JP4687083B2 - Liquid transfer device - Google Patents

Description

  The present invention relates to a liquid transfer apparatus for transferring a liquid.

  A liquid transfer device such as an ink jet head that discharges ink to a recording medium generally has an actuator that applies transfer energy to the liquid. For example, the ink jet head described in Patent Document 1 includes a liquid chamber unit having a plurality of pressurized liquid chambers (pressure chambers) and a piezoelectric actuator unit provided to face the plurality of pressurized liquid chambers. ing. This actuator unit is composed of a plurality of laminated piezoelectric material layers made of lead zirconate titanate (PZT) or the like, and is opposed to a pressurized liquid chamber (pressure chamber), and a plurality of piezoelectric material layers It has a plurality of internal electrodes arranged between them. The plurality of internal electrodes are alternately drawn out to the two end faces of the piezoelectric element and connected to two end face electrodes (side electrodes) formed on the two end faces. A substrate made of the same material as the piezoelectric element such as PZT is disposed on the opposite side of the piezoelectric element from the liquid chamber unit. This substrate has an individual extraction electrode connected to one end face electrode. A common electrode connected to the pattern and the other end face electrode is formed. Further, a flexible printed wiring board (FPC) is connected to the individual extraction electrode and the common electrode formed on the substrate. When a driving pulse is supplied from an unshown head driver to the individual extraction electrode via the FPC, an electric field in the stacking direction is generated in the piezoelectric material layer sandwiched between the internal electrodes, and the piezoelectric element extends in the stacking direction. Since the diaphragm covering the pressurized liquid chamber is deformed, pressure is applied to the ink in the pressurized liquid chamber.

JP-A-8-142324

  However, in the above-described ink jet head of Patent Document 1, the end face electrodes formed on each piezoelectric element are connected to the FPC via a relatively expensive substrate formed of the same material as the piezoelectric element such as PZT. . As a result, the cost of components increases and the connection structure between the actuator unit and the head driver becomes complicated, which increases the manufacturing cost of the inkjet head.

  On the other hand, it is possible to omit the above-mentioned substrate and directly connect the end face electrode and the head driver with a flexible wiring member such as FPC. However, in recent years, for the purpose of reducing the size of an inkjet head and improving the quality of a recorded image, a plurality of piezoelectric elements tend to be arranged densely and the interval between adjacent piezoelectric elements has become considerably narrow. There are many cases. In addition, it is very difficult to connect the terminals of the wiring members such as FPC to the end surface electrodes formed on the end surfaces of the plurality of piezoelectric elements arranged at such a narrow interval, and the manufacturing cost increases. Further, even if the connection can be made, the reliability of the electrical connection is lowered.

  An object of the present invention is to simplify the electrical connection structure of side electrodes formed on a piezoelectric element, thereby improving the reliability of the electrical connection and reducing the manufacturing cost.

Means for Solving the Problems and Effects of the Invention

  According to a first aspect of the present invention, a liquid transfer device includes 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 selectively changes the volumes of the plurality of pressure chambers. The piezoelectric actuator comprises a diaphragm that covers the plurality of pressure chambers and a plurality of laminated piezoelectric films, on the opposite side of the diaphragm from the pressure chambers, A plurality of piezoelectric elements respectively disposed at positions facing the plurality of pressure chambers, and a plurality of first electrodes and a plurality of second electrodes alternately disposed between the plurality of piezoelectric films in each piezoelectric element. A first side electrode formed on a side surface of each piezoelectric element and connected to each of the plurality of first electrodes; and also formed on a side surface of each piezoelectric element and connected to each of the plurality of second electrodes. Second diaphragm electrode, and the diaphragm On the opposite side of the pressure chamber, a first wiring portion connected to the diaphragm side end of the first side electrode, and a second side connected to the diaphragm side end of the second side electrode. The wiring part is arranged along the diaphragm.

  In this liquid transfer device, when a drive voltage is applied to any of the plurality of first electrodes and the plurality of second electrodes of a certain piezoelectric element, the piezoelectric film sandwiched between the two electrodes is parallel to the thickness direction thereof. An electric field is generated. At this time, the piezoelectric film extends in the thickness direction, which is the polarization direction, and the diaphragm is also deformed due to the deformation of the piezoelectric film, so that pressure is applied to the liquid in the pressure chamber. Here, the first side electrode that conducts to the plurality of first electrodes and the second side electrode that conducts to the plurality of second electrodes are arranged along the surface of the diaphragm at the end portion on the diaphragm side. The first wiring part and the second wiring part thus connected are respectively connected. This connection structure is considerably easier than the case where a wiring member such as an FPC is directly connected to the side electrode, and the reliability of the electrical connection is increased. Moreover, since the structure of the electrical connection between the first and second side electrodes and the driving device that supplies the driving voltage to the first electrode or the second electrode can be simplified, the manufacturing cost can be reduced.

  In the liquid transfer device according to a second aspect of the present invention, in the first aspect of the invention, the diaphragm has an insulating property on the surface on the side opposite to the pressure chamber, The first wiring part and the second wiring part are directly formed. In this case, the number of parts can be reduced by omitting the wiring member, and the manufacturing cost of the liquid transfer device can be further reduced.

  According to a third aspect of the present invention, there is provided the liquid transfer device according to the first aspect, wherein the first wiring portion and the second wiring portion are arranged on one side of the piezoelectric element side. It is arrange | positioned in the surface on the opposite side to the said pressure chamber of the said diaphragm so that it may be located in this. In this case, a wiring member having a first wiring portion and a second wiring portion is disposed on the diaphragm, and a plurality of piezoelectric elements are disposed on the wiring member. Therefore, since the first side electrode and the first wiring part, and the second side electrode and the second wiring part are connected in the vicinity of the portion where the piezoelectric element contacts the wiring member, the connection is easy. In addition, the reliability of the electrical connection is increased.

  In the liquid transfer device according to a fourth aspect, in the third aspect, a plurality of through holes are formed in a region of the wiring member facing the pressure chamber, and the plurality of piezoelectric elements are the plurality of through holes. In this case, each of the wiring members penetrates the wiring member and is in direct contact with the diaphragm. Generally, since the wiring member is formed of a material having a relatively low elastic modulus such as a synthetic resin material, if the wiring member is interposed between the piezoelectric element and the diaphragm, the piezoelectric element during driving The deformation is absorbed by the wiring member. However, when the piezoelectric element penetrates the wiring member in the through hole and is in direct contact with the diaphragm as in the present invention, the deformation of the piezoelectric element is not absorbed by the wiring member and vibrates efficiently. Since the plate can be deformed, a predetermined pressure can be applied to the liquid in the pressure chamber with a lower driving voltage. In addition, since the plurality of piezoelectric elements and the wiring member can be easily aligned by the plurality of through holes, the manufacturing process can be shortened and the manufacturing cost can be reduced.

  According to a fifth aspect of the present invention, there is provided the liquid transfer device according to the fourth aspect, wherein an insulating material is filled between the wiring member and the plurality of piezoelectric elements penetrating the plurality of through holes. It is a feature. Therefore, in particular, when the first side electrode and the first wiring part, and the second side electrode and the second wiring part are joined by the conductive joining material, the gap between the wiring member in the through hole and the piezoelectric element is obtained. The insulating material prevents the conductive material from entering the substrate, and the disconnection between the side electrode and the wiring portion can be prevented, so that the reliability of the electrical connection is improved.

  According to a sixth aspect of the present invention, there is provided the liquid transfer device according to any one of the third to fifth aspects, wherein the first side surface electrode and the second side surface electrode respectively formed on the plurality of piezoelectric elements are formed of the single sheet. The wiring member is connected to the first wiring portion and the second wiring portion formed on the wiring member, respectively. As described above, with respect to the plurality of piezoelectric elements, the first side surface electrode and the second side surface electrode are connected to the first wiring portion and the second wiring portion by only one wiring member disposed on the surface of the diaphragm. As a result, the connection structure can be further simplified.

According to a seventh aspect of the present invention, there is provided the liquid transfer device according to any one of the first to sixth aspects, wherein the first wiring portion and the second wiring are connected to the first side surface electrode and the second side surface electrode, respectively. Each end of the part is drawn out to the same end side of the diaphragm as viewed from a direction orthogonal to the plane on the side opposite to the pressure chamber of the diaphragm. . Therefore, when the first and second wiring portions are formed directly on the diaphragm as in the second invention, a driving device that supplies a driving voltage to the first electrode or the second electrode is provided. It becomes possible to arrange | position on a diaphragm, and the electrical connection structure between a drive device and a 1st side electrode and a 2nd side electrode can be simplified. Further, when a wiring member is used as in the third aspect of the invention, it is possible to electrically connect the driving device and the first and second side electrodes with only one wiring member. become.

According to an eighth aspect of the present invention, there is provided the liquid transfer device according to any one of the first to sixth aspects, wherein the first electrode is an electrode to which a driving voltage is applied, while the second electrode is always a predetermined constant potential. The plurality of pressure chambers are arranged in a predetermined first direction parallel to the plane, and each of the plurality of piezoelectric elements is parallel to the plane and the first direction. The first side surface electrode is disposed on one side surface in the second direction orthogonal to the second direction, the second side surface electrode is disposed on the other side surface in the second direction, and a plurality of the first wiring portions are arranged on the side surface. multiple extend into the one side of each said second direction from a plurality of said first side surface electrodes formed in the piezoelectric element, the second wiring portion, a plurality of which are formed on the plurality of piezoelectric elements multiple extending to the other side of each said second direction from said second side surface electrode A first conductive portion, and conducting all of the first conductive portion of the plurality and the second conductive portion extending in the first direction, the one side of the conduction between the second conductive portion and and the second direction And a third conductive portion extending to the surface.

  As described above, the first wiring portion and the third conductive portion of the second wiring portion both extend to one side in the second direction and are drawn out in the same direction. When the first and second wiring portions are formed directly on the diaphragm as in the invention, the drive device can be disposed on the diaphragm. Further, when the wiring member is used as in the third invention, the driving device and the first and second side electrodes can be electrically connected by one wiring member. Become.

  According to a ninth aspect of the present invention, there is provided the liquid transfer device according to any one of the first to eighth aspects, wherein the first side electrode and the first wiring portion are joined together, and the second side electrode and the second wiring. The joining with the part is characterized in that both are made through a conductive material in contact with both. In this case, the connection between the first side electrode and the first wiring part and the connection between the second side electrode and the second wiring part are further ensured, and the reliability of the electrical connection is increased.

Embodiments of the present invention will be described. This embodiment is an example in which the present invention is applied to an inkjet head that ejects ink from a nozzle to a recording sheet as a liquid transfer device.
First, the ink jet printer 100 including the ink jet head 1 will be briefly described. As shown in FIG. 1, an inkjet printer 100 includes a carriage 101 that can move in the left-right direction in FIG. 1, a serial inkjet head 1 that is provided on the carriage 101 and that ejects ink onto a recording paper P, A conveyance roller 102 that conveys 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 101 and emits from the nozzles 20 (see FIGS. 2 to 4, 6, and 7) formed on the lower ink ejection surface. Ink is ejected from the mouth to the recording paper P. Then, the recording paper P recorded by the inkjet head 1 is discharged forward (paper feeding direction) by the transport roller 102.

Next, the inkjet head 1 will be described in detail with reference to FIGS.
As shown in FIGS. 2 to 7, the inkjet head 1 includes a flow path unit 2 having an ink flow path formed therein, and a piezoelectric actuator 3 disposed above the flow path unit 2. . 2 is a plan view of the inkjet head 1, FIG. 3 is a plan view of a portion below the diaphragm 30 of the inkjet head 1 shown in FIG. 2, and FIG. 4 is a plan view of the laminate 41 from the inkjet head 1 shown in FIG. FIG. 5 is a plan view of the laminate 41, FIG. 6 is a sectional view taken along line VI-VI in FIG. 2, and FIG. 7 is a sectional view taken along line VII-VII in FIG.

  First, the flow path unit 2 will be described. As shown in FIGS. 6 and 7, the flow path unit 2 includes a cavity plate 10, a base plate 11, a manifold plate 12, and a nozzle plate 13, and these four plates 10 to 13 are joined in a stacked state. 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 4, 6, and 7, the cavity plate 10 is formed with a plurality of pressure chambers 14 arranged along a plane. The plurality of pressure chambers 14 are open to a diaphragm 30 side (upper side in FIG. 6) described later. The plurality of pressure chambers 14 are arranged in two rows in the paper feeding direction (up and down direction in FIG. 2). 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.

  Communication holes 15 and 16 are formed at positions overlapping with both longitudinal ends of the pressure chamber 14 in plan view of the base plate 11. Further, the manifold plate 12 is formed with a manifold 17 that extends in the paper feeding direction (vertical direction in FIG. 2) and overlaps either one of the right and left ends of the pressure chamber 14 in FIG. Ink is supplied to the manifold 17 from an ink tank (not shown) through an ink supply port 18 formed in a vibration plate 30 described later. A communication hole 19 is also formed at a position overlapping the end of the pressure chamber 14 opposite to the manifold 17 in plan view. Further, the nozzle plate 13 is formed with a plurality of nozzles 20 at positions overlapping with the plurality of communication holes 19 in plan view. The nozzle 20 is formed, for example, by performing excimer laser processing on a polymer synthetic resin substrate such as polyimide.

  As shown in FIG. 6, 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. In this way, the individual ink flow path 21 extending from the manifold 17 to the nozzle 20 through the pressure chamber 14 is formed in the flow path unit 2.

  Next, the piezoelectric actuator 3 will be described. As shown in FIGS. 2 to 7, the piezoelectric actuator 3 is arranged at a position facing the plurality of pressure chambers 14 on the upper side of the vibration plate 30 covering the plurality of pressure chambers 14 opened upward. And a laminated body 41 including a plurality of laminated piezoelectric sheets 40.

  The diaphragm 30 is a plate having a substantially rectangular shape in plan view. For example, a metal material such as an iron-based alloy such as stainless steel, a copper-based alloy, a nickel-based alloy, or a titanium-based alloy, silicon, glass material, alumina, or the like. Or a ceramic material such as zirconia, or a synthetic resin material such as polyimide. The diaphragm 30 is joined to the upper surface of the cavity plate 10 so as to cover the plurality of pressure chambers 14.

  A piezoelectric sheet 40 (piezoelectric film) made of a ferroelectric piezoelectric material such as lead zirconate titanate (PZT) is provided on the upper surface of the diaphragm 30 via a flexible printed circuit (FPC) 50 described later. ) Is provided. A plurality of individual electrodes 32 (first electrodes) and a plurality of common electrodes 34 (second electrodes) are alternately arranged between the plurality of laminated piezoelectric sheets 40. The laminated body 41 is formed, for example, by forming the individual electrode 32 and the common electrode 34 on the surface of the PZT green sheet by screen printing or the like, and then laminating a plurality of green sheets, and then a high temperature (for example, about 1000 ° C.). It is obtained by firing with Further, the plurality of piezoelectric sheets 40 constituting the laminated body 41 are polarized in the thickness direction. As shown in FIGS. 6 and 7, the laminate 41 is joined to a metal frame 45 on the upper surface thereof, and the laminate 41 is fixed to the flow path unit 2 via the frame 45. . The plurality of individual electrodes 32 are electrodes to which a driving voltage is selectively supplied from a driver IC 37 (see FIG. 2) described later, and the plurality of common electrodes 34 are always held at the ground potential via the driver IC 37. Electrode.

  By the way, as shown in FIGS. 2 and 5 to 7, a plurality of piezoelectric elements 42 that protrude downward are divided by grooves in the lower portion of the laminated body 41 that are opposed to the plurality of pressure chambers 14. Is formed. The plurality of piezoelectric elements 42 are respectively arranged at positions overlapping with the central portions of the plurality of pressure chambers 14 in plan view, and in the same manner as the plurality of pressure chambers 14, the paper feeding direction (vertical direction in FIG. 2: first Direction) in two rows. Each piezoelectric element 42 has a substantially rectangular planar shape that is long in the scanning direction (left-right direction in FIG. 2), similarly to the pressure chamber 14, and is formed in a shape in which four corners thereof are chamfered. ing. In addition, the groove | channel which divides | segments the some piezoelectric element 42 can be formed by a dicer, microblast, or ultrasonic processing etc., for example. As shown in FIGS. 2 and 5, a pair of support portions 43 that extend in the paper feed direction and support the plurality of piezoelectric elements 42 from the left and right are also protruded downward on the left and right sides of the laminate 41. Is formed.

  Further, as shown in FIG. 6, first side electrodes 35 respectively connected to the plurality of individual electrodes 32 are formed on one side surface (right side surface in FIG. 6) of each piezoelectric element 42. The first side surface electrode 35 extends to the lower end of the piezoelectric element 42. Further, second side electrodes 36 respectively connected to the plurality of common electrodes 34 are formed on the other side surface portion (the left side surface portion in FIG. 6) of each piezoelectric element 42. Also extends to the lower end of the piezoelectric element 42. The first side surface electrode 35 and the second side surface electrode are arranged side by side in the left-right direction (second direction) orthogonal to the arrangement direction (first direction) of the piezoelectric elements 42 in plan view. The first side surface electrode 35 and the second side surface electrode 36 can be formed by depositing a conductive material on the side surface portion of the piezoelectric element 42 by, for example, sputtering or vapor deposition. The first side surface electrode 35 and the second side surface electrode 36 are connected to a driver IC 37 (see FIG. 4) via a first wiring portion 52 and a second wiring portion 53 of the FPC 50 described below.

  Next, the FPC 50 (wiring member) that connects the first side surface electrode 35 and the second side surface electrode 36 and the driver IC 37 will be described. As shown in FIGS. 6 and 7, the FPC 50 is disposed along the diaphragm 30 in a state of being sandwiched between the diaphragm 30 and the plurality of piezoelectric elements 42. It is bonded to both the diaphragm 30 and the piezoelectric element 42 by a system adhesive or the like. The FPC 50 includes a flexible base material 51 made of an insulating synthetic resin material such as polyimide, and a first wiring portion 52 and a second wiring portion 53 formed on the upper surface of the base material 51. . As shown in FIG. 6, the lower end portion of the first side surface electrode 35 formed on each piezoelectric element 42 is connected to the first wiring portion 52 on the upper surface of the base material 51. On the other hand, the lower end portion of the second side electrode 36 formed on each piezoelectric element 42 is connected to the second wiring portion 53 on the upper surface of the base material 51.

  As shown in FIG. 6, the first side electrode 35 and the first wiring portion 52 are in the vicinity of the joint portion between the piezoelectric element 42 and the base material 51 of the FPC 50. They are joined via a conductive material 60 such as solder or conductive adhesive in contact with both of them. Similarly, both the second side surface electrode 36 and the second wiring portion 53 are in contact with both the second side surface electrode 36 and the second wiring portion 53 in the vicinity of the joint portion between the piezoelectric element 42 and the base material 51 of the FPC 50. It is joined via the material 61. In this case, compared with the case where a wiring member such as an FPC is directly connected to the first side electrode 35 and the second side electrode 36, the first side electrode 35, the first wiring portion 52, and the second side electrode 36 It is quite easy to connect the second wiring part 53, and the reliability of their electrical connection is increased.

  As shown in FIGS. 2, 4, and 6, the plurality of first wiring portions 52 are arranged to the right (one in the second direction) from the plurality of first side surface electrodes 35 respectively located at the right end portions of the plurality of piezoelectric elements 42. Side). On the other hand, the second wiring portion 53 includes a plurality of first conductive portions 54 that extend to the left (the other side in the second direction) from the plurality of second side surface electrodes 36 that are respectively positioned at the left end portions of the plurality of piezoelectric elements 42. A second conductive portion 55 that is electrically connected to all of the plurality of first conductive portions 54 and extends in the vertical direction (first direction) in FIG. 2, and is electrically connected to the second conductive portion 55 and to the right. The third conductive portion 56 extends. The second wiring portion 53 is drawn to the right in the third conductive portion 56 in the same manner as the plurality of first wiring portions 52. In addition, a driver IC 37 that supplies a drive voltage to the individual electrode 32 is disposed at the right end portion of the substrate 51. The plurality of first wiring parts 52 and second wiring parts 53 drawn to the right are connected to the driver IC 37. Thus, since the plurality of first wiring parts 52 and second wiring parts 53 are both pulled out to the right, the first side electrode 35 and the second side electrode 36 and the driver IC 37 are connected to only one FPC 50. It becomes possible to connect with.

  The plurality of individual electrodes 32 of each piezoelectric element 42 are connected to the driver IC 37 via the first side electrode 35 and the first wiring portion 52, and a driving voltage is supplied from the driver IC 37 to the individual electrode 32. On the other hand, the plurality of common electrodes 34 of each piezoelectric element 42 are always held at the ground potential via the second side electrode 36, the second wiring portion 53, and the driver IC 37. The base material 51 is also formed with a connection terminal 57 for connecting the driver IC 37 and a control device (not shown) of the ink jet printer 100.

Next, the operation of the piezoelectric actuator 3 during ink ejection will be described.
When a driving voltage is applied to the plurality of individual electrodes 32 of a certain piezoelectric element 42 from the driver IC 37 via the first side surface electrode 35 and the first wiring portion 52, the individual electrodes 32 are held at the ground potential. A potential difference is generated between the common electrode 34 and the common electrode 34. Then, an electric field in a direction parallel to the thickness direction that is the polarization direction is generated in the piezoelectric sheet 40 sandwiched between the individual electrode 32 and the common electrode 34, so that the piezoelectric sheet 40 extends in the thickness direction due to the piezoelectric longitudinal effect. The vibration plate 30 is deformed in accordance with the deformation of the piezoelectric element 42 and the volume in the pressure chamber 14 is changed, so that pressure is applied to the ink in the pressure chamber 14 and the nozzle 20 communicated with the pressure chamber 14. From which ink droplets are ejected.

According to the inkjet head 1 described above, the following effects can be obtained.
An FPC 50 having a first wiring portion 52 and a second wiring portion 53 is disposed on the upper surface of the diaphragm 30 in a state of being sandwiched between the diaphragm 30 and the plurality of piezoelectric elements 42, and the first wiring The part 52 is connected to the lower end of the first side electrode 35, and the second wiring part 53 is connected to the lower end of the second side electrode 36. Therefore, a special configuration for connecting the first side surface electrode 35 and the second side surface electrode 36 and the FPC 50 (for example, the substrate in Patent Document 1 described above) is not necessary, and the first side surface electrode 35 is formed only by the FPC 50. In addition, the second side electrode 36 and the driver IC 37 can be connected. Therefore, the connection structure between the first side surface electrode 35 and the second side surface electrode 36 and the driver IC 37 is simplified, and the manufacturing cost can be reduced. Further, since the plurality of first wiring parts 52 and the second wiring parts 53 are both drawn out in one direction, the first side surface electrode 35 and the second side surface electrode 36 and the driver IC 37 are connected by only one FPC 50. And the manufacturing cost can be further reduced.

  In addition, the first side electrode 35 and the first wiring portion 52, and the second side electrode 36 and the second wiring portion 53 are in the vicinity of the joint portion between the piezoelectric element 42 and the base material 51 of the FPC 50. , 61. Therefore, compared to the case where a wiring member such as an FPC is directly connected to the first side electrode 35 and the second side electrode 36, the connection is easy and the reliability of the electrical connection is increased.

Next, modified embodiments in which various modifications are made to the embodiment will be described. However, those having the same configuration as in the above embodiment are given the same reference numerals and description thereof is omitted as appropriate.
1] It is not always necessary that the first wiring part 52 and the second wiring part 53 of the FPC 50 are all drawn out in one direction (see FIG. 2) as in the above embodiment. For example, in the inkjet head 1A of the first modification shown in FIG. 8, a plurality of first wiring portions 52A and second wiring portions 53A are formed on the base 51A of the FPC 50A. Then, the first wiring portion 52A corresponding to the column of the left piezoelectric elements 42 is drawn leftward from the left end of the piezoelectric elements 42, and the first wiring portion 52A corresponding to the column of the right piezoelectric elements 42 is extracted from these piezoelectric elements. It is pulled out from the right end of 42 to the right. The second wiring portion 53A includes a plurality of first conductive portions 54A extending from the left end or the right end of the plurality of piezoelectric elements 42 to the piezoelectric elements 42 arranged in two rows, and the plurality of first conductive portions 54A. A second conductive portion 55A that is electrically connected to all of the conductive portions 54A and extends in the arrangement direction of the piezoelectric elements 42 (vertical direction in FIG. 8), and a third conductive portion that is electrically connected to the second conductive portions 55A and extends to the right. A conductive portion 56A. That is, the second wiring portion 53A is drawn rightward in the third conductive portion 56A. Even in such a configuration, a special configuration for connecting the first side surface electrode 35 and the second side surface electrode 36 and the FPC 50A is unnecessary, and the first side surface electrode 35 and the second side surface electrode 36 and the driver are connected only by the FPC 50A. Since the IC 37 can be connected, the connection structure is simplified.

  2] In the inkjet head 1 of the above-described embodiment, a plurality of piezoelectric elements 42 are disposed on the upper surface side of the diaphragm 30 via the FPC 50 (see FIG. 6). Since it is often formed of a material having a relatively low elastic modulus such as polyimide, the deformation of the piezoelectric element 42 during driving is absorbed by the base material. Therefore, as shown in FIG. 9, a plurality of through holes 70 are formed in regions of the base material 51 </ b> B of the FPC 50 </ b> B facing the plurality of pressure chambers 14, and the plurality of piezoelectric elements 42 are respectively in the plurality of through holes 70. May be in direct contact with the diaphragm 30 (Modification 2). In this case, the deformation of the piezoelectric element 42 is not absorbed by the FPC 50B, and the diaphragm 30 can be efficiently deformed. Therefore, a predetermined pressure is applied to the ink in the pressure chamber 14 with a lower driving voltage. can do. In addition, since the plurality of piezoelectric elements 42 and the FPC 50B can be easily aligned by the plurality of through holes 70, the manufacturing process can be shortened and the manufacturing cost can be reduced.

  Further, if the processing accuracy of the through hole 70 is low, a gap may be formed between the through hole 70 formed in the FPC 50B and the piezoelectric element 42. In this case, when the first side surface electrode 35 and the first wiring portion 52 and the second side surface electrode 36 and the second wiring portion 53 are joined using the conductive materials 60 and 61, the through hole 70 and the piezoelectric element are used. There is a possibility that the conductive materials 60 and 61 may enter between them and be disconnected. Further, when the diaphragm 30 has conductivity, there is a possibility that a short circuit may occur due to the conductive materials 60 and 61 that have entered the gap. Therefore, as shown in FIG. 10, it is preferable that the insulating material 71 is filled between the FPC 50B and the plurality of piezoelectric elements 42 penetrating the plurality of through holes 70 (Modification 3).

  3] The first wiring part 52 and the second wiring part 53 may be formed directly on the upper surface of the diaphragm 30 without using a wiring member such as an FPC. However, in this case, in order to insulate the first wiring part 52 and the second wiring part 53 from each other, it is necessary that the upper surface of the diaphragm 30 has an insulating property. For example, when the diaphragm 30 is made of a metal material, as shown in FIG. 11, an insulating material layer 80 made of alumina or the like is formed on the upper surface of the diaphragm 30, and the first wiring is formed on the surface of the insulating material layer 80. The part 52 and the second wiring part 53 are formed (Modification 4). The insulating material layer 80 can be formed by an aerosol deposition method (AD method), a sputtering method, a sol-gel method, or the like. When the diaphragm 30 is made of silicon, a silicon oxide film is formed on the diaphragm 30, and the first wiring portion 52 and the second wiring portion 53 are formed on the surface of the oxide film. On the other hand, when the diaphragm 30 is made of an insulating material such as a ceramic material such as alumina or zirconia, a glass material, or a synthetic resin material such as polyimide, as shown in FIG. The first wiring part 52 and the second wiring part 53 can be directly formed on (Modification 5). In such a form, the number of components can be reduced by omitting a wiring member such as an FPC. Furthermore, the driver IC 37 can be disposed on the upper surface of the diaphragm 30, and the electrical connection structure between the individual electrode 32 and the common electrode 34 and the driver IC 37 can be further simplified.

  4] The piezoelectric actuator 3 of the above embodiment is configured to change the volume of the pressure chamber 14 by using the piezoelectric longitudinal effect in which the piezoelectric sheet 40 extends in the thickness direction when a driving voltage is applied to the individual electrode 32. However, when the piezoelectric sheet extends in the thickness direction, the volume of the pressure chamber 14 is changed by utilizing the so-called piezoelectric lateral effect, at the same time, the piezoelectric sheet contracts in a direction parallel to the surface. There may be. For example, as shown in FIG. 13, in the piezoelectric actuator 3C according to the modified embodiment 6, the FPC 50 is disposed on the upper surface of the diaphragm 30, and a plurality of sheets constituting each piezoelectric element 42C are further formed on the upper surface of the FPC 50. The piezoelectric sheets 40C are arranged in a state where they are laminated on the left and right. A plurality of individual electrodes 32C and a plurality of common electrodes 34C are alternately arranged between the plurality of piezoelectric sheets 40C. The plurality of individual electrodes 32C are drawn upward, and the FPC 50 has a first electrode 35C formed on the upper surface of the multilayer body 41C and the first side electrode 35C formed on the right side surface of the multilayer body 41C. One wiring portion 52 is connected. On the other hand, the plurality of common electrodes 34C are drawn downward, and the FPC 50 of the FPC 50 is connected via the lead electrode 82 formed on the bottom surface of the multilayer body 41C and the second side surface electrode 36C formed on the left side surface of the multilayer body 41C. Two wiring parts 53 are connected. Note that a metal frame 45 is bonded to the upper surface of the laminated body 41C as in the above embodiment.

  In the piezoelectric actuator 3C, when a driving voltage is applied to the individual electrode 32C, an electric field parallel to the thickness direction, which is a polarization direction, is applied to the piezoelectric sheet 40C sandwiched between the individual electrode 32C and the common electrode 34C. Works. Then, the piezoelectric sheet 40C extends in the thickness direction and contracts in a direction parallel to the surface (vertical direction). At this time, the diaphragm 30 is also deformed with the deformation of the piezoelectric sheet 40 </ b> C, so that the volume of the pressure chamber 14 is changed and pressure is applied to the ink in the pressure chamber 14.

  5] Instead of the piezoelectric sheet 40 obtained by firing a PZT green sheet, a piezoelectric material film formed by an aerosol deposition method, a sputtering method, or the like may be used. In this case, the laminated body 41 is formed by alternately forming a piezoelectric film and forming electrodes (individual electrode 32 and common electrode 34) by screen printing or the like.

  6] The above-described embodiment and its modification are examples in which the present invention is applied to an inkjet head that ejects ink from a nozzle as a liquid transfer device. However, the liquid is applied by applying pressure to a liquid other than ink. The present invention can also be applied to other liquid transfer devices for transfer.

1 is a schematic perspective view of an inkjet head according to an embodiment of the present invention. It is a top view of an inkjet head. FIG. 3 is a plan view of a portion below the diaphragm of the inkjet head shown in FIG. 2. It is a top view of the part except a laminated body from the inkjet head shown in FIG. 3 is a plan view of a laminated body 41. FIG. FIG. 6 is a sectional view taken along line VI-VI in FIG. 2. It is the VII-VII sectional view taken on the line of FIG. It is a top view of the inkjet head of the modification 1. It is sectional drawing equivalent to FIG. It is sectional drawing equivalent to FIG. It is sectional drawing equivalent to FIG. 6 of the modification 4. It is sectional drawing equivalent to FIG. 6 of the modification 5. FIG. It is sectional drawing equivalent to FIG. 6 of the modified form 6. FIG.

Explanation of symbols

1, 1A Inkjet head 2 Flow path unit 3, 3C Piezoelectric actuator 14 Pressure chamber 30 Diaphragm 32, 32C Individual electrode 34, 34C Common electrode 35, 35C First side electrode 36, 36C Second side electrode 40, 40C Piezoelectric sheet 42 , 42C Piezoelectric elements 52, 52A First wiring part 53, 53A Second wiring part 54 First conductive part 55 Second conductive part 56 Third conductive part 60, 61 Conductive material 70 Through hole 71 Insulating material

Claims (9)

A liquid transfer device comprising: 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 selectively changes the volume of the plurality of pressure chambers. ,
The piezoelectric actuator is
A diaphragm covering the plurality of pressure chambers;
A plurality of piezoelectric films made of a plurality of laminated layers, a plurality of piezoelectric elements respectively disposed at positions opposite to the pressure chambers on the side opposite to the pressure chambers of the diaphragm;
In each piezoelectric element, a plurality of first electrodes and a plurality of second electrodes alternately arranged between the plurality of piezoelectric films,
A first side electrode formed on a side surface of each piezoelectric element and connected to each of the plurality of first electrodes, and also formed on a side surface of each piezoelectric element and connected to each of the plurality of second electrodes. A second side electrode;
On the opposite side of the diaphragm to the pressure chamber, the first wiring part connected to the diaphragm side end of the first side electrode and the second side electrode connected to the diaphragm side end The liquid transfer device, wherein the second wiring portion is disposed along the diaphragm. The diaphragm has an insulating property on a surface opposite to the pressure chamber,
2. The liquid transfer device according to claim 1, wherein the first wiring portion and the second wiring portion are directly formed on a surface of the diaphragm opposite to the pressure chamber.   The wiring member in which the first wiring portion and the second wiring portion are formed on one surface of the diaphragm is arranged such that the first wiring portion and the second wiring portion are located on the piezoelectric element side. The liquid transfer device according to claim 1, wherein the liquid transfer device is disposed on a surface opposite to the pressure chamber.   A plurality of through holes are formed in a region of the wiring member facing the pressure chamber, and the plurality of piezoelectric elements pass through the wiring member in the plurality of through holes and directly contact the diaphragm. The liquid transfer device according to claim 3, wherein the liquid transfer device is a liquid transfer device.   The liquid transfer device according to claim 4, wherein an insulating material is filled between the wiring member and the plurality of piezoelectric elements penetrating the plurality of through holes.   The first side electrode and the second side electrode formed on each of the plurality of piezoelectric elements are respectively connected to the first wiring portion and the second wiring portion formed on one wiring member. The liquid transfer apparatus according to claim 3, wherein the liquid transfer apparatus is a liquid transfer apparatus. The end portions of the first wiring portion and the second wiring portion connected to the first side surface electrode and the second side surface electrode, respectively, are on the plane on the side opposite to the pressure chamber of the diaphragm. The liquid transfer device according to claim 1, wherein the liquid transfer device is drawn to the same end side of the diaphragm as viewed from a direction orthogonal to the diaphragm . The first electrode is an electrode to which a driving voltage is applied, while the second electrode is an electrode that is always maintained at a predetermined constant potential,
The plurality of pressure chambers are arranged in a predetermined first direction parallel to the plane,
In each of the plurality of piezoelectric elements, the first side surface electrode is disposed on one side surface in the second direction parallel to the plane and orthogonal to the first direction, and on the other side surface in the second direction. The second side electrode is disposed;
A plurality of the first wiring portion extends to the one side of each said second direction from a plurality of said first side electrode formed on the plurality of piezoelectric elements,
The second wiring portion includes a plurality of first conductive portion extending from a plurality of said second side electrode formed on the plurality of piezoelectric elements to the other side of each said second direction, the first plurality a second conductive portion extending in continuity with and the first direction and all of the conductive portion, and a third conductive portion extending into the one side of the second conductive portion and the conductive and the second direction The liquid transfer device according to claim 1, wherein the liquid transfer device is a liquid transfer device. The joining of the first side electrode and the first wiring part and the joining of the second side electrode and the second wiring part are both made through a conductive material in contact with both. The liquid transfer device according to any one of claims 1 to 8.

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