043] As a specific example, as shown in Figure 7, the common electrode 119 is formed on the substrate 111, avoiding the inner surfaces of each air chamber 1132, the inclined surfaces 1134 of the actuator 113, and the areas where the individual electrodes 118 are formed. Specifically, the common electrode 119 is formed by the second electrode portion 1172 on the side surfaces of the piezoelectric elements 1133 that form each air chamber 1132, and on the bottom surfaces of the air chambers 1132 (air grooves). The common electrode 119 is also provided by the first electrode portion 1171 on the inclined surfaces 1134, extending from within each air chamber 1132 toward the center of the substrate 111, and is also formed on the polished surface of the substrate 111 between the pair of actuators 113 and on the inner circumferential surface of the supply port 1111. Furthermore, the common electrode 119 extends to the short-side end of the substrate 111, with its end positioned at the connection portion 1116 to which the circuit board 13 of the substrate 111 is connected.

[0044] In other words, the common electrode 119 is integrally provided on the inclined surface 1134 of the actuator 113 and the inner surface of the multiple air chambers 1132, via the connection portion 1116 formed at the short-side end of the substrate 111, the area where the multiple individual electrodes 118 are not formed, and the short-side central part of the substrate 111 between the pair of actuators 113. Furthermore, a portion of the common electrode 119 provided in the air chambers 1132 is positioned between the outer surface of the liquid-proof wall 1135 and the inner surface of the air chambers 1132.

[0045] As shown in Figures 1, 4, and 5, the manifold unit 12 comprises a manifold 121, a top plate 122, an ink supply pipe 123, an ink discharge pipe 124, and a pair of temperature control pipes, namely a temperature-controlled water supply pipe 125 and a temperature-controlled water discharge pipe. The number of ink supply pipes 123, ink discharge pipes 124, temperature-controlled water supply pipes 125, and temperature-controlled water discharge pipes can be set as appropriate.

[0046] The manifold 121 is formed in the shape of a plate or a block. As shown in Figure 5, the manifold 121 includes a supply channel 1211 which is continuous with the supply port 1111 of the substrate 111 and forms a liquid supply channel, a discharge channel which is continuous with the discharge port 1112 of the substrate 111 and forms a liquid discharge channel, and a temperature control channel 1213 which forms a channel for a temperature control fluid.

[0047] One main surface of the manifold 121 is fixed to the main surface of the substrate 111. The top plate 122 is fixed to the main surface of the manifold 121 opposite to the main surface to which the substrate 111 is fixed. Furthermore, for example, an ink supply pipe 123, an ink discharge pipe 124, a temperature-controlled water supply pipe 125, and a temperature-controlled water discharge pipe are fixed to the manifold 121 via the top plate 122.

[0048] The supply channel 1211 is a channel formed in the manifold 121 by holes or grooves. The supply channel 1211 fluidly connects the ink supply pipe 123 and the supply port 1111 of the substrate 111.

[0049] The discharge channel is a channel formed in the manifold 121 by holes or grooves. The discharge channel fluidly connects the ink discharge pipe 124 and the discharge port 1112 of the substrate 111.

[0050] The temperature control channel 1213 is a channel formed in the manifold 121 by holes or grooves. The temperature control channel 1213 fluidly connects the temperature-controlled water supply pipe 125 and the temperature-controlled water discharge pipe.

[0051] Both ends of the temperature control channel 1213 are openings that connect to the temperature-controlled water supply pipe 125 and the temperature-controlled water discharge pipe, which are provided on one main surface of the manifold 121. The temperature control channel 1213 is also formed to allow heat exchange with the substrate 111 fixed to the manifold 121.

[0052] The top plate 122 is provided on the side of the manifold 121 opposite to the side on which the substrate 111 is provided. By covering the manifold 121, the top plate 122 seals the supply channel 1211, the discharge channel, and the temperature control channel 1213.

[0053] Furthermore, the top plate 122 has openings for connecting the pipes 123, 124, and 125, and for connecting the pipes 123, 124, and 125 and the flow paths 1211 and 1213.

[0054] The ink supply pipe 123 is connected to the supply channel 1211. The ink discharge pipe 124 is connected to the discharge channel. The temperature-controlled water supply pipe 125 and the temperature-controlled water discharge pipe are connected to the primary and secondary sides of the temperature-controlled channel 1213.

[0055] As shown in Figure 4, the circuit board 13 comprises a wiring film 131 with one end connected to a connection portion 1116 of the board 111, a driver IC 132 mounted on the wiring film 131, and a printed wiring board 133 mounted on the other end of the wiring film 131.

[0056] The circuit board 13 drives the actuator 113 by applying a drive voltage to the wiring pattern of the actuator 113 using the driver IC 132, thereby increasing or decreasing the volume of the pressure chamber 1131 and ejecting droplets from the nozzle 1141.

[0057] The wiring film 131 is connected to a plurality of individual electrodes 118 and a common electrode 119. For example, the wiring film 131 is an ACF (anisotropic conductive film) fixed to the connection part of the substrate 111 by thermocompression or the like. Multiple wiring films 131 are provided for a single head body 11, for example. In this embodiment, two wiring films 131 are connected to a single actuator 113. The wiring film 131 is, for example, a COF (Chip on Film) on which a driver IC 132 is mounted.

[0058] The driver IC 132 is connected to a plurality of individual electrodes 118 and a common electrode 119 via a wiring film 131. Alternatively, the driver IC 132 may be connected to the plurality of individual electrodes 118 and the common electrode 119 by means other than the wiring film 131, such as ACP (anisotropic conductive paste), NCF (non-conductive film), and NCP (non-conductive paste).

[0059] The printed wiring board 133 is a PWA (Printing Wiring Assembly) on which various electronic components and connectors are mounted.

[0060] The cover 14 includes, for example, an outer casing 141 that covers the sides of the pair of head bodies 11, the manifold unit 12 and the circuit board 13, and a mask plate 142 that covers a portion of the nozzle plate 114 side of the pair of head bodies 11.

[0061] The outer casing 141 exposes, for example, the ink supply pipe 123, ink discharge pipe 124, temperature-controlled water supply pipe 125, and temperature-controlled water discharge pipe of the manifold unit 12, as well as the end of the circuit board 13, to the outside.

[0062] The mask plate 142 covers the portion of the pair of head bodies 11 excluding the multiple nozzles 1141 and the area around the multiple nozzles 1141 of the nozzle plate 114.

[0063] Next, as an example of a manufacturing method for the liquid dispensing head 1, an example of molding the electrodes 117 of the head body 11 will be explained using the flowchart shown in Figure 10.

[0064] First, sputtering is performed on predetermined areas of the substrate 101 and actuator 113 that constitute the substrate 111 to form a Ni sputtered film 11731 (ACT1). Here, as shown in Figure 11, the substrate 101 is formed in a rectangular shape that is larger than the substrate 111, and includes a polished surface in the area that will become the substrate 111. In addition, a pair of actuators 113 are bonded to the area of ​​the substrate 101 that will become the substrate 111.

[0065] As a specific example of ACT1, a Ni sputtered film 11731 is formed on the substrate 101, which includes a region that will become a substrate 111 including a polished surface, on the inclined surface 1134 of the actuator 113 and on the inner surfaces of multiple piezoelectric elements 1133 (multiple grooves) that constitute multiple pressure chambers 1131 and multiple air chambers 1132 of the actuator 113.

[0066] Next, an electroless Ni plating film 11732 is formed on the Ni sputtered film 11731 using an electroless plating method (ACT2). For example, the Ni sputtered film 11731 is used as a catalyst to form the electroless Ni plating film 11732.

[0067] Next, the electrodes formed by the Ni sputtered film 11731 / electroless Ni plating film 11732 are patterned using photolithography such as PEP (Photo Engraving Process) (ACT3). The electrode pattern at this time is similar to the pattern of the multiple individual electrodes 118 and common electrode 119 formed on the substrate 111 and actuator 113. Since the base material 101 is larger in shape than the substrate 111, electrodes are formed in areas other than those where the individual electrodes 118 and common electrode 119 are formed on the base material 101, as shown in Figure 11, and these electrodes are continuous with the individual electrodes 118 and common electrode 119.

[0068] Next, an electrolytic Au plating film 11733 is formed on the patterned electroless Ni plating film 11732 using an electrolytic plating method (ACT4). As a result, the electrolytic Au plating film 11733 is formed on multiple individual electrodes 118 and a common electrode 119. At this time, the plating thickness of the electrolytic Au plating film 11733 is the same for both the individual electrodes 118 and the common electrode 119.

[0069] Next, as shown by the dashed line C in Figure 11, the electrodes formed on the substrate 101 are cut using a laser processing method or the like so that the multiple individual electrodes 118 and the common electrode 119 become discontinuous (ACT5). At this time, not only the electrodes formed on the substrate 101 but also a part of the substrate 101 may be cut off.

[0070] As a specific example, before ACT5, electrodes continuous with multiple individual electrodes 118 and a common electrode 119 are formed in the area of ​​the base material 101 other than the area constituting the substrate 111. Then, in ACT5, the electrodes are cut along line C by laser processing, electrically separating the electrodes connected to the multiple individual electrodes 118 from the electrodes connected to the common electrode 119. In addition, the mounting side electrode portion 1011 of the base material 101 that is continuous with the multiple individual electrodes 118 in the direction of the alignment of the pair of actuators 113 is separated from the multiple individual electrodes 118 together with the base material 101. Note that the electrode cutting in ACT5 may be performed by other methods such as photolithography instead of laser processing.

[0071] Next, an electrolytic Au plating film is selectively formed on the common electrode 119 using an electrolytic plating method (ACT6). That is, an electrolytic Au plating film is formed on top of the electrolytic Au plating film 11733 on the common electrode 119. In ACT5, the individual electrodes 118 and the common electrode 119 are electrically isolated, so even if current is applied to the common electrode 119 for electrolytic plating, the individual electrodes 118 are not currented, and only the common electrode 119 can be electrolytically plated. As a result of this electrolytic plating, as shown in Figure 8, the thickness t2 of the electrolytic Au plating film 11733 on the common electrode 119 becomes thicker than the thickness t1 of the electrolytic Au plating film 11733 on the individual electrodes 118.

[0072] Next, the base material 101 is cut to the shape of the substrate 111 (ACT7), and a liquid-proof wall 1135 is formed as a resin wall on the side adjacent to the first common liquid chamber 1161 and the side adjacent to the second common liquid chamber 1162 of the air chamber 1132 (air groove) (ACT8). For example, the side adjacent to the first common liquid chamber 1161 of the air chamber 1132 (air groove) is designated as the primary side, and the side adjacent to the second common liquid chamber 1162 is designated as the secondary side. However, the side adjacent to the second common liquid chamber 1162 may be designated as the primary side, and the side adjacent to the first common liquid chamber 1161 may be designated as the secondary side. As a result, a liquid-proof wall 1135 is formed inside the air chamber 1132, and the liquid-proof wall 1135 is in contact with the surface of a part of the common electrode 119 formed inside the air chamber 1132. Next, the upper surfaces of the pair of actuators 113 are polished (ACT9).

[0073] These steps form the electrodes 117 of the head body 11. After these steps, one end of the circuit board 13 is connected to the connection portion 1116 of the substrate 111, the frame member 112 is joined to the substrate, and the nozzle plate 114 is joined to the substrate 111, the frame member 112, and the actuator 113, thereby forming the head body 11. Note that the connection of the circuit board 13 and the joining of the frame member 112 are performed after ACT8, and in ACT9, the upper surface of the frame member 112 may be polished in addition to the pair of actuators 113.

[0074] The liquid discharge head 1 configured in this way has a head body 11 which includes a plurality of individual electrodes 118 that can individually apply a driving voltage to each piezoelectric element 1133, and a common electrode 119 that can apply a driving voltage to all piezoelectric elements 1133.

[0075] Therefore, the liquid ejection head 1 can selectively, individually, or collectively drive multiple pressure chambers 1131. When a pressure chamber 1131 is driven, it undergoes shear-mode deformation, and the ink supplied into the pressure chamber 1131 is pressurized. Thus, the liquid ejection head 1 can selectively eject the pressurized ink from the nozzle 1141 facing the deformed pressure chamber 1131.

[0076] Furthermore, since the common electrode 119 has a thicker film than the individual electrodes 118, the resistance value of the common electrode 119 to which the driving voltage connected to the multiple air chambers 1132 is applied can be reduced. In other words, by reducing the resistance value of the common electrode 119, when driving the multiple pressure chambers 1131, it is possible to suppress differences in discharge performance between the central and end parts in the direction in which the nozzles 1141 of the head body 11 are arranged.

[0077] Furthermore, because the liquid-blocking wall 1135 is filled in the groove width direction within the air chamber 1132, a portion of the common electrode 119 is held down by the liquid-blocking wall 1135 within the air chamber 1132. In addition, since the liquid-blocking wall 1135 is provided on the side adjacent to the first common liquid chamber 1161 and the side adjacent to the second common liquid chamber 1162 of the air chamber 1132, the adjacent piezoelectric elements 1133 of the actuator 113 become one unit with the liquid-blocking wall 1135, thereby improving the rigidity of the piezoelectric elements 1133 of the actuator 113.

[0078] Therefore, even if the film thickness increases and the adhesion force of the electrolytic Au plating film 11733 decreases, the liquid-proof wall 1135 can suppress electrode peeling of the common electrode 119. In particular, during the molding of the electrode 117, the polishing process of the actuator 113 generates vibrations in the polishing direction of the actuator 113. However, even if vibrations occur during the polishing process of the actuator 113, the liquid-proof wall 1135 is provided on a part of the surface of the common electrode 119, so the head body 11 can suppress peeling of the common electrode 119.

[0079] According to the liquid discharge head 1 of the embodiment described above, by providing a liquid-proof wall 1135 (resin wall) on the common electrode 119 in the air chamber 1132, the film thickness of the common electrode 119 can be made thicker than the film thickness of the individual electrodes 118, and even if the resistance value of the common electrode 119 is reduced, peeling of the electrolytic Au plating film 11733, which is the electrode film, can be suppressed.

[0080] The inkjet recording device 2 having a liquid ejection head 1 will be described below with reference to Figure 12. The inkjet recording device 2 comprises a housing 2111, a media supply unit 2112, an image forming unit 2113, a media discharge unit 2114, a transport device 2115 which is a support device, a temperature control device 2116, a maintenance device 2117, and a control unit 2118. The inkjet recording device 2 also includes a temperature control device that adjusts the temperature of the ink supplied to the liquid ejection head 1.

[0081] The inkjet recording device 2 is an inkjet printer that performs image formation processing on paper P by transporting paper P, for example, as a recording medium to be ejected, along a predetermined transport path 2001 from the media supply unit 2112 through the image forming unit 2113 to the media ejection unit 2114, while ejecting a liquid such as ink.

[0082] The media supply unit 2112 includes a plurality of paper feed cassettes 21121. The image forming unit 2113 includes a support unit 2120 for supporting paper and a plurality of head units 2130 positioned opposite each other above the support unit 2120. The media discharge unit 2114 includes a paper output tray 21141.

[0083] The support unit 2120 includes a conveyor belt 21201 provided in a loop shape in a predetermined area where image formation is performed, a support plate 21202 that supports the conveyor belt 21201 from the back, and a plurality of belt rollers 21203 provided on the back of the conveyor belt 21201.

[0084] The head unit 2130 comprises a liquid ejection head 1 which is a plurality of inkjet heads, a plurality of supply tanks 2132 which are liquid tanks mounted on each liquid ejection head 1, a pump 2134 which supplies ink, and a connecting channel 2135 which connects the liquid ejection head 1 and the supply tanks 2132.

[0085] In this embodiment, the liquid ejection head 1 comprises four liquid ejection heads 1 for cyan, magenta, yellow, and black, and four supply tanks 2132 each containing ink of one of these colors. The supply tanks 2132 are connected to the liquid ejection head 1 by a connecting channel 2135.

[0086] Pump 2134 is a liquid transfer pump, for example, a piezoelectric pump. Pump 2134 is connected to the control unit 2118 and is driven and controlled by the control unit 2118.

[0087] The connecting channel 2135 includes a supply channel connected to the ink supply pipe 123 of the liquid ejection head 1. The connecting channel 2135 also includes a recovery channel connected to the ink discharge pipe 124 of the liquid ejection head 1. For example, if the liquid ejection head 1 is a non-circulating type, the recovery circuit is connected to the maintenance device 2117, and if the liquid ejection head 1 is a circulating type, the recovery channel is connected to the supply tank 2132.

[0088] The transport device 2115 transports the paper P along a transport path 2001 from the paper feed cassette 21121 of the media supply unit 2112, through the image forming unit 2113, to the paper output tray 21141 of the media discharge unit 2114. The transport device 2115 comprises a plurality of guide plate pairs 21211 to 21218 and a plurality of transport rollers 21221 to 21228 arranged along the transport path 2001. The transport device 2115 supports the paper P so that it can move relative to the liquid discharge head 1.

[0089] The temperature control device 2116 includes a temperature-controlled water tank 21161, a temperature control circuit 21162 such as piping and tubes for supplying temperature-controlled water, a pump for supplying temperature-controlled water, and a temperature controller for adjusting the temperature of the temperature-controlled water. The temperature control device 2116 supplies temperature-controlled water from the temperature-controlled water tank 21161, which has been adjusted to a predetermined temperature by the temperature controller, to the temperature-controlled water supply pipe 125 of the liquid discharge head 1 via the temperature control circuit 21162 using water supplied by the pump. The temperature control device 2116 also recovers water discharged from the temperature-controlled water discharge pipe through the manifold unit 12 back into the temperature-controlled water tank 21161 via the temperature control circuit 21162. The temperature controller is, for example, a heater or a cooler. The temperature control device 2116 may also be configured to adjust the temperature of the ink supplied to the liquid discharge head 1.

[0090] The maintenance device 2117, for example, sucks up and recovers ink remaining on the outer surface of the nozzle plate 114 during maintenance. Furthermore, if the liquid discharge head 1 is a non-circulating type, the maintenance device 2117 recovers ink from within the head body 11 during maintenance. Such a maintenance device 2117 includes a tray or tank for storing the recovered ink.

[0091] The control unit 2118 includes a CPU 21181 as an example of a processor, a memory such as ROM (Read Only Memory) for storing various programs, RAM (Random Access Memory) for temporarily storing various variable data and image data, and an interface unit for inputting data from the outside and outputting data to the outside.

[0092] According to the liquid dispensing device 2 of the embodiment described above, by providing a liquid-proof wall 1135 (resin wall) on the common electrode 119 in the air chamber 1132, the film thickness of the common electrode 119 can be made thicker than the film thickness of the individual electrodes 118, and even if the resistance value of the common electrode 119 is reduced, peeling of the electrolytic Au plating film 11733, which is the electrode film, can be suppressed.

[0093] It should be noted that the embodiments of the present invention are not limited to the configurations described above. For example, in the above example, the liquid discharge head 1 was described as having a pair of head bodies 11, but it is not limited to this, and may have a configuration with a single head body 11. Also, in the above example, the liquid discharge head 1 was described as a non-circulating type, but it may also be a circulating type.

[0094] Furthermore, in the example described above, the liquid discharge head 1 is provided with a liquid-proof wall 1135 as a resin wall within the air chamber 1132 (air groove) of the actuator 113, but it is not limited to this. For example, as shown in Figure 13, the head body 11 of the liquid discharge head 1 may further have a resin wall 1136 that forms a constriction 11361 that restricts the liquid flowing through the pressure chamber 1131 within the pressure chamber 1131 (pressure groove) of the actuator 113. The resin wall 1136 is molded by the same molding method as the liquid-proof wall 1135.

[0095] According to at least one embodiment described above, by providing a resin wall on the common electrode in the air chamber, the peeling of the electrode film can be suppressed even if the resistance value of the common electrode is reduced.

[0096] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. The following is a description equivalent to the invention described in the original claims of this application. [1] An actuator having a plurality of pressure chambers arranged in one direction and a plurality of air chambers having resin walls, which are arranged alternately with the plurality of pressure chambers, A substrate on which the actuator is provided, An electrode formed of a metal film, including a plurality of individual electrodes that drive each of the plurality of pressure chambers and a common electrode that drives the plurality of air chambers, Equipped with, A liquid dispensing head wherein the film thickness of the common electrode is thicker than the film thickness of the individual electrodes. [2] The liquid discharge head according to [1], wherein the resin wall is positioned on the common electrode in the air chamber, and is provided on the primary and secondary sides of the air chamber, and closes the primary and secondary sides of the air chamber, respectively. [3] The liquid dispensing head according to [2], wherein the individual electrodes and the common electrode are formed of a multilayer film including a Ni sputtered film, an electroless Ni plating film, and an electrolytic metal plating film of a different metal from the Ni sputtered film and the electroless Ni plating film. [4] The electrolytic metal plating film is an Au plating film, The liquid dispensing head according to [3], wherein the Au plating thickness of the common electrode is greater than the Au plating thickness of the individual electrodes. [5] The actuators are provided in pairs, The common electrode is positioned between the pair of actuators. The liquid dispensing head according to any one of [1] to [4], wherein the substrate has an elongated hole between the pair of actuators that extends along the longitudinal direction of the actuators. [Explanation of Symbols]

[0097] 1...Liquid ejection head (inkjet head), 2...Liquid ejection device (inkjet recording device), 11...Head body, 12...Manifold unit, 13...Circuit board, 14...Cover, 111...Substrate, 112...Frame member, 113...Actuator, 114...Nozzle plate, 116...Common liquid chamber, 117...Electrode, 118...Individual electrode, 119...Common electrode, 121...Manifold, 122...Top plate, 123...Ink supply pipe, 124...Ink discharge pipe, 125...Temperature-controlled water supply pipe, 131...Wiring film, 132...Driver IC, 13 3…Printed wiring board, 141…Outer casing, 142…Mask plate, 1111…Supply port, 1112…Discharge port, 1116…Connection part, 1131…Pressure chamber, 1132…Air chamber, 1133…Piezoelectric element (driving element), 1134…Inclined surface, 1135…Liquid-proof wall, 1141…Nozzle, 1142…Nozzle row, 1161…First common liquid chamber, 1162…Second common liquid chamber, 1163…Third common liquid chamber, 1171…First electrode section, 1172…Second electrode section, 1211…Supply channel, 1213…Temperature control channel, 2001…Conveyor path, 2111…Housing, 2112…Media supply 2113…Image forming unit, 2114…Media discharge unit, 2115…Conveyor device, 2116…Temperature control device, 2117…Maintenance device, 2118…Control unit, 2120…Support unit, 2130…Head unit, 2132…Supply tank, 2134…Pump, 2135…Connecting channel, 11731…Ni sputtered film, 11732…Electroless Ni plating film, 11733…Electrolytic Au plating film (electrolytic metal plating film), 21121…Paper feed cassette, 21141…Paper output tray, 21201…Conveyor belt, 21202…Support plate, 21203…Belt Roller, 21211... Guide plate pair, 21212... Guide plate pair, 21213... Guide plate pair, 21214... Guide plate pair, 21215... Guide plate pair, 21216... Guide plate pair, 21217... Guide plate pair, 21218... Guide plate pair, 21221... Conveyor roller, 21222... Conveyor roller, 21223... Conveyor roller, 21224... Conveyor roller, 21225... Conveyor roller, 21226... Conveyor roller, 21227... Conveyor roller, 21228... Conveyor roller, P... Paper.

Claims

1. An actuator having a plurality of pressure chambers arranged in one direction and a plurality of air chambers having resin walls, arranged alternately with the plurality of pressure chambers, A substrate on which the actuator is provided, An electrode formed of a metal film, including a plurality of individual electrodes that drive each of the plurality of pressure chambers and a common electrode that drives the plurality of air chambers, Equipped with, The film thickness of the common electrode is thicker than the film thickness of the individual electrodes. The resin wall is positioned on the common electrode in the air chamber, provided on the primary and secondary sides of the air chamber, and closes the primary and secondary sides of the air chamber, respectively. A liquid dispensing head in which the individual electrodes and the common electrode are formed by a multilayer film including a Ni sputtered film, an electroless Ni plating film, and an electrolytic metal plating film of a dissimilar metal to the Ni sputtered film and the electroless Ni plating film.

2. The electrolytic metal plating film is an Au plating film. The liquid dispensing head according to claim 1, wherein the Au plating film thickness of the common electrode is greater than the Au plating film thickness of the individual electrodes.

3. The actuators are provided in pairs, The common electrode is positioned between the pair of actuators. The liquid dispensing head according to claim 1 or claim 2, wherein the substrate has an elongated hole formed between the pair of actuators, extending along the longitudinal direction of the actuators.

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