JP2009126167A - Manufacturing process of piezoelectric actuator, manufacturing process of liquid discharge head containing piezoelectric actuator, piezoelectric actuator, and liquid discharge head containing this - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable to realize the execution of an electrical inspection and the reduction of a manufacturing cost together. <P>SOLUTION: Upon manufacturing of an piezoelectric actuator, first, an inner common electrode is sandwiched between these piezoelectric ceramic layers, individual electrodes and a surface common electrode are formed on the surface of the piezoelectric ceramic layer at the opposite side to the inner common electrode in the one piezoelectric ceramic layer, Further, a laminated body in which a through-hole arriving at the inner common electrode is formed through this one piezoelectric ceramic layer, is manufactured (S11 to S15). Thereafter, an inspector is inserted into the through-hole, and is touched to the inner electrode. Thereby, the electrical characteristic of the laminated body is inspected (S16). In case of determining as a result of the inspection that there is no defect in the electrical characteristic (S16: YES), individual lands, a common land, and a conductive paste becoming a conductor are printed at the respective positions most separated from COF on the individual electrodes, on the surface common electrode and in the through-hole to become the same diameter (S18). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a piezoelectric actuator, a method for manufacturing a liquid discharge head including a piezoelectric actuator, a piezoelectric actuator, and a liquid discharge head including the same.

  An ink jet head, which is a type of liquid ejection head, includes a flow path unit in which a large number of individual ink flow paths including nozzles and pressure chambers are formed, and a piezoelectric actuator fixed to the upper surface of the flow path unit where the pressure chambers are open. In addition, there is known a technique in which ink is ejected from a number of nozzles formed on the lower surface of a flow path unit by selectively applying ejection energy to ink in a pressure chamber by driving a piezoelectric actuator (see Patent Document 1). . According to the document 1, the piezoelectric actuator includes a plurality of piezoelectric ceramic layers stacked on each other, a common electrode formed between the piezoelectric ceramic layers, and a plurality of individual ceramic layers formed on the surface of the uppermost piezoelectric ceramic layer. Including an electrode and an extraction electrode formed on the same plane as the individual electrode and electrically connected to the common electrode via a through conductor, and via a land formed on the surface of each of the individual electrode and the extraction electrode It is electrically connected to a wiring member that supplies a driving voltage to the piezoelectric actuator.

  In order to manufacture the piezoelectric actuator, first, a conductive paste is printed with a common electrode pattern on substantially the entire surface of one piezoelectric ceramic green sheet in which a through hole is formed, and the conductive paste is applied to the piezoelectric ceramic sheet. A laminated body is formed by laminating another piezoelectric ceramic green sheet so as to sandwich the conductive material, and after filling the through holes with a conductive paste, the laminated body is fired. Then, a conductive paste is printed on the surface of the laminate with the extraction electrode pattern and the individual electrode pattern, and lands are formed on the surfaces of the individual electrode and the extraction electrode, thereby completing the piezoelectric actuator.

  On the other hand, in order to guarantee the ejection reliability of the inkjet head, a technique is known in which electrical characteristics of a piezoelectric actuator are inspected before the piezoelectric actuator is fixed to a flow path unit.

JP 2004-304025 A

  For example, in the piezoelectric actuator described above, in the manufacturing process, before performing the step of forming lands on the surfaces of the individual electrodes and the extraction electrodes, an electrical property inspection can be performed by bringing an inspection tool such as a probe into contact with the through conductor. Done. If there is a defect in the electrical characteristics as a result of the inspection, the laminate, that is, the precursor of the piezoelectric actuator before the land formation is discarded, and a land is formed in the laminate that has passed the inspection. The piezoelectric actuator is fixed on the flow path unit. By performing the inspection before forming the lands in this way, it is possible to avoid a situation in which the lands are formed even in the laminated body having an electrical defect and the material is used wastefully.

  However, in the method of manufacturing a piezoelectric actuator including the above-described inspection process, it is difficult to reduce the manufacturing cost because the number of processes is large.

  An object of the present invention is to provide a method of manufacturing a piezoelectric actuator capable of realizing both electrical inspection and manufacturing cost reduction, and a method of manufacturing a liquid discharge head including the piezoelectric actuator.

  Other objects of the present invention will become apparent from the following description and drawings.

  In order to achieve the above object, according to a first aspect of the present invention, a first electrode is sandwiched between a piezoelectric ceramic layer and a diaphragm laminated thereon, and the first electrode in the piezoelectric ceramic layer is provided. A second electrode and a third electrode spaced apart from the second electrode are formed on the surface opposite to the first electrode, and further penetrates through the piezoelectric ceramic layer to reach the first electrode A laminated body producing step for producing a laminated body in which holes are formed, an inspection step for inspecting electrical characteristics of the laminated body by bringing an inspection tool inserted into the through-hole into contact with the first electrode, and the first A first land connected to a terminal of the wiring member, a second land connected to another terminal of the wiring member, on the second electrode, on the third electrode, and in the through hole; and , A conductor serving as a conductor connecting the first electrode and the third electrode. A printing step of printing sexual paste respectively, the manufacturing method of a piezoelectric actuator and a is provided.

  According to the first aspect, by forming the first land, the second land, and the conductor at a time in the printing process, the number of processes is reduced, and the manufacturing cost can be reduced. Therefore, it is possible to implement both electrical inspection and manufacturing cost reduction.

  According to the second aspect of the present invention, the first electrode is sandwiched between the piezoelectric ceramic layer and the diaphragm laminated thereon, and on the surface of the piezoelectric ceramic layer opposite to the first electrode. A second electrode and a third electrode spaced apart from the second electrode, and a first through hole extending through the piezoelectric ceramic layer to reach the first electrode. A laminated body producing step of producing a laminated body in which a second through hole that is separated from the first through hole and has a diameter smaller than the diameter of the first through hole is formed; and the first through hole An inspection process for inspecting the electrical characteristics of the laminate by bringing the inspection tool inserted into the first electrode into contact with the first electrode, the second electrode, the third electrode, and the second penetration In the hole, the first land connected to the terminal of the wiring member, and another terminal of the wiring member A method of manufacturing a piezoelectric actuator, comprising: a second land to be continued; and a printing step of printing a conductive paste serving as a conductor connecting the first electrode and the third electrode. Provided.

  According to the second aspect, in addition to the effect of the first aspect, there is an effect that the conductive paste is prevented from adhering to the surface facing the piezoelectric ceramic layer in the mask used in the printing process. .

  In the first aspect, it is preferable that in the printing step, the conductive paste serving as the conductor is printed at a position farthest from the wiring member in the through hole. In this case, since the contact between the conductor and the wiring member is effectively suppressed, the electrical connection between the piezoelectric actuator and the wiring member is ensured.

  In the first aspect, it is preferable that printing is performed so that a plurality of the conductors separated from each other are formed in the printing step. In this case, the presence of a plurality of conductors improves the reliability of connection between the first electrode and the third electrode.

  In the first and second aspects, it is preferable that in the printing step, printing is performed so that the first land, the second land, and the conductor have the same diameter. In the first and second aspects, it is preferable that in the printing step, the first land, the second land, and the conductor are printed using a conductive paste made of the same material. . Thereby, a printing process can be performed easily.

  According to the third aspect of the present invention, the first electrode is sandwiched between the piezoelectric ceramic layer and the diaphragm laminated thereon, and on the surface of the piezoelectric ceramic layer opposite to the first electrode. A second electrode and a third electrode spaced apart from the second electrode, and a first through hole extending through the piezoelectric ceramic layer to reach the first electrode. A laminated body producing step of producing a laminated body in which a second through hole that is separated from the first through hole and has a diameter smaller than the diameter of the first through hole is formed; and the first through hole An inspection process for inspecting the electrical characteristics of the laminate by bringing the inspection tool inserted into the first electrode into contact with the first electrode, and on the second electrode and in the second through-hole, A land connected to a terminal, and the first electrode and the third electrode are connected. Manufacturing method of a piezoelectric actuator and a, a printing step of printing each separate terminal and connected conductor and becomes conductive pastes of the wiring member is provided together.

  According to the third aspect, in addition to the effect of the second aspect, since the conductor also has the function of the second land in the first and second aspects, the material cost can be reduced. The effect that reduction and the further reduction of the number of processes are implement | achieved is acquired.

  In the third aspect, it is preferable that printing is performed so that the land and the conductor have the same diameter in the printing step. Moreover, in the said 3rd viewpoint, it is preferable to print the said land and the said conductor using the electrically conductive paste which consists of the same material in the said printing process. Thereby, a printing process can be performed easily.

  According to a fourth aspect of the present invention, a plurality of individual liquid channels including nozzles and pressure chambers are formed, and a plurality of the pressure chambers are formed on the surface. It is manufactured by the manufacturing method according to any one of the first to third aspects so that the piezoelectric ceramic layer extends over the plurality of pressure chambers and the second electrode corresponds to the pressure chambers on the surface. A step of disposing a piezoelectric actuator, and a step of connecting a terminal of a wiring member to the second electrode and the third electrode of the piezoelectric actuator. A method is provided.

  According to the fourth aspect, the effect of the manufacturing method of the corresponding piezoelectric actuator can be obtained.

  In addition, when a piezoelectric actuator is manufactured by the method based on the first to third aspects, a laminated body having a through hole into which an inspection tool can be inserted is manufactured, so that both electrical inspection and manufacturing cost reduction are realized. Although it is possible, if the height of the conductor from the piezoelectric ceramic layer exceeds the height of the land, the conductor contacts the wiring member, thereby preventing the connection between the terminal of the wiring member and the land. In addition, a failure may occur in the electrical connection between the piezoelectric actuator and the wiring member. Therefore, in order to solve such a problem, the present inventor has devised a piezoelectric actuator having the following configuration.

  That is, according to a fifth aspect of the present invention, a piezoelectric ceramic layer, a diaphragm laminated on the piezoelectric ceramic layer, a first electrode disposed between the piezoelectric ceramic layer and the diaphragm, A second electrode formed on the surface of the piezoelectric ceramic layer opposite to the first electrode, and a third electrode formed on the surface of the piezoelectric ceramic layer so as to be separated from the second electrode. A through hole penetrating the third electrode and the piezoelectric ceramic layer so that the first electrode is exposed, and a diameter smaller than the diameter of the through hole on the second electrode. The formed first land connected to the terminal of the wiring member, and on the third electrode, has a diameter smaller than the diameter of the through hole and has the same height as the first land. Connected to another terminal of the wiring member formed in The second land to be in contact with only a part of the region exposed from the through hole of the first electrode, and the height from the piezoelectric ceramic layer is equal to or lower than the first and second lands. There is provided a piezoelectric actuator comprising: a conductor formed in the through hole and connecting the first electrode and the third electrode.

  According to a sixth aspect of the present invention, a piezoelectric ceramic layer, a diaphragm laminated on the piezoelectric ceramic layer, a first electrode disposed between the piezoelectric ceramic layer and the diaphragm, and the piezoelectric A second electrode formed on a surface of the ceramic layer opposite to the first electrode; a third electrode formed on the surface of the piezoelectric ceramic layer so as to be separated from the second electrode; A first through hole penetrating the piezoelectric ceramic layer so that the first electrode is exposed; a first through hole penetrating the piezoelectric ceramic layer so that the first electrode is exposed; And a second through hole having a diameter smaller than that of the first through hole and a diameter smaller than the diameter of the first through hole on the second electrode. The first run connected to the terminal of the wiring member And another terminal of the wiring member formed on the third electrode so as to have a diameter smaller than the diameter of the first through hole and to be the same height as the first land. The second electrode to be connected, and the first electrode and the first electrode formed in the second through hole so that the height from the piezoelectric ceramic layer is equal to or lower than the first and second lands. A piezoelectric actuator comprising: a conductor connecting the three electrodes.

  According to the fifth and sixth aspects, since the height of the conductor from the piezoelectric ceramic layer is equal to or less than the height of the first and second lands, the electrical connection between the piezoelectric actuator and the wiring member is guaranteed. The

  In the fifth aspect, it is preferable that the conductor is formed at a position farthest from the wiring member in the through hole. In this case, since the contact between the conductor and the wiring member is effectively suppressed, the electrical connection between the piezoelectric actuator and the wiring member is reliably ensured.

  Moreover, in the said 5th viewpoint, it is preferable to provide the said several conductor spaced apart mutually. In this case, the presence of a plurality of conductors improves the reliability of connection between the first electrode and the third electrode.

  In the fifth and sixth aspects, it is preferable that the first land, the second land, and the conductor have the same diameter. In the fifth and sixth aspects, it is preferable that the first land, the second land, and the conductor are made of the same material. As a result, the first land, the second land, and the conductor can be more easily formed, so that the cost can be reduced.

  According to a seventh aspect of the present invention, a piezoelectric ceramic layer, a diaphragm laminated on the piezoelectric ceramic layer, a first electrode disposed between the piezoelectric ceramic layer and the diaphragm, and the piezoelectric A second electrode formed on a surface of the ceramic layer opposite to the first electrode; a third electrode formed on the surface of the piezoelectric ceramic layer so as to be separated from the second electrode; The first through hole that penetrates the piezoelectric ceramic layer so that the first electrode is exposed, and the third electrode and the piezoelectric ceramic layer penetrate so that the first electrode is exposed. A second through hole spaced from the first through hole and having a smaller diameter than the first through hole, and a diameter smaller than the diameter of the first through hole on the second electrode Connected to the terminal of the wiring member formed to have And connecting the first electrode and the third electrode formed in the second through hole so that the height from the piezoelectric ceramic layer is the same as the land, and There is provided a piezoelectric actuator comprising a conductor connected to another terminal of the wiring member.

  According to the seventh aspect, since the height of the conductor from the piezoelectric ceramic layer is equal to or less than the height of the land, the electrical connection between the piezoelectric actuator and the wiring member is similar to the fifth and sixth aspects. Guaranteed. In addition, since the conductor also has the function of the second land in the fifth and sixth aspects, the structure can be simplified and the material cost and the number of processes can be reduced. Cost reduction is possible.

  In the seventh aspect, it is preferable that the land and the conductor have the same diameter. In the seventh aspect, it is preferable that the land and the conductor are made of the same material. Thereby, since it becomes possible to form a land and an electric conductor more easily, further cost reduction is implement | achieved.

  According to an eighth aspect of the present invention, a plurality of individual liquid channels including nozzles and pressure chambers are formed, and a plurality of the pressure chambers open to the surface, and the surface of the channel unit includes the The piezoelectric actuator according to any one of the fifth to seventh aspects, wherein the piezoelectric ceramic layer is disposed so as to straddle the plurality of pressure chambers and the second electrode corresponds to the pressure chamber, and the piezoelectric There is provided a liquid ejection head comprising: a wiring member connected to the second electrode and the third electrode of an actuator.

  According to the eighth aspect, the effect of the corresponding piezoelectric actuator can be obtained.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  First, an overall configuration of an inkjet printer 101 including an inkjet head 1 according to a first embodiment of the present invention will be described with reference to FIG. The ink jet printer 101 is a color ink jet printer having four ink jet heads 1. The inkjet printer 101 is provided with a paper feed tray 11 on the left side in FIG. 1 and a paper discharge tray 12 on the right side in FIG. 1, and the paper P is conveyed from the paper feed tray 11 toward the paper discharge tray 12. A sheet transport path is formed. A pair of feed rollers 5a and 5b for feeding the paper P from the paper feed tray 11 to the right in FIG. 1 while sandwiching the paper P is disposed immediately downstream of the paper feed tray 11.

  A belt transport mechanism 13 is provided in the middle of the paper transport path. The belt conveyance mechanism 13 has two belt rollers 6, 7, an endless conveyance belt 8 wound between the two rollers 6, 7, and a position facing the inkjet head 1 in a region surrounded by the conveyance belt 8. And a platen 15 disposed on the surface. The platen 15 supports the conveyance belt 8 so that the conveyance belt 8 does not bend downward in the image forming area facing the inkjet head 1. A nip roller 4 that presses the paper P fed from the paper feed tray 11 by the feed rollers 5 a and 5 b against the outer peripheral surface 8 a of the transport belt 8 is disposed at a position facing the belt roller 7.

  When the belt roller 6 is rotated clockwise in FIG. 1 by a transport motor (not shown), the transport belt 8 travels along the arrow X. As a result, the paper P pressed against the outer peripheral surface 8a of the conveying belt 8 by the nip roller 4 is conveyed toward the paper discharge tray 12 while being held on the outer peripheral surface 8a.

  A peeling plate 14 is provided immediately downstream of the belt roller 6 along the paper conveyance path. The peeling plate 14 peels the paper P held on the outer peripheral surface 8 a of the transport belt 8 from the outer peripheral surface 8 a and sends it to the paper discharge tray 12.

  The four inkjet heads 1 are arranged in parallel along the paper transport direction, and eject magenta, yellow, cyan, and black ink, respectively. That is, the ink jet printer 101 is a line printer. A head body 2 having an elongated rectangular parallelepiped shape that is elongated in a direction orthogonal to the paper transport direction is provided at the lower end of each inkjet head 1. The head body 2 is disposed such that the lower surface thereof faces the outer peripheral surface 8a, and the lower surface is an ink ejection surface on which a number of nozzles 108 (see FIG. 5) are formed. When the paper P transported by the transport belt 8 passes immediately below the four head bodies 2 in order, the ink of each color is ejected from the lower surface of each head body 2 toward the surface of the paper P. A desired color image is formed on the surface of P.

  Next, the inkjet head 1 will be described.

  As shown in FIG. 2, the head main body 2 provided at the lower end of the inkjet head 1 has a channel unit 9 having an elongated rectangular parallelepiped shape along the main scanning direction (direction perpendicular to the paper surface of FIGS. 1 and 2). And four actuator units 21 having a trapezoidal shape in plan view fixed on the flow path unit 9 (FIG. 2 shows only a cross section of one actuator unit 21). As shown in FIG. 4, a large number of pressure chambers 110 are formed in a matrix in the arrangement region of each actuator unit 21 on the upper surface of the flow path unit 9. On the other hand, an area corresponding to the actuator unit 21 on the lower surface of the flow path unit 9 is an ink ejection area in which a large number of nozzles 108 are formed in a matrix like the pressure chambers 110. Each actuator unit 21 is fixed to the upper surface of the flow path unit 9 so as to close the corresponding openings of the plurality of pressure chambers 110, and includes an actuator corresponding to each pressure chamber 110. The discharge energy is selectively applied.

  Returning to FIG. 2, the vicinity of one end of a COF (Chip On Film) 50 is fixed to the upper surface of each actuator unit 21. The COF 50 is a flat flexible board on which a driver IC 52 is mounted. Each terminal of the COF 50 is disposed opposite to the individual land 136 and the common land 146 (see FIG. 7) of the actuator unit 21 and is electrically connected to these via a conductive adhesive. Connected. The portion of the COF 50 that faces the upper surface of the actuator unit 21, that is, the vicinity of one end, has a trapezoidal shape substantially the same as that of the actuator unit 21. One end of the COF 50 is disposed in the vicinity of the upper base of the actuator unit 21, extends from the upper base toward the lower base, and is further drawn upward. The other end of the COF 50 is located above a later-described reservoir unit 71 and is electrically connected to the control board 54 via a connector 54a. The control board 54 controls driving of the actuator unit 21 via the driver IC 52. The driver IC 52 generates a drive signal that drives the actuator unit 21.

  A reservoir unit 71 that supplies ink to the flow path unit 9 is fixed to the upper surface of the head body 2. The actuator unit 21, the reservoir unit 71, the COF 50, and the control board 54 are covered with a side cover 53 and a head cover 55. The side cover 53 that is a metal plate extends along the longitudinal direction of the flow path unit 9, that is, the main scanning direction, and is fixed near both ends in the width direction of the upper surface of the flow path unit 9. The head cover 55 is fixed to the upper ends of the two side covers 53 so as to straddle them.

  The reservoir unit 71 includes four plates 91, 92, 93, 94 stacked on each other. Inside the reservoir unit 71, an ink inflow channel (not shown) through which ink flows from an ink supply source (not shown) such as an ink tank, an ink reservoir 61 for temporarily storing ink, and 10 Ink outflow channels 62 (only one is shown in FIG. 2) are formed to communicate with each other. The ink outflow channel 62 is formed corresponding to ten ink supply ports 105b (see FIG. 3) formed on the upper surface of the channel unit 9, and is connected to the channel unit 9 via the ink supply port 105b. Communicate. The ink from the ink supply source sequentially passes through the ink inflow channel, the ink reservoir 61, and the ink outflow channel 62, and is supplied to the channel unit 9 from the ink supply port 105b. On the lower surface of the plate 94, a portion facing the region including the ink supply port 105b defined by the two-dotted line in FIG. 3 becomes a convex portion, and a portion facing the region containing the four actuator units 21 becomes a concave portion. As shown in FIG. A gap is formed between the COF 50 fixed to the upper surface of each actuator unit 21 and the lower surface of the plate 94 as shown in FIG.

  The COF 50 extends upward while being sandwiched between the side cover 53 and the reservoir unit 71, and is connected to a connector 54 a mounted on the control board 54 at the other end. The driver IC 52 is urged toward the side cover 53 by a sponge 82 attached to the side surface of the reservoir unit 71 and is fixed to the side cover 53 via a heat sink 81.

  Next, the head body 2 will be described in more detail. In FIG. 4, the aperture 112 and the nozzle 108 which are formed inside and on the lower surface of the flow path unit 9 and should be drawn with a broken line are drawn with a solid line.

  The flow path unit 9 has a rectangular parallelepiped shape substantially the same as the plate 94 of the reservoir unit 71. As shown in FIG. 3, a total of ten ink supply ports 105 b are provided on the upper surface 9 a of the flow path unit 9 corresponding to the ink outflow flow paths 62 (see FIG. 2) of the reservoir unit 71. A manifold channel 105 communicating with the ink supply port 105 b and a sub-manifold channel 105 a branched from the manifold channel 105 are formed inside the channel unit 9.

  As shown in FIG. 4, 16 rows of pressure chambers 110 along the main scanning direction are formed in the arrangement region of each actuator unit 21 on the upper surface of the flow path unit 9. The number of pressure chambers 110 included in each pressure chamber row is larger as it is closer to the long side (lower bottom) of the actuator unit 21 and is smaller as it is closer to the short side (upper bottom). The same applies to the nozzle 108.

  Each pressure chamber 110 has a rhombic planar shape with rounded corners, and the longer diagonal line is parallel to the sub-scanning direction. One end of each pressure chamber 110 corresponding to one acute angle portion of the pressure chamber 110 communicates with the nozzle 108, and the other end corresponding to the other acute angle portion of the pressure chamber 110 is connected to the sub manifold channel 105 a via the aperture 112. Communicating with

  As shown in FIG. 5, the flow path unit 9 includes a cavity plate 122, a base plate 123, an aperture plate 124, a supply plate 125, three manifold plates 126, 127, 128, a cover plate 129, and a nozzle plate in order from the top. It includes nine metal plates such as 130 stainless steel. The plates 122 to 130 each have a rectangular planar shape elongated in the main scanning direction, and are stacked while being aligned with each other so that the individual ink flow paths 132 for the pressure chambers 110 are formed in the flow path unit 9. ing. Inside the flow path unit 9, a manifold flow path 105, a sub-manifold flow path 105 a, an aperture 112 functioning as a throttle from the outlet of the sub-manifold flow path 105 a, and a flow path from the pressure chamber 110 to the nozzle 108 are formed. Has been. Among these, the individual ink flow path 132 is a portion from the outlet of the sub-manifold flow path 105a to the nozzle 108.

  Next, the actuator unit 21 will be described.

  As shown in FIG. 3, the four actuator units 21 are arranged in a staggered manner in the main scanning direction so as to avoid the ink supply ports 105b. The parallel opposing sides of the actuator unit 21 extend in the main scanning direction. The hypotenuses of adjacent actuator units 21 overlap in the sub-scanning direction.

  As shown in FIG. 6A, the actuator unit 21 is formed corresponding to each pressure chamber 110 on the upper surface of the three piezoelectric ceramic layers 41, 42, 43 stacked on top of each other and the uppermost piezoelectric ceramic layer 41. The individual electrode 135, the individual land 136 electrically connected to the individual electrode 135, and the internal common electrode 134 formed over the entire surface between the piezoelectric ceramic layer 41 and the piezoelectric ceramic layer 42 below the piezoelectric ceramic layer 41. including. No electrode is disposed between the piezoelectric ceramic layer 42 and the piezoelectric ceramic layer 43. The piezoelectric ceramic layers 41 to 43 are both made of a lead zirconate titanate (PZT) ceramic material having ferroelectricity, and have a trapezoidal shape that defines the outer shape of the actuator unit 21 with a thickness of about 15 μm.

  As shown in FIG. 6B, the individual electrode 135 is substantially similar to the pressure chamber 110, and has a main electrode portion 135a having a substantially rhombic planar shape that is slightly smaller than the pressure chamber 110, and an acute angle portion in the main electrode portion 135a. It includes an extended portion 135b extending from one side in the longitudinal direction of the main electrode portion 135a. The main electrode portion 135a is disposed in a region facing the corresponding pressure chamber 110, and the extending portion 135b extends from one end of the main electrode portion 135a to a region not facing the pressure chamber 110. The individual land 136 is disposed on the surface of the tip of the extending portion 135b, so that the height from the surface of the piezoelectric ceramic layer 41 is higher than that of the individual electrode 135 (see FIG. 6A).

  7 and 8, the actuator unit 21 is further formed with a surface common electrode 145 formed on the upper surface of the piezoelectric ceramic layer 41 near both ends of the trapezoidal upper base (in FIG. 7, it is formed near one end of the upper base. And a common land 146 formed on the surface common electrode 145 and electrically connected to the surface common electrode 145. The surface common electrode 145 is substantially L-shaped, and includes a long portion along the upper bottom of the actuator unit 21 and a short portion connected to be orthogonal to the long portion. A common land 146 is disposed in the vicinity of the tip of the short portion, and a through hole 140 that reaches the internal common electrode 134 through the surface common electrode 145 and the piezoelectric ceramic layer 41 in the vicinity of the connection portion between the short portion and the long portion. Is formed.

  The internal common electrode 134 is exposed as the bottom surface of the through hole 140 and is electrically connected to the surface common electrode 145 through a conductor 141 provided in the through hole 140. The conductor 141 is not formed in the entire through-hole 140, but in a position farthest from the COF 50 in the through-hole 140 so as to contact only a part of the region exposed from the through-hole 140 of the internal common electrode 134. Is formed. More specifically, the conductor 141 according to the first embodiment is formed at a position in the through hole 140 that is biased in the direction opposite to the direction in which the COF 50 is drawn out (the direction indicated by the arrow A in FIGS. 7 and 8). A part of which protrudes outward in the radial direction from the through hole 140. As a result, the conductor 141 has a shape in which a part of a cylinder is notched, and the height H1 of the conductor 141 from the piezoelectric ceramic layer 41 is constant, but the thickness of the conductor 141 is not in the above-described extent. This portion is smaller than the portion corresponding to the inside of the through hole 140.

  Each of the individual electrode 135, the internal common electrode 134, and the surface common electrode 145 is made of, for example, an Ag-Pd metal material, and among these, the individual electrode 135 and the surface common electrode 145 have the same thickness of approximately 1 μm, The common electrode 134 has a thickness of approximately 2 μm. The individual lands 136, the common lands 146, and the conductors 141 are made of, for example, gold containing glass frit, and have a substantially cylindrical shape with a diameter D1 of approximately 160 μm. The diameter D2 of the through-hole 140 is larger than the diameter D1 of the individual land 136, the common land 146, and the conductor 141, and is 200, for example, so that an inspection tool 170 (see FIG. 11) used in the inspection step S15 described later can be inserted. It is -300 micrometers. As shown in FIG. 8, the height H2 of the common land 146 from the piezoelectric ceramic layer 41 is higher than the height H1 of the conductor 141 from the piezoelectric ceramic layer 41. Although not shown, the height of the individual land 136 from the piezoelectric ceramic layer 41 is substantially the same as the height H2 of the common land 146.

  The common land 146 is disposed opposite to the terminal 51 of the COF 50 and the individual land 136 is disposed opposite to the other terminal (not shown) of the COF 50 and electrically connected via a conductive adhesive. As a result, the internal common electrode 134 and the individual electrode 135 are connected to the driver IC 52 via the wiring provided in the COF 50, the signal held at the ground potential is printed on the internal common electrode 134, and the individual electrode 135 should be printed. Drive signals that alternately take the ground potential and the positive potential according to the image pattern are supplied from the driver IC 52, respectively.

  Here, a driving method of the actuator unit 21 will be described. The piezoelectric ceramic layer 41 is polarized in the thickness direction. That is, the actuator unit 21 uses the piezoelectric ceramic layer 41 farthest from the pressure chamber 110 as a layer in which an active portion exists and two piezoelectric ceramic layers 42 and 43 close to the pressure chamber 110 below the inactive layer as inactive layers. The so-called unimorph type. When an electric field is applied to the active portion sandwiched between the individual electrode 135 and the internal common electrode 134 of the piezoelectric ceramic layer 41 by setting the individual electrode 135 to a predetermined positive or negative potential, the polarization direction is caused by the piezoelectric lateral effect. It shrinks in the direction orthogonal to the direction, that is, the surface direction. On the other hand, since the piezoelectric ceramic layers 42 and 43 are not affected by the electric field and do not spontaneously deform, there is a difference in strain in the plane direction between the upper piezoelectric ceramic layer 41 and the lower piezoelectric ceramic layers 42 and 43. Therefore, the entire piezoelectric ceramic layers 41 to 43 try to be deformed so as to protrude toward the pressure chamber 110 (unimorph deformation). Here, since the piezoelectric ceramic layers 41 to 43 are fixed to the upper surface of the cavity plate 122 that partitions the pressure chamber 110, a region corresponding to the active portion of the piezoelectric ceramic layers 41 to 43 eventually faces the pressure chamber 110. And deforms to become convex. Due to such deformation, the volume of the pressure chamber 110 is reduced, pressure, that is, ejection energy is applied to the ink in the pressure chamber 110, and ink droplets are ejected from the nozzle 108. Thereafter, when the individual electrode 135 is returned to the same potential as the internal common electrode 134, the piezoelectric ceramic layers 41 to 43 return to the original shape, and the volume of the pressure chamber 110 returns to the original volume. Ink is sucked in.

  As another driving method, the individual electrode 135 is set to a potential different from that of the internal common electrode 134 in advance, and the individual electrode 135 is once set to the same potential as the internal common electrode 134 every time there is a discharge request, and then again individually at a predetermined timing. The electrode 135 can be at a different potential from the internal common electrode 134. In this case, in the initial state, the region corresponding to the active portion of the piezoelectric ceramic layers 41 to 43 is deformed so as to protrude toward the pressure chamber 110. When the discharge request is made, at the timing when the individual electrode 135 becomes the same potential as the internal common electrode 134, the piezoelectric ceramic layers 41 to 43 become flat, and the volume of the pressure chamber 110 increases compared to the initial state. As a result, ink is sucked into the pressure chamber 110 from the manifold channel 105. Thereafter, at a timing when the individual electrode 135 is set to a potential different from that of the internal common electrode 134 again, the region corresponding to the active portion of the piezoelectric ceramic layers 41 to 43 is deformed so as to protrude toward the pressure chamber 110, and the pressure chamber 110 As the volume of the ink drops, the pressure on the ink increases and ink is ejected.

  Next, a method for manufacturing the inkjet head 1 will be described with reference to FIGS.

  In order to manufacture the inkjet head 1, first, when the head body 2 is manufactured, the flow path unit 9 and the four actuator units 21 are separately manufactured (S 1 and S 2 in FIG. 9). In addition, since the flow path unit manufacturing step (S1) and the actuator unit manufacturing step (S2) are performed independently, any of them may be performed first or in parallel.

  In the flow path unit manufacturing step (S1), first, nine metal plates such as stainless steel are etched using a patterned photoresist as a mask to form holes, and plates 122 to 130 are manufactured. Thereafter, the plates 122 to 130 are laminated via an epoxy thermosetting adhesive while being aligned with each other so that the individual ink flow paths 132 shown in FIG. 5 are formed, and the curing temperature of the thermosetting adhesive is set. Pressurization while heating to the above temperature. Thereby, the thermosetting adhesive is cured and the plates 122 to 130 are fixed to each other, and the flow path unit 9 is completed.

  In the actuator unit manufacturing step (S2), first, three green sheets to be the piezoelectric ceramic layers 41 to 43 formed in advance in consideration of the shrinkage due to firing are prepared. And the through-hole 140 which has the diameter D2 is formed in the green sheet used as the piezoelectric ceramic layer 41 (S11 of FIG. 10). Thereafter, an Ag-Pd-based pattern of the individual electrode 135 and the surface common electrode 145 on the green sheet to be the piezoelectric ceramic layer 41 and an internal common electrode 134 pattern on the green sheet to be the piezoelectric ceramic layer 42, respectively. Conductive paste is screen printed (S12).

  Thereafter, while aligning using a jig, a green sheet to be the piezoelectric ceramic layer 42 is placed on the green sheet to be the piezoelectric ceramic layer 43 that has not been printed, with the surface on which the internal common electrode 134 is printed facing up. Further, a green sheet to be the piezoelectric ceramic layer 41 is overlaid thereon with the surface on which the individual electrode 135 and the surface common electrode 145 are printed facing up (S13). And the green sheet laminated | stacked mutually is degreased like a well-known ceramic, and is baked at predetermined temperature (S14). Thus, the three green sheets become the piezoelectric ceramic layers 41 to 43, and the conductive paste becomes the individual electrode 135, the surface common electrode 145, and the internal common electrode 134. Therefore, the precursor body (hereinafter referred to as a laminated body) of the actuator unit 21 in which the individual lands 136, the common lands 146, and the conductors 141 are not yet formed is completed by the steps S11 to S14.

  Thereafter, as shown in FIG. 11, an inspection tool 170 such as a probe is inserted into the through hole 140 formed in the piezoelectric ceramic layer 41 and brought into contact with the internal common electrode 134 to inspect the electrical characteristics of the laminate ( S15). As a result of the inspection, if it is determined that there is a defect in the electrical characteristics (S16: NO), the laminate is discarded before the lands 136, 146 and the conductor 141 are formed (S17). On the other hand, when it is determined that there is no defect in the electrical characteristics (S16: YES), the surface common electrode 145 is formed on the extended portion 135b of each individual electrode 135 using the mask 180 patterned as shown in FIG. Each of the above-mentioned predetermined position and the position farthest away from the COF 50 in the through hole 140 (see FIGS. 7 and 8) is an Au-based material including a glass frit to be an individual land 136, a common land 146, and a conductor 141. The conductive paste is printed so as to have the same diameter D1 (S18). Thereby, the individual land 136, the common land 146, and the conductor 141 are formed, and the actuator unit 21 is completed.

  Returning to FIG. 9, the four actuator units 21 manufactured as described above are fixed to the upper surface of the flow path unit 9 (S3). Here, first, a thermosetting adhesive is applied to the upper surface of the flow path unit 9, and the four actuator units 21 are positioned in a staggered arrangement as shown in FIG. At this time, each actuator unit 21 is aligned so that the individual electrode 135 faces the pressure chamber 110. Then, a heating / pressurizing device such as a ceramic heater is placed on the actuator unit 21 so as to be supported by the individual lands 136 and the common land 146, and the flow path unit 9 and the actuator unit 21 are made of a thermosetting adhesive. After pressurizing while heating above the curing temperature, naturally cool. Thereby, the head main body 2 is completed.

  Thereafter, the vicinity of one end of the COF 50 is joined to each actuator unit 21 (S4). Here, first, for each actuator unit 21, a thermosetting conductive adhesive is applied on the individual land 136 and the common land 146, respectively, so that the terminal 51 of the COF 50 and the common land 146 face each other, and The COF 50 is heated while being pressurized toward the head body 2 in a state where the COF 50 is positioned so that another terminal (not shown) of the COF 50 and the individual land 136 face each other. As a result, the vicinity of one end of the COF 50 is joined to each actuator unit 21.

  Thereafter, the reservoir unit 71 is fixed to the upper surface 9a of the flow path unit 9 (S5). Thereby, the main part of the inkjet head 1 is completed.

  As described above, according to the manufacturing method of the actuator unit 21 according to the first embodiment, in the printing process of S18, the individual lands 136, the common lands 146, and the conductors 141 are formed at a time, so that the number of processes is increased. The manufacturing cost can be reduced. Therefore, it is possible to implement both electrical inspection and manufacturing cost reduction.

  In the printing step of S18, the contact between the conductor 141 and the COF 50 is effectively suppressed by printing the conductive paste to be the conductor 141 at the position farthest from the COF 50 in the through-hole 140, so that the actuator The electrical connection between the unit 21 and the COF 50 is guaranteed.

  By performing printing so that the individual land 136, the common land 146, and the conductor 141 have the same diameter D1 in S18, the process can be easily performed. Further, by using a conductive paste made of the same material (in this embodiment, Au-based including glass frit) in S18, the process can be performed more easily. And since the process becomes easier in this way, further cost reduction is realized.

  According to the actuator unit 21 according to the first embodiment, since the height H1 of the conductor 141 from the piezoelectric ceramic layer 41 is lower than the height H2 of the individual land 136 and the common land 146, the electric power between the actuator unit 21 and the COF 50 is obtained. Connection is more reliably ensured.

  In the first embodiment described above, only one conductor 141 is formed in the through hole 140. However, the present invention is not limited to this, and a plurality of conductors separated from each other are formed in the through hole 140. It's okay. For example, as shown in FIG. 13, in addition to the conductor 141, a conductor 142 similar to the conductor 141 may be formed in the through hole 140 so as to be symmetric with respect to the conductor 141 with respect to the center of the through hole 140. . By forming a plurality of conductors as in this modification, the connection reliability between the internal common electrode 134 and the surface common electrode 145 is improved.

  Further, in each of the step of fixing the actuator unit 21 to the upper surface of the flow path unit 9 (S3) and the step of bonding the COF 50 to the actuator unit 21 (S4), the pressure distribution is made uniform and good bonding is realized. In view of this, in the modification shown in FIG. 13, the height of the conductors 141 and 142 from the piezoelectric ceramic layer 41 is preferably equal to or less than the height H2 of the individual land 136 and the common land 146. In the example, as described above, the height is lower than H2. Since the conductor 142 is disposed closer to the end of the COF 50, when the height from the piezoelectric ceramic layer 41 is higher than the height H2 of the individual land 136 and the common land 146, the COF 50 is joined. There may be a problem that the vicinity of the end of the COF 50 gets on the conductor 142 and the COF 50 is easily peeled off. On the other hand, in the present modification, the height of the conductor 142 from the piezoelectric ceramic layer 41 is lower than the height H2 of the individual land 136 and the common land 146, and thus the above-described problem is avoided.

  Next, a second embodiment will be described with reference to FIGS. 14 and 15. This embodiment is different from the first embodiment in the configuration of the actuator unit and the manufacturing process thereof, and is otherwise the same as in the first embodiment. Therefore, the same components as those described above are denoted by the same reference numerals and description thereof is omitted.

  In the actuator unit 221 according to the second embodiment, in addition to the through hole 140, another through hole 240 penetrates the surface common electrode 145 and the piezoelectric ceramic layer 41 to the internal common electrode 134 in the same manner as the through hole 140. It is formed to reach. The through hole 240 is smaller than the diameter D <b> 2 of the through hole 140 and has the same diameter D <b> 1 as the common land 146, and is formed approximately in the middle between the through hole 140 and the common land 146. In the present embodiment, the conductor 241 that electrically connects the internal common electrode 134 and the surface common electrode 145 is formed not in the through hole 140 but in the through hole 240. The conductor 241 is formed so as to fill the entire through hole 240, that is, the through hole 240 so that the internal common electrode 134 is not exposed from the through hole 240. As shown in FIG. 15, the height H <b> 1 of the conductor 241 from the piezoelectric ceramic layer 41 is the same as that of the conductor 141 of the first embodiment and is lower than the height H <b> 2 of the common land 146.

  The manufacturing process of the actuator unit 221 according to the second embodiment is different from the first embodiment in S11 and S18 in the actuator manufacturing process according to the first embodiment shown in FIG. Specifically, in this embodiment, in S11, in addition to the through hole 140 having the diameter D2, the through hole 240 having the diameter D1 is further formed in the green sheet to be the piezoelectric ceramic layer 41. In S18, printing of the conductive paste into the through holes 140 is omitted, and individual lands are provided on the extended portions 135b of the individual electrodes 135, the predetermined positions on the surface common electrode 145, and the through holes 240, respectively. 136, the common land 146, and an Au-based conductive paste including glass frit to be the conductor 241 are printed so as to have the same diameter D1.

  As described above, according to the manufacturing method of the actuator unit actuator unit 221 according to the second embodiment, in addition to the effect of the manufacturing method of the actuator unit 21 according to the first embodiment, it is used in the printing process of S18. The effect of preventing the conductive paste from adhering to the surface of the mask 180 (see FIG. 12) facing the piezoelectric ceramic layer 41 is obtained. For example, when the conductor 141 is formed in a non-uniform shape so as to partially protrude from the through hole 140 in the radial direction as in the first embodiment, it faces the piezoelectric ceramic layer 41 in the mask 180. The conductor paste corresponding to the protruding portion is likely to adhere to the surface to be processed. However, when the cylindrical conductor 241 is formed so as to fill the through hole 240 as in the present embodiment, the above-described problems are prevented.

  In addition, according to the actuator unit 221 according to the second embodiment, the same effect as that of the actuator unit 21 according to the first embodiment, that is, the electrical connection between the actuator unit 221 and the COF 50 is ensured. can get.

  In the second embodiment described above, the surface common electrode 145 extends to the formation region of the through hole 140, and the through hole 140 penetrates the surface common electrode 145 and the piezoelectric ceramic layer 41. However, the present invention is not limited to this. . For example, as shown in FIG. 16, a surface common electrode 245 smaller than the surface common electrode 145 may be formed so as to reach the formation region of the through hole 240 but not the formation region of the through hole 140. In this case, the through hole 140 penetrates only the piezoelectric ceramic layer 41, and the through hole 240 penetrates the surface common electrode 245 and the piezoelectric ceramic layer 41. By reducing the surface common electrode 245 as in the modification, it is economically advantageous from the viewpoint of material cost.

  Next, a third embodiment will be described with reference to FIGS. 17 and 18. This embodiment is different from the first embodiment in the configuration of the actuator unit and the manufacturing process thereof, and is otherwise the same as in the first embodiment. Therefore, the same components as those described above are denoted by the same reference numerals and description thereof is omitted.

  In the actuator unit 321 according to the third embodiment, in addition to the through hole 140, another through hole 340 penetrates the surface common electrode 145 and the piezoelectric ceramic layer 41 to the internal common electrode 134 in the same manner as the through hole 140. It is formed to reach. The through hole 340 is smaller than the diameter D2 of the through hole 140 and has the same diameter D1 as the common land 146 of the first embodiment, and is formed at the same position as the common land 146. In the present embodiment, the conductor 346 that electrically connects the internal common electrode 134 and the surface common electrode 145 is formed in the through hole 340 instead of the through hole 140, and the common land 146 is omitted. ing. In other words, the conductor 346 has the functions of the conductors 141 and 241 according to the first and second embodiments and the function of the common land 146, that is, the internal common electrode 134 and the surface common electrode 145. It has a function of being electrically connected and a function of being connected to the terminal 51 of the COF 50. The conductor 346 is formed so as to fill the entire through hole 340, that is, the through hole 340 so that the internal common electrode 134 is not exposed from the through hole 346. As shown in FIG. 18, the height H2 of the conductor 346 from the piezoelectric ceramic layer 41 is the same as the common land 146 of the first embodiment, and is substantially the same as the height (not shown) of the individual land 136. Are the same.

  The manufacturing process of the actuator unit 321 according to the third embodiment is different from the first embodiment in S11 and S18 in the actuator manufacturing process according to the first embodiment shown in FIG. Specifically, in this embodiment, in S11, in addition to the through hole 140 having the diameter D2, the through hole 340 having the diameter D1 is further formed in the green sheet to be the piezoelectric ceramic layer 41. In S18, printing of the conductive paste in the through holes 140 and on the surface common electrode 145 is omitted, and the individual lands 136 and the conductors are respectively formed on the extended portions 135b of the individual electrodes 135 and in the through holes 340, respectively. An Au-based conductive paste containing glass frit 346 is printed so as to have the same diameter D1.

  As described above, according to the manufacturing method of the actuator unit actuator unit 321 according to the third embodiment, in addition to the effect of the manufacturing method of the actuator unit 221 according to the second embodiment, the conductor 346 has the first unit. And since it also has the function of the common land 146 in 2nd Embodiment, the effect that the reduction of material cost and the further reduction of the number of processes is implement | achieved is acquired.

  The actuator unit 321 according to the third embodiment has the same effect as the effect of the actuator unit 21 according to the first embodiment, that is, the effect that the electrical connection between the actuator unit 321 and the COF 50 is ensured. can get. Furthermore, as described above, since the conductor 346 also has the function of the common land 146 in the first and second embodiments, the configuration is simplified and the material cost and the number of processes are reduced. Therefore, the cost can be reduced.

  In the third embodiment described above, the surface common electrode 145 extends to the formation region of the through hole 140, and the through hole 140 penetrates the surface common electrode 145 and the piezoelectric ceramic layer 41. However, the present invention is not limited to this. . For example, as shown in FIG. 19, a surface common electrode 345 smaller than the surface common electrode 145 may be formed so as to reach the formation region of the through hole 340 but not the formation region of the through hole 140. In this case, the through hole 140 penetrates only the piezoelectric ceramic layer 41, and the through hole 340 penetrates the surface common electrode 345 and the piezoelectric ceramic layer 41. In the modification shown in FIG. 16, it is necessary to form the surface common electrode 245 so as to extend to the formation region of the common land 146 in addition to the through hole 240, but in the modification shown in FIG. 19, the formation of the through hole 340 is formed. Since the surface electrode 345 only needs to be formed so as to cover only the region, the surface electrode 345 can be made smaller, which is more economical from the viewpoint of material cost.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various design changes can be made as long as they are described in the claims.

  In the present invention, the land and conductor may be formed in various positions and shapes. For example, as long as the conductor 141 according to the first embodiment is formed in the through hole 140 so as to perform the function of electrically connecting the internal common electrode 134 and the surface common electrode 145, the formation position and shape thereof are various. It may be. That is, the conductor 141 may not be formed at the position farthest from the COF 50 in the through hole 140, and the diameter thereof may not be the same as the diameter of the lands 136 and 146. Further, various materials other than gold including glass frit may be used as the material of the land and the conductor, and the material of the land and the material of the conductor may be different.

  In the modification shown in FIG. 13, the two conductors 141 and 142 are formed in the through hole 140, but three or more conductors may be formed, and the positions of the plurality of conductors are the through holes 140. It is not limited to being symmetrical with respect to the center.

  The configuration of the piezoelectric actuator is not limited to that described above. For example, in the above-described embodiment, the piezoelectric ceramic layer 42 functions as a diaphragm according to the present invention, but a member other than the piezoelectric ceramic layer may be applied as the diaphragm. In addition, the piezoelectric ceramic layer 43 is replaced with a flat plate made of a conductive material, the number of piezoelectric ceramic layers is increased, an internal common electrode is further provided, the number of layers including active portions and the number of inactive layers are set. It may be changed as appropriate.

  In the third embodiment, the through hole 340 and the conductor 346 are such that the height of the conductor 346 from the piezoelectric ceramic layer 41 is different from the individual land 136 from the viewpoint of ensuring the reliability of the electrical connection between the actuator unit 321 and the COF 50. As long as it is substantially the same as the height, the size and shape can be variously changed. For example, the conductor 346 may have a portion filled in the through hole 340 and a portion radially expanded from the center of the through hole 340 on the surface common electrode 145.

  The ink jet head according to the present invention is not limited to a line printer, but can also be applied to a serial printer in which the head reciprocates. Further, the present invention is not limited to a printer, and can be applied to an ink jet facsimile, a copier, and the like.

1 is a schematic side view illustrating an overall configuration of an inkjet printer including an inkjet head according to a first embodiment of the present invention. It is sectional drawing along the width direction of the inkjet head. It is a top view of the head main body contained in an inkjet head. It is an enlarged view of the area | region enclosed with the dashed-dotted line shown in FIG. FIG. 5 is a sectional view taken along line VV shown in FIG. 4. (A) is an enlarged view of the area | region enclosed with the dashed-dotted line shown in FIG. (B) is a top view which shows an individual electrode. FIG. 5 is a plan view of an actuator unit in a region VII surrounded by an alternate long and short dash line shown in FIG. 4. It is the VIII-VIII sectional view taken on the line shown in FIG. It is a flowchart which shows the manufacturing method of an inkjet head. It is a flowchart which shows an actuator unit production process. It is explanatory drawing of the test process in an actuator unit production process. It is explanatory drawing of the printing process in an actuator unit production process. FIG. 9 is a plan view corresponding to FIG. 7 and showing a modification of the actuator unit according to the first embodiment. It is a top view corresponding to Drawing 7 of an actuator unit concerning a 2nd embodiment. It is the XV-XV sectional view taken on the line shown in FIG. FIG. 15 is a plan view corresponding to FIG. 14 and showing a modification of the actuator unit according to the second embodiment. It is a top view corresponding to Drawing 7 of an actuator unit concerning a 3rd embodiment. It is the XVIII-XVIII sectional view taken on the line shown in FIG. FIG. 18 is a plan view corresponding to FIG. 17 and showing a modification of the actuator unit according to the third embodiment.

Explanation of symbols

1 Inkjet head (liquid ejection head)
9 Channel unit 21; 221; 321 Actuator unit (piezoelectric actuator)
41 Piezoelectric ceramic layer 42 Piezoelectric ceramic layer (diaphragm)
50 COF (wiring member)
51 COF terminal (another terminal of the wiring member)
101 Inkjet printer 108 Nozzle 110 Pressure chamber 132 Individual ink flow path (individual liquid flow path)
134 Internal common electrode (first electrode)
135 Individual electrode (second electrode)
136 Individual land (first land; land)
140 Through hole (first through hole)
145; 245; 345 Surface common electrode (third electrode)
146 Common land (second land)
141, 142; 241; 346 Conductor 170 Inspection tool 180 Mask 240; 340 Through hole (second through hole)

Claims (20)

A first electrode is sandwiched between the piezoelectric ceramic layer and the diaphragm laminated thereon, and on the surface of the piezoelectric ceramic layer opposite to the first electrode, the second electrode and the first electrode A laminated body producing step of producing a laminated body formed with a third electrode spaced apart from the second electrode and further having a through-hole that penetrates the piezoelectric ceramic layer and reaches the first electrode;
An inspection step of inspecting the electrical characteristics of the laminate by bringing the inspection tool inserted into the through-hole into contact with the first electrode;
A first land connected to the terminal of the wiring member and a second land connected to another terminal of the wiring member on the second electrode, on the third electrode, and in the through hole. And a printing step of printing a conductive paste to be a conductor connecting the first electrode and the third electrode,
A method of manufacturing a piezoelectric actuator comprising: A first electrode is sandwiched between the piezoelectric ceramic layer and the diaphragm laminated thereon, and on the surface of the piezoelectric ceramic layer opposite to the first electrode, the second electrode and the first electrode A third electrode spaced apart from the second electrode and further spaced from the first through hole and the first through hole so as to penetrate the piezoelectric ceramic layer and reach the first electrode; A laminate manufacturing step of manufacturing a laminate in which a second through hole having a diameter smaller than the diameter of the first through hole is formed;
An inspection step of inspecting the electrical characteristics of the laminate by bringing the inspection tool inserted into the first through-hole into contact with the first electrode;
On the second electrode, on the third electrode, and in the second through hole, a first land connected to a terminal of the wiring member, and a first land connected to another terminal of the wiring member A printing step of printing a conductive paste serving as a conductor connecting the two lands and the first electrode and the third electrode;
A method of manufacturing a piezoelectric actuator comprising:   2. The method of manufacturing a piezoelectric actuator according to claim 1, wherein, in the printing step, the conductive paste serving as the conductor is printed at a position farthest from the wiring member in the through hole.   4. The method of manufacturing a piezoelectric actuator according to claim 1, wherein printing is performed so that the plurality of conductors separated from each other are formed in the printing step.   5. The piezoelectric actuator according to claim 1, wherein in the printing step, printing is performed so that the first land, the second land, and the conductor have the same diameter. Manufacturing method.   6. The printing process according to claim 1, wherein the first land, the second land, and the conductor are printed using a conductive paste made of the same material. A manufacturing method of the piezoelectric actuator described in 1. A first electrode is sandwiched between the piezoelectric ceramic layer and the diaphragm laminated thereon, and on the surface of the piezoelectric ceramic layer opposite to the first electrode, the second electrode and the first electrode A third electrode spaced apart from the second electrode and further spaced from the first through hole and the first through hole so as to penetrate the piezoelectric ceramic layer and reach the first electrode; A laminate manufacturing step of manufacturing a laminate in which a second through hole having a diameter smaller than the diameter of the first through hole is formed;
An inspection step of inspecting the electrical characteristics of the laminate by bringing the inspection tool inserted into the first through-hole into contact with the first electrode;
On the second electrode and in the second through hole, the land connected to the terminal of the wiring member, the first electrode and the third electrode are connected, and the wiring member A printing step of printing a conductive paste that becomes a conductor connected to another terminal;
A method of manufacturing a piezoelectric actuator comprising:   8. The method of manufacturing a piezoelectric actuator according to claim 7, wherein printing is performed so that the land and the conductor have the same diameter in the printing step.   The method for manufacturing a piezoelectric actuator according to claim 7 or 8, wherein, in the printing step, the land and the conductor are printed using a conductive paste made of the same material. Producing a flow path unit in which a plurality of individual liquid flow paths including a nozzle and a pressure chamber are formed, and a plurality of the pressure chambers open on the surface;
10. The method according to claim 1, wherein the piezoelectric ceramic layer extends over the plurality of pressure chambers on the surface of the flow path unit, and the second electrode corresponds to the pressure chambers. Arranging the piezoelectric actuator manufactured by the manufacturing method described above;
Connecting a terminal of a wiring member to the second electrode and the third electrode of the piezoelectric actuator;
A method of manufacturing a liquid ejection head, comprising: A piezoelectric ceramic layer;
A diaphragm laminated on the piezoelectric ceramic layer;
A first electrode disposed between the piezoelectric ceramic layer and the diaphragm;
A second electrode formed on a surface of the piezoelectric ceramic layer opposite to the first electrode;
A third electrode formed on the surface of the piezoelectric ceramic layer to be separated from the second electrode;
A through-hole penetrating the third electrode and the piezoelectric ceramic layer so that the first electrode is exposed;
A first land connected to a terminal of the wiring member formed on the second electrode so as to have a diameter smaller than the diameter of the through hole;
The second electrode connected to another terminal of the wiring member, which is formed on the third electrode so as to have a diameter smaller than the diameter of the through hole and to be the same height as the first land. The land of
The first electrode is formed in the through hole so as to contact only a part of the region exposed from the through hole and to have a height from the piezoelectric ceramic layer equal to or lower than the first and second lands. A conductor connecting the first electrode and the third electrode;
A piezoelectric actuator comprising: A piezoelectric ceramic layer;
A diaphragm laminated on the piezoelectric ceramic layer;
A first electrode disposed between the piezoelectric ceramic layer and the diaphragm;
A second electrode formed on a surface of the piezoelectric ceramic layer opposite to the first electrode;
A third electrode formed on the surface of the piezoelectric ceramic layer to be separated from the second electrode;
A first through hole penetrating the piezoelectric ceramic layer so that the first electrode is exposed;
A second through-hole penetrating the piezoelectric ceramic layer so as to expose the first electrode, spaced from the first through-hole, and having a diameter smaller than the diameter of the first through-hole; ,
A first land connected to a terminal of the wiring member formed on the second electrode so as to have a diameter smaller than a diameter of the first through hole;
On the third electrode, connected to another terminal of the wiring member having a diameter smaller than that of the first through hole and having the same height as the first land. The second land,
A conductor connecting the first electrode and the third electrode formed in the second through-hole so that the height from the piezoelectric ceramic layer is equal to or less than the first and second lands. When,
A piezoelectric actuator comprising:   The piezoelectric actuator according to claim 11, wherein the conductor is formed at a position farthest from the wiring member in the through hole.   The piezoelectric actuator according to claim 11, comprising a plurality of the conductors separated from each other.   The piezoelectric actuator according to claim 11, wherein the first land, the second land, and the conductor have the same diameter.   The piezoelectric actuator according to claim 11, wherein the first land, the second land, and the conductor are made of the same material. A piezoelectric ceramic layer;
A diaphragm laminated on the piezoelectric ceramic layer;
A first electrode disposed between the piezoelectric ceramic layer and the diaphragm;
A second electrode formed on a surface of the piezoelectric ceramic layer opposite to the first electrode;
A third electrode formed on the surface of the piezoelectric ceramic layer to be separated from the second electrode;
A first through hole penetrating the piezoelectric ceramic layer so that the first electrode is exposed;
The third electrode and the piezoelectric ceramic layer penetrate through the third electrode so that the first electrode is exposed, are spaced apart from the first through hole, and have a smaller diameter than the first through hole. Two through holes,
A land connected to the terminal of the wiring member, formed on the second electrode so as to have a diameter smaller than the diameter of the first through hole,
The first electrode and the third electrode, which are formed in the second through-hole so that the height from the piezoelectric ceramic layer is the same as the land, are connected, and the wiring member is separated A conductor connected to the terminal of
A piezoelectric actuator comprising:   The piezoelectric actuator according to claim 17, wherein the land and the conductor have the same diameter.   The piezoelectric actuator according to claim 17 or 18, wherein the land and the conductor are made of the same material. A plurality of individual liquid channels including nozzles and pressure chambers, and a plurality of the pressure chambers opened on the surface;
20. The device according to claim 11, wherein the piezoelectric ceramic layer is disposed on the surface of the flow path unit so as to straddle the plurality of pressure chambers, and the second electrode corresponds to the pressure chambers. The piezoelectric actuator according to the paragraph,
A wiring member connected to the second electrode and the third electrode of the piezoelectric actuator;
A liquid discharge head comprising:

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