JP4867252B2 - LAMINATE MANUFACTURING METHOD AND INK JET HEAD MANUFACTURING METHOD - Google Patents

Description

  The present invention relates to a method of manufacturing a laminate by joining a plurality of stacked metal plates by diffusion bonding, and a method of manufacturing an inkjet head.

  Conventionally, metal diffusion bonding (hereinafter referred to as diffusion bonding), in which a plurality of laminated metal plates are heated while being pressed to join the plurality of metal plates, is generally used in various fields. It has been. For example, Patent Document 1 discloses that a flow path unit of an inkjet head having an ink flow path therein is manufactured by bonding a plurality of stacked plates by diffusion bonding.

JP 2004-136462 A (FIGS. 1 to 5)

  By the way, a manufacturer that manufactures an ink jet head needs to manufacture (mass production) a large number of laminates obtained by diffusion bonding a metal plate assembly including a plurality of metal plates. In such a case, if one laminated body is manufactured by performing diffusion bonding once for each set of metal plates, the manufacturing efficiency is low and the manufacturing cost is increased. For this reason, a technique for efficiently mass-producing metal plate assemblies by diffusion bonding is required.

  An object of the present invention is to manufacture a plurality of laminated bodies at a time by collectively diffusion-bonding metal plates of a plurality of metal plate sets without causing diffusion bonding between two metal plates belonging to different metal plate sets. It is providing the manufacturing method of the laminated body which can do, and the manufacturing method of an inkjet head.

Means for Solving the Problems and Effects of the Invention

According to the first aspect of the present invention, there is provided a method for producing a plurality of laminates obtained by joining a plurality of metal plate assemblies by diffusion bonding, wherein the plurality of metal plates of each metal plate assembly A first step of forming an insulating ceramic layer on a surface of a metal plate forming a predetermined surface of the laminate, and a plurality of the metal plate groups are stacked via the insulating ceramic layer. A second step and a third step of heating the plurality of stacked metal plate sets and simultaneously bonding a plurality of metal plates belonging to the plurality of metal plate sets by diffusion bonding , In 3 processes, the manufacturing method of the laminated body which complete | finishes a heating is performed before joining between the two metal plates which are each laminated | stacked through the said insulating ceramic layer and belong to a different metal plate group is provided.

  In order to manufacture a plurality of laminated bodies at once, if a plurality of metal plate sets are laminated as they are and diffusion bonding is performed, bonding is also performed between two metal plates belonging to different metal plate sets. Therefore, it is necessary to devise such as stacking a plurality of metal plate sets by interposing a plate or the like for preventing diffusion bonding between two metal plates belonging to different metal plate sets. In this case, a plate for preventing diffusion bonding must be prepared separately, and an additional step of interposing this plate between a plurality of metal plate sets is necessary, resulting in high manufacturing costs. turn into. Therefore, the method for manufacturing a laminate of the present invention is a method used when manufacturing a plurality of laminates obtained by diffusion bonding a metal plate assembly having a plurality of metal plates. In the method of the present invention, an insulating ceramic layer is formed on the surface of one of the metal plates of each metal plate set (first step), and a plurality of sets of metal plate sets are interposed via the insulating ceramic layer. Are laminated (second step), and diffusion bonding is performed collectively on the plurality of laminated metal plate sets (third step). Therefore, a plurality of laminated bodies can be manufactured at a time, and the manufacturing process can be shortened. In addition, the diffusion of atoms in the ceramic material is much slower than the diffusion of atoms in the metal. Therefore, when multiple metal plates belonging to the same metal plate assembly are joined, the insulating ceramic layer and the metal plate Diffusion does not progress between them as much as they are joined. Therefore, by laminating through the insulating ceramic layer, it is possible to suppress the diffusion of atoms between two metal plates belonging to different metal plate sets, so that a plurality of sets of metal plate sets can be formed before diffusion bonding. There is no need to interpose a diffusion bonding prevention plate or the like between them. That is, according to the laminate manufacturing method of the present invention, in the third step, a plurality of metal plates belonging to the plurality of sets of metal plates are laminated with two metals laminated via the insulating ceramic layer. Bonding can be performed simultaneously by diffusion bonding except between the plates.

  In the present application, the term “insulating ceramics” means ceramics having insulating properties, and includes ceramics having other functions in addition to insulating properties, such as “piezoelectric ceramics” and “water-repellent ceramics”. In particular, the ceramic materials exemplified in Tables 1 and 2 are included in the “insulating ceramics”.

  According to the method for manufacturing a laminate of the present invention, in the first step, the insulating ceramic material powder is sprayed toward the predetermined surface of the laminate and deposited by an aerosol deposition method. A functional ceramic layer may be formed. In this case, the insulating ceramic layer can be formed more easily.

  According to the laminate manufacturing method of the present invention, the laminate is a metal substrate on which an electronic component is mounted, and the insulating ceramic layer includes a wiring portion connected to the electronic component and the metal substrate. An insulating ceramic layer for insulation may be used. When the laminate of a plurality of metal plates is a metal substrate on which electronic components are mounted, a wiring portion is formed on the surface of the insulating ceramic layer formed for diffusion bonding in the first step described above. Thus, the insulating ceramic layer can insulate between the wiring portion and the metal substrate.

  According to the laminate manufacturing method of the present invention, before the second step, at least one of the plurality of metal plates belonging to the metal plate set is formed with a hole or groove for flowing a liquid. Also good. Therefore, the heat generated in the electronic component is transferred from the insulating ceramic layer to the metal plate, and further transferred to the liquid flowing through the holes or grooves formed in the metal plate. And since heat is transferred to the place away from the electronic component by this liquid, heat can be dissipated efficiently.

According to the second aspect of the present invention, a flow path unit having a laminate of a plurality of metal plates that forms an ink flow path including a plurality of pressure chambers communicating with a nozzle, and a volume of the pressure chamber are changed. An insulating ceramic layer forming step of forming an insulating ceramic layer on an outermost metal plate constituting an outermost layer of a laminate of the plurality of metal plates, comprising: manufacturing a plurality of inkjet heads including piezoelectric actuators; A lamination step of laminating a plurality of metal plate sets of a plurality of metal plates constituting the laminated body through the insulating ceramic layer, and heating the plurality of metal plate groups laminated, a plurality of said metal plate belonging to a plurality of sets of metal plates set, and a bonding step of bonding simultaneously by diffusion bonding, in the bonding step, are stacked via the insulating ceramic layer, different Before joining of two metal plates belonging respectively to the genus plate assembly is made, the manufacturing method of the ink jet head to terminate the heating is provided.

  In this inkjet head manufacturing method, an insulating ceramic layer is formed on the outermost metal plate in a metal plate assembly having a plurality of stacked metal plates constituting a flow path unit (insulating ceramic layer forming step). Then, a plurality of sets of metal plates are stacked via an insulating ceramic layer (stacking step), and diffusion bonding is performed collectively on the plurality of sets of stacked metal plates (bonding step). Therefore, a plurality of laminated bodies having flow path units can be manufactured at a time, and the manufacturing process can be shortened. That is, according to the method for manufacturing an ink jet head of the present invention, in the joining step, a plurality of the metal plates can be joined simultaneously by diffusion joining except for the space between the metal plates laminated via the insulating ceramic layer. it can. At this time, since the two metal plates laminated via the insulating ceramic layer are not diffusion bonded, it is necessary to interpose a plate for preventing diffusion bonding between the plurality of metal plate sets before diffusion bonding. Absent.

  According to the inkjet head manufacturing method of the present invention, the outermost metal plate is a diaphragm that covers the pressure chamber, and the inkjet head includes a piezoelectric layer disposed on the opposite side of the diaphragm to the pressure chamber. May be. In this case, since the metal plate assembly including the diaphragm is laminated via the insulating ceramic layer formed on one surface of the diaphragm, the diaphragm can be joined at the same time during diffusion bonding. The manufacturing process can be shortened.

  According to the inkjet head manufacturing method of the present invention, the individual electrode forming step of forming a plurality of individual electrodes on the surface of the insulating ceramic layer opposite to the pressure chambers at positions facing the plurality of pressure chambers. And forming a piezoelectric layer on the surface of the insulating ceramic layer on which the individual electrodes are formed, and forming a common electrode on the surface of the piezoelectric layer opposite to the individual electrodes. And a process. Therefore, by forming individual electrodes on the surface of the insulating ceramic layer formed for diffusion bonding in the above-described insulating ceramic layer forming step, the insulating ceramic layer is formed between the individual electrodes and the metal diaphragm. Can be insulated.

  According to the inkjet head manufacturing method of the present invention, the outermost metal plate may be a nozzle plate. When the nozzle plate is made of metal, the nozzle plate can be bonded at the same time at the time of diffusion bonding, so that the manufacturing process can be shortened. In order to prevent ink from adhering to the nozzle, when a water-repellent ceramic layer such as water-repellent zirconia is provided on the surface of the nozzle plate, diffusion bonding can be performed through the water-repellent ceramic.

  According to the inkjet head manufacturing method of the present invention, the outermost metal plate may include a vibration plate and a nozzle plate. In this case, since an insulating ceramic layer is formed on both the vibration plate and the nozzle plate, diffusion bonding according to the present invention is performed regardless of the orientation of each metal plate set when laminating a plurality of metal plate sets. Therefore, the lamination process is further simplified.

  According to the method for manufacturing an ink jet head of the present invention, the insulating ceramic layer may be formed of alumina or zirconia having excellent insulating characteristics.

  According to the method for manufacturing an inkjet head of the present invention, the piezoelectric actuator may have a piezoelectric layer, and the insulating ceramic layer may be the piezoelectric layer. In this case, since a plurality of metal plate sets are laminated via the piezoelectric layer, the piezoelectric layer not only functions as an original function of the piezoelectric actuator but also prevents the bonding between the plurality of metal plate sets during diffusion bonding. Also have. Accordingly, the manufacturing process of the ink jet head can be shortened. In particular, the piezoelectric layer usually requires a sintering and annealing process. However, according to the present invention, the metal plate assembly is heated in the joining process, so that the piezoelectric layer is also sintered and annealed. Therefore, the sintering and annealing processes of the piezoelectric layer can be omitted, the manufacturing process can be shortened and energy can be saved.

  According to the method of manufacturing an ink jet head of the present invention, the diaphragm may be a common electrode. In this case, the step of forming the common electrode can be omitted.

  According to the inkjet head manufacturing method of the present invention, the outermost metal plate has a diaphragm, and the insulating ceramic layer is one of an aerosol deposition method, a sol-gel method, and a sputtering method following the joining step. You may have the process formed in one surface of the said diaphragm by two methods. In particular, when the insulating ceramic layer is a piezoelectric layer, the piezoelectric layer can be annealed at an optimum temperature and time according to the thickness of the piezoelectric layer.

<First Embodiment>
A first embodiment of the present invention will be described. The first embodiment is an example in which the present invention is applied to the manufacture of an inkjet head that ejects ink.

  First, the inkjet head 1 will be described with reference to FIGS. In the following description, the vertical direction in FIG. 1 is defined as the vertical direction. As shown in FIG. 1, the ink jet head 1 includes a rectangular flow path unit 2 having an ink flow path formed therein and a piezoelectric actuator 3 stacked on the upper surface of the flow path unit 2.

  As shown in FIGS. 2 to 4, the flow path unit 2 includes a cavity plate 10, a base plate 11, a manifold plate 12, and a nozzle plate 13, and these four plates 10 to 13 are joined in a stacked state. Among these, the cavity plate 10, the base plate 11, and the manifold plate 12 are substantially rectangular metal (for example, stainless steel) plates, and these three plates 10 to 12 include a manifold 17 and a pressure chamber 14 described later. Holes for forming the ink flow paths are provided. These holes can be easily formed by etching since the plates 10 to 12 are made of metal. The nozzle plate 13 is formed of, for example, a polymer synthetic resin material such as polyimide, and is bonded to the lower surface of the manifold plate 12.

  As shown in FIG. 2, the cavity plate (pressure chamber forming plate) 10 has a plurality of pressure chambers 14 arranged along a plane. The plurality of pressure chambers 14 are open on the surface of the flow path unit 2 (the upper surface of the cavity plate 10 to which a diaphragm 30 described later is joined). FIG. 2 shows some (eight) of the plurality of pressure chambers 14. Each pressure chamber 14 is formed in a substantially elliptical shape in plan view, and is arranged so that the major axis direction thereof is parallel to the longitudinal direction of the cavity plate 10.

  Communication holes 15 and 16 are formed at positions overlapping the both ends in the long axis direction of the pressure chamber 14 in plan view of the base plate 11, respectively. The manifold plate 12 is formed with a manifold 17 extending in two rows in the short direction (vertical direction in FIG. 2) and overlapping the right half of the pressure chamber 14 in FIG. Ink is supplied to the manifold 17 from an ink tank (not shown) through an ink supply port 18 formed in the cavity plate 10. A communication hole 19 is also formed at a position overlapping the left end of the pressure chamber 14 in FIG. Further, the nozzle plate 13 is formed with a plurality of nozzles 20 at positions overlapping the left end portions of the plurality of pressure chambers 14 in plan view. The nozzle 20 is formed, for example, by performing excimer laser processing on a polymer synthetic resin substrate such as polyimide.

  As shown in FIG. 3, the manifold 17 communicates with the pressure chamber 14 through the communication hole 15, and the pressure chamber 14 communicates with the nozzle 20 through the communication holes 16 and 19. As described above, an individual ink flow path from the manifold 17 to the nozzle 20 through the pressure chamber 14 is formed in the flow path unit 2.

  Next, the piezoelectric actuator 3 will be described. As shown in FIGS. 1 to 4, the piezoelectric actuator 3 includes a vibration plate 30 disposed on the upper surface of the flow path unit 2 so as to cover the plurality of pressure chambers 14, and an insulation formed on the upper surface of the vibration plate 30. A ceramic layer 31, a plurality of individual electrodes 32 formed on the top surface of the insulating ceramic layer 31 at positions facing the plurality of pressure chambers 14, and a piezoelectric layer formed on the top surface of the insulating ceramic layer 31. 33 and a common electrode 34 formed on the upper surface of the piezoelectric layer 33. As described above, since the diaphragm 30 covers the pressure chamber 14 and defines the flow path of the flow path unit 2, the vibration board 30 may be regarded as a part of the flow path unit 2.

  The diaphragm 30 is a substantially rectangular metal plate (for example, stainless steel) in plan view, and the diaphragm 30 is laminated on the upper surface of the cavity plate 10 so as to close the plurality of pressure chambers 14. It is joined in a state. An insulating ceramic layer 31 made of a ceramic material having high insulation resistance such as alumina is formed on the surface of the diaphragm 30. Table 1 shows examples of ceramic materials that can be used to form the insulating ceramic layer 31 and their volume resistance values. The material of the insulating ceramic layer in the present invention is not limited to the materials shown in Table 1, but examples of suitable materials for the insulating ceramic layer of the inkjet head of the present invention include alumina and zirconia.

  As will be described later, the insulating ceramic layer 31 includes a plurality of sets of metal plates each having four plates (cavity plate 10, base plate 11, manifold plate 12, and diaphragm 30) constituting the inkjet head 1. It is formed for diffusion bonding, and it also serves to electrically insulate the individual electrode 32 and the wiring portion 35 and the diaphragm 30 formed on the upper side of the diaphragm 30 from each other. Have. In addition, as a ceramic material which comprises the insulating ceramic layer 31, it is preferable to use a thing with a high elastic modulus, In that case, the rigidity of the piezoelectric actuator 3 increases and responsiveness becomes higher.

  A plurality of individual electrodes 32 having an elliptical planar shape that is slightly smaller than the pressure chamber 14 are formed on the surface of the insulating ceramic layer 31. The individual electrode 32 is formed at a position overlapping the central portion of the corresponding pressure chamber 14 in plan view. The individual electrode 32 is made of a conductive material such as gold. The individual electrodes 32 are electrically insulated from the conductive metal diaphragm 30 and other adjacent individual electrodes 32 by the insulating ceramic layer 31.

  On the upper surface of the insulating ceramic layer 31, a plurality of wiring portions 35 extend in parallel with the long axis direction of the individual electrode 32 from one end portion (the right end portion in FIG. 2) of the plurality of individual electrodes 32. A terminal portion 36 is formed at each end of the plurality of wiring portions 35. The wiring portion 35 is also electrically insulated from the diaphragm 30 and other adjacent wiring portions 35 by the insulating ceramic layer 31 as in the case of the individual electrode 32 described above. An output terminal 37a of a driver IC 37 that selectively supplies a drive voltage to the plurality of individual electrodes 32 is formed on a plurality of terminal portions 36 respectively corresponding to the plurality of individual electrodes 32 from a conductive brazing material such as solder. The driver IC 37 is disposed on the upper surface of the insulating ceramic layer 31. Thus, a wiring member such as a flexible printed circuit board (FPC) having a high cost is obtained by connecting the plurality of individual electrodes 32 and the driver IC 37 to the wiring section 35 formed on the same plane as the individual electrodes 32. Therefore, the cost of electrical connection between the individual electrode 32 and the driver IC 37 can be reduced, and the reliability of this electrical connection is increased.

  Furthermore, a plurality of connection terminals 40 that are joined to the input terminals 37 b of the driver IC 37 are also formed on the insulating ceramic layer 31. The plurality of connection terminals 40 and the input terminals 37b of the driver IC 37 are joined to each other via bumps made of solder or the like, so that the driver IC 37 and a control device (not shown) for controlling the driver IC 37 are connected to the connection terminals. 40 can be easily connected.

  On the surface of the plurality of individual electrodes 32, a piezoelectric layer 33 mainly composed of lead zirconate titanate (PZT), which is a solid solution and is a ferroelectric substance, of lead titanate and lead zirconate is formed. The piezoelectric layer 33 is formed as one continuous layer over all of the plurality of individual electrodes 32 so as to cover the entire surface of the plurality of individual electrodes 32. Further, a common electrode 34 common to the plurality of individual electrodes 32 is formed on the entire surface of the piezoelectric layer 33 on the upper surface of the piezoelectric layer 33. The common electrode 34 is also made of a conductive material such as gold, like the individual electrode 32. As shown in FIG. 2, one wiring part 41 extends from the common electrode 34 over the upper surface of the piezoelectric layer 33 and the upper surface of the insulating ceramic layer 31, and this wiring part 41 is connected to the driver IC 37. It is electrically connected to a terminal (not shown). The common electrode 34 is grounded via the wiring portion 41 and the driver IC 37 and is held at the ground potential.

  Next, the operation of the piezoelectric actuator 3 during ink ejection will be described. When a driving voltage is selectively supplied from the driver IC 37 to the plurality of individual electrodes 32 via the wiring part 35, the individual electrodes 32 below the piezoelectric layer 33 to which the driving voltage is supplied are held at the ground potential. The potential of the common electrode 34 on the upper side of the piezoelectric layer 33 is different, and an electric field in the vertical direction is generated in the piezoelectric layer 33 sandwiched between the electrodes 32 and 34. Then, a portion of the piezoelectric layer 33 immediately above the individual electrode 32 to which the drive voltage is applied contracts in a horizontal direction orthogonal to the vertical direction that is the polarization direction. Here, since the lower vibration plate 30 of the piezoelectric layer 33 is fixed to the cavity plate 10, the portion of the piezoelectric layer 33 sandwiched between the electrodes 32 and 34 protrudes toward the pressure chamber 14. As the piezoelectric layer 33 is partially deformed, the portion of the diaphragm 30 that covers the pressure chamber 14 is also deformed so as to protrude toward the pressure chamber 14. Then, since the volume in the pressure chamber 14 decreases, the pressure of the ink increases, and ink is ejected from the nozzle 20 communicating with the pressure chamber 14.

  Next, the manufacturing method of the inkjet head 1 demonstrated above is demonstrated. As shown in FIG. 5, first, an insulating ceramic layer 31 is formed on one surface of the diaphragm 30 (insulating ceramic layer forming step). Here, by using an aerosol deposition method (AD method) in which powder of an insulating ceramic material is sprayed and deposited toward a predetermined surface of the diaphragm 30, the insulating ceramic layer 31 is easily formed. be able to. In addition, the insulating ceramic layer 31 may be formed by a sol-gel method or a sputtering method.

  Next, as shown in FIG. 6, the cavity plate 10, the base plate 11, the manifold plate 12, and the vibration plate 30 that constitute the flow path unit 2 in which holes for forming the ink flow paths are provided in advance. Then, the vibration plate 30 is laminated so that the surface opposite to the surface on which the insulating ceramic layer 31 is formed is in contact with the upper surface of the cavity plate 10. Further, a plurality of sets (for example, three sets) of the plate sets 50 having these four metal plates are laminated via the insulating ceramic layer 31, and the insulating ceramics formed on the diaphragm 30 belonging to the plate set 50. The manifold plate 12 of another plate set 50 is laminated on the surface of the layer 31 (lamination process).

  Then, the plurality of plate sets 50 stacked in this way are sandwiched between a pair of upper and lower plate-shaped jigs 51, and heated to about 1000 ° C. while pressing the plurality of plate sets 50 through the jigs 51. Then, the four plates (the cavity plate 10, the base plate 11, the manifold plate 12, and the vibration plate 30) belonging to each of the plurality of plate sets 50 are joined by diffusion joining (joining process). An area where pressure can be uniformly applied by sandwiching the jig 51 between a pair of upper and lower plates is called a joining work space, and usually has a width, depth and height of about several tens of centimeters. On the other hand, the size of the flow path unit of the ink jet head is usually about several tens of millimeters square and the thickness is about several millimeters. Therefore, a plurality of plate sets or modules incorporating a plurality of plate sets can be arranged on a plane at the same time in the bonding work space of the jig 51, and these can be stacked in layers. In this way, a large number of plate sets can be diffusion-bonded at the same time. As described above, diffusion bonding is performed in a state in which a plurality of sets of plates 50 are stacked via the insulating ceramic layer 31 for each plate set 50. At this time, diffusion of atoms in the ceramic material is caused in the metal. Therefore, when four plates belonging to the same plate set 50 are joined, the insulating ceramic layer 31 and the manifold plate 12 of another plate set 50 are not connected to each other. Diffusion does not proceed to the extent that is bonded. Accordingly, when four plates belonging to the same plate set 50 are joined, if the pressurization and heating by the jig 51 are immediately terminated, they belong to different plate sets 50 and are laminated via the insulating ceramic layer 31. In addition, the two plates (the vibration plate 30 and the manifold plate 12) are not joined.

  Next, the individual electrode 32, the piezoelectric layer 33, and the common electrode 34 are respectively applied to each of the plurality of laminated bodies obtained by joining the cavity plate 10, the base plate 11, the manifold plate 12, and the vibration plate 30 in the joining step. And so on. That is, as shown in FIG. 7, the individual electrode 32, the wiring part 35, the terminal part 36, and the connection terminal 40 are also formed on the surface of the insulating ceramic layer 31 (individual electrode forming step). At this time, for example, the individual electrode 32, the wiring part 35, the terminal part 36, and the connection terminal 40 that are patterned by screen printing a conductive paste on the surface of the insulating ceramic layer 31 can be formed at a time. Alternatively, after forming a conductive layer on the entire surface of the insulating ceramic layer 31 by plating, sputtering, vapor deposition, or the like, the conductive layer is partially removed by a laser, mask, resist method, or the like, and the individual electrodes 32 are removed. The wiring part 35, the terminal part 36, and the connection terminal 40 may be patterned.

  Next, as shown in FIG. 8, the piezoelectric layer 33 is formed on the surface of the individual electrode 32 by using an aerosol deposition method, a sol-gel method, a sputtering method, or the like (piezoelectric layer forming step). In order to promote crystal growth of the structure, heat treatment at about 600 ° C. is performed. Furthermore, as shown in FIG. 9, the common electrode 34 and the wiring part 41 (see FIG. 2) are formed on the entire surface of the piezoelectric layer 33 by using screen printing, vapor deposition, sputtering, or the like (common electrode). Forming step).

  Then, as shown in FIG. 10, a driver IC 37 is arranged on the insulating ceramic layer 31, and the output terminal 37a of the driver IC 37 is joined to the terminal part 36 of the wiring part 35, and the input terminal 37b of the driver IC 37 is connected. Bonded to the terminal 40. Finally, as shown in FIG. 11, the nozzle plate 13 is bonded to the lower surface of the manifold plate 12.

  In the case where the nozzle plate 13 is formed of a polymer synthetic resin material having a low heat resistance temperature such as polyimide, as described above, the four metal plates are first bonded by diffusion bonding, and then the nozzle plate 13 13 is required to be joined to the manifold plate 12, but when the nozzle plate 13 is formed of a metal material such as stainless steel, the nozzle plate 13 is also connected to the cavity plate 10 and the base plate 11 in the joining step of FIG. The manifold plate 12 and the diaphragm 30 can be joined together by diffusion joining.

  According to the method for manufacturing the inkjet head 1 described above, the following effects can be obtained. A plurality of plate sets 50 made of four metal plates, the cavity plate 10, the base plate 11, the manifold plate 12, and the vibration plate 30, are stacked via an insulating ceramic layer 31 formed on the vibration plate 30. Since diffusion bonding is performed collectively on the set of plates 50, a plurality of laminated bodies including the flow path unit and the diaphragm 30 can be manufactured at a time, and the manufacturing process can be shortened. At this time, since the manifold plate 12 and the diaphragm 30 belonging to the two different plate sets 50 are laminated via the insulating ceramic layer 31, the two plates are joined together by the insulating ceramic. It can be prevented by the layer 31, and it is not necessary to interpose a plate for preventing diffusion bonding between the plurality of plate sets 50 before diffusion bonding.

  In addition, since the plurality of individual electrodes 32 and the plurality of wiring portions 35 are formed on the surface of the insulating ceramic layer 31 formed to collectively diffuse and bond the plurality of plate sets 50, the insulating ceramics The layer 31 can electrically insulate the individual electrode 32 and the wiring part 35 from the conductive diaphragm 30 and other adjacent individual electrode 32 and wiring part 35. Furthermore, since the driver IC 37 can be arranged on the surface of the insulating ceramic layer 31, the plurality of individual electrodes 32 and the driver IC 37 can be directly connected by the wiring portion 35 formed on the same plane as the individual electrodes 32. By omitting wiring members such as FPC, the manufacturing cost of the inkjet head 1 can be reduced.

<Second Embodiment>
Next, a second embodiment of the present invention will be described with reference to FIGS. In the present embodiment, a metal nozzle plate 13a is provided on the lower surface of the manifold plate 12, a water repellent ceramic layer 13b as an insulating ceramic layer is formed on one surface, and a plate set is laminated via the water repellent ceramic layer 13b. And diffusion bonding.

  As shown in FIG. 19, the water-repellent zirconia water-repellent ceramic layer 13b is formed on the lower surface (ink ejection side by the nozzle) of the metal nozzle plate 13a in which the nozzles 20 that are through holes are formed by using the AD method. (Insulating ceramic layer forming step). Next, as shown in FIG. 20, the vibration plate 30, the cavity plate 10, the base plate 11, the manifold plate 12, and the five metal plates of the nozzle plate 13 a having the water repellent ceramic layer 13 b formed on the lower surface are stacked. A set 50a is formed. At this time, the water repellent ceramic layer 13b is incorporated into the plate set 50a so as to be the outermost surface of the plate set 50a. A plurality (three in this case) of plate sets 50a having such a structure are prepared and stacked as shown in FIG. That is, the plurality of sets 50a are stacked so that the water repellent ceramic layer 13b formed on the lower surface of the nozzle plate 13 of the uppermost plate set 50a and the diaphragm 30 of the center plate set 50a abut. Further, the central plate set 50a and the lowermost plate set 50a are laminated in the same manner (lamination process).

  Five plates (vibrating plate 30, cavity plate) belonging to each plate set 50a are heated by about 1000 ° C. while simultaneously pressing a plurality of plate sets 50a through a jig 51 on a pair of upper and lower plates. 10, the base plate 11, the manifold plate 12, and the nozzle plate 13a) are joined by diffusion joining (joining process). At this time, since these plate sets 50a are laminated with the water-repellent ceramic layer 13b interposed therebetween, the plate sets 50a are not joined to each other.

  Next, as shown in FIG. 21, by using an aerosol deposition method (AD method) in which powder of an insulating ceramic material is sprayed and deposited on a predetermined surface of a metal plate, An insulating ceramic layer 31 is formed on the upper surface.

  Subsequent steps, that is, a step of forming the individual electrode 32, the wiring portion 35, the terminal portion 36 and the connection terminal 40 on the surface of the insulating ceramic layer 31 (individual electrode forming step), and the piezoelectric layer 33 on the surface of the individual electrode 32. Forming using aerosol deposition (AD) method, sol-gel method, sputtering method, etc. (piezoelectric layer forming step), screen printing, vapor deposition method, sputtering method, etc. on the entire surface of the piezoelectric layer 33 The step of forming the common electrode 34 and the wiring portion 41 using the same (common electrode forming step) is the same as in the first embodiment. Further, the driver IC 37 is disposed on the insulating ceramic layer 31, and the terminal of the driver IC 37 and the connection terminal are joined in the same manner as in the first embodiment, whereby the inkjet head 1 is manufactured.

  In the present embodiment, since the metal nozzle plate 13a is also included in the plate set 50a, there is an advantage that the metal members constituting the inkjet head can be joined by a single joining process. When the metal nozzle plate 13a is used as in this embodiment, it is desirable that the surface be water-repellent to prevent ink adhesion. Therefore, in the present embodiment, the water-repellent zirconia water-repellent ceramic layer 13b is formed on the surface of the nozzle plate 13a, and the diffusion bonding according to the present invention can be performed through the layer. Here, the water-repellent ceramic layer 13b and the insulating ceramic layer 31 may be formed by a method other than the aerosol deposition method (AD method), for example, a sol-gel method or a sputtering method. In this embodiment, the insulating ceramic layer 31 is formed on the upper surface of the vibration plate 30 after the bonding step. However, the insulating ceramic layer 31 is formed on the upper surface of the vibration plate 30 before the bonding step as in the first embodiment. May be. In this case, the plate set 50 a has two ceramic layers, a water repellent ceramic layer 13 b and an insulating ceramic layer 31. Therefore, it is not necessary to consider the orientation of the plate sets 50a that are in contact with each other during diffusion bonding.

<Third Embodiment>
A third embodiment of the present invention will be described with reference to FIGS. In the present embodiment, an ink jet head is manufactured in the same manner as in the second embodiment, except that the piezoelectric layer is formed directly on the diaphragm without using an insulating ceramic layer.

  After performing the joining process shown in FIG. 20 in the same manner as in the second embodiment, the aerosol deposition method (AD method), sol-gel method, or sputtering method is used on the upper surface of the diaphragm 30 in FIG. 22A. A piezoelectric ceramic layer (piezoelectric layer) 33a mainly composed of lead zirconate titanate (PZT) as shown is formed. Next, a heat treatment at about 600 ° C. is performed in order to promote crystal growth of the PZT structure of the piezoelectric layer 33a. Thereafter, individual electrodes 32a are formed on the surface of the piezoelectric layer 33a as shown in FIG. 22B by a printing method (individual electrode formation step). As a printing method, a screen printing method, a vapor deposition method, or a sputtering method can be used.

  Next, as shown in FIG. 22C, an individual head 32a formed on the piezoelectric layer 33a and a terminal of a driver IC (not shown) are connected using a TAB (Tape Automated Bonding) 38 to manufacture an ink jet head. TAB 38 is an outer lead that connects an inner lead that connects the IC element and an external lead at a position where the IC element is disposed on a flexible resin film such as polyimide resin using a photo-etching technique or the like. Is widely used for mounting semiconductor integrated circuits such as ICs.

  In the present embodiment, the diaphragm 30 also serves as a common electrode, and is grounded through a driver IC and a TAB 38 (not shown). Therefore, the process of forming the piezoelectric layer 33a on the vibration plate 30 also serves as the common electrode forming process.

<Fourth embodiment>
A fourth embodiment of the present invention will be described with reference to FIGS. In this embodiment, a metal plate assembly is laminated through a piezoelectric layer as an insulating ceramic layer, and diffusion bonding is performed.

  First, as shown in FIG. 23, a piezoelectric layer 33b of piezoelectric ceramic is formed on one surface of the diaphragm 30 by using an aerosol deposition method (AD method), a sol-gel method, or a sputtering method (insulating ceramics). Layer forming step). Next, as shown in FIG. 24, the cavity plate 10, the base plate 11, the manifold plate 12, and the vibration plate 30 constituting the flow path unit provided with the holes for forming the ink flow paths are connected to the vibration plate 30. The plate set 50b is formed by stacking so that the surface opposite to the surface on which the piezoelectric layer 33b is formed is in contact with the upper surface of the cavity plate 10. Plural sets (three sets here) of plate sets 50b having such a structure are prepared and stacked as shown in FIG. That is, the plurality of sets of plate sets 50b are stacked so that the lower surface of the manifold plate 12 of the uppermost plate set 50b and the piezoelectric layer 33b formed on the upper surface of the vibration plate 30 of the center plate set 50b come into contact with each other. The central plate set 50b and the lowermost plate set 50b are laminated in the same manner. A plurality of sets of plates 50b stacked in this manner are sandwiched between a pair of upper and lower plate-shaped jigs 51 (stacking step).

  While pressing the plurality of plate sets 50 through the jig 51, the plate sets 50 are heated to about 1000 ° C., and four plates (cavity plate 10, base plate 11, manifold plate 12, and The diaphragm 30) is joined by diffusion joining (joining process). By the heating during the diffusion bonding, the piezoelectric layer 33b formed on the upper surface of the vibration plate 30 is sintered and subsequently annealed.

  Next, as shown in FIG. 25, an individual electrode 32b is formed on the surface of the piezoelectric layer 33b by screen printing, vapor deposition, or sputtering (individual electrode forming step), and is formed on the piezoelectric layer 33b using TAB38. The formed individual electrode 32b and a terminal of a driver IC (not shown) are connected. Further, the nozzle plate 13 is bonded to the lower surface of the manifold plate 12 as in the first embodiment.

  Also in this embodiment, since the diaphragm 30 also serves as a common electrode, the process of forming the piezoelectric layer 33b on the upper surface of the diaphragm 30 also serves as the common electrode formation process. The piezoelectric layer 33b plays a role of preventing diffusion bonding between different plate sets in the bonding process. In particular, in the process of this embodiment, the sintering and annealing steps necessary for forming the piezoelectric layer 33b are also performed using heat at the time of diffusion bonding. Therefore, it is necessary to separately perform the sintering and annealing steps. There is no. As a result, the entire process time can be shortened, resulting in energy saving. In the present embodiment, the nozzle plate 13 is finally bonded to the lower surface of the manifold plate 12. However, as shown in the second and third embodiments, a metal nozzle plate 13a is used to perform diffusion bonding. It may be adhered to the lower surface of the manifold plate 12. Furthermore, a water-repellent ceramic layer such as water-repellent zirconia may be formed on the surface of the nozzle plate 13a.

  Next, a fifth embodiment of the present invention will be described with reference to FIGS. The fifth embodiment is an example in which the present invention is applied when manufacturing a metal substrate on which electronic components used in electronic devices such as mobile phones and personal computers will be mounted. The structure disclosed in FIGS. 12 to 17 is the structure disclosed in Japanese Patent Application No. 2004-220202, which is a Japanese patent application filed by the present applicant. FIG. 2 is a plan view of the top surface of the metal substrate as viewed from above. As shown in FIGS. 12 to 14, the metal substrate 60 (hereinafter simply referred to as the substrate 60) is composed of two metal plates 61 and 62 as a base material and insulation formed on the upper surface of the upper plate 61. And a ceramic layer 63.

  The two plates 61 and 62 are made of a metal material having high thermal conductivity, such as stainless steel, iron, copper, nickel, or aluminum. An insulating ceramic layer 63 is formed on the upper surface of the upper plate 61 from a ceramic material having a high insulation resistance. As will be described later, the insulating ceramic layer 63 is formed for diffusion bonding of a plurality of plate sets 80 including two plates 61 and 62, and is mounted on the surface thereof. The wiring part 67 connected to the electronic component 65 also has a role of electrically insulating the metal plate 61. Furthermore, the insulating ceramic layer 63 is made of a ceramic material having a high thermal conductivity so that heat generated in the electronic components such as the ICs 65 and 66 is easily transmitted to the plate 61. Examples of the ceramic materials that can be used are listed in Table 2. Among them, it is more preferable to use alumina, silica, yttria, silicon nitride, aluminum nitride, or the like, which has a particularly high thermal conductivity. The insulating ceramic layer 63 can be easily formed by using the AD method. In addition, a sol-gel method, a sputtering method, or a CVD (chemical vapor deposition) method can also be used.

  Note that the thermal conductivity of the epoxy resin of a glass epoxy substrate (in which the surface of the glass cloth is impregnated with an epoxy resin as an insulating material) widely used as a mounting substrate for electronic components is 0.19 (W / m · K), the thermal conductivity of the ceramic materials described in Table 2 are all much higher than that of the epoxy resin.

  A large number of electronic components such as ICs 65 and 66, resistors (not shown), capacitors (not shown), and the like are mounted on the upper surface of the insulating ceramic layer 63 via terminals. Further, as shown in FIG. 13, a plurality of wiring portions 67 are joined to the upper surface of the insulating ceramic layer 63 to connect the electronic components to each other by joining the terminals (for example, the terminals 65 a) of the electronic components such as the ICs 65 and 66. Is also formed. The wiring part 67 is electrically insulated from the metal plate 61 and another adjacent wiring part 67 by the insulating ceramic layer 63, thereby preventing a short circuit.

  As described above, since the insulating ceramic layer 63 is formed of a ceramic material having a high thermal conductivity, most of the heat generated in the IC 65 passes through the terminals 65a as shown by arrows in FIG. The heat is transferred from the insulating ceramic layer 63 to the metal plate 61 and to a position away from the IC 65 via the plate 61. Here, generally, a ceramic material is more expensive than a metal material, and since the thermal conductivity of the ceramic material is often smaller than that of the metal material, the substrate is inexpensive and has good heat dissipation efficiency. Therefore, the thickness of the insulating ceramic layer 63 made of a ceramic material is preferably sufficiently thinner than that of a metal plate. In order to increase the contact area between the IC 65 and the insulating ceramic layer 63 so that the heat generated by the IC 65 is easily transmitted to the insulating ceramic layer 63, as shown in FIG. A high thermal conductivity material 71 such as a metal paste or a metal film may be interposed between the two.

  Further, as shown in FIGS. 12 to 14, a groove 72 is formed on the lower surface side of the upper plate 61, and the groove 72 is closed by the lower plate 62, so that the two plates 61, 62 are formed. A closed-loop flow path 70 (liquid flow path) is formed in the interior. The flow path 70 is filled with water W, and the water W is pressurized by a pressurizing mechanism 68 (for example, an actuator pump) and circulates in the closed loop flow path 70. Furthermore, as shown in FIG. 12, the flow path 70 is formed so as to pass through a region where the ICs 65 and 66 generating a large amount of heat are disposed and a region where the radiator 69 is disposed. The flow path 70 is formed in a rectangular cross section inside the two plates 61 and 62, and the thin portion 61 a of the upper plate 61 is interposed between the flow path 70 and the insulating ceramic layer 63. . As described above, in the portion where the flow path 70 is formed, a high strength metal material layer (thin wall portion) is formed below the insulating ceramic layer 63 made of a ceramic material having a lower strength than the metal plates 61 and 62. 61a), the strength reduction of the substrate 60 in the portion where the flow path 70 is formed is suppressed.

  The heat generated in the ICs 65 and 66 is transferred to the water W in the flow path 70 through the insulating ceramic layer 63 having high thermal conductivity and the metal plates 61 and 62, and the water W is transferred by the pressurizing mechanism 68. While being pressurized and circulating in the flow path 70, heat is dissipated to the outside through the plates 61 and 62. Further, since a radiator 69 is provided in the middle of the flow path 70 and away from the ICs 65 and 66, the heat transmitted from the radiator 69 to the water W is reliably dissipated to the outside. The

  Next, a method for manufacturing the substrate 60 will be described. As shown in FIG. 15, first, an insulating ceramic layer 63 is formed on one surface of the plate 61 (first step). Here, if an aerosol deposition method (AD method) in which powder of an insulating ceramic material is sprayed and deposited toward a predetermined surface of the plate 61, the insulating ceramic layer 63 can be easily formed. Can do. In addition, the insulating ceramic layer 63 may be formed by a sol-gel method or a sputtering method.

  Next, as shown in FIG. 16, a groove 72 for flowing water W is formed on the side of the plate 61 opposite to the insulating ceramic layer 63. The groove 72 can be easily formed by, for example, half-etching the metal plate 61.

  Then, as shown in FIG. 17, two plates 61 and 62 are laminated, and a plurality of sets (for example, a set of plates 80 made of these two plates 61 and 62 are interposed via an insulating ceramic layer 63 (for example, 3 sets) Stacking is performed so that the plate 62 of another plate set 80 is stacked on the surface of the insulating ceramic layer 63 formed on the plate 61 belonging to a certain plate set 80 (second step).

  The plurality of plate sets 80 stacked in this way are sandwiched between a pair of upper and lower plate-shaped jigs 81 and heated to about 1000 ° C. while pressing the plurality of plate sets 80 via the jigs 81. Then, the two plates 61 and 62 belonging to the plurality of sets of plates 80 are joined by diffusion joining (third step). Thus, since the insulating ceramic layer 63 is interposed between the plurality of plate sets 80, the two plates 61 and 62 belonging to different plate sets 80 are not joined. A plurality of wiring portions 67 are formed on the surface of the insulating ceramic layer 63 for each of the plurality of plate sets 80 that are joined, and further, an electronic device such as ICs 65 and 66 that are connected to these wiring portions 67. Arrange the parts.

  According to the manufacturing method of the metal substrate 60 described above, the following effects can be obtained. A plurality of plate sets 80 made of two metal plates 61 and 62 are laminated through an insulating ceramic layer 63 formed on the plate, and then diffusion bonding is performed collectively on the plurality of plate sets 80. Therefore, a plurality of laminated bodies composed of the two plates 61 and 62 can be manufactured at a time, and the manufacturing process can be shortened. At this time, since the two plates 61 and 62 belonging to the two different plate sets 80 are laminated via the insulating ceramic layer 63, the two plates 61 and 62 are diffusion-bonded. This can be prevented by the insulating ceramic layer 63. Furthermore, the insulating ceramic layer is formed between the wiring portion 67 and the substrate 60 by forming the wiring portion 67 on the surface of the insulating ceramic layer 63 formed for diffusion bonding the plurality of sets of plates 80 together. 63 can be insulated.

  In the manufacturing method of the metal substrate 60 of the fifth embodiment described above, the flow path 70 through which water flows is formed in the substrate 60 by forming the grooves 72 in the plates 61 and 62, but FIG. As shown, a through hole 72A may be formed in the upper plate 61A, and a flow path through which water W flows may be formed by the hole 72A. In this case, since the water W in the flow path is in direct contact with the insulating ceramic layer, the heat generated by the IC 65 is more efficiently transferred to the fluid. The through hole 72A can also be easily formed by performing full etching on the plate 61A.

  As mentioned above, although the form which applied this invention to the inkjet head (1st Embodiment-4th Embodiment) and the metal substrate (5th Embodiment) was demonstrated, this invention is these 1st Embodiment-5th Embodiment. It is not limited to. That is, the present invention can be applied to various types of laminated bodies obtained by diffusion bonding of a plurality of laminated metal plates.

1 is a perspective view of an inkjet head according to a first embodiment of the present invention. It is a top view of the right half part of the inkjet head in FIG. It is the III-III sectional view taken on the line of FIG. It is the IV-IV sectional view taken on the line of FIG. It is a figure which shows an insulating ceramic layer formation process. It is a figure which shows the lamination process and joining process in 1st Embodiment. It is a figure which shows an individual electrode formation process. It is a figure which shows a piezoelectric layer formation process. It is a figure which shows a common electrode formation process. It is a figure which shows the process of arrange | positioning driver IC on an insulating ceramic layer. It is a figure which shows the process of joining a nozzle plate. It is a schematic plan view of the metal substrate which concerns on 2nd Embodiment of this invention. FIG. 13 is an enlarged view around the IC of FIG. 12. It is the XIV-XIV sectional view taken on the line of FIG. It is a figure which shows the process (1st process) which forms an insulating ceramic layer in a plate. It is a figure which shows the process of forming a groove | channel in a plate. It is a figure which shows the process (2nd, 3rd process) which joins multiple sets of plate groups. It is sectional drawing equivalent to FIG. 14 which concerns on the modification of 25th Embodiment. It is a figure which shows the process of forming a water repellent ceramic layer in the nozzle plate 13a. It is a figure which shows the lamination process and joining process in 2nd Embodiment. It is a figure which shows the process of forming the insulating ceramic layer 31 in 2nd Embodiment. 22A is a diagram illustrating a process of forming the piezoelectric ceramic layer 33a on the diaphragm 30, FIG. 22B is a diagram illustrating a process of forming the individual electrode 32a on the piezoelectric ceramic layer 33a, and FIG. 22C is a diagram illustrating the process of forming the individual electrode 32a and the TAB 38. It is a figure which shows the process of connecting. 6 is a diagram illustrating a process of forming a piezoelectric ceramic layer 33b on the vibration plate 30. FIG. It is a figure which shows the lamination process and joining process in 4th Embodiment. It is a figure which shows the process of connecting the separate electrode 32b and TAB38 in 4th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inkjet head 2 Flow path unit 3 Piezoelectric actuator 10 Cavity plate 11 Base plate 12 Manifold plate 13 Nozzle plate 14 Pressure chamber 20 Nozzle 30 Diaphragm 31 Insulating ceramic layer 32 Individual electrode 33 Piezoelectric layer 34 Common electrode 35 Wiring part 50 Plate set 60 Metal substrates 61, 62 Plate 61A Plate 63 Insulating ceramic layer 67 Wiring part 72 Groove 72A Hole 80 Plate assembly

Claims (14)

A method of producing a plurality of laminates obtained by joining metal plate sets of a plurality of metal plates by diffusion bonding,
A first step of forming an insulating ceramic layer on a surface of a metal plate forming a predetermined surface of the laminate among the plurality of metal plates of each metal plate set;
A second step of laminating a plurality of the metal plate sets via the insulating ceramic layer;
A third step of heating the plurality of sets of laminated metal plates and simultaneously joining a plurality of metal plates belonging to the plurality of sets of metal plates by diffusion bonding ;
In the third step, the heating is terminated before joining between two metal plates belonging to different metal plate groups, which are laminated via the insulating ceramic layer, is finished . Production method. In the first step, the insulating ceramic layer is formed by an aerosol deposition method in which a powder of an insulating ceramic material is sprayed and deposited on a predetermined surface of the laminate. Item 2. A method for producing a laminate according to Item 1 . The laminate is a metal substrate on which electronic components are mounted,
It said insulating ceramic layer, method for producing a laminate according to claim 1 or 2, characterized in that said an insulating ceramic layer for insulating the wiring portion connected to the electronic component and the metal substrate. 4. The laminate according to claim 3 , wherein a hole or a groove for flowing a liquid is formed in at least one of the plurality of metal plates belonging to the metal plate set before the second step. Manufacturing method. Manufactures a plurality of inkjet heads including a flow path unit having a laminate of a plurality of metal plates that forms an ink flow path including a plurality of pressure chambers communicating with nozzles, and a piezoelectric actuator that changes the volume of the pressure chambers. A way to
An insulating ceramic layer forming step of forming an insulating ceramic layer on the outermost metal plate constituting the outermost layer of the laminate of the plurality of metal plates;
A laminating step of laminating a plurality of metal plate sets of a plurality of metal plates constituting the laminate through the insulating ceramic layer;
A step of heating the plurality of sets of metal plates stacked and joining a plurality of the metal plates belonging to the plurality of sets of metal plates at the same time by diffusion bonding ;
In the above-described joining step, heating is terminated before joining between two metal plates belonging to different metal plate groups laminated via the insulating ceramic layer, and the inkjet head is manufactured. Method. The method of manufacturing an ink jet head according to claim 5 , wherein the outermost metal plate is a vibration plate covering the pressure chamber, and the ink jet head has a piezoelectric layer disposed on a side of the vibration plate opposite to the pressure chamber. An individual electrode forming step of forming a plurality of individual electrodes at positions opposite to the plurality of pressure chambers on the surface of the insulating ceramic layer opposite to the pressure chamber;
A piezoelectric layer forming step of forming the piezoelectric layer on the surface of the insulating ceramic layer on which the individual electrodes are formed;
Forming a common electrode on the surface of the piezoelectric layer opposite to the individual electrode;
The method of manufacturing an ink jet head according to claim 6 , comprising: One of the said outermost metal plates is a nozzle plate, The manufacturing method of the inkjet head in any one of Claims 5-7 . The method of manufacturing an ink jet head according to claim 5, wherein the outermost metal plate is a vibration plate and a nozzle plate. The method for manufacturing an ink jet head according to claim 5, wherein the insulating ceramic layer is made of alumina or zirconia. The inkjet head manufacturing method according to claim 5 , wherein the piezoelectric actuator has a piezoelectric layer, and the insulating ceramic layer is the piezoelectric layer. 6. The method of manufacturing an ink jet head according to claim 5 , wherein the insulating ceramic layer is a piezoelectric layer, and the piezoelectric layer is subjected to at least one of sintering and annealing in the joining step. The method of manufacturing an ink jet head according to claim 6 , wherein the diaphragm is a common electrode. The other of the outermost metal plates is a diaphragm, and following the joining step, an insulating ceramic layer is formed on one surface of the diaphragm by any one of an aerosol deposition method, a sol-gel method, and a sputtering method. The method for producing an ink jet head according to claim 8 , further comprising the step of:

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