JP2010214714A - Manufacturing method of piezoelectric actuator and manufacturing method of liquid transfer device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain the deformation of a diaphragm caused by the spurting of aerosol thereto in a deposition process. <P>SOLUTION: First, among two sheets of diaphragm 40 consisting of a ferromagnetic body which is not magnetized, an external magnetic field is applied to one sheet of diaphragm 40. Thereby, the diaphragm 40 is magnetized, and another sheet of diaphragm 40 is brought close to the magnetized one sheet of diaphragm 40, then two sheets of diaphragm 40 are cemented by the magnetic force. Then, a deposition of a piezoelectric layer 41 is carried out by an aerosol deposition method (AD method) on each surface of the not-opposite sides of two sheets of diaphragm 40. Heat treatment for the piezoelectric layer 41 formed as film is performed at a predetermined temperature. Concretely, two sheets of diaphragm 40 wherein the piezoelectric layer 41 has been formed, respectively, are heated at the annealing temperature of the piezoelectric layer 41 and at a temperature of the demagnetization temperature of the diaphragm 40 (heating process) or higher. Thereby, in the heating process, the demagnetization of the magnetized diaphragm 40 is performed, and then two sheets of diaphragm 40 are separated. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a piezoelectric actuator and a method for manufacturing a liquid transfer device.

  2. Description of the Related Art Conventionally, there is known a piezoelectric actuator that includes a diaphragm and a piezoelectric layer formed on the diaphragm, and drives an object using deformation (piezoelectric strain) of the piezoelectric layer when an electric field is applied. When manufacturing such a piezoelectric actuator, various methods are conventionally known as a method for forming (depositing) a piezoelectric layer on a diaphragm. Among them, particles of a piezoelectric material and a carrier gas are used. There is a method (aerosol deposition method: AD method) in which the contained aerosol is sprayed onto the diaphragm at high speed to deposit particles of piezoelectric material to form a piezoelectric layer.

  By the way, it is preferable that the thickness of the diaphragm is thin from the viewpoint of increasing the deformation efficiency of the piezoelectric actuator (that is, greatly deforming the diaphragm with a low driving voltage). However, when the piezoelectric layer is formed on the diaphragm by the above-described AD method, the thinner the diaphragm, the higher the velocity of the aerosol sprayed at high speed, the more the diaphragm is affected by the collision energy. Deform. When film formation is performed with the vibration plate deformed, it becomes difficult to form a piezoelectric layer having a uniform thickness.

  Therefore, the diaphragm itself has a relatively thin thickness so that it can be easily deformed by reducing the rigidity, and when spraying aerosol onto the diaphragm, a thick reinforcing member is joined to the diaphragm in advance to increase the rigidity. Things have been done. For example, there is an ink jet head configured such that a piezoelectric actuator is connected to a flow path unit in which a liquid flow path including a pressure chamber is formed, and pressure is applied to ink in the pressure chamber by driving the piezoelectric actuator. In such an ink jet head, a piezoelectric layer may be formed on the diaphragm by the AD method with the flow path unit joined to the diaphragm. As an example of this, in the inkjet head described in Patent Document 1, a relatively thick cavity plate, which is a part of a flow path unit and in which a pressure chamber is formed, is joined to a diaphragm, and the diaphragm is formed by the AD method. A piezoelectric layer is formed.

Japanese Patent Laying-Open No. 2005-35018 (FIG. 4)

  However, as described in Patent Document 1, when a cavity plate is joined to a diaphragm and a piezoelectric layer is formed by the AD method, some of the particles of the piezoelectric material sprayed on the diaphragm are deposited on the diaphragm. Instead, the liquid may enter and remain in the liquid flow path such as the pressure chamber, and the remaining particles may clog the flow path. Thus, if a member joined to the diaphragm at the time of product is used as a reinforcing member, the degree of freedom in design is reduced. Further, when a reinforcing member that is not necessary as a product is joined to the diaphragm and the piezoelectric layer is formed by the AD method, a step of removing the reinforcing member is required, which increases the number of manufacturing steps.

  Therefore, it is desired to suppress deformation of the diaphragm in film formation of the piezoelectric layer on the diaphragm by the AD method while solving the above-described problems.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a piezoelectric actuator and a method for manufacturing a liquid transfer device that can suppress deformation of a diaphragm caused by spraying aerosol in a film forming process.

  The method for manufacturing a piezoelectric actuator of the present invention includes a laminating step of laminating two diaphragms, and an aerosol containing particles of piezoelectric material and a carrier gas on each surface of the two laminating diaphragms. A film forming step for forming the piezoelectric layer by spraying and depositing the particles; and a separation step for separating the two diaphragms on which the piezoelectric layer is formed.

  According to the method of manufacturing a piezoelectric actuator of the present invention, the two diaphragms reinforce each other to increase the rigidity as a whole, so that no special reinforcing member is required and aerosol is sprayed in the film forming process. This can suppress the deformation of the diaphragm. As a result, a piezoelectric layer having a uniform thickness can be formed. In addition, a plurality of diaphragms on which a piezoelectric layer is formed can be easily manufactured in a series of steps, so that the manufacturing time can be shortened and the manufacturing process can be simplified, thereby increasing the productivity.

  In the film forming step, it is preferable that the piezoelectric layer is simultaneously formed on the surfaces of the two diaphragms. According to this, the formation time of the piezoelectric layers on the two diaphragms is shortened, and the piezoelectric layers can be quickly formed on the two diaphragms.

  Further, in the piezoelectric layer forming step, the piezoelectric layer is formed on the surface of the vibration plate while changing a relative position between the spray nozzle for injecting the aerosol and the vibration plate. In the piezoelectric layer forming step, Preferably, the particles are deposited by spraying the aerosol at the same position on the two diaphragms as viewed from the direction orthogonal to the diaphragms. According to this, since aerosol is sprayed simultaneously on the same position as seen from the direction orthogonal to the diaphragm to deposit particles, deformation of the diaphragm can be further suppressed. As a result, a piezoelectric layer having a more uniform thickness can be formed.

  In addition, in the laminating step, it is preferable to bond the two diaphragms. According to this, by firmly bonding the two diaphragms, the two laminated diaphragms are difficult to separate even during film formation.

  Further, the two diaphragms are made of a ferromagnetic material, and in the stacking step, an external magnetic field is applied to at least one of the two diaphragms to magnetize at least one of the diaphragms, The two diaphragms are bonded by the magnetized magnetic force of the at least one diaphragm, and in the separation step, the magnetized diaphragm is heated to a demagnetization temperature or higher so that the magnetized diaphragm It is preferable to demagnetize the magnetization. According to this, two diaphragms can be laminated and firmly bonded by the magnetic force of at least one magnetized diaphragm. In the separation step, the magnetized diaphragm is heated to the demagnetization temperature, so that the magnetization generated in the diaphragm can be removed and the two diaphragms can be easily separated.

  In the laminating step, the liquid is solidified by lowering the temperature of the liquid to the solidification temperature of the liquid in a state where the opposing surfaces of the two diaphragms are laminated via the liquid. The diaphragm may be bonded, and the film formation step may be performed in a state where the liquid is solidified, and in the separation step, the liquid may be heated to a temperature equal to or higher than the melting point of the liquid to melt the liquid. . According to this, by solidifying the liquid, the two diaphragms can be stacked and firmly bonded. In the separation step, the two diaphragms can be easily separated by melting the liquid.

  In the laminating step, the two diaphragms may be bonded with an adhesive, and in the separating step, the adhesive may be heated to a temperature higher than the thermal decomposition temperature of the adhesive to remove the adhesive. Good. According to this, two diaphragms can be laminated | stacked and firmly adhere | attached with an adhesive agent. In the separation step, the two diaphragms can be easily separated by removing the adhesive.

  In addition, after the film formation step, further comprising an annealing treatment step of heating the piezoelectric layer formed on each of the two diaphragms, the annealing treatment step also serves as the separation step, It is preferable to heat both the two diaphragms. When a piezoelectric layer is formed by spraying aerosol and depositing particles in the film forming step, a step of heating the piezoelectric layer is required as an annealing process for improving the piezoelectric characteristics of the piezoelectric layer. At this time, since the annealing process also serves as the separation process, the manufacturing process can be simplified.

  The method for manufacturing a liquid transfer device of the present invention includes a flow path unit in which a liquid flow path including a pressure chamber is formed, a vibration plate disposed on one surface of the flow path unit so as to cover at least the pressure chamber, And a piezoelectric actuator including a piezoelectric layer disposed on a side of the diaphragm opposite to the pressure chamber, wherein the piezoelectric actuator manufacturing process includes two diaphragms. Laminating step for laminating, and spraying aerosol containing piezoelectric material particles and carrier gas on each surface of the two laminated diaphragms to deposit the particles to form the piezoelectric layer And a separation step of separating the two diaphragms on which the piezoelectric layer is formed.

  According to the method for manufacturing a liquid transfer device of the present invention, the two diaphragms reinforce each other to increase the rigidity as a whole, so that no special reinforcing member is required and aerosol is sprayed in the film forming process. This can suppress the deformation of the diaphragm. As a result, a piezoelectric layer having a uniform thickness can be formed. In addition, a diaphragm in which two piezoelectric layers are formed can be easily manufactured through a series of steps, so that the manufacturing time can be shortened and the manufacturing process can be simplified, thereby increasing the productivity.

  Since the two diaphragms reinforce each other to increase the rigidity as a whole, no special reinforcing member is required, and deformation of the diaphragm due to the spraying of aerosol in the film forming process is suppressed. Can do.

1 is a schematic plan view of an ink jet printer according to an embodiment. It is a top view of an inkjet head. FIG. 3 is a partially enlarged view of FIG. 2. FIG. 4 is a sectional view taken along line IV-IV in FIG. 3. It is a figure explaining the manufacturing process of an inkjet head schematically, (a) is a figure which shows the process of joining a piezoelectric actuator to a flow path unit, (b) is a figure which shows the inkjet head after joining. It is a figure explaining the film-forming process of the piezoelectric layer in the manufacturing process of a piezoelectric actuator. It is a top view of the diaphragm in a modification.

  Next, an embodiment of the present invention will be described. This embodiment is an example in which the present invention is applied to an inkjet printer that includes an inkjet head (liquid transfer device) that ejects ink onto a recording sheet.

  First, a schematic configuration of the inkjet printer 1 of the present embodiment will be described. FIG. 1 is a schematic plan view of the ink jet printer of the present embodiment. As shown in FIG. 1, a printer 1 includes a carriage 2 configured to be reciprocally movable along a predetermined scanning direction (left-right direction in FIG. 1), an inkjet head 3 mounted on the carriage 2, and a recording sheet. A transport mechanism 4 for transporting P in a transport direction orthogonal to the scanning direction is provided.

  The carriage 2 is configured to be able to reciprocate along two guide shafts 17 extending in parallel with the scanning direction (left-right direction in FIG. 1). An endless belt 18 is connected to the carriage 2. When the endless belt 18 is driven to travel by the carriage drive motor 19, the carriage 2 moves in the scanning direction as the endless belt 18 travels. It has become. The printer 1 is provided with a linear encoder 10 having a large number of light transmitting portions (slits) arranged at intervals in the scanning direction. On the other hand, the carriage 2 is provided with a transmissive photosensor 11 having a light emitting element and a light receiving element. The printer 1 can recognize the current position in the scanning direction of the carriage 2 from the count value (number of detections) of the light transmitting portion of the linear encoder 10 detected by the photosensor 11 while the carriage 2 is moving. .

  An ink jet head 3 is mounted on the carriage 2. The inkjet head 3 includes a large number of nozzles 30 (see FIG. 2) on the lower surface (the surface on the other side of the paper in FIG. 1). The inkjet head 3 is configured to eject ink supplied from an ink cartridge (not shown) from a large number of nozzles 30 onto a recording paper P that is conveyed downward (conveying direction) in FIG. ing.

  The transport mechanism 4 includes a paper feed roller 12 disposed on the upstream side in the transport direction with respect to the ink jet head 3 and a paper discharge roller 13 disposed on the downstream side in the transport direction with respect to the ink jet head 3. The paper feed roller 12 and the paper discharge roller 13 are rotationally driven by a paper feed motor 14 and a paper discharge motor 15, respectively. The transport mechanism 4 transports the recording paper P from above in FIG. 1 to the ink jet head 3 by the paper feed roller 12, and records the images and characters recorded by the ink jet head 3 by the paper discharge roller 13. The paper P is discharged downward in FIG.

  Next, the inkjet head 3 will be described. FIG. 2 is a plan view of the inkjet head. FIG. 3 is a partially enlarged view of FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. As shown in FIGS. 2 to 4, the inkjet head 3 includes a flow path unit 6 in which an ink flow path including a nozzle 30 and a pressure chamber 24 is formed, and a piezoelectric actuator 7 that applies pressure to the ink in the pressure chamber 24. And have.

  First, the flow path unit 6 will be described. As shown in FIG. 4, the flow path unit 6 includes a cavity plate 20, a base plate 21, a manifold plate 22, and a nozzle plate 23, and these four plates 20 to 23 are joined in a stacked state. Among these, the cavity plate 20, the base plate 21, and the manifold plate 22 are each substantially rectangular plates in plan view made of a metal material such as stainless steel. Therefore, ink flow paths such as a manifold 27 and a pressure chamber 24 described later can be easily formed on these three plates 20 to 22 by etching. The nozzle plate 23 is made of, for example, a polymer synthetic resin material such as polyimide, and is bonded to the lower surface of the manifold plate 22 with an adhesive.

  As shown in FIGS. 2 to 4, among the four plates 20 to 23, the uppermost cavity plate 20 has holes in which a plurality of pressure chambers 24 arranged along a plane penetrate the plate 20. It is formed by. The plurality of pressure chambers 24 are arranged in two rows in a staggered manner in the transport direction (the vertical direction in FIG. 2). Further, as shown in FIG. 4, the plurality of pressure chambers 24 are respectively covered with a diaphragm 40 and a base plate 21 described later from above and below. Furthermore, each pressure chamber 24 is formed in a substantially elliptical shape that is long in the scanning direction (left-right direction in FIG. 2) in plan view.

  As shown in FIGS. 3 and 4, communication holes 25 and 26 are formed at positions where the base plate 21 overlaps both longitudinal ends of the pressure chamber 24 in plan view, respectively. The manifold plate 22 is formed with two manifolds 27 extending in the transport direction so as to overlap with the communication hole 25 side portions of the pressure chambers 24 arranged in two rows in a plan view. These two manifolds 27 communicate with an ink supply port 28 (see FIG. 2) formed in a vibration plate 40 described later, and ink is supplied from an ink tank (not shown) to the manifold 27 via the ink supply port 28. The Further, a plurality of communication holes 29 that are continuous with the plurality of communication holes 26 are formed at positions where the manifold plate 22 overlaps the ends of the plurality of pressure chambers 24 opposite to the manifolds 27 in plan view.

  Further, a plurality of nozzles 30 are formed at positions where the nozzle plate 23 overlaps the plurality of communication holes 29 in plan view. As shown in FIG. 2, the plurality of nozzles 30 are disposed so as to overlap with the end portions of the plurality of pressure chambers 24 arranged in two rows along the transport direction on the side opposite to the manifold 27.

  As shown in FIG. 4, the manifold 27 communicates with the pressure chamber 24 through the communication hole 25, and the pressure chamber 24 communicates with the nozzle 30 through the communication holes 26 and 29. As described above, a plurality of individual ink flow paths 31 from the manifold 27 to the nozzles 30 through the pressure chambers 24 are formed in the flow path unit 6.

  Next, the piezoelectric actuator 7 will be described. As shown in FIGS. 2 to 4, the piezoelectric actuator 7 includes a vibration plate 40 disposed on the upper surface of the flow path unit 6 (cavity plate 20) so as to cover the plurality of pressure chambers 24, and an upper surface of the vibration plate 40. In addition, a piezoelectric layer 41 disposed so as to face the plurality of pressure chambers 24 and a plurality of individual electrodes 42 disposed on the upper surface of the piezoelectric layer 41 are provided.

  The diaphragm 40 is a substantially rectangular metal plate in plan view, and is made of, for example, a ferromagnetic metal material such as ferritic stainless steel (SUS430). The vibration plate 40 is joined to the cavity plate 20 in a state of being disposed on the upper surface of the cavity plate 20 so as to cover the plurality of pressure chambers 24. In addition, the upper surface of the conductive diaphragm 40 is disposed on the lower surface side of the piezoelectric layer 41, thereby generating an electric field in the thickness direction in the piezoelectric layer 41 with the plurality of individual electrodes 42 on the upper surface. Also serves as an electrode. The diaphragm 40 as the common electrode is connected to the ground wiring of a head driver (not shown) that drives the piezoelectric actuator 7 and is always held at the ground potential.

  The piezoelectric layer 41 is made of a piezoelectric material mainly composed of lead zirconate titanate (PZT), which is a solid solution of lead titanate and lead zirconate and is a ferroelectric substance. As shown in FIG. 2, the piezoelectric layer 41 is continuously formed across the plurality of pressure chambers 24 on the upper surface of the vibration plate 40. The piezoelectric layer 41 is polarized in the thickness direction at least in a region facing the pressure chamber 24.

  A plurality of individual electrodes 42 are respectively disposed in regions on the upper surface of the piezoelectric layer 41 facing the plurality of pressure chambers 24. Each individual electrode 42 has a substantially oval planar shape that is slightly smaller than the pressure chamber 24, and faces the central portion of the pressure chamber 24. Further, a plurality of contact portions 45 are drawn from the end portions of the plurality of individual electrodes 42 along the longitudinal direction of the individual electrodes 42. The plurality of contact portions 45 are electrically connected to a head driver (not shown) through a flexible printed circuit (FPC) (not shown). As a result, the head driver can selectively apply one of the two types of potentials of the predetermined drive potential and the ground potential to the plurality of individual electrodes 42.

  Next, the operation of the piezoelectric actuator 7 during ink ejection will be described. When a predetermined drive potential is applied to a certain individual electrode 42 from the head driver, between the individual electrode 42 to which this drive potential is applied and the diaphragm 40 as a common electrode held at the ground potential. A potential difference is generated, and an electric field in the thickness direction acts on the piezoelectric layer 41 sandwiched between the individual electrode 42 and the diaphragm 40. Since the direction of the electric field is parallel to the polarization direction of the piezoelectric layer 41, the piezoelectric layer 41 in the region (active region) facing the individual electrode 42 contracts in a plane direction perpendicular to the thickness direction. Here, since the lower vibration plate 40 of the piezoelectric layer 41 is fixed to the cavity plate 20, as the piezoelectric layer 41 positioned on the upper surface of the vibration plate 40 contracts in the surface direction, the vibration plate 40. The portion covering the pressure chamber 24 is deformed so as to protrude toward the pressure chamber 24 (unimorph deformation). At this time, since the volume in the pressure chamber 24 decreases, the ink pressure in the pressure chamber 24 rises, and ink is ejected from the nozzle 30 communicating with the pressure chamber 24.

  Next, the manufacturing process of the inkjet head 3 described above will be described. FIG. 5 is a diagram schematically illustrating the manufacturing process of the inkjet head 3. FIG. 6 is a diagram for explaining a piezoelectric layer forming process in the piezoelectric actuator manufacturing process. In the present embodiment, as shown in FIG. 5A, after the flow path unit 6 and the piezoelectric actuator 7 are manufactured in separate steps, the piezoelectric actuator 7 is joined to the upper surface of the flow path unit 6, and FIG. The inkjet head 3 of (b) is produced. In addition, two diaphragms 40 on which the piezoelectric layer 41 is formed can be simultaneously manufactured in one manufacturing process of the piezoelectric actuator 7.

(Channel unit manufacturing process)
First, among the four plates 20 to 23 constituting the flow path unit 6, ink such as the pressure chamber 24 and the manifold 27 is applied to the three plates of the metal cavity plate 20, the base plate 21, and the manifold plate 22. The holes constituting the flow path are formed by etching. A plurality of nozzles 30 are formed on the nozzle plate 23 made of synthetic resin by laser processing. Then, the four plates 20 to 23 are bonded together with an adhesive in a state where the plates 20 to 23 are stacked on each other, thereby completing the flow path unit 6.

  Alternatively, in a state where the three metal plates 20 to 23 are laminated, the three plates 20 to 23 are metal diffusion bonded by pressing in the plate lamination direction while heating to a high temperature (for example, about 900 ° C.). May be joined together. In this case, the nozzle plate 23 made of synthetic resin is bonded to the laminated body of the three plates 20 to 23 obtained by metal diffusion bonding with an adhesive.

(Piezoelectric actuator manufacturing process)
In the manufacturing process of the piezoelectric actuator 7, the piezoelectric layers 41 are simultaneously formed on the two diaphragms 40. First, the two diaphragms 40 are laminated and bonded (lamination process). As an adhesion method of the two diaphragms 40, an external magnetic field having a magnetic flux density component in a plane orthogonal direction is applied to one diaphragm 40 of the two diaphragms 40 made of a non-magnetized ferromagnetic material. As a result, the diaphragm 40 is magnetized. When the other diaphragm 40 is brought close to one diaphragm 40 having spontaneous magnetization, a magnetic force acts between the two diaphragms 40, and the two diaphragms 40 are easily moved by the magnetic force. And can be firmly bonded.

  Then, the piezoelectric layer 41 is formed on each surface of the two non-opposing sides of the two bonded diaphragms 40 by the aerosol deposition method (AD method) (film forming step). As shown in FIG. 6, the film forming apparatus 50 for forming the piezoelectric layer 41 on the vibration plate 40 surrounds and grips the outer periphery of the two bonded vibration plates 40 provided in the chamber 51 and the chamber 51. A frame-like frame 52, a moving mechanism 60 which is provided in the chamber 51 and reciprocates in the direction parallel to the surface of the diaphragm 40 (Y and Z directions in FIG. 6), and particles of the film forming material And an aerosol chamber 54 in which an aerosol composed of a carrier gas is sealed, and two injection nozzles that are connected to the aerosol chamber 54 and inject the aerosol toward the respective surfaces of the two diaphragms 40 held by the frame 52 55.

  The moving mechanism 60 includes screwed shafts 61 and 65, stepping motors 62 and 66 for rotating the shafts 61 and 65, metal fittings 63 and 67 engaged with the shafts 61 and 65, respectively, and one end portion of the moving mechanism 60. The support member 64 is connected to the metal fitting 63 and has the other end connected to the stepping motor 66. The stepping motor 62 is fixed to the inner wall of the chamber 51. The moving mechanism 60 rotates the shaft 61 by driving the stepping motor 62 to reciprocate the metal fitting 63 in the vertical direction (Z direction) in FIG. The moving mechanism 60 rotates the shaft 65 by driving the stepping motor 66 to reciprocate the metal fitting 67 in a direction (Y direction) perpendicular to the paper surface of FIG. Since the metal fitting 67 is connected to the frame 52, the frame 52 moves in the Y direction as the metal fitting 67 moves in the Y direction. Further, since the metal fitting 63 is connected to the metal fitting 67 via the support member 64, the stepping motor 66, and the shaft 65, the frame 52 moves in the Z direction as the metal fitting 63 moves in the Z direction. With such a configuration, the frame 52 can reciprocate in the surface direction of the diaphragm 40.

  The two injection nozzles 55 are arranged at the same position when viewed from a direction (X direction) orthogonal to the two diaphragms 40 held by the frame 52. The film forming apparatus 50 fixes the positions of the two injection nozzles 55 and moves the positions of the two diaphragms 40 held by the frame 52 back and forth in the plane direction at the same timing from the two injection nozzles 55. Thus, it is possible to inject aerosol and deposit particles at the same position when viewed from the X direction of the two diaphragms 40.

  In such a configuration of the film forming apparatus 50, first, the two bonded diaphragms 40 are held by the frame 52. Next, the piezoelectric layer 41 is formed on each surface of the two diaphragms 40 by the AD method. More specifically, first, the inside of the chamber 51 is brought into a substantially vacuum state by a vacuum pump (not shown). In this state, when a valve 56 provided between the spray nozzle 55 and the aerosol chamber 54 is opened, a mixture (aerosol) of particles of piezoelectric material (PZT) and gas (carrier gas) enclosed in the aerosol chamber 54. ) Is sent to the two injection nozzles 55 in the chamber 51 by the pressure difference between the aerosol chamber 54 and the chamber 51. The two injection nozzles 55 simultaneously spray the aerosol at high speed toward the same position as viewed from the X direction of the two diaphragms 40 held by the frame 52 to deposit particles.

  As the carrier gas, an inert gas such as helium, argon or nitrogen, air, oxygen or the like can be used. Further, during the aerosol injection, the frame 52 is reciprocated in the surface direction of the diaphragm 40 by the moving mechanism 60. As a result, particles of the piezoelectric material contained in the aerosol are deposited in predetermined regions on the respective surfaces of the two diaphragms 40 held by the frame 52, and the piezoelectric layers 41 are formed.

  When the piezoelectric material particles collide with the surface of the diaphragm at a high speed, the surface of the diaphragm is scraped and the strength is lowered. Thereby, when the diaphragm is thin, deformation occurs such that the surface side on which the particles of the piezoelectric material collide is convex. Here, when the two diaphragms 40 are bonded and the piezoelectric material particles collide with the respective surfaces, forces in directions away from each other act on the diaphragms 40. However, as described above, the two diaphragms 40 are firmly bonded and fixed by magnetic force. For this reason, even when the aerosol sprayed from the spray nozzle 55 is subjected to collision, a special reinforcing member is not required, and the film formation target is more than the case where the aerosol is sprayed on only one diaphragm and the piezoelectric layer is formed. Since the two diaphragms 40 that are objects have high rigidity as a whole, deformation of the two diaphragms 40 can be suppressed. By holding the two diaphragms flat without being deformed, the piezoelectric layer 41 having a uniform thickness can be formed on the surfaces of the two diaphragms 40.

  Even when two diaphragms 40 are bonded, if each diaphragm 40 is thin, when the piezoelectric layer 41 is formed by spraying aerosol on the diaphragm 40, the diaphragm 40 is deformed. There is a risk. When the aerosol is sprayed by grasping the end portion of the diaphragm 40, the portion to which the aerosol is sprayed is deformed to be convex toward the spray surface, but the end portion of the diaphragm 40 is fixed, A deformation occurs in which the surface opposite to the spraying surface is convex around the applied portion. That is, when aerosol is sprayed on one diaphragm 40 of the two diaphragms 40, a force in a direction away from the other diaphragm 40 is generated in the portion of the one diaphragm 40 on which the aerosol is sprayed. A force in a direction in which the other diaphragm 40 is pressed is generated in a portion around the portion where the nozzle is sprayed.

  Here, in order to deposit particles by simultaneously spraying aerosol at the same position when viewed from the X direction of the two diaphragms 40, the above-mentioned force in the separating direction and the force in the pressing direction acting on each diaphragm 40 However, the two diaphragms 40 act simultaneously on the same position as viewed from the X direction, and the force acting on one diaphragm 40 can be canceled by the force acting on the other diaphragm 40. Thereby, deformation of the two diaphragms 40 can be further suppressed. Therefore, the piezoelectric layer 41 having a uniform thickness can be formed on the surfaces of the two diaphragms 40. In addition, the two diaphragms 40 are not arranged in the horizontal direction, but are arranged in the vertical direction, and the piezoelectric layer 41 is formed by depositing particles from the X direction. The velocity in the X direction is not affected by gravity, and the piezoelectric layer 41 having the same thickness can be formed on each surface of the diaphragm 40.

  By the way, when the piezoelectric layer 41 is formed by the above-described AD method, particle refinement or lattice defects may occur at the time of particle collision. Therefore, usually, the piezoelectric layer removed from the frame 52 of the film forming apparatus 50 after the film forming process in order to grow the crystal grains of the piezoelectric material and repair the lattice defects in the crystal to improve the piezoelectric characteristics. The two diaphragms 40 each formed with 41 are accommodated in a furnace (not shown) and heat-treated at a predetermined temperature (for example, 900 ° C.) (annealing process).

  Then, this temperature is equal to or higher than the demagnetizing temperature of the vibration plate 40 (about 770 ° C. in the case of an iron-based metal such as ferritic stainless steel), so the direction of the magnetic moment of the atoms aligned in one direction Can be shaken by the influence of thermal energy to remove the magnetization. Thereby, the magnetization which acted between the two diaphragms 40 is removed, and the two diaphragms 40 can be separated. Thereby, in the heating process, the annealing process of the piezoelectric layer 41 and the separation of the two diaphragms 40 by demagnetization of the magnetization of the diaphragm 40 can be performed at the same time, so that the manufacturing process can be performed without increasing the total number of processes. In a simplified manner, the two diaphragms 40 can be separated. In this way, two diaphragms 40 on which the piezoelectric layer 41 is formed can be easily produced in a series of steps, and the production time can be shortened and the production process can be simplified, resulting in high productivity. Become.

  When the heating step is completed, a plurality of individual electrodes 42 are formed on the surface of the piezoelectric layer 41 facing the plurality of pressure chambers 24 by screen printing, vapor deposition, sputtering, etc., and the piezoelectric actuator 7 is manufactured. Complete.

  After that, as shown in FIG. 5B, the vibration plate 40 of the piezoelectric actuator 7 is bonded to the upper surface of the flow path unit 6 where the plurality of pressure chambers 24 are opened by using an adhesive, whereby the inkjet head 3 is manufactured. To complete.

  Next, modified embodiments in which various modifications are made to the embodiment will be described. However, components having the same configuration as in the above embodiment are given the same reference numerals and description thereof is omitted as appropriate.

  In the embodiment, as a method of bonding the two diaphragms 40 before the film forming process, one diaphragm 40 is magnetized, and the two diaphragms 40 are bonded by the magnetic force of the one diaphragm 40. However, various other methods as exemplified below can be adopted.

  1) In a state where two diaphragms 40 are laminated, an external magnetic field having a magnetic flux density component in a direction perpendicular to the plane is applied to the two diaphragms 40 so as to be magnetized and firmly bonded by the magnetic force of both. May be. Also in this case, in the heating process performed after the film forming process of the piezoelectric layer 41, the magnetization of the vibration plate 40 is erased by heating to a temperature higher than the demagnetization temperature of the vibration plate 40, and the two vibration plates 40 can be easily separated. Can do.

  2) Two diaphragms 40 are laminated through water. Then, by placing the two laminated diaphragms 40 in the chamber 51 in the film forming process and evacuating the chamber 51, the boiling point of the water interposed between the two diaphragms 40 is lowered. The water will boil. And when the boiling water changes into water vapor, the heat of vaporization is taken away from the water, and the water is cooled and solidified (freezes) by the removal of the heat of vaporization. Thus, by lowering the temperature of the water to the solidification temperature, the water solidifies and becomes ice, and the two diaphragms 40 may be firmly bonded. In this case, in the heating process performed after the film forming process of the piezoelectric layer 41, the ice intervening between the two diaphragms 40 is melted and returned to water so that the two diaphragms 40 can be easily separated. Can do. Further, in the heating process, even if the heating is not actively performed above the melting point of water, the two diaphragms 40 interposing ice are taken out of the chamber 51, and the ice is naturally returned to water at room temperature. The two diaphragms 40 may be separated. Furthermore, it is not limited to water, and any liquid may be used as long as it is a material that is solidified in the film forming step and melts by raising the temperature.

  3) Two diaphragms 40 may be bonded with an adhesive. Thereby, the two diaphragms 40 can be firmly bonded. In this case, in the heating process performed after the film formation process of the piezoelectric layer 41, the adhesive is thermally decomposed and removed by heating to a temperature equal to or higher than the thermal decomposition temperature of the adhesive, and the two diaphragms 40 are easily separated. be able to. Further, in the heating step, the two diaphragms 40 may be separated by chemically removing the adhesive with a solvent without removing the adhesive by thermal decomposition.

  4) Since the two diaphragms 40 are very thin, they may be electrostatically adsorbed and fixed firmly by simply contacting them under normal pressure. In this case, the pressure inside the chamber 51 during the piezoelectric layer forming process is set to normal pressure, and an atmospheric pressure difference that allows the aerosol to collide with the diaphragm 40 at high speed is generated between the chamber 51 and the aerosol chamber 54. In addition, the aerosol chamber 54 may be in a pressurized state.

  When the two diaphragms 40 are not bonded by the magnetic force as in (2) to (4), the material of the diaphragm 40 is not limited to a ferromagnetic material such as SUS430. For example, a paramagnetic metal material such as SUS304 may be used. Further, ceramics such as zirconia may be used. However, in the case of a diaphragm made of ceramics, this diaphragm has no electrical conductivity and cannot serve as a common electrode. Therefore, it is necessary to separately form a common electrode between the diaphragm and the piezoelectric layer.

  In the present embodiment, the piezoelectric layer 41 is simultaneously formed at the same position when viewed from the X direction of the two diaphragms 40. However, the piezoelectric layer 41 is formed at a different position on each of the two diaphragms 40. Also good. For example, the piezoelectric layer 41 may be formed on the other vibration plate 40 after the piezoelectric layer 41 is formed on one vibration plate 40 using only one injection nozzle 55. At this time, since only one injection nozzle 55 is required, the equipment can be simplified. However, even if the piezoelectric layers 41 are formed at different positions instead of the same position when viewed from the X direction of the two diaphragms, the two film forming nozzles 55 are formed on the surfaces of the two diaphragms 40 with the same film formation time. It is preferable to form the piezoelectric layer 41 because the piezoelectric layer 41 can be quickly formed on the two vibration plates 40.

  In the present embodiment, the frame 52 holding the two diaphragms 40 in the film forming process is reciprocated in the surface direction of the diaphragm 40 to fix the positions of the two injection nozzles 55, and the piezoelectric layer 41, the frame 52 holding the two diaphragms 40 is fixed, and the two injection nozzles 55 are connected to a movement mechanism similar to the movement mechanism 60 of the frame 52, so that the diaphragm 40 The piezoelectric layer 41 may be formed by reciprocating in the surface direction.

  Further, as shown in FIG. 7, two planar plate-like members 140 capable of forming a plurality of diaphragms 40 in the surface direction are stacked, and a plurality of plates are formed on the respective surfaces of the two plate-like members 140. The piezoelectric layers 41 are formed apart from each other, the two plate-like members 140 are separated, and then the plate-like members are divided (cut) between the adjacent piezoelectric layers 41 to form the piezoelectric layer. A plurality of diaphragms may be produced. At this time, an area of the plate-like member that is not the diaphragm can be used for screwing to the frame. In addition, a plurality of diaphragms each having a piezoelectric layer formed thereon can be quickly produced. Note that the film forming step, the heating step, and the step of dividing the plate member may be sequentially performed while moving the two plate members along one direction.

  As described above, in the embodiment described above and the modifications thereof, the present invention is applied to a method for manufacturing a piezoelectric actuator for an inkjet head that records an image or the like by ejecting ink onto a recording sheet. The present invention is not limited to such a piezoelectric actuator for an ink jet head, and can be applied to a method for manufacturing a piezoelectric actuator used for various purposes. In addition, the present invention is applied to a method of manufacturing an ink jet head that discharges ink in a pressure chamber. However, the application target of the present invention is to apply pressure to a liquid in a pressure chamber such as a liquid discharge head that discharges liquid other than ink from a nozzle. Can be applied to a method of manufacturing a liquid transfer device that transfers liquid in a liquid transfer channel including a pressure chamber.

DESCRIPTION OF SYMBOLS 1 Inkjet printer 3 Inkjet head 6 Flow path unit 7 Piezoelectric actuator 40 Diaphragm 41 Piezoelectric layer

Claims (9)

A laminating step of laminating two diaphragms;
A film forming step of forming a piezoelectric layer by spraying aerosol containing particles of a piezoelectric material and a carrier gas on each surface of the two laminated diaphragms to deposit the particles;
And a separation step of separating the two diaphragms on which the piezoelectric layer is formed.   2. The method of manufacturing a piezoelectric actuator according to claim 1, wherein in the film forming step, the piezoelectric layer is formed simultaneously on the surfaces of the two diaphragms. In the piezoelectric layer forming step, the piezoelectric layer is formed on the surface of the vibration plate while changing a relative position between the spray nozzle for spraying the aerosol and the vibration plate,
The said piezoelectric layer formation process WHEREIN: Seeing from the direction orthogonal to the said diaphragm, the said aerosol is simultaneously sprayed on the same position of the said 2 diaphragm, and the said particle | grain is deposited. Manufacturing method of the piezoelectric actuator.   The method for manufacturing a piezoelectric actuator according to claim 1, wherein the two diaphragms are bonded in the stacking step. The two diaphragms are made of a ferromagnetic material,
In the laminating step, by applying an external magnetic field to at least one of the two diaphragms, at least one of the diaphragms is magnetized, and by the magnetic force of the magnetized at least one diaphragm, the 2 Adhere the diaphragm of the sheet,
5. The method of manufacturing a piezoelectric actuator according to claim 4, wherein in the separation step, the magnetized diaphragm is heated to a demagnetization temperature or higher to demagnetize the magnetization of the magnetized diaphragm. In the laminating step, the liquids are solidified by lowering the temperature of the liquid to the solidification temperature of the liquid in a state where the opposing surfaces of the two diaphragms are laminated via the liquid. Glue the diaphragm,
The film forming step is performed in a state where the liquid is solidified,
5. The method of manufacturing a piezoelectric actuator according to claim 4, wherein in the separation step, the liquid is heated to a melting point or higher of the liquid to melt the liquid. In the laminating step, the two diaphragms are bonded with an adhesive,
5. The method of manufacturing a piezoelectric actuator according to claim 4, wherein, in the separation step, the adhesive is removed by heating the adhesive to a temperature equal to or higher than a thermal decomposition temperature of the adhesive. After the film forming step, further comprising an annealing treatment step of heating the piezoelectric layer formed on each of the two diaphragms;
The method for manufacturing a piezoelectric actuator according to claim 5, wherein the annealing process also serves as the separation process, and the two diaphragms are also heated. A flow path unit in which a liquid flow path including a pressure chamber is formed; a diaphragm disposed on at least one surface of the flow path unit so as to cover the pressure chamber; and a vibration plate disposed on the opposite side of the pressure chamber. A method of manufacturing a liquid transfer device comprising: a piezoelectric actuator including a piezoelectric layer formed;
The manufacturing process of the piezoelectric actuator is as follows:
A laminating step of laminating the two diaphragms;
A film forming step of forming the piezoelectric layer by spraying aerosol containing particles of a piezoelectric material and carrier gas on each surface of the laminated diaphragms to deposit the particles;
A separation step of separating the two diaphragms on which the piezoelectric layer is formed; and a method of manufacturing a liquid transfer device.

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