JP2008074091A - Liquid transfer device and manufacturing method for liquid transfer device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid transfer device which can prevent separation of a wiring member and damage of a piezoelectric element as much as possible when an external force acts to the wiring member connected to an electrode of a surface of the piezoelectric element, and to provide a manufacturing method for the liquid transfer device. <P>SOLUTION: A plurality of the piezoelectric elements 31 are arranged at regions respectively opposite a plurality of pressure chambers 14 of a face of the opposite side to the pressure chambers 14 of a diaphragm 30. At the same time, a supporting part 36 formed of the same piezoelectric material as that of the plurality of piezoelectric elements 31 is prepared at a region outside of the regions opposite the plurality of pressure chambers 14. An FPC 50 is electrically connected to discrete electrodes 32 arranged at faces of the opposite side to the diaphragm 30 of the plurality of piezoelectric elements 31. Moreover, the FPC 50 is joined also to a face of the opposite side to the diaphragm 30 of the supporting part 36. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a liquid transfer device for transferring a liquid and a method for manufacturing the liquid transfer device.

  2. Description of the Related Art Conventionally, an inkjet head that ejects ink droplets includes a piezoelectric actuator that applies ejection pressure to ink in a pressure chamber that forms part of an ink flow path.

For example, in the inkjet head of Patent Document 1 (Japanese Patent Laid-Open No. 2005-125773 (FIG. 4)), a flow path including a plurality of nozzles and a plurality of pressure chambers communicating with the plurality of nozzles is formed. And a piezoelectric actuator disposed on one surface of the flow path unit. The piezoelectric actuator includes a diaphragm that covers a plurality of pressure chambers, and a plurality of stacked piezoelectric elements that are discretely arranged in a region of the diaphragm facing the plurality of pressure chambers. Each piezoelectric element is provided with a plurality of internal electrodes for applying an electric field in the thickness direction. The plurality of internal electrodes are vibrations as individual electrodes on the surface of the piezoelectric element and a common electrode of the plurality of piezoelectric elements. Each is connected to the board. In addition, a flexible wiring member (flexible substrate: FPC) is electrically connected to the individual electrodes of the plurality of piezoelectric elements. When a drive voltage is applied to the individual electrodes via the FPC, the piezoelectric element expands and contracts in the stacking direction, and accordingly, the diaphragm is deformed to change the volume in the pressure chamber, thereby changing the pressure chamber. Pressure is applied to the ink. In the piezoelectric actuator having such a configuration, the adjacent piezoelectric elements are separated from each other. Therefore, the deformation of the piezoelectric element to which the drive voltage is applied is difficult to propagate to the adjacent piezoelectric element, and there is an advantage that the crosstalk is small. .
Japanese Patent Laying-Open No. 2005-125773 (FIG. 4)

  However, since the FPC that supplies the driving voltage to the piezoelectric actuator of Patent Document 1 is merely joined to the individual electrodes of a plurality of discretely arranged piezoelectric elements by solder or the like, the FPC and the plurality of piezoelectric elements The joint area is small. Therefore, when some external force is applied to the FPC during manufacturing, the FPC is easily peeled off from the piezoelectric element. Further, there is a possibility that the external force acting on the FPC acts locally on the specific piezoelectric element, and the piezoelectric element is damaged. For this reason, it has become one of the factors that deteriorate the manufacturing yield. Furthermore, since the individual piezoelectric elements are isolated from each other and provided on the diaphragm, the bonding area between the diaphragm and each piezoelectric element is small. Therefore, when an external force acts between the piezoelectric element and the diaphragm provided with the piezoelectric element, the piezoelectric element may be peeled off from the diaphragm individually.

  An object of the present invention is to provide a liquid transfer device capable of preventing the peeling of the wiring member and the damage to the piezoelectric element when external force is applied to the wiring member connected to the electrode on the surface of the piezoelectric element, and It is to provide a method for manufacturing a liquid transfer device. In addition, the code | symbol with the parenthesis attached | subjected to each element shown below is only the illustration of the element, and does not limit each element.

  According to the first aspect of the present invention, a flow path unit (4) in which a liquid flow path including a plurality of pressure chambers (14) arranged along a plane is formed, and the pressure chamber (14) A piezoelectric actuator (5) that applies pressure to the liquid, and the piezoelectric actuator (5) includes a diaphragm (30) disposed in the flow path unit (4) so as to cover the plurality of pressure chambers. A plurality of piezoelectric elements (31) disposed on a surface of the diaphragm (30) opposite to the pressure chamber (14), and a surface of the diaphragm (30) in contact with the plurality of piezoelectric elements (31). And a second electrode (32) disposed on a surface opposite to the surface of the plurality of piezoelectric elements in contact with the diaphragm (30), the plurality of piezoelectric elements (31) ) Are provided opposite to the corresponding pressure chambers (14), and A wiring member (50) having flexibility is connected to the second electrode (32), and a surface of the diaphragm (30) opposite to the pressure chamber (14) is provided. The support member (36) made of the same piezoelectric material as the piezoelectric element (31) is provided in a region different from the region facing the plurality of pressure chambers (14), and the wiring member (50) A liquid transfer device is provided that is joined to a surface of the support portion (36) opposite to the diaphragm (30).

  In this liquid transfer device, when a drive voltage is applied between the first electrode and the second electrode via the wiring member, the piezoelectric element disposed therebetween is distorted, and the diaphragm is deformed accordingly. At this time, since the volume in the pressure chamber changes, pressure is applied to the liquid in the pressure chamber. Here, in the present invention, a support member made of the same piezoelectric material as the piezoelectric element is provided in a region different from the region facing the plurality of pressure chambers on the surface opposite to the pressure chambers of the diaphragm, and the wiring member Is joined to the support. That is, the wiring member is joined to the piezoelectric actuator at the support portion in addition to the connection portions with the plurality of second electrodes. Therefore, it becomes difficult for the wiring member to peel from the piezoelectric actuator when an external force is applied to the wiring member. Here, since the piezoelectric element and the support portion are formed of the same piezoelectric material, their thermal expansion coefficients are the same. Even if the liquid transfer device is repeatedly used in a situation where there is a temperature change, stress due to a difference in thermal expansion coefficient is less likely to occur at the joint portion between the wiring member and the plurality of support portions. For this reason, even when an external force is applied to the wiring member, the wiring member is difficult to peel from the support portion, and the support portion is difficult to peel from the diaphragm. In addition, it is possible to prevent the external force acting on the wiring member from acting locally on the specific piezoelectric element and damaging the piezoelectric element, thereby improving the manufacturing yield. Furthermore, since the support portion is formed of the same piezoelectric material as that of the piezoelectric element, it is possible to simplify the manufacturing process by simultaneously forming the piezoelectric element and the support portion. The present invention also includes a mode in which at least the surface opposite to the pressure chamber of the diaphragm has conductivity, and this conductive surface also serves as the first electrode. In addition, in the present application, “joined to the surface of the support portion opposite to the diaphragm” does not only mean that the wiring member is directly connected to the support portion, but also other members such as surface electrodes. It includes the case where it is indirectly connected to the support portion via the.

  In the liquid transfer device of the present invention, the support portion (36) may be disposed in a region outside the region of the diaphragm (30) facing the plurality of pressure chambers (14). According to this structure, a large external force is likely to act on the wiring member, and the support portion is disposed outside the region facing the plurality of pressure chambers, and the wiring member is fixed to the support portion. The member becomes more difficult to peel off.

  In the liquid transfer device of the present invention, the support portion (36) may be disposed in a region surrounding the region facing the plurality of pressure chambers (14) of the diaphragm (30). According to this structure, since the support portion is disposed so as to surround the region facing the plurality of pressure chambers, and the wiring member is fixed to the support portion, the wiring member is further hardly peeled off.

  In the liquid transfer device of the present invention, the first electrode is a common electrode of the plurality of piezoelectric elements (31) formed on the surface of the diaphragm (30) opposite to the pressure chamber (14) without any gap. The second electrode (32) can be an individual electrode of each of the plurality of piezoelectric elements (14). When the second electrode is an individual electrode, the wiring member is connected to each of the plurality of individual electrodes. When the piezoelectric actuator is driven, a driving voltage is selectively applied to the plurality of individual electrodes. Therefore, it is necessary that each of the plurality of individual electrodes and the wiring member is securely connected. In such a case, the reliability of the electrical connection for applying the drive voltage to the plurality of individual electrodes is increased by fixing the wiring member to the support portion and preventing the separation of the wiring member. .

  In the liquid transfer device of the present invention, the diaphragm (30) has a conductive surface as the common electrode on the side opposite to the pressure chamber (14), and the diaphragm (30) of the support portion (36). The surface electrode (37) is formed on the surface opposite to the surface, the surface electrode (37) and the conductive surface of the diaphragm (30) are electrically connected, and the wiring member (50) It can be electrically connected to the electrode (37). According to this structure, since the diaphragm has a conductive surface on the side opposite to the pressure chamber, it is not necessary to provide a common electrode separately from the diaphragm for generating an electric field in the piezoelectric element facing the individual electrode. Furthermore, since the wiring member is electrically connected to the conductive surface of the diaphragm via the surface electrode, it is possible to apply a predetermined reference potential to the conductive surface as the common electrode.

  In the liquid transfer device of the present invention, the wiring member (50) can be joined to the surface of the support portion (36) opposite to the diaphragm (30) by a thermosetting adhesive (40). Joining with a thermosetting adhesive has a stronger joining strength than joining with solder, and therefore, peeling of the wiring member is more reliably prevented. Further, since the adhesive is thermosetting, when the plurality of second electrodes and the wiring member are bonded by heating and melting the solder, it is possible to bond the wiring member and the support portion at the same time.

  In the liquid transfer device of the present invention, the thermosetting adhesive (40) may be conductive. The wiring member is connected to the surface electrode via a thermosetting adhesive, and the surface electrode and the conductive surface of the diaphragm are electrically connected. Therefore, it is possible to always keep the potential of the diaphragm at the ground potential by the control unit connected to the wiring member.

  In the liquid transfer device of the present invention, the support (36) may extend in the longitudinal direction of the wiring member (50). Thereby, a support part can be used as a surface and the conduction | electrical_connection part which conducts a surface electrode and a diaphragm can be provided in the arbitrary positions in the longitudinal direction of a support part.

  In the liquid transfer device of the present invention, the width of the support portion (36) in the direction orthogonal to the extending direction of the support portion (36) may be different in the extending direction. Thereby, the joining area of a support part and a wiring member can be increased.

  In the liquid transfer device of the present invention, the liquid transfer device may be an ink jet head.

  According to a second aspect of the present invention, there is provided a method for manufacturing a liquid transfer device including a piezoelectric actuator (5), wherein the flow has a liquid flow path including a plurality of pressure chambers (14) arranged along a plane. A step of providing a path unit (4), a step of disposing a diaphragm (30) in the flow path unit (4) so as to cover the plurality of pressure chambers (14), and the pressure of the diaphragm (30) An element formation step of forming a plurality of piezoelectric elements (31) isolated from each other by discretely depositing particles of piezoelectric material on a surface opposite to the chamber (14); and the plurality of piezoelectric elements (31) A first electrode forming step of forming a first electrode on the surface of the diaphragm (30) in contact; and a second electrode on a surface opposite to the surfaces of the plurality of piezoelectric elements (31) in contact with the diaphragm (30). (32) forming a second electrode; and (32) a wiring connection step of connecting a flexible wiring member (50), and in the element formation step, the vibration plate (30) has a surface opposite to the pressure chamber (14). The plurality of piezoelectric elements (31) and a support portion (36) made of the same piezoelectric material as the piezoelectric elements (31) are simultaneously formed, and in the wiring connection step, the wiring member (50) is connected to the second member. A method for manufacturing a liquid transfer device is provided which is connected to the electrode (32) and bonded to the surface of the support portion (36) opposite to the diaphragm (30).

  According to the method for manufacturing the liquid transfer device, in the element forming step, a plurality of piezoelectric elements and a support portion made of the same piezoelectric material as the piezoelectric elements are formed on the surface of the diaphragm opposite to the pressure chamber. In the wiring connection step, the wiring member is connected to the second electrode, and the wiring member is also bonded to the support portion. That is, the wiring member is joined to the piezoelectric actuator at the support portion in addition to the connection portions with the plurality of second electrodes. Therefore, it becomes difficult for the wiring member to peel from the piezoelectric actuator when an external force is applied to the wiring member. In addition, it is possible to prevent the external force acting on the wiring member from acting locally on the specific piezoelectric element and damaging the piezoelectric element, thereby improving the manufacturing yield. Furthermore, the manufacturing process can be simplified by simultaneously forming the piezoelectric element and the support portion. This manufacturing method includes a mode in which at least a surface opposite to the pressure chamber of the diaphragm has conductivity, and the conductive surface also serves as the first electrode.

  In the method for manufacturing a liquid transfer device according to the present invention, in the element forming step, the support portion (36) is provided in a region outside the region facing the plurality of pressure chambers (14) of the diaphragm (30). Can be formed. In this way, a large external force is likely to act on the wiring member, a support portion is formed in a region outside the region facing the plurality of pressure chambers, and the wiring member is joined to the support portion, whereby the wiring member is Furthermore, it becomes difficult to peel.

  In the method for manufacturing a liquid transfer device of the present invention, the first electrode is formed on the surface of the diaphragm (30) opposite to the pressure chamber (14) without a gap, and the plurality of piezoelectric elements (31) A common electrode, the second electrode (32) is an individual electrode of each of the plurality of piezoelectric elements (31), and the diaphragm (30) is opposite to the pressure chamber (14). The common electrode has a conductive surface, and in the electrode forming step, a surface electrode (37) is disposed on the surface of the support portion (36) opposite to the diaphragm (30), and the plurality of individual electrodes. At the same time, a conductive portion (38) is formed to connect the surface electrode (37) and the conductive surface of the diaphragm (30), and in the wiring connection step, the wiring member (50) and the surface Electrically connected to electrode (37) It may be.

  Thus, when the diaphragm has a conductive surface on the side opposite to the pressure chamber, and this conductive surface also serves as a common electrode, the common electrode for generating an electric field in the piezoelectric element facing the individual electrode Need not be provided separately. Furthermore, since the wiring member is electrically connected to the conductive surface of the diaphragm via the surface electrode, it is possible to apply a predetermined reference potential to the conductive surface as the common electrode.

  In the method for manufacturing a liquid transfer device of the present invention, in the wiring connection step, the wiring member (50) and the surface of the support portion (36) opposite to the diaphragm (30) are bonded to a thermosetting adhesive. You may join using (40). Joining with a thermosetting adhesive has a stronger joining strength than joining with solder, and therefore, peeling of the wiring member is more reliably prevented. Further, since the adhesive is thermosetting, when the plurality of second electrodes and the wiring member are bonded by heating and melting the solder, it is possible to bond the wiring member and the support portion at the same time.

  In the method for manufacturing a liquid transfer device of the present invention, the thermosetting adhesive may be conductive. In the wiring member, the surface electrode connected to the surface electrode via a thermosetting adhesive and the conductive surface of the diaphragm are electrically connected. Therefore, it is possible to always keep the potential of the diaphragm at the ground potential by the control unit connected to the wiring member.

  In the method for manufacturing a liquid transfer device of the present invention, the support portion may extend in the longitudinal direction of the wiring member. Thereby, a support part can be used as a surface and the conduction | electrical_connection part which conducts a surface electrode and a diaphragm can be provided in the arbitrary positions in the longitudinal direction of a support part.

  In the method for manufacturing a liquid transfer device of the present invention, the width of the support portion in the direction orthogonal to the direction in which the support portion extends may be varied in the longitudinal direction. Thereby, the joining area of a support part and a wiring member can be increased.

  In the method for manufacturing a liquid transfer device of the present invention, the liquid transfer device may be an ink jet head.

  According to the present invention, the support member made of the same piezoelectric material as the piezoelectric element is provided in a region different from the region facing the plurality of pressure chambers on the surface opposite to the pressure chambers of the diaphragm, and the wiring member supports It is joined to the part. That is, the wiring member is joined to the piezoelectric actuator at the support portion in addition to the connection portions with the plurality of second electrodes. Therefore, it becomes difficult for the wiring member to peel from the piezoelectric actuator when an external force is applied to the wiring member. In addition, it is possible to prevent the external force acting on the wiring member from acting locally on the specific piezoelectric element and damaging the piezoelectric element, thereby improving the manufacturing yield. Furthermore, since the support portion is made of the same piezoelectric material as the piezoelectric element, the piezoelectric element and the support portion can be formed simultaneously.

  Embodiments of the present invention will be described. In this embodiment, as a liquid transfer device, an ink jet head that applies pressure to ink and transfers the ink to a nozzle, and ejects ink droplets from the nozzle onto a recording sheet to record a desired image, character, or the like. It is an example to which the present invention is applied.

  First, an ink jet printer provided with the ink jet head of this embodiment will be briefly described. As shown in FIG. 1, an inkjet printer 100 includes a carriage 2 that can move in the left-right direction in FIG. 1, a serial type inkjet head 1 that is provided on the carriage 2 and that ejects ink onto recording paper P, A transport roller 3 for transporting the recording paper P forward in FIG. 1 is provided. The inkjet head 1 moves in the left-right direction (scanning direction) integrally with the carriage 2 and ejects ink onto the recording paper P from the nozzles 20 (see FIGS. 2 to 5) disposed on the lower surface thereof. Record desired characters and images. The recording paper P on which an image or the like is recorded by the inkjet head 1 is discharged forward (paper feeding direction) by the transport roller 3.

  Next, the inkjet head 1 will be described. As shown in FIGS. 2 to 5, the inkjet head 1 includes a flow path unit 4 in which an ink flow path including a nozzle 20 and a pressure chamber 14 is formed, and a piezoelectric actuator that applies ejection pressure to ink in the pressure chamber 14. And 5.

  First, the flow path unit 4 will be described. As shown in FIGS. 4 and 5, the flow path unit 4 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. Yes. Among these, the cavity plate 10, the base plate 11 and the manifold plate 12 are stainless steel plates, and ink flow paths such as a manifold 17 and a pressure chamber 14 described later can be easily etched in these three plates 10-12. It can be formed. 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. Or this nozzle plate 13 may be formed with metal materials, such as stainless steel, similarly to the three plates 10-12.

  As shown in FIGS. 2 to 5, among the four plates 10 to 13, the cavity plate 10 located at the uppermost position has holes through which a plurality of pressure chambers 14 arranged along a plane penetrate the plate 10. It is formed by. The plurality of pressure chambers 14 are arranged in two rows in a staggered manner in the paper feeding direction (vertical direction in FIG. 2). The plurality of pressure chambers 14 are respectively covered with a diaphragm 30 and a base plate 11 described later from above and below. Furthermore, each pressure chamber 14 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 15 and 16 are formed at positions where the base plate 11 overlaps both end portions of the pressure chamber 14 in a plan view, respectively. The manifold plate 12 is formed with two manifolds 17 extending in the paper feeding direction so as to overlap with the communication hole 15 side portions of the pressure chambers 14 arranged in two rows in a plan view. These two manifolds 17 communicate with an ink supply port 18 formed in a vibration plate 30 described later, and ink is supplied to the manifold 17 from an ink tank (not shown) via the ink supply port 18. Furthermore, a plurality of communication holes 19 that are continuous with the plurality of communication holes 16 are also formed at positions where the manifold plate 12 overlaps the ends of the plurality of pressure chambers 14 opposite to the manifold 17 in plan view.

  Further, a plurality of nozzles 20 are formed at positions where the nozzle plate 13 respectively overlaps the plurality of communication holes 19 in plan view. As shown in FIG. 2, the plurality of nozzles 20 are arranged so as to respectively overlap the ends of the plurality of pressure chambers 14 arranged in two rows along the paper feed direction on the side opposite to the manifold 17. That is, the plurality of nozzles 20 are arranged in two rows in a staggered manner corresponding to the plurality of pressure chambers 14 respectively.

  As shown in FIG. 4, 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, a plurality of individual ink flow paths 21 extending from the manifold 17 to the nozzles 20 through the pressure chambers 14 are formed in the flow path unit 4.

  Next, the piezoelectric actuator 5 will be described. As shown in FIGS. 2 to 5, the piezoelectric actuator 5 includes a vibration plate 30 disposed on the upper surface of the cavity plate 10 so as to cover the plurality of pressure chambers 14, and an upper surface 30 a (the pressure chamber 14 and the pressure chamber 14). The plurality of piezoelectric elements 31 respectively disposed in regions facing the plurality of pressure chambers 14 and the top surfaces 31c of the plurality of piezoelectric elements 31 (surfaces opposite to the diaphragm 30). And a plurality of individual electrodes 32 (second electrodes). The piezoelectric elements 31 are isolated from each other and are dispersed in an island shape on the upper surface 30 a of the diaphragm 30.

  The diaphragm 30 is a substantially rectangular metal plate in plan view, and is made of, for example, an iron-based alloy such as stainless steel, a copper-based alloy, a nickel-based alloy, or a titanium-based alloy. The diaphragm 30 is joined to the cavity plate 10 in a state of being disposed on the upper surface of the cavity plate 10 so as to cover the plurality of pressure chambers 14. Further, the upper surface 30 a (conductive surface) of the conductive diaphragm 30 is disposed on the lower surface 31 d side of the plurality of piezoelectric elements 31, so that the piezoelectric element 31 has a thickness between the plurality of individual electrodes 32 on the upper surface. It also serves as a common electrode (first electrode) of the plurality of piezoelectric elements 31 that generates an electric field in the direction. Therefore, it is not necessary to provide a common electrode separately from the diaphragm 30, and the configuration of the piezoelectric actuator 5 is simplified correspondingly. The diaphragm 30 as the common electrode is always held at the ground potential which is the reference potential. The configuration for that will be described in detail later.

  Each of the plurality of piezoelectric elements 31 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 plurality of piezoelectric elements 31 are arranged in two rows in the paper feed direction corresponding to the plurality of pressure chambers 14, respectively. Each piezoelectric element 31 is formed in a substantially elliptical shape that is slightly smaller than the pressure chamber 14, and a drive unit 31 a disposed in a region facing the central portion of the plurality of pressure chambers 14 on the upper surface 30 a of the diaphragm 30; A contact arrangement portion 31b that extends from one end portion of the drive portion 31a (an end portion on the outer side in the left-right direction in FIG. 2) to the region outside the peripheral edge of the pressure chamber 14 along the longitudinal direction thereof.

  Further, the upper surface of the vibration plate 30 is formed of the same piezoelectric material as the plurality of piezoelectric elements 31 in a region outside the region facing the plurality of pressure chambers 14 in the paper feeding direction (vertical direction in FIG. 2). Two support portions 36 are disposed so as to sandwich the plurality of piezoelectric elements 31. These two support portions 36 are formed with substantially the same thickness as the piezoelectric element 31. Further, a surface electrode 37 is formed on almost the entire upper surface of the two support portions 36, and is further disposed on the upper surface of the support portions 36 on the outer end face in the paper feeding direction of the two support portions 36. A plurality of conductive portions 38 made of a conductive material are provided across the surface electrode 37 and the upper surface 30a (conductive surface) of the diaphragm 30 positioned below the support portion 36. The surface electrode 37 and the upper surface 30a of the diaphragm 30 are electrically connected.

  Each individual electrode 32 has a substantially elliptical planar shape, and is disposed on the upper surface of the corresponding drive portion 31a of the piezoelectric element 31 (the upper surface 31c of the piezoelectric element 31). In addition, a contact portion 35 drawn from the end portion of the individual electrode 32 in the longitudinal direction is disposed in the contact placement portion 31 b of each piezoelectric element 31. The tip of the contact portion 35 drawn out from the individual electrode 32 is located in a relatively high rigidity area outside the periphery of the pressure chamber 14 in plan view.

  2 to 5, above the piezoelectric actuator 5, a flexible printed wiring board (Flexible) which is a flexible wiring member connected to a driver IC as a driving circuit (not shown) is provided. A printed circuit (FPC) 50 is disposed so as to cover the plurality of piezoelectric elements 31 (the plurality of individual electrodes 32). The FPC 50 includes a sheet-like base material 51 made of an insulating and flexible material such as a synthetic resin material, and a plurality of wiring portions 52 formed on the lower surface of the base material 51 facing the individual electrodes 32. It has. The wiring portion 52 of the FPC 50 and the plurality of contact portions 35 respectively drawn from the plurality of individual electrodes 32 are electrically connected by solder 39. As a result, a drive voltage can be selectively applied from the driver IC to the plurality of individual electrodes 32 via the FPC 50.

  By the way, some of the plurality of wiring portions 52 of the FPC 50 are not connected to the plurality of individual electrodes 32 and are mechanically joined to the surface electrodes 37 respectively formed on the two support portions 36 by the adhesive 40. . Moreover, the adhesive 40 used here is a thermosetting adhesive having conductivity in which conductive particles are contained in a thermosetting resin such as an epoxy resin. Therefore, the wiring part 52 of the FPC 50 and the surface electrode 37 are also electrically connected via the adhesive 40, and as a result, the diaphragm 30 is electrically connected to the driver IC via the wiring part 52 of the FPC 50. Then, the driver IC always maintains the potential of the diaphragm 30 serving also as the common electrode of the plurality of piezoelectric elements 31 at the ground potential via the wiring portion 52, the surface electrode 37, and the conduction portion 38 of the FPC 50. .

  As described above, the FPC 50 that is electrically connected to the contact portions 35 of the plurality of piezoelectric elements 31 is supported from below by the two support portions 36 having the same thickness as the piezoelectric elements 31, and further, by the adhesive 40. Since it is mechanically fixed to the two support portions 36, even when some external force acts on the FPC 50, the FPC 50 becomes difficult to peel off from the plurality of piezoelectric elements 31, and a drive voltage is applied to the plurality of individual electrodes 32. The reliability of the electrical connection for applying is increased. Further, it is possible to prevent the external force acting on the FPC 50 from acting locally on the specific piezoelectric element 31 and damaging the piezoelectric element 31. Further, as shown in FIG. 2, the two support portions 36 are disposed in a region outside the region where the plurality of pressure chambers 14 (the plurality of piezoelectric elements 31) are disposed. That is, the FPC 50 is fixed by the two support portions 36 in a region outside the plurality of piezoelectric elements 31 where a large external force is likely to be applied, so that the separation from the piezoelectric actuator 5 is more reliably prevented. In particular, the piezoelectric element and the support portion are formed of the same piezoelectric material, and their thermal expansion coefficients are the same. Therefore, even if the liquid transfer device is repeatedly used in a situation where there is a temperature change, stress due to the difference in thermal expansion coefficient is less likely to occur at the joint portion between the wiring member and the plurality of support portions. Therefore, even when an external force is applied to the wiring member, the wiring member is hardly separated from the support portion, and the support portion is difficult to peel from the diaphragm.

  Note that the wiring portion 52 of the FPC 50 and the surface electrode 37 may be electrically and mechanically joined by soldering instead of the conductive thermosetting adhesive described above. However, since the bonding strength of the solder is inferior to that of the thermosetting adhesive, it is preferable that both are bonded by the thermosetting adhesive from the viewpoint of reliably bonding the FPC 50 and the support portion 36. .

  Next, the operation of the piezoelectric actuator 5 during ink ejection will be described. When a drive voltage is selectively applied from the driver IC to the plurality of individual electrodes 32 via the FPC 50, the drive electrode 31a upper side (the upper surface 31c of the piezoelectric element 31) of the piezoelectric element 31 to which the drive voltage is applied is applied. Since the individual electrode 32 and the potential of the diaphragm 30 as a common electrode on the lower side of the piezoelectric element 31 (the lower surface 31d of the piezoelectric element 31) held at the ground potential are different from each other, An electric field in the thickness direction is generated in the piezoelectric element 31 sandwiched between the plates 30. When the polarization direction of the piezoelectric element 31 and the direction of the electric field are the same, the piezoelectric element 31 extends in the thickness direction, which is the polarization direction, and contracts in the horizontal direction. The portion of the diaphragm 30 that faces the pressure chamber 14 is deformed so as to protrude toward the pressure chamber 14. At this time, since the volume of the pressure chamber 14 is reduced, pressure is applied to the ink inside the pressure chamber 14, and ink droplets are ejected from the nozzle 20 communicating with the pressure chamber 14.

  Next, a method for manufacturing the inkjet head 1 will be described. First, holes that constitute part of the ink flow path are formed in the four plates (cavity plate 10, base plate 11, manifold plate 12, and nozzle plate 13) constituting the flow path unit 4 by etching, laser processing, or the like. After the formation, as shown in FIG. 6, these four plates 10 to 13 are laminated with five plates obtained by adding a metallic diaphragm 30 and bonded by an adhesive, metal diffusion bonding, or the like.

  Next, as shown in FIGS. 7 and 8, a mask 60 is disposed on the upper surface of the diaphragm 30. As shown in FIG. 9, the mask 60 has a plurality of through holes 60 a having a shape corresponding to the shape of the piezoelectric element 31 described above. They are arranged in two rows so as to face the central portions of the plurality of pressure chambers 14 when arranged on the upper surface. As shown in FIG. 7, the length of the mask 60 in the arrangement direction of the pressure chambers 14 is slightly longer than one row of pressure chambers and shorter than the diaphragm 30. Accordingly, the region on the upper surface of the vibration plate 30 where the plurality of holes 60 a of the mask 60 are arranged and the regions outside both sides in the arrangement direction of the pressure chambers 14 are not covered with the mask 60.

  After disposing the mask 60 on the upper surface of the vibration plate 30 in this way, as shown in FIGS. 10 and 11, the particles of the piezoelectric material are deposited on the upper surface of the vibration plate 30 covered with the mask 60, and then, FIG. As shown in FIG. 5, by removing the mask 60 from the diaphragm 30, the plurality of piezoelectric elements 31 having the drive unit 31a and the contact arrangement unit 31b are respectively provided in the regions where the plurality of holes 60a of the mask 60 are arranged. Form (element formation step). Here, as a method for depositing the piezoelectric material on the upper surface of the vibration plate 30, for example, an aerosol deposition method in which particles composed of fine particles and carrier gas are sprayed onto the substrate (vibration plate 30) to deposit the particles. AD method), sputtering method, CVD (chemical vapor deposition) method and the like can be employed. Since a ceramic material is used for the piezoelectric element, an AD method capable of depositing such a material at a desired site is particularly advantageous.

  Here, as described above, since the length of the mask 60 in the arrangement direction of the pressure chambers 14 is shorter than that of the diaphragm 30, the mask 60 is disposed in a region outside the arrangement direction with respect to the plurality of pressure chambers 14. The particles of the piezoelectric material are deposited, and as shown in FIG. 10, two support portions 36 having substantially the same thickness as the plurality of piezoelectric elements 31 are formed in these regions. That is, in this element forming step, the plurality of piezoelectric elements 31 are discretely formed on the upper surface of the vibration plate 30, and the two support portions 36 are formed in a region outside the plurality of piezoelectric elements 31. As described above, since the plurality of piezoelectric elements 31 and the two support portions 36 made of the same piezoelectric material can be simultaneously formed, the manufacturing process is simplified.

  Next, as shown in FIGS. 13 and 14, a plurality of individual electrodes 32 made of a conductive material are formed on the upper surfaces of the drive portions 31 a and the contact placement portions 31 b of the plurality of piezoelectric elements 31 by screen printing, vapor deposition, or the like. A plurality of contact portions 35 are formed (electrode formation step). At the same time, the surface electrode 37 is formed on almost the entire upper surface of the two support portions 36. A plurality of conductive portions 38 made of a conductive material are formed on the outer end surfaces of the two support portions 36 with respect to the arrangement direction of the pressure chambers 14 from the surface electrode 37 to the upper surface 30 a of the diaphragm 30. Then, the surface electrode 37 and the diaphragm 30 are electrically connected by the plurality of conductive portions 38. Note that either the surface electrode 37 or the conductive portion 38 may be formed first. That is, the conductive portion 38 may be formed after the surface electrode 37 is formed on the upper surface of the support portion 36, or the conductive portion 38 is formed on the end surface of the support portion 36 and then the conductive portion 38 is formed on the upper surface of the support portion 36. The surface electrode 37 may be formed so as to be in contact with 38.

  Finally, as shown in FIG. 15, a flexible FPC 50 is arranged so as to cover the plurality of individual electrodes 32, and a plurality of wiring portions 52 formed on the lower surface of the base 51 of the FPC 50, and a piezoelectric element A plurality of contact portions 35 formed on the upper surface 31c of 31 are joined by solder 39, and both are electrically connected (wiring connection step). Here, since the tip end portion of the contact portion 35 is drawn out to the outside and the highly rigid region beyond the peripheral edge of the pressure chamber 14, the solder portion 39 is sufficiently pressed against the contact portion 35 while pressing the wiring portion 52 of the FPC 50 sufficiently. They can be joined, and the joining state of both is improved.

  Further, in this wiring connection process, the wiring part 52 and the surface electrode 37 that are not connected to the contact part 35 of the FPC 50 are electrically and mechanically joined by the conductive adhesive 40 (see FIGS. 2 and 5). ). Here, by using a thermosetting adhesive whose main component is an epoxy resin or the like as the adhesive 40, the solder 39 can be heated and melted and the adhesive 40 can be heated and cured simultaneously. That is, it is possible to simultaneously join the FPC 50 and the individual electrode 32 (contact point portion 35) and the FPC 50 and the surface electrode 37, thereby reducing the time required for these joining steps.

  According to the inkjet head 1 and the manufacturing method thereof described above, the following effects can be obtained.

  Two support portions 36 made of the same piezoelectric material as the piezoelectric element 31 are provided in a region outside the plurality of pressure chambers 14 on the upper surface 30 a of the vibration plate 30, and the FPC 50 is joined to the two support portions 36. Yes. That is, the FPC 50 is joined to the piezoelectric actuator 5 at the support portion 36 in addition to the connection portions with the plurality of individual electrodes 32 (the plurality of contact portions 35). Therefore, when an external force is applied to the FPC 50, the FPC 50 is difficult to peel off from the piezoelectric actuator 5, and the reliability of electrical connection for applying a driving voltage to the plurality of individual electrodes 32 is increased. In addition, it is possible to prevent the external force acting on the FPC 50 from acting locally on the specific piezoelectric element 31 and damaging the piezoelectric element 31, thereby improving the manufacturing yield. In particular, since the support portion 36 is made of the same material as that of the piezoelectric element 31, the stress strain caused by the temperature change in the atmosphere is caused by the FPC 50, the joint between the FPC 50 and the piezoelectric element 31, and Less likely to occur at joints.

  Further, by adopting a method of depositing the particles of the piezoelectric element 31 on the upper surface of the vibration plate 30, a plurality of piezoelectric elements 31 and two support portions 36 made of the same piezoelectric material can be simultaneously formed. Can be simplified.

  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.

  1] The installation position of the support portion to be joined to the FPC can be changed as appropriate in consideration of the arrangement of the piezoelectric elements, the flow path structure, and the like within a region different from the region facing the plurality of pressure chambers. For example, as shown in FIG. 16, the support portion 36 </ b> A joined to the FPC 50 is formed so as to surround the plurality of piezoelectric elements 31 in a region surrounding the plurality of pressure chambers 14 on the upper surface of the diaphragm 30. It may be. According to this configuration, since the FPC is fixed to the support portion 36A on the entire circumference of the region outside the plurality of piezoelectric elements 31 where a large external force is likely to act on the FPC 50, the separation of the FPC 50 is further reliably prevented.

  Alternatively, although not particularly illustrated, a support portion may be disposed in a region between the plurality of piezoelectric elements 31 on the upper surface 30a of the diaphragm 30, and such a support portion and the FPC 50 may be joined. Even in this case, the effect of preventing the peeling of the FPC 50 as described above can be obtained to some extent as compared with the case where the support portion is not provided.

  2] In the above-described embodiment, all the piezoelectric elements are arranged in a state of being completely separated from the surroundings, but adjacent piezoelectric elements may be partially connected. For example, as shown in FIG. 17, the piezoelectric elements 31 </ b> B arranged in the paper feeding direction may be partially separated by a hole 70 extending in the longitudinal direction of the pressure chamber 14 between the piezoelectric elements 31 </ b> B. . Even in this configuration, the deformation does not easily propagate between the piezoelectric elements 31B close to the paper feed direction, so that crosstalk is suppressed. However, in particular, since there is no piezoelectric material layer along the FPC 50 in the outer region with respect to the paper feed direction in which the plurality of piezoelectric elements 31B are divided, a large external force is likely to act on the FPC 50 and the FPC 50 is easily peeled off. Therefore, the present invention is applied to such a configuration, and the support portion 36 is provided in a region outside the plurality of piezoelectric elements 31B in the paper feeding direction, and the FPC 50 is mechanically joined to the support portion 36. Accordingly, similarly to the above-described embodiment, it is possible to prevent the FPC 50 from being peeled off and the piezoelectric element 31B from being damaged.

  3] The diaphragm 30 as the common electrode is not necessarily held at the ground potential via the FPC 50, and may be held at the ground potential by other configurations. In this case, the surface electrode 37 and the conduction portion 38 on the upper surface of the support portion 36 are not necessary, and the support portion 36 and the FPC 50 may be merely mechanically joined with an adhesive or the like.

  4] It is not always necessary that the diaphragm 30 also serves as a common electrode, and a common electrode made of a conductive material may be formed on the upper surface 30a of the diaphragm 30 separately from the diaphragm. However, in this case, it is necessary that at least the upper surface of the diaphragm has an insulating property.

  5] In the above embodiment, a plurality of individual electrodes 32 are arranged on the upper surfaces 31c of the plurality of piezoelectric elements 31, and a drive voltage is selectively applied to the plurality of individual electrodes 32 via the FPC 50. However, the arrangement relationship between the electrode to which the drive voltage is applied and the electrode held at the ground potential may be reversed. That is, an electrode (an electrode corresponding to the individual electrode 32 in the above embodiment) to which a driving voltage is selectively applied is arranged on the upper surface of the insulating diaphragm, and on the other hand, each electrode is arranged on the upper surface of the plurality of piezoelectric elements. Further, the FPC may be connected to the other electrode (the electrode corresponding to the common electrode), and the electrodes on the upper surfaces of the plurality of piezoelectric elements may be always held at the ground potential via the FPC.

  6] In the manufacturing method of the above embodiment, a plurality of piezoelectric elements 31 and support portions 36 are formed by depositing particles of piezoelectric material on the upper surface 30a of the vibration plate 30 (see FIGS. 10 and 11). ), The method of forming the piezoelectric element and the support portion is not limited to this. For example, a piezoelectric sheet obtained by firing a green sheet is cut to form a plurality of piezoelectric elements and supporting parts, and these piezoelectric elements and supporting parts are individually bonded to the upper surface of the diaphragm with an adhesive or the like. May be. Alternatively, the piezoelectric sheet may be attached to the upper surface of the diaphragm, and then the piezoelectric sheet may be cut into a plurality of piezoelectric elements and support portions.

  The above-described embodiment and its modifications are examples in which the present invention is applied to an inkjet head that ejects ink from nozzles. However, targets to which the present invention can be applied are not limited to such an inkjet head. For example, a conductive paste is sprayed to form a fine wiring pattern on the substrate, an organic light emitter is sprayed to the substrate to form a high-definition display, and an optical resin is sprayed to the substrate. The present invention can be applied to various droplet ejecting apparatuses for forming microelectronic devices such as optical waveguides.

  In addition to a liquid droplet ejecting apparatus, the apparatus transfers a liquid in a pressure chamber using a piezoelectric actuator, and can be applied to any liquid transferring apparatus as long as the electrode of the piezoelectric actuator is joined by a wiring member. Is possible. For example, a liquid transfer device that transfers a liquid such as a chemical solution or a biochemical solution inside a micro total analysis system (μTAS), a liquid transfer device that transfers a liquid such as a solvent or a chemical solution inside a microchemical system, etc. The present invention can also be applied to a liquid transfer device for transferring the liquid.

1 is a schematic configuration diagram of an inkjet printer according to an embodiment of the present invention. 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 the VV sectional view taken on the line of FIG. It is sectional drawing of the inkjet head in the middle of manufacture in the state in which the plate and diaphragm which comprise a flow path unit were joined. It is a top view of the inkjet head in the state where the mask is arrange | positioned on the upper surface of a diaphragm. It is the VIII-VIII sectional view taken on the line of FIG. It is a top view of a mask. FIG. 3 is a plan view of the ink jet head in a state where particles of piezoelectric material are deposited on the upper surface of a vibration plate. It is the XI-XI sectional view taken on the line of FIG. It is sectional drawing of the inkjet head in the state from which the mask was removed. It is a top view of the inkjet head in the state in which the individual electrode, the contact part, and the surface electrode were formed. It is the XIV-XIV sectional view taken on the line of FIG. It is sectional drawing of the inkjet head in the state in which FPC was connected. It is a top view of the ink jet head concerning a change form. It is a top view of the ink-jet head concerning another modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inkjet head 5 Piezoelectric actuator 14 Pressure chamber 30 Diaphragm 31, 31B Piezoelectric element 32 Individual electrode 35 Contact part 36, 36A Support part 37 Surface electrode 38 Conductive part 40 Adhesive 50 Flexible printed wiring board (FPC)

Claims (18)

A flow path unit in which a liquid flow path including a plurality of pressure chambers arranged along a plane is formed, and a piezoelectric actuator that applies pressure to the liquid in the pressure chamber,
The piezoelectric actuator is
A diaphragm disposed in the flow path unit so as to cover the plurality of pressure chambers;
A plurality of piezoelectric elements disposed on a surface of the diaphragm opposite to the pressure chamber;
A first electrode disposed on a surface of the diaphragm in contact with the plurality of piezoelectric elements;
A second electrode disposed on a surface opposite to a surface of the plurality of piezoelectric elements in contact with the diaphragm;
With
The plurality of piezoelectric elements are disposed opposite to the corresponding pressure chambers, and are disposed separately from each other,
A flexible wiring member is connected to the second electrode, and the piezoelectric plate is provided on a surface of the diaphragm opposite to the pressure chambers in a region different from a region facing the plurality of pressure chambers. A support made of the same piezoelectric material as the element is provided,
The liquid transfer device according to claim 1, wherein the wiring member is joined to a surface of the support portion opposite to the diaphragm.   2. The liquid transfer device according to claim 1, wherein the support portion is disposed in a region outside the region of the diaphragm facing the plurality of pressure chambers.   The liquid transfer device according to claim 2, wherein the support portion is arranged in a region surrounding the region facing the plurality of pressure chambers of the diaphragm. The first electrode is a common electrode of the plurality of piezoelectric elements formed on the surface of the diaphragm opposite to the pressure chamber without a gap,
The liquid transfer device according to claim 1, wherein the second electrode is an individual electrode of each of the plurality of piezoelectric elements. The diaphragm has a conductive surface as the common electrode on a surface opposite to the pressure chamber,
A surface electrode is formed on the surface of the support portion opposite to the diaphragm, and the surface electrode and the conductive surface of the diaphragm are electrically connected.
Furthermore, the said wiring member is electrically connected with the said surface electrode, The liquid transfer apparatus of Claim 4 characterized by the above-mentioned.   The liquid transfer device according to claim 1, wherein the wiring member is bonded to a surface of the support portion opposite to the vibration plate with a thermosetting adhesive.   The liquid transfer apparatus according to claim 6, wherein the thermosetting adhesive is conductive.   The liquid transfer device according to claim 1, wherein the support portion extends in a longitudinal direction of the wiring member.   The liquid transfer device according to claim 8, wherein the support portion is different in a direction in which a width in a direction orthogonal to the extending direction extends.   It is an inkjet head, The liquid transfer apparatus in any one of Claims 1-9 characterized by the above-mentioned. A method of manufacturing a liquid transfer device including a piezoelectric actuator,
Providing a flow path unit having a liquid flow path including a plurality of pressure chambers disposed along a plane;
Arranging a diaphragm so as to cover the plurality of pressure chambers in the flow path unit;
An element forming step of forming a plurality of piezoelectric elements isolated from each other by discretely depositing particles of piezoelectric material on a surface of the diaphragm opposite to the pressure chamber;
A first electrode forming step of forming a first electrode on a surface of the diaphragm in contact with the plurality of piezoelectric elements;
A second electrode forming step of forming a second electrode on a surface opposite to the surface of the plurality of piezoelectric elements in contact with the diaphragm;
A wiring connection step of connecting a flexible wiring member to the second electrode,
In the element formation step, simultaneously forming the plurality of piezoelectric elements and a support portion made of the same piezoelectric material as the piezoelectric elements on the surface of the diaphragm opposite to the pressure chamber,
In the wiring connection step, the wiring member is connected to the second electrode and joined to the surface of the support portion on the side opposite to the vibration plate.   12. The method of manufacturing a liquid transfer device according to claim 11, wherein, in the element formation step, the support portion is formed in a region outside the region of the diaphragm facing the plurality of pressure chambers. . The first electrode is formed on the surface of the diaphragm opposite to the pressure chamber without a gap, and is a common electrode of the plurality of piezoelectric elements;
The second electrode is an individual electrode of each of the plurality of piezoelectric elements;
Furthermore, the diaphragm has a conductive surface as the common electrode on the side opposite to the pressure chamber,
In the electrode forming step, a conductive portion that forms a surface electrode simultaneously with the plurality of individual electrodes on the surface of the support portion opposite to the diaphragm, and electrically connects the surface electrode and the conductive surface of the diaphragm. Form the
The method for manufacturing a liquid transfer device according to claim 11, wherein in the wiring connection step, the wiring member and the surface electrode are electrically connected.   In the said wiring connection process, the surface on the opposite side to the said diaphragm of the said wiring member and the said support part is joined using a thermosetting adhesive agent. Method for manufacturing the liquid transfer apparatus of the present invention.   The manufacturing method according to claim 14, wherein the thermosetting adhesive is conductive.   The manufacturing method according to claim 11, wherein the support portion is extended in a longitudinal direction of the wiring member.   The manufacturing method according to claim 16, wherein widths of the support portions in a direction orthogonal to a direction in which the support portions extend are different in the longitudinal direction.   The manufacturing method according to claim 11, wherein the liquid transfer device is an inkjet head.

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