JP4831186B2 - Method for manufacturing liquid transfer device - Google Patents

Description

  The present invention relates to a method for manufacturing a liquid transfer device that transfers a liquid by applying pressure to the liquid in a pressure chamber.

  2. Description of the Related Art Conventionally, in various fields, a liquid transfer device having a piezoelectric actuator that applies pressure to a liquid is known. For example, Patent Document 1 discloses an ink jet head having a piezoelectric actuator that applies pressure to ink to be ejected from a nozzle.

  The inkjet head includes a flow path unit (cavity unit) in which an ink flow path is formed, such as a plurality of nozzles and a plurality of pressure chambers communicating with the nozzles, and a flow path unit so as to cover the plurality of pressure chambers. And a joined piezoelectric actuator. The piezoelectric actuator has a plurality of stacked piezoelectric layers (piezoelectric sheets) and individual electrodes and a common electrode arranged so as to sandwich each of the plurality of piezoelectric layers in the thickness direction in a region facing the pressure chamber. . In this piezoelectric actuator, when a voltage is applied between the individual electrode and the common electrode, and an electric field in the thickness direction acts on the piezoelectric layer (active part) sandwiched between the two, the piezoelectric actuator is deformed ( The pressure chamber is configured to change the volume of the pressure chamber using a piezoelectric strain) and apply pressure to the ink in the pressure chamber.

  Moreover, as a structure of a piezoelectric actuator, there exists a thing as described in Japanese Patent Application No. 2008-094150 other than what is described in patent document 1 (refer FIG. 6 of this application). In this piezoelectric actuator 32, two piezoelectric layers 41 and 42 are laminated on the upper surface of the vibration plate 40 disposed on the upper surface of the flow path unit, and the upper and lower piezoelectric layers of the vibration plate 40 are arranged. A second constant potential electrode 43, a first constant potential electrode 44a, and an individual electrode 45 are formed on the upper surface of the layer 41 and the upper surface of the upper piezoelectric layer 42, respectively. A portion of the upper piezoelectric layer 42 sandwiched between the first constant potential electrode 44 a and the individual electrode 45 and facing the central portion of the pressure chamber 10 is polarized in a direction from the first constant potential electrode 44 a toward the individual electrode 45. The first active part R1. On the other hand, among the portions of the two piezoelectric layers 41 and 42 facing the pressure chamber 10, the portion between the individual electrode 45 and the second constant potential electrode 43 and the outer periphery of the first active portion R1 in plan view is It is polarized in a direction from the individual electrode 45 toward the second constant potential electrode 43 to form a second active part R2.

  Such a piezoelectric actuator holds the second constant potential electrode at the ground potential, and also holds the first constant potential electrode at a predetermined positive potential (for example, about 20 V), and sets the potential of the individual electrode to the ground potential. And the positive potential are selectively switched. Then, with the deformation generated in the first active part and the second active part by switching the potential, the portions facing the pressure chambers of the diaphragm and the two piezoelectric layers are placed on the pressure chamber side and the opposite side of the pressure chamber. By deforming the piezoelectric layer and the diaphragm in this way, the volume of the pressure chamber is greatly changed, and pressure is applied to the ink in the pressure chamber.

JP 2006-110824 A

  Here, in the piezoelectric actuator described in Japanese Patent Application No. 2008-094150, when the formation position of the first constant potential electrode is shifted from the position overlapping the central portion of the pressure chamber in a plan view, the formation position of the individual electrode is shifted. Unlike the first active portion, the first active portion is displaced from the position overlapping the central portion of the pressure chamber in plan view. Then, the amount of displacement of the portion facing the pressure chamber of the piezoelectric material due to the deformation generated in the first active portion becomes small, and a predetermined pressure cannot be applied to the liquid in the pressure chamber formed in the flow path unit.

  Accordingly, an object of the present invention is to arrange the first constant potential electrode so as to overlap with the central portion of the pressure chamber, so that the first active portion overlaps with the central portion of the pressure chamber. It is an object of the present invention to provide a method of manufacturing a liquid transfer device capable of applying a predetermined pressure to a liquid in a pressure chamber without reducing the amount of displacement of the piezoelectric material due to the above.

The liquid transfer device manufacturing method of the present invention includes a flow path unit in which a liquid transfer flow path including a pressure chamber is formed, a piezoelectric actuator that is provided in the flow path unit and applies pressure to the liquid in the pressure chamber; The piezoelectric actuator is sandwiched between the first and second piezoelectric layers stacked on each other, and is disposed so as to overlap the central portion of the pressure chamber. A first constant potential electrode to which one potential is applied, and a surface of the first piezoelectric layer opposite to the first constant potential electrode, at least outside a portion overlapping the first constant potential electrode of the pressure chamber. A second constant potential electrode disposed overlapping the portion and applied with a second potential different from the first potential, and disposed on a surface of the second piezoelectric layer opposite to the first constant potential electrode, One constant potential electrode and the second piezoelectric layer are sandwiched In conjunction with opposed, with the second constant electric potential electrode face each other across both the said first piezoelectric layer and the second piezoelectric layer, individual of the first conductive level and said second potential is selectively applied An electrode, a first active portion of the second piezoelectric layer sandwiched between the first constant potential electrode and the individual electrode, and a portion overlapping the central portion of the pressure chamber; and the first piezoelectric layer; A second active portion comprising a portion that is sandwiched between the second constant potential electrode and the individual electrode outside the first active portion of the second piezoelectric layer and overlaps the outer portion of the pressure chamber; A flow path unit manufacturing process for manufacturing the flow path unit, an actuator manufacturing process for manufacturing the piezoelectric actuator, and the first constant potential electrode of the piezoelectric actuator manufactured in the actuator manufacturing process. , Plan view And a bonding step of bonding the flow channel unit and the piezoelectric actuator so as to overlap with a central portion of the pressure chamber of the flow channel unit manufactured in the flow channel unit manufacturing step. .

  According to the method for manufacturing a liquid transfer device of the present invention, in the joining step, the first constant potential electrode is disposed so as to overlap the central portion of the pressure chamber in plan view, so that the first active portion and the central portion of the pressure chamber are arranged. Since they overlap, the displacement amount of the piezoelectric material due to the deformation generated in the first active portion is not reduced, and a predetermined pressure can be applied to the liquid in the pressure chamber.

Also, before Kia actuator manufacturing process, the light forming the piezoelectric actuator pressure material charge you transmitted, in the joining step, by irradiating light toward the piezoelectric actuator, the first constant electric potential electrode It is preferable that the position of the first constant potential electrode is detected, the first constant potential electrode is aligned so as to overlap the central portion of the pressure chamber of the flow path unit, and the flow path unit and the piezoelectric actuator are joined. According to this, by irradiating the piezoelectric actuator with light, the first constant potential electrode can be seen through, and the first constant potential electrode can be aligned with the central portion of the pressure chamber.

  Furthermore, in the actuator manufacturing step, the first constant potential is applied to a region other than a region where the individual electrode, the first constant potential electrode, and the second constant potential electrode are formed in a plan view of the piezoelectric actuator. A first mark that is separated from the center of the electrode by a predetermined distance in one direction parallel to the surface to be joined to the flow path unit is formed, and the position of the first constant potential electrode can be calculated in the joining step. Based on the position of the first mark, the first constant potential electrode is aligned so as to overlap the central portion of the pressure chamber of the flow path unit, and the flow path unit and the piezoelectric actuator are joined. Is preferred. According to this, even when it is difficult to see the first constant potential electrode directly, the position of the first constant potential electrode is calculated from the first mark separated from the center of the first constant potential electrode by a predetermined distance. Therefore, by aligning based on the first mark, the first constant potential electrode can be easily aligned with the central portion of the pressure chamber.

  In addition, in the flow path unit manufacturing step, a second mark is formed that is separated from the center of the pressure chamber by the predetermined distance with respect to the one direction in a plan view of the flow path unit. Therefore, it is preferable that the flow path unit and the piezoelectric actuator are joined by aligning the first mark and the second mark so as to overlap each other. According to this, in order to form the second mark that is separated from the center of the pressure chamber by a predetermined distance also in the flow path unit, the first constant potential electrode is connected to the pressure chamber by aligning the first mark and the second mark. Can be easily aligned with the central part.

  The piezoelectric actuator includes a first piezoelectric sheet on which the first constant potential electrode is formed, a second piezoelectric sheet on which the second constant potential electrode is formed, and a third piezoelectric sheet on which the individual electrode is formed. It is preferable that the first mark is formed on the first piezoelectric sheet. According to this, even if the first piezoelectric sheet, the second piezoelectric sheet, and the third piezoelectric sheet are laminated and the first constant potential electrode is an electrode inside the piezoelectric actuator, the first constant potential electrode and the pressure chamber The central part can be aligned.

  In the bonding step, the first constant potential electrode is arranged so as to overlap the central portion of the pressure chamber, so that the first active portion overlaps the central portion of the pressure chamber. Therefore, the piezoelectric material is deformed by the deformation generated in the first active portion. A predetermined amount of pressure can be applied to the liquid in the pressure chamber without reducing the amount of displacement.

1 is a schematic configuration diagram of a printer according to an embodiment. It is a perspective view of an inkjet head. It is a top view of an inkjet head. (A) is the elements on larger scale of FIG. 3, (b)-(d) is a figure of the surface of the diaphragm of (a) and each piezoelectric layer. It is the VV sectional view taken on the line of Fig.4 (a). It is the VI-VI sectional view taken on the line of Fig.4 (a). It is process drawing which shows the manufacture process of an inkjet head, (a) is a flow-path unit preparation process, (b) is a piezoelectric actuator preparation process, (c) is a joining process.

  Hereinafter, preferred embodiments of the present invention will be described. FIG. 1 is a schematic configuration diagram of a printer according to the present embodiment. As shown in FIG. 1, the printer 1 includes a carriage 2, an inkjet head 3, a transport roller 4, and the like.

  The carriage 2 reciprocates in the scanning direction (left and right direction in FIG. 1). The inkjet head 3 is attached to the lower surface of the carriage 2 and ejects ink from nozzles 15 (see FIG. 3) formed on the lower surface. The transport roller 4 transports the recording paper P in the paper feed direction (front side in FIG. 1). In the printer 1, printing is performed on the recording paper P by ejecting ink onto the recording paper P from the nozzles 15 of the inkjet head 3 that reciprocates in the scanning direction together with the carriage 2. Further, the recording paper P for which printing has been completed is discharged in the paper feeding direction by the transport roller 4.

  Next, the inkjet head 3 will be described in detail. FIG. 2 is an exploded perspective view of the inkjet head of FIG. FIG. 3 is a plan view of the inkjet head of FIG. FIG. 4A is a partially enlarged view of FIG. 4B to 4D are views showing the upper surfaces of a diaphragm 40, a lower piezoelectric layer 41, and an upper piezoelectric layer 42, which will be described later, in FIG. 4A, respectively. FIG. 5 is a cross-sectional view taken along line VV in FIG. FIG. 6 is a cross-sectional view taken along line VI-VI in FIG.

  For easy understanding of the drawings, in FIGS. 3 and 4, an ink flow path excluding a pressure chamber 10 and a nozzle 15 of the flow path unit 31 described later is omitted, and in FIG. Illustration of the electrode 43 and the intermediate electrode 44 is omitted. In FIG. 4A, the lower electrode 43 and the intermediate electrode 44, both of which are to be illustrated by dotted lines, are illustrated by two-dot chain lines and one-dot chain lines, respectively. Further, in FIGS. 4B to 4D, a lower electrode 43, an intermediate electrode 44, and an upper electrode 45, which will be described later, are hatched. Further, in FIG. 6, illustration of a portion below the pressure chamber 10 of the flow path unit 31 is omitted.

  As shown in FIGS. 2 to 6, the inkjet head 3 includes a flow path unit 31 and a piezoelectric actuator 32. In the flow path unit 31, a plurality of plates 21 to 27 are stacked on each other, whereby the manifold flow path 11 to which ink is supplied from the ink supply port 9, and the outlet of the manifold flow path 11 through the aperture flow path 12. An ink channel (liquid transfer channel) having a plurality of individual ink channels from the pressure chamber 10 to the nozzle 15 through the descender channel 14 is formed. As will be described later, when pressure is applied to the ink in the pressure chamber 10 by the piezoelectric actuator 32, ink is ejected from the nozzle 15 communicating with the pressure chamber 10.

  The plurality of pressure chambers 10 have a substantially elliptical planar shape with the scanning direction (left-right direction in FIG. 3) as the longitudinal direction, and are arranged along the paper feed direction (up-down direction in FIG. 3). Two pressure chamber rows 8 are formed, and such pressure chamber rows 8 are arranged in two rows in the scanning direction to form one pressure chamber group 7. Further, five such pressure chamber groups 7 are arranged along the scanning direction. Here, the pressure chambers 10 constituting the two pressure chamber rows 8 included in one pressure chamber group 7 are arranged so as to be shifted from each other in the paper feeding direction. The plurality of nozzles 15 are also arranged in the same manner as the plurality of pressure chambers 10.

  Then, among these five pressure chamber groups 7, black ink is ejected from the nozzles 15 corresponding to the pressure chambers 10 constituting the right two in FIG. 3, and the pressure constituting the left three in FIG. From the nozzles 15 corresponding to the chambers 10, yellow, cyan, and magenta inks are ejected in order from the nozzles arranged on the right side of FIG. The configuration of other portions of the ink flow path is the same as that of the conventional one, and therefore detailed description thereof is omitted here.

  In addition, the flow path unit 31 is separated from the center of a certain pressure chamber 10 by a predetermined distance with respect to one direction parallel to the surface of the pressure chamber 10, and is described later in plan view. A hole 60 (second mark) that overlaps the mark 61 and the intermediate electrode mark 62 and penetrates in the stacking direction of the plates 21 to 27 is formed. The hole 60 is formed at a position that does not overlap electrodes 43 to 45 described later in plan view.

  The piezoelectric actuator 32 includes a diaphragm 40 (second piezoelectric sheet), a lower piezoelectric layer 41 (first piezoelectric sheet), an upper piezoelectric layer 42 (third piezoelectric sheet), a lower electrode 43 (second constant potential electrode), and an intermediate electrode. 44 (first constant potential electrode), upper electrode 45 (individual electrode), intermediate electrode mark 62 (first mark), and upper electrode mark 61. The diaphragm 40 is made of a piezoelectric material mainly composed of lead zirconate titanate, which is a mixed crystal of lead titanate and lead zirconate, and is formed on the upper surface of the flow path unit 31 so as to cover the plurality of pressure chambers 10. Has been placed. The thickness of the diaphragm 40 is about 20 μm. The diaphragm 40 does not necessarily need to be made of a piezoelectric material.

  The lower piezoelectric layer 41 and the upper piezoelectric layer 42 are made of the same piezoelectric material as that of the diaphragm 40, and are laminated on each other and disposed on the upper surface of the diaphragm 40. Moreover, the thickness of the lower piezoelectric layer 41 and the upper piezoelectric layer 42 is about 20 μm, respectively.

  The lower electrode 43 is formed on the upper surface of the vibration plate 40, and is disposed between the vibration plate 40 and the lower piezoelectric layer 41, and corresponds to each pressure chamber group 7 and constitutes each pressure chamber group 7. It extends in the paper feed direction along the pressure chamber rows 8 in a row, and faces a plurality of pressure chambers 10 constituting these two pressure chamber rows 8. Although not shown, the portions extending in the paper feeding direction are connected to each other. The lower electrode 43 is connected to the driver IC 51 via a flexible printed circuit board (FPC) 50 disposed above the piezoelectric actuator 32, and is always held at the ground potential (second potential) by the driver IC 51. .

  The intermediate electrode 44 is formed on the upper surface of the lower piezoelectric layer 41 and is disposed between the lower piezoelectric layer 41 and the upper piezoelectric layer 42. For each pressure chamber group 7, a plurality of facing portions 44a and connecting portions are provided. 44b, 44c. The plurality of facing portions 44 a have a substantially rectangular planar shape whose length in the paper feeding direction is shorter than that of the pressure chamber 10, and is disposed so as to face the central portion of the plurality of pressure chambers 10.

  The connecting portion 44b extends in the paper feeding direction, and among the two pressure chamber rows 8 constituting each pressure chamber group 7, a plurality of pressure chambers 10 constituting the pressure chamber row 8 arranged on the right side in FIG. 4 are connected to each other on the right side in FIG. 4. The connecting portion 44c extends in the paper feeding direction, and among the two pressure chamber rows 8 constituting each pressure chamber group 7, a plurality of pressure chambers 10 constituting the pressure chamber row 8 arranged on the left side in FIG. 4 are connected to each other on the left side in FIG. The intermediate electrode 44 is connected to the driver IC 51 via the FPC 50, and is always held at a predetermined potential (for example, about 20V: the first potential) different from the ground potential by the driver IC 51.

  The plurality of upper electrodes 45 are formed on the upper surface (the surface opposite to the lower piezoelectric layer 41) of the upper piezoelectric layer 42, so as to face almost the entire area of the plurality of pressure chambers 10 corresponding to the plurality of pressure chambers 10. And has a substantially rectangular planar shape whose length in the paper feed direction is longer than the facing portion 44a of the intermediate electrode 44. Further, the upper electrode 45 has a portion at the end opposite to the nozzle 15 in the scanning direction extending to a portion not facing the pressure chamber 10 in the scanning direction, and this portion serves as a connection terminal 45 a connected to the FPC 50. Yes. The upper electrode 45 is connected to the driver IC 51 via the FPC 50, and the potential can be selectively switched between the ground potential and the predetermined potential (for example, 20V).

  By arranging the lower electrode 43, the intermediate electrode 44, and the upper electrode 45 as described above, the upper electrode 45 and the intermediate electrode 44 are opposed to each other in the portion facing the central portion of the pressure chamber 10 in the upper piezoelectric layer 42. Will be. Then, the region is a first active portion R1 by being polarized upward from the intermediate electrode 44 toward the upper electrode 45.

  Further, in the upper piezoelectric layer 42 and the lower piezoelectric layer 41 that face the pressure chamber 10, the upper electrode 45 and the lower electrode in the outer peripheral part (the part that does not face the intermediate electrode 44) than the part that faces the intermediate electrode 44. 43 will be opposed to each other. The region is a second active portion R2 because it is polarized downward from the upper electrode 45 toward the lower electrode 43.

  A portion of the lower piezoelectric layer 41 sandwiched between the intermediate electrode 44 and the lower electrode 43 is polarized downward from the intermediate electrode 44 toward the lower electrode 43.

  The upper electrode mark 61 is made of the same material as that of the upper electrode 45, is formed on the upper surface of the upper piezoelectric layer 42, and is an alignment mark with an X mark that is not electrically connected to any electrode. The upper electrode mark 61 is separated by a predetermined distance from the center of the upper electrode 45 corresponding to the pressure chamber separated from the hole 60 formed in the flow path unit 31 by a predetermined distance, and the hole 60 of the flow path unit 31 in plan view. And the intermediate electrode mark 62 is formed so as to overlap.

  The intermediate electrode mark 62 is made of the same material as that of the intermediate electrode 44, is formed on the upper surface of the lower piezoelectric layer 41, and is an alignment mark with a + mark that is not electrically connected to any electrode. The intermediate electrode mark 62 is formed at a predetermined distance from the center of the intermediate electrode 44 corresponding to the pressure chamber separated from the hole 60 formed in the flow path unit 31 by a predetermined distance. The upper electrode mark 61 and the intermediate electrode mark 62 are formed at positions that do not overlap the electrodes 43 to 45 in plan view.

  Since the hole 60 of the flow path unit 31 and the intermediate electrode mark 62 of the piezoelectric actuator 32 overlap in plan view, the facing portion 44 a of the intermediate electrode 44 overlaps the central portion of the pressure chamber 10. That is, the first active portion R1 is disposed so as to overlap the central portion of the pressure chamber 10 in plan view.

  Here, the operation of the piezoelectric actuator 32 will be described. First, in the standby state before the piezoelectric actuator 32 performs the operation of ejecting ink, as described above, the lower electrode 43 and the intermediate electrode 44 are always set to the ground potential and the predetermined potential (for example, 20 V), respectively. In addition to being held, the potential of the upper electrode 45 is previously held at the ground potential. In this state, the upper electrode 45 has a lower potential than the intermediate electrode 44 and has the same potential as the lower electrode 43.

  As a result, a potential difference is generated between the upper electrode 45 and the intermediate electrode 44, an electric field upward in the same direction as the polarization direction is generated in the first active part R1, and the horizontal direction in which the first active part R1 is orthogonal to this electric field. Shrink to. As a result, so-called unimorph deformation occurs, and the upper piezoelectric layer 42, the lower piezoelectric layer 41, and the portion of the diaphragm 40 facing the pressure chamber 10 are deformed so as to be convex toward the pressure chamber 10 as a whole. In this state, the volume of the pressure chamber 10 is smaller than when the upper piezoelectric layer 42, the lower piezoelectric layer 41, and the diaphragm 40 are not deformed.

  When the piezoelectric actuator 32 is driven to eject ink, the potential of the upper electrode 45 is once switched to the predetermined potential and then returned to the ground potential. When the potential of the upper electrode 45 is switched to the predetermined potential, the upper electrode 45 becomes the same potential as the intermediate electrode 44 and at a higher potential than the lower electrode 43. Thereby, the contraction of the first active part R1 is restored. At the same time, a potential difference is generated between the upper electrode 45 and the lower electrode 43, a downward electric field that is the same as the polarization direction is generated in the second active part R2, and the second active part R2 contracts in the horizontal direction. To do. As a result, the upper piezoelectric layer 42, the lower piezoelectric layer 41, and the vibration plate 40 are deformed so as to be convex on the opposite side to the pressure chamber 10, and the volume of the pressure chamber 10 increases.

  Thereafter, when the potential of the upper electrode 45 is returned to the ground potential, the portions of the upper piezoelectric layer 42, the lower piezoelectric layer 41, and the diaphragm 40 facing the pressure chamber 10 as a whole are directed toward the pressure chamber 10 as described above. And the volume of the pressure chamber 10 is reduced. As a result, the pressure of the ink in the pressure chamber 10 increases (pressure is applied to the ink in the pressure chamber 10), and the ink is ejected from the nozzle 15 communicating with the pressure chamber 10.

  Further, when the piezoelectric actuator 32 is driven as described above, when the potential of the upper electrode 45 is switched from the ground potential to a predetermined potential, the first active portion R1 expands from the contracted state to the pre-contracted state at the same time. Since the second active part R2 contracts, the extension of the first active part R1 is partially absorbed by the contraction of the second active part R2. On the other hand, when the potential of the upper electrode 45 is returned from the predetermined potential to the ground potential, the first active portion R1 contracts and the second active portion R2 expands to the state before contraction. The contraction is partially absorbed by the extension of the second active part R2.

  From the above, the deformation of the portion of the lower piezoelectric layer 41 and the upper piezoelectric layer 42 facing the pressure chamber 10 is transmitted to the portion facing the other pressure chamber 10 to communicate with the other pressure chamber 10. In other words, the so-called crosstalk, in which the ink ejection characteristics fluctuate, is suppressed.

  Note that a potential difference is always generated in the portion between the intermediate electrode 44 and the lower electrode 43 of the lower piezoelectric layer 41 during the standby state described above and while the piezoelectric actuator 32 is being driven. An electric field in the same direction as the polarization direction is generated in this portion. Thereby, this portion of the lower piezoelectric layer 41 is always contracted in a direction perpendicular to the electric field direction.

  Here, when the opposed portion 44a of the intermediate electrode 44 of the piezoelectric actuator 32 is displaced from the central portion of the pressure chamber 10 of the flow path unit 31, unlike the case where the upper electrode 45 is displaced, 1 active part R1 will shift | deviate from the center part of the pressure chamber 10. FIG. Then, the displacement amount of the portion of the upper piezoelectric layer 42, the lower piezoelectric layer 41, and the diaphragm 40 facing the pressure chamber 10 due to the deformation generated in the first active portion R1 is reduced, and the volume of the pressure chamber 10 is changed accordingly. The amount is reduced, and a predetermined pressure cannot be applied to the ink in the pressure chamber 10. Therefore, the facing portion 44a of the intermediate electrode 44 of the piezoelectric actuator 32 is disposed so as to overlap the central portion of the pressure chamber 10 of the flow path unit 31 so that a predetermined pressure can be applied to the ink in the pressure chamber 10. Must.

  Next, a method for manufacturing the inkjet head 3 will be described. 7A and 7B are process diagrams showing the manufacturing process of the ink jet head. FIG. 7A is a flow path unit manufacturing process, FIG. 7B is a piezoelectric actuator manufacturing process, and FIG. 7C is a joining process. The inkjet head 3 performs a process of manufacturing the flow path unit 31, a process of manufacturing the piezoelectric actuator 32, and a process of joining the flow path unit 31 and the piezoelectric actuator 32 separately manufactured in these two processes. It is manufactured by.

  First, holes penetrating in the thickness direction constituting the ink flow paths such as the pressure chamber 10, the manifold flow path 11, and the nozzle 15 are formed in the seven plates 21 to 27 constituting the flow path unit 31. Moreover, the through-hole used as the hole 60 penetrated in the thickness direction when the flow path unit 31 is comprised is formed in the seven plates 21-27, respectively. These holes are formed by etching or laser processing. Then, as shown in FIG. 7A, the seven plates 21 to 27 are laminated and heated and pressed, and the plates are joined with an adhesive to produce a flow channel unit 31 (flow channel). Unit production process). The seven plates 21 to 27 may be joined by metal diffusion bonding or the like when made of a metal material. The hole 60 may be formed after the seven plates 21 to 27 are stacked.

  Separately from the flow path unit manufacturing step, the upper electrode 45 and the intermediate electrode are formed by screen printing on one surface of three green sheets having the same outer shape, which are made of piezoelectric ceramics and are preliminarily formed to allow for shrinkage due to firing. 44 and the lower electrode 43 are formed. At this time, the green sheet on which the upper electrode 45 is formed overlaps with the hole 60 formed in the flow path unit 31 in the joining process described later, and is separated from the upper electrode 45 described above by a predetermined distance. The upper electrode mark 61 is formed together with the upper electrode 45 by screen printing. Further, in the position where the green sheet on which the intermediate electrode 44 is formed overlaps with the hole 60 formed in the flow path unit 31 in the joining process described later, the intermediate sheet 44 is separated from the intermediate electrode 44 by a predetermined distance. The intermediate electrode mark 62 is formed together with the intermediate electrode 44 by screen printing.

  Then, as shown in FIG. 7B, the green sheets on which the lower electrode 43 is formed, the green sheets on which the intermediate electrode 44 is formed, and the green sheets on which the upper electrode 45 are formed are stacked in order from the bottom. To do. In a state where the green sheets are laminated, the upper electrode mark 61 and the intermediate electrode mark 62 are arranged so as to overlap in a plan view. After that, the laminated body is fired at a predetermined temperature, so that the piezoelectric actuator 32 that has the vibration plate 40, the lower piezoelectric layer 41, and the upper piezoelectric layer 42 in order from the bottom is manufactured (piezoelectric actuator manufacturing step). Here, in the produced piezoelectric actuator 32, the upper electrode is caused by a difference in shrinkage amount of the plurality of green sheets at the time of firing, a positional deviation of the plurality of green sheets at the time of lamination, a printing deviation of the electrodes, or the like. The mark 61 and the intermediate electrode mark 62 may not overlap in plan view.

  Then, as shown in FIG. 7C, the flow path unit 31 manufactured in the flow path unit manufacturing process while irradiating light from below to the hole 60 of the flow path unit 31 manufactured in the flow path unit manufacturing process. The flow path unit 31 and the piezoelectric actuator 32 are aligned so that the hole 60 and the intermediate electrode mark 62 formed on the lower piezoelectric layer 41 of the piezoelectric actuator 32 created in the piezoelectric actuator manufacturing process overlap in plan view. Join (joining process). At this time, since the piezoelectric actuator 32 is formed by laminating thin ceramics, the intermediate electrode mark 62 can be seen through when irradiated with light.

  Then, the central portion of the pressure chamber 10 of the flow path unit 31 and the facing portion 44 a of the intermediate electrode 44 of the piezoelectric actuator 32 overlap in a plan view, so that the pressure chamber 10 of the upper piezoelectric layer 42, the lower piezoelectric layer 41, and the vibration plate 40 is overlapped. The ink jet head 3 that can apply a predetermined pressure to the ink in the pressure chamber 10 can be manufactured by displacing the portion facing the.

  At this time, since the hole 60 of the flow path unit 31 penetrates in the stacking direction of the plates, it can be easily seen by irradiating light from below, and the flow path unit 31 and the piezoelectric actuator 32 can be easily aligned. it can.

  According to the method of manufacturing the inkjet head 3 in the present embodiment, the intermediate electrode 44 is an electrode inside the piezoelectric actuator 32, and the intermediate electrode 44 is hidden behind the upper electrode 45 and cannot be seen. Although it is difficult to align the center portion of the intermediate electrode 44 with the center portion of the intermediate electrode 44, the intermediate electrode mark 62 separated from the center of the intermediate electrode 44 by a predetermined distance and the hole 60 separated from the center of the pressure chamber 10 by a predetermined distance are aligned. By doing so, it is possible to easily align the intermediate electrode 44 so as to overlap the central portion of the pressure chamber.

  As described above, when the piezoelectric actuator 32 in which the relative positions of the upper electrode 45 and the intermediate electrode 44 are shifted is formed, the intermediate electrode 44 of the piezoelectric actuator 32 is disposed in the central portion of the pressure chamber 10. Since the central portion of the upper electrode 45 of the piezoelectric actuator 32 is displaced from the pressure chamber 10 in plan view, the second active portion R2 is not evenly arranged on both sides of the paper feed direction across the first active portion R1. The predetermined pressure cannot be applied to the ink in the pressure chamber 10.

  Therefore, the upper electrode mark of the piezoelectric actuator 32 manufactured in the piezoelectric actuator manufacturing process so that a predetermined pressure can be applied to the ink in the pressure chamber 10 even if the intermediate electrode 44 is not disposed in the central portion of the upper electrode 45. The piezoelectric actuators 32 are ranked into a plurality of ranks according to the degree of positional deviation between 61 and the intermediate electrode mark 62. Then, the voltage applied from the driver IC 51 to the upper electrode 45 is increased as the piezoelectric actuator 32 has a rank with a large positional deviation. Then, since the displacement amount of the upper piezoelectric layer 42, the lower piezoelectric layer 41, and the portion of the vibration plate 40 facing the pressure chamber 10 can be increased, the central portion of the upper electrode 45 is shifted from the central portion of the pressure chamber 10. In addition, the piezoelectric actuator 32 that can apply a predetermined pressure to the ink in the pressure chamber 10 can be manufactured.

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

  In the present embodiment, the upper electrode mark 61 and the intermediate electrode mark 62 are formed in the piezoelectric actuator 32 and the hole 60 is formed in the flow path unit 31, but the upper electrode mark 61 is formed in the piezoelectric actuator 32. It is not necessary that the intermediate electrode mark 62 be formed. At this time, for example, the intermediate electrode 44 may overlap the central portion of the pressure chamber 10 by detecting and aligning the relative position between the intermediate electrode mark 62 and the outer edge of the flow path unit 31.

  In this embodiment, the intermediate electrode mark 62 formed in the piezoelectric actuator 32 and the hole 60 formed in the flow path unit 31 are aligned. However, the intermediate electrode mark 62 and the hole 60 are formed. Without irradiating light on the upper surface of the piezoelectric actuator 32 (the surface on which the upper electrode 45 is formed), the intermediate electrode 44 transparent from the upper electrode 45 is directly aligned with the central portion of the pressure chamber 10. May be. According to this, since the electrode is thin, by irradiating light, the intermediate electrode 44 can be seen through and can be directly aligned, and the alignment accuracy is increased.

  Furthermore, the upper electrode mark 61 and the intermediate electrode mark 62 are not limited to marks made of a conductive material formed by screen printing together with electrodes on the piezoelectric layer, but may be marks made by notches formed on the surface of the piezoelectric layer. It may be a mark made of colored ink applied to the surface of the ink.

  In addition, the mark formed on the flow path unit 31 may be a notch formed on the surface of the plate 21 instead of the hole 60, or may be a mark based on colored ink applied to the surface of the plate 21.

  In addition, the upper electrode mark 61, the intermediate electrode mark 62, and the hole 60 are each formed at one place, but may be formed at a plurality of places. According to this, the center-of-gravity positions of the plurality of formed intermediate electrode marks 62 and holes 60 can be calculated, and the piezoelectric actuator 32 and the flow path unit 31 can be aligned. The manufacturing errors of the plurality of intermediate electrodes 44 and the pressure chamber 10 in the 31 manufacturing processes can be minimized. Similarly, for the upper electrode mark 61, the rank of the piezoelectric actuator 32 can be determined in consideration of the manufacturing error of the plurality of upper electrodes 45 in the manufacturing process.

  Further, as long as the positional relationship between the intermediate electrode mark 62 and the intermediate electrode 44 can be grasped, the intermediate electrode mark 62 and the pressure are not adjusted without aligning the intermediate electrode mark 62 of the piezoelectric actuator 32 and the hole 60 of the flow path unit 31. The center of the chamber 10 may be aligned so that the intermediate electrode 44 overlaps the central portion of the pressure chamber 10. That is, even if it is difficult to directly view the intermediate electrode 44, the position of the intermediate electrode 44 can be calculated from the intermediate electrode mark 62. Therefore, by aligning based on the intermediate electrode mark 62, the intermediate electrode 44 can be positioned. Can be easily aligned with the central portion of the pressure chamber 10.

  Further, in the present embodiment, the lower electrode 43 to which the ground potential is always applied in order from the flow path unit 31 side, the intermediate electrode 44 to which the predetermined potential is always applied, and the ground potential and the predetermined potential are selectively applied. However, the positions of the lower electrode 43 and the upper electrode 45 may be reversed. Further, although the lower electrode 43 is continuously formed extending in the paper feeding direction, the lower electrode 43 may not be provided in a region corresponding to the intermediate electrode 44.

  In the above description, the present invention is applied to a method for manufacturing an inkjet head that ejects ink in a pressure chamber. However, the present invention is not limited to this. For example, the present invention relates to a method of manufacturing a liquid transfer device that transfers liquid in a liquid transfer channel including a pressure chamber by applying pressure to the liquid in the pressure chamber, such as a liquid ejecting head that ejects liquid other than ink from a nozzle. Can be applied.

DESCRIPTION OF SYMBOLS 1 Printer 3 Inkjet head 31 Flow path unit 32 Piezoelectric actuator 43 Lower electrode 44 Intermediate electrode 45 Upper electrode R1 1st active part R2 2nd active part

Claims (5)

A flow path unit in which a liquid transfer flow path including a pressure chamber is formed;
A piezoelectric actuator that is provided in the flow path unit and applies pressure to the liquid in the pressure chamber;
The piezoelectric actuator is
A first constant potential electrode sandwiched between a first piezoelectric layer and a second piezoelectric layer stacked on top of each other and overlapping a central portion of the pressure chamber, to which a first potential is applied;
On the surface of the first piezoelectric layer opposite to the first constant potential electrode, the pressure chamber is disposed so as to overlap with at least an outer portion of the pressure chamber that overlaps the first constant potential electrode, and is different from the first potential. A second constant potential electrode to which a second potential is applied;
The second piezoelectric layer is disposed on a surface opposite to the first constant potential electrode, and is opposed to the first constant potential electrode with the second piezoelectric layer in between, and the second constant potential electrode is also the first constant potential electrode. face each other across both piezoelectric layer and the second piezoelectric layer, and the individual electrode to which the first conductive level and said second potential is selectively applied,
A first active part of the second piezoelectric layer, which is sandwiched between the first constant potential electrode and the individual electrode, and which overlaps the central part of the pressure chamber;
The first piezoelectric layer and the second piezoelectric layer are sandwiched between the second constant potential electrode and the individual electrode on the outer side of the first active portion and overlap with the outer portion of the pressure chamber. A second active part,
A flow path unit manufacturing step for manufacturing the flow path unit;
An actuator manufacturing step of manufacturing the piezoelectric actuator;
The first constant potential electrode of the piezoelectric actuator manufactured in the actuator manufacturing step is positioned so as to overlap with a central portion of the pressure chamber of the flow channel unit manufactured in the flow channel unit manufacturing step in a plan view. In addition, a method for manufacturing a liquid transfer device, comprising: a bonding step of bonding the flow path unit and the piezoelectric actuator. Prior Kia actuator manufacturing process, the light forming the piezoelectric actuator pressure material charge you transmission,
In the joining step, the position of the first constant potential electrode is detected by irradiating light toward the piezoelectric actuator, and the first constant potential electrode is connected to a central portion of the pressure chamber of the flow path unit. The liquid transfer device manufacturing method according to claim 1, wherein the flow path unit and the piezoelectric actuator are joined so as to overlap each other. In the actuator manufacturing step, the first constant potential electrode is formed in a region other than the region where the individual electrode, the first constant potential electrode, and the second constant potential electrode are formed in a plan view of the piezoelectric actuator. Forming a first mark separated from the center by a predetermined distance in one direction parallel to the surface to be joined to the flow path unit;
In the joining step, based on the position of the first mark from which the position of the first constant potential electrode can be calculated, the first constant potential electrode is positioned so as to overlap the central portion of the pressure chamber of the flow path unit. The method for manufacturing a liquid transfer device according to claim 1, wherein the flow path unit and the piezoelectric actuator are joined together. In the flow path unit manufacturing step, in a plan view of the flow path unit, a second mark is formed that is separated from the center of the pressure chamber by the predetermined distance with respect to the one direction,
4. The liquid according to claim 3, wherein in the joining step, the flow path unit and the piezoelectric actuator are joined by aligning the first mark and the second mark so as to overlap each other in plan view. Manufacturing method of transfer device. The piezoelectric actuator includes: a first piezoelectric sheet on which the first constant potential electrode is formed; a second piezoelectric sheet on which the second constant potential electrode is formed; a third piezoelectric sheet on which the individual electrode is formed; It is composed by laminating
5. The method of manufacturing a liquid transfer device according to claim 3, wherein the first mark is formed on the first piezoelectric sheet.

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