JP2010030131A - Liquid transporting device and method for manufacturing liquid transporting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid transporting device capable of preventing warpage of a piezoelectric layer which may occur in calcinating. <P>SOLUTION: In order to manufacture an inkjet head 3 a green sheet made of a piezoelectric material to be piezoelectric sheets 41 to 43 having electrodes 44 to 46 printed thereon and a green sheet made of a piezoelectric material to be a cavity plate 21 having formed thereon a through-hole to be a pressure chamber 10 are stacked with each other and heated at temperature of roughly 1,100°C to be calcinated. After that, protection films 50 are formed at parts to be the lower face of the cavity plate 21 and the sidewall face of the pressure chamber 10, and at a part to be a top face of the pressure chamber 10 at the lower face of the piezoelectric sheet 41. Additionally, the laminated body, plates 22, 23 each made of a metallic material having a hole to be an ink channel formed by etching and a nozzle plate 24 made of a synthetic resin material having a nozzle 15 formed by laser processing are stacked and bonded with each other. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

  In the ink jet head described in Patent Document 1, an actuator unit having a plurality of piezoelectric layers made of piezoelectric material stacked on the upper surface of a flow path unit formed by stacking a plurality of plates made of a metal material. (Piezoelectric actuator) is arranged, and by applying a so-called unimorph deformation to the piezoelectric layer of the actuator unit, pressure is applied to the ink in the pressure chamber of the flow path unit, and ink is ejected from the nozzle communicating with the pressure chamber. . Further, when manufacturing such an ink jet head, after laminating a green sheet on which an electrode pattern is not formed on a green sheet of a piezoelectric material printed with a common electrode pattern, and firing these laminates In addition to manufacturing an actuator unit by printing an electrode pattern of individual electrodes on the uppermost surface of the laminate, a flow path unit was manufactured by stacking and joining a plurality of metal plates separately from each other. The actuator unit and the flow path unit are joined by an adhesive or the like.

JP 2008-62553 A

  Here, in the actuator unit that applies pressure to the ink in the pressure chamber by causing unimorph deformation as described in Patent Document 1, it is necessary to reduce the thickness of the piezoelectric layer. However, when an actuator unit having a thin piezoelectric layer is formed by firing a plurality of green sheets stacked on each other as described in Patent Document 1, a large warp occurs in the piezoelectric layer due to heating during firing. End up. For this reason, when the actuator unit and the flow path unit are joined, a positional deviation between the pressure chamber and the individual electrode occurs, and there is a possibility that the ink ejection characteristics from the nozzles may vary.

  Here, unlike what is described in Patent Document 1, a plurality of piezoelectric material green sheets constituting the actuator unit and a plurality of metal plates constituting the flow path unit are laminated, and the laminated body is heated. By doing so, it seems that the above-mentioned problems do not occur if the green sheet is fired. However, when firing a green sheet of piezoelectric material, it is necessary to heat it at about 1100 ° C., and this temperature is higher than the melting point of a metal material such as stainless steel. The green sheet cannot be fired by heating the body.

  The objective of this invention is providing the manufacturing method of the liquid transfer apparatus with a small curvature in a piezoelectric layer in the case of manufacture, and a liquid transfer apparatus.

  The liquid transfer device according to the first invention includes a flow path unit in which a liquid transfer flow path including a pressure chamber is formed, a piezoelectric layer, and an electrode for generating an electric field in the piezoelectric layer, A piezoelectric actuator that applies pressure to the liquid in the pressure chamber, and only a part of the flow path unit is formed of a piezoelectric material, and the liquid transfer is provided in the piezoelectric material portion formed of the piezoelectric material. A part of the flow path is formed, and the piezoelectric material portion is integrated with the piezoelectric layer.

  According to this, since the thickness of the piezoelectric material body in which the piezoelectric layer and the piezoelectric material portion are integrated increases, the warpage of the piezoelectric layer and the piezoelectric material portion that occurs during firing is caused by firing the piezoelectric material body. Can be reduced.

  A liquid transfer device according to a second invention is the liquid transfer device according to the first invention, wherein the pressure chamber is included in a part of the liquid transfer channel formed in the piezoelectric material portion. It is characterized by this.

  According to this, since the pressure chamber is a relatively large portion in the liquid transfer channel, the pressure chamber can be easily formed in the piezoelectric material portion.

  A liquid transfer device according to a third invention is the liquid transfer device according to the second invention, wherein the piezoelectric material portion forms a side wall portion of the pressure chamber and the piezoelectric layer of the piezoelectric actuator. Forms a ceiling portion of the pressure chamber.

  According to this, since both the side wall portion and the ceiling portion of the pressure chamber are made of piezoelectric material, even if the piezoelectric actuator is driven to deform the ceiling portion of the pressure chamber of the piezoelectric layer, Cracks are unlikely to occur at the boundary with the ceiling.

  A liquid transfer device according to a fourth invention is the liquid transfer device according to the third invention, wherein the piezoelectric layer and the piezoelectric material portion are laminated with each other.

  According to this, when the piezoelectric layer is thin, by laminating the piezoelectric layer and the piezoelectric material portion, the thickness of these laminated bodies is increased, so that the warp when these laminated bodies are fired is reduced.

  A liquid transfer device according to a fifth invention is the liquid transfer device according to the fourth invention, wherein the piezoelectric layer of the piezoelectric actuator is formed by laminating a plurality of piezoelectric sheets made of a piezoelectric material. It is characterized by being.

  According to this, by forming a piezoelectric layer by laminating a plurality of piezoelectric sheets, a piezoelectric actuator in which electrodes are arranged between the plurality of piezoelectric sheets can be formed.

  A liquid transfer device according to a sixth invention is the liquid transfer device according to the fourth or fifth invention, wherein the piezoelectric material portion is formed by laminating a plurality of piezoelectric sheets made of a piezoelectric material. It is characterized by being.

  According to this, a part of the liquid transfer channel including the pressure chamber can be easily formed by laminating a plurality of piezoelectric sheets to form the piezoelectric material portion.

  A liquid transfer device according to a seventh invention is the liquid transfer device according to the sixth invention, wherein a part of the piezoelectric material portion forming the pressure chamber has a plurality of holes in which the pressure chambers are formed. The piezoelectric sheet is formed by laminating, and a hole serving as the pressure chamber formed in the piezoelectric sheet disposed at the end on the piezoelectric actuator side with respect to the laminating direction of the plurality of piezoelectric sheets. As viewed from the thickness direction of the piezoelectric sheet, the piezoelectric sheet is located inside the hole serving as the pressure chamber formed in another piezoelectric sheet.

  According to this, the hole which becomes the pressure chamber formed in the piezoelectric sheet located at the end on the piezoelectric actuator side with respect to the stacking direction of the piezoelectric sheet has a pressure chamber formed in another piezoelectric sheet when viewed from the stacking direction of the piezoelectric sheet. Since the pressure chamber is located inside the hole, the pressure chamber has a shape in which a bubble in which a step is formed at a corner portion is difficult to collect.

  A liquid transfer device according to an eighth invention is the liquid transfer device according to any one of the first to seventh inventions, wherein a portion joined to the piezoelectric material portion of the flow path unit is made of metal or silicon. It is characterized by being formed.

  According to this, the flow path can be easily and accurately formed in the portion joined to the piezoelectric material portion of the flow path unit by etching.

  A liquid transfer device according to a ninth invention is the liquid transfer device according to any one of the first to eighth inventions, wherein the piezoelectric layer and the piezoelectric material portion are provided on the wall surface of the liquid transfer channel. Further, a protective film is formed to prevent the liquid in the liquid transfer channel from contacting the piezoelectric layer and the piezoelectric material portion.

  According to this, since the protective film is formed on the portion of the piezoelectric layer and the piezoelectric material portion that becomes the wall surface of the liquid transfer channel, the piezoelectric material portion is eroded by the liquid transferred through the liquid transfer channel. Can be prevented.

  A method for manufacturing a liquid transfer device according to a tenth aspect of the present invention includes a flow path unit in which a liquid transfer flow path including a pressure chamber is formed, a piezoelectric layer, and an electrode for generating an electric field in the piezoelectric layer. And a piezoelectric layer forming step of forming the piezoelectric layer of the piezoelectric actuator with a piezoelectric material, and a piezoelectric material, The first part forming step of the flow channel unit that forms the piezoelectric material portion that is a portion that forms a part of the liquid transfer flow channel in the flow channel unit, the electrode forming step of forming the electrode, and the piezoelectric A firing step of firing a piezoelectric material body in which a layer and the piezoelectric material portion are integrated, a second portion forming step of the flow path unit that forms a portion of the flow path unit other than the piezoelectric material portion, and the firing After degree, and the piezoelectric material portion, and is characterized in that it comprises a bonding step of bonding the piezoelectric material other than portions of the channel unit.

  According to this, since the piezoelectric material body in which the piezoelectric layer and the piezoelectric material portion are integrated has a large thickness, the piezoelectric material body and the piezoelectric material portion warped during firing are fired by firing the piezoelectric material body. Can be reduced.

  A method for manufacturing a liquid transfer device according to an eleventh aspect of the invention is a method for manufacturing a liquid transfer device according to the tenth aspect of the invention, wherein the piezoelectric layer and the piezoelectric material part are laminated before the firing step. The method further comprises a laminating step for forming the piezoelectric material body.

  According to this, when the piezoelectric layer and the piezoelectric material portion are formed separately, a piezoelectric material body combining the piezoelectric layer and the piezoelectric material portion can be formed by laminating them.

  A liquid transfer device manufacturing method according to a twelfth aspect of the present invention is the liquid transfer device manufacturing method according to the eleventh aspect of the present invention, wherein in the piezoelectric layer forming step, a plurality of piezoelectric sheets made of a piezoelectric material are laminated. The piezoelectric layer is formed.

  According to this, by forming a piezoelectric layer by laminating a plurality of piezoelectric sheets, a piezoelectric actuator in which electrodes are arranged between the plurality of piezoelectric sheets can be formed.

  A manufacturing method of a liquid transfer device according to a thirteenth invention is a manufacturing method of a liquid transfer device according to the eleventh or twelfth invention, wherein a plurality of piezoelectric sheets made of a piezoelectric material are provided in the first part forming step. The piezoelectric material portion is formed by laminating.

  According to this, a part of the liquid transfer channel can be easily formed by laminating a plurality of piezoelectric sheets to form the piezoelectric material portion.

  A method for manufacturing a liquid transfer device according to a fourteenth aspect of the invention is a method for manufacturing a liquid transfer device according to the tenth aspect of the invention, wherein the piezoelectric layer and the piezoelectric material portion are integrally formed to form the piezoelectric layer. The forming step and the first partial forming step are performed simultaneously.

  According to this, since the piezoelectric layer and the piezoelectric material part can be formed at a time, the manufacturing process of the liquid transfer device is simplified.

  A method for manufacturing a liquid transfer device according to a fifteenth aspect of the invention is a method for manufacturing a liquid transfer device according to any of the tenth to fourteenth aspects of the invention, wherein after the firing step, the liquid in the piezoelectric layer and the piezoelectric material portion. A protective film forming step of forming a protective film for preventing the liquid in the liquid transfer flow channel from coming into contact with the piezoelectric layer and the piezoelectric material portion is further provided on a portion serving as a wall surface of the transfer flow channel. It is characterized by this.

  According to this, since the protective film is formed on the part of the piezoelectric layer and the piezoelectric material part that becomes the wall surface of the liquid transfer channel, the piezoelectric material unit is eroded by the liquid transferred through the liquid transfer channel. Can be prevented.

  According to the present invention, the piezoelectric material body in which the piezoelectric layer and the piezoelectric material portion are integrated has a large thickness. Therefore, by firing the piezoelectric material body, the piezoelectric layer and the piezoelectric material portion that are generated at the time of firing. Can be reduced.

  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 ink jet head 3 (liquid transport device), 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. 2) 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 a plan view of the inkjet head 3 of FIG. FIG. 3 is a partially enlarged view of FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 5 is a cross-sectional view taken along line VV in FIG. In FIGS. 2 and 3, an intermediate electrode 45 to be described later, which should be drawn with a dotted line, is drawn with a one-dot chain line for easy understanding of the drawings.

  As shown in FIGS. 2 to 5, the inkjet head 3 applies pressure to the ink in the pressure chamber 10 and a flow path unit 31 in which an ink flow path (liquid transfer flow path) such as a pressure chamber 10 described later is formed. A piezoelectric actuator 32 (pressure applying means) for applying is provided.

  The flow path unit 31 is configured by laminating the cavity plate 21, the base plate 22, the manifold plate 23, and the nozzle plate 24 with each other. Of these four plates 21 to 24, the cavity plate 21 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 a base plate. 22 and the manifold plate 23 are made of a metal material such as stainless steel, and the nozzle plate 24 is made of a synthetic resin material such as polyimide. Or the nozzle plate 24 may be comprised with the metal material similarly to the plates 22 and 23. FIG. As described above, in the present embodiment, only the cavity plate 21 which is a part of the flow path unit 31 is made of a piezoelectric material.

  The cavity plate 21 made of a piezoelectric material has a plurality of pressure holes 10 (parts of the liquid transfer channel) formed therein, and a portion surrounding the through hole of the cavity plate 21 is a pressure chamber. 10 side walls. The pressure chamber 10 has a substantially elliptical planar shape whose longitudinal direction is the scanning direction (left-right direction in FIG. 2). The plurality of pressure chambers 10 are arranged in the paper feeding direction (vertical direction in FIG. 2) to form a pressure chamber row, and such pressure chamber rows are arranged in two rows in the scanning direction. ing. The cavity plate 21 has a thickness of 40 to 50 μm. In the present embodiment, the cavity plate 21 corresponds to the piezoelectric material part according to the present invention.

  Through holes 12 and 13 are formed in the base plate 22 at portions overlapping with both ends in the longitudinal direction of the pressure chamber 10 in plan view. A manifold channel 11 is formed in the manifold plate 23. The manifold channels 11 are arranged in two rows in the paper feed direction so as to overlap the substantially right half of the pressure chambers 10 arranged on the right side of FIG. 2 and the substantially left half of the pressure chambers 10 arranged on the left side of FIG. In addition, the portions extending in the two rows at the lower end in FIG. 2 are connected to each other. Ink is supplied to the manifold channel 11 from an ink supply channel 9 formed at the lower end in FIG. Further, a through hole 14 is formed in the manifold plate 23 at a portion overlapping the through hole 13 in plan view.

  A nozzle 15 is formed in the nozzle plate 24 at a portion overlapping the through hole 14 in plan view. In the flow path unit 31, the manifold flow path 11 communicates with the pressure chamber 10 via the through hole 12, and the pressure chamber 10 communicates with the nozzle 15 via the through holes 13 and 14. That is, a plurality of individual ink channels are formed in the channel unit 31 from the outlet of the manifold channel 11 to the nozzle 15 via the pressure chamber 10.

  The piezoelectric actuator 32 has three piezoelectric sheets 41, 42, 43, a lower electrode 44, an intermediate electrode 45, and a plurality of upper electrodes 46. The piezoelectric sheets 41 to 43 are sheets made of the same piezoelectric material as the cavity plate 21 and having a thickness of about 20 μm. The piezoelectric sheets 41 to 43 are stacked on each other and cover the plurality of pressure chambers 10. It is disposed on the upper surface and is integrated with the cavity plate 21. And the part which opposes the pressure chamber 10 of the piezoelectric sheets 41-43 is the ceiling part of the pressure chamber 10 by arrange | positioning the piezoelectric sheets 41-43 in this way. In the present embodiment, the piezoelectric sheets 41 to 43 stacked on each other correspond to the piezoelectric layer according to the present invention.

  Further, of the piezoelectric sheets 41 to 43, a portion that overlaps with the pressure chamber 10 in a plan view of the lower surface of the piezoelectric sheet 41 that is the lowermost layer, and a portion that becomes the lower surface of the cavity plate 21 and the side wall surface of the pressure chamber 10 (piezoelectric layer and A protective film 50 made of a fluorine-based resin, an epoxy-based resin, or the like is formed on a portion of the piezoelectric material portion that becomes the wall surface of the liquid flow path. However, erosion by the ink in the pressure chamber 10 is prevented. Therefore, various types of ink can be used for the inkjet head 3, and the versatility of the inkjet head 3 is enhanced.

  The lower electrode 44 is continuously formed in almost the entire region between the piezoelectric sheet 41 and the piezoelectric sheet 42, and through a through hole that penetrates the upper end portion of the piezoelectric sheets 42 and 43 in FIG. The connection terminal 44 a formed on the upper surface of the piezoelectric sheet 43 is connected. A driver IC (not shown) is connected to the connection terminal 44a via a wiring of a flexible wiring board (FPC) (not shown), and the lower electrode 44 is always held at the ground potential by the driver IC.

  The intermediate electrode 45 is formed between the piezoelectric sheet 42 and the piezoelectric sheet 43, and has a plurality of facing portions 45a and connecting portions 45b. The plurality of facing portions 45a have a substantially rectangular shape whose longitudinal direction is the scanning direction, and are respectively disposed at substantially central portions in the paper feeding direction of the plurality of pressure chambers 10 in plan view. The connecting portion 45b extends in the paper feed direction at a portion overlapping the two pressure chamber rows in plan view, and connects the end portions on the nozzle 15 side of the plurality of facing portions 45a. 2 is connected to a connection terminal 45c formed on the upper surface of the piezoelectric sheet 43 through a through hole formed so as to penetrate the piezoelectric sheet 43. A driver IC (not shown) is connected to the connection terminal 45c via an FPC wiring (not shown), and the intermediate electrode 45 is always held at a predetermined drive potential (for example, about 20 V) by the driver IC.

  The plurality of upper electrodes 46 have a substantially elliptical planar shape similar to that of the pressure chamber 10, and are disposed on the upper surface of the piezoelectric sheet 43 so as to overlap the entire area of the pressure chamber 10 in plan view. Thereby, the upper electrode 46 is opposed to the intermediate electrode 45 (opposing portion 45a) in a portion overlapping the substantially central portion in the paper feeding direction of the pressure chamber 10 in plan view, and is related to the paper feeding direction of the pressure chamber 10. It faces the lower electrode 44 in a portion that overlaps both ends. Further, the upper electrode 46 has an end opposite to the nozzle 15 in the scanning direction extending to a portion not facing the pressure chamber 10, and a tip of the upper electrode 46 serves as a connection terminal 46a. A driver IC (not shown) is connected to the connection terminal 46a via an FPC wiring (not shown), and the plurality of upper electrodes 46 are individually connected to the ground potential and any one of the above-described drive potentials by the driver IC. Is selectively given.

  Further, the portion sandwiched between the lower electrode 44 and the upper electrode 46 of the piezoelectric sheets 42 and 43 is polarized downward in the vertical direction, and the portion sandwiched between the intermediate electrode 45 and the upper electrode 46 of the piezoelectric sheet 43 is It is polarized vertically upward.

  Here, a driving method of the piezoelectric actuator 32 will be described. In the piezoelectric actuator 32, the lower electrode 44 and the intermediate electrode 45 are held at the ground potential and the driving potential as described above, and the plurality of upper electrodes 46 are all held at the ground potential.

  In this state, due to the potential difference between the intermediate electrode 45 held at the driving potential and the upper electrode 46 held at the ground potential, the portion sandwiched between the intermediate electrode 45 and the upper electrode 46 of the piezoelectric sheet 43 is vertically aligned. An upward electric field is generated. Since the direction of this electric field coincides with the polarization direction of this portion of the piezoelectric sheet 43, this portion of the piezoelectric sheet 43 contracts in the horizontal direction perpendicular to the direction of this electric field. Accordingly, the portions of the piezoelectric sheets 41 to 43 facing the pressure chamber 10 are deformed so as to be convex toward the pressure chamber 10 (so-called unimorph deformation). Thereby, the volume of the pressure chamber 10 is small compared with the state where the piezoelectric sheets 41 to 43 are not deformed.

  When the piezoelectric actuator 32 is driven, the potential of the upper electrode 46 corresponding to the nozzle 15 that ejects ink is switched from the ground potential to the drive potential, and after a predetermined time has elapsed, the potential is returned to the ground potential again.

  When the potential of the upper electrode 46 is switched from the ground potential to the driving potential, the intermediate electrode 45 and the upper electrode 46 become the same potential, and the electric field of the portion sandwiched between these electrodes of the piezoelectric sheet 43 disappears. This part of the deformation is restored. At the same time, a potential difference is generated between the lower electrode 44 and the upper electrode 46, and a vertically downward electric field is generated in the portion of the piezoelectric sheets 42 and 43 sandwiched between these electrodes. Since the direction of the electric field coincides with the polarization direction of this portion of the piezoelectric sheets 42 and 43, this portion of the piezoelectric sheets 42 and 43 contracts in the horizontal direction orthogonal to the polarization direction. Thereby, the part which overlaps with the approximate center part of the pressure chamber 10 of the piezoelectric sheets 41-43 will be pulled upwards, and the part facing the pressure chamber 10 of the piezoelectric sheets 41-43 will be on the opposite side to the pressure chamber 10 as a whole. By deforming so as to be convex, the volume of the pressure chamber 10 is increased.

  When the potential of the upper electrode 46 is returned from the driving potential to the ground potential in this state, the electric field in the portion sandwiched between the lower electrode 44 and the upper electrode 46 of the piezoelectric sheets 42 and 43 disappears and the intermediate electrode of the piezoelectric sheet 43 is removed. Since a vertical upward electric field is generated at a portion sandwiched between the upper electrode 46 and the upper electrode 46, the portion facing the pressure chamber 10 of the piezoelectric sheets 41 to 43 protrudes toward the pressure chamber 10 as a whole as described above. It transforms to become. As a result, the volume of the pressure chamber 10 decreases, the pressure of the ink in the pressure chamber 10 increases, and ink is ejected from the nozzle 15 communicating with the pressure chamber 10.

  Here, in such a piezoelectric actuator 32, when the potential of the upper electrode 46 is switched from the ground potential to the driving potential, the portion sandwiched between the intermediate electrode 45 and the upper electrode 46 of the piezoelectric sheet 43 contracts. The portion between the lower electrode 44 and the upper electrode 46 of the piezoelectric sheets 42 and 43 contracts, so that the contraction of the piezoelectric sheets 42 and 43 is caused by the expansion of the piezoelectric sheet 43. Some will be absorbed. As a result, the deformation of the piezoelectric sheets 42 and 43 hardly propagates to the portion facing the other pressure chamber 10, and the ejection characteristics of the ink from the nozzle 15 communicating with the other pressure chamber 10 fluctuate. Is prevented.

  Even when the potential of the upper electrode 46 is switched from the driving potential to the ground potential, the portion sandwiched between the lower electrode 44 and the upper electrode 46 of the piezoelectric sheets 42 and 43 expands from the contracted state to the state before contracting. In addition, since the portion sandwiched between the intermediate electrode 45 and the upper electrode 46 of the piezoelectric sheet 43 contracts, the contraction of the piezoelectric sheet 43 is partially absorbed by the expansion of the piezoelectric sheets 42 and 43. . As a result, the deformation of the piezoelectric sheets 42 and 43 hardly propagates to the portion facing the other pressure chamber 10, and the ejection characteristics of the ink from the nozzle 15 communicating with the other pressure chamber 10 fluctuate. Is prevented.

  Furthermore, when the piezoelectric actuator 32 is driven in this manner, the portion of the piezoelectric sheets 41 to 43 that becomes the ceiling portion of the pressure chamber 10 is deformed, but the cavity plate 21 that forms the side wall portion of the pressure chamber 10 and Since the piezoelectric sheets 41 to 43 that form the ceiling portion of the pressure chamber 10 are both made of a piezoelectric material, the cavity plate 21 that forms the side wall portion of the pressure chamber 10 is made of a metal material. Unlikely, when the piezoelectric sheets 41 to 43 are deformed, it is possible to prevent a crack from occurring at the boundary portion between the side wall portion and the ceiling portion of the pressure chamber 10.

  Next, a method for manufacturing the inkjet head 3 will be described. FIG. 6 is a process diagram showing the manufacturing process of the inkjet head 3.

  In order to manufacture the ink jet head 3, first, as shown in FIG. 6A, green sheets of piezoelectric material to be the piezoelectric sheets 41 to 43 on which patterns of the electrodes 44 to 46 are printed are stacked on each other. (Piezoelectric layer forming step, electrode forming step) As shown in FIG. 6B, a through hole that becomes the pressure chamber 10 is formed in the green sheet of the piezoelectric material that becomes the cavity plate 21 by laser processing or the like (first portion). Forming step). Here, since the pressure chamber 10 is a relatively large portion in the ink flow path formed in the flow path unit 31, the pressure chamber 10 is formed by laser processing or the like on a green sheet of a piezoelectric material that becomes the cavity plate 21 made of the piezoelectric material. The through-hole which becomes becomes can be formed easily.

  Then, as shown in FIG. 6C, the piezoelectric sheets 41 to 43 and the green sheet to be the cavity plate 21 are laminated to each other (lamination process), and a laminated body (piezoelectric material body) in which these are integrated is 1100. Baking by heating at about ° C. (firing step).

  Here, if the piezoelectric sheets 41 to 43 and the cavity plate 21 are not laminated with each other and only the green sheets that become the piezoelectric sheets 41 to 43 are fired, the total thickness of the piezoelectric sheets 41 to 43 is as thin as about 60 μm. There is a possibility that large warpage may occur in the sheets 41 to 43.

  On the other hand, in the present embodiment, the cavity plate 21 is made of a piezoelectric material, and the piezoelectric sheets 41 to 43 and the green sheet to be the cavity plate 21 are stacked on each other, and firing is performed. The total thickness of the piezoelectric sheets 41 to 43 and the cavity plate 21 is about 100 to 110 μm, which is larger than the case described above, and the warpage of the piezoelectric sheets 41 to 43 and the cavity plate 21 generated during firing can be reduced.

  Next, as shown in FIG. 6 (d), the protective film 50 is formed on the lower surface of the cavity plate 21 and the portion serving as the side wall surface of the pressure chamber 10 and the portion serving as the ceiling surface of the pressure chamber 10 on the lower surface of the piezoelectric sheet 41. Form. The protective film 50 can be formed by applying PVD (physical vapor deposition), CVD (chemical vapor deposition), a resin material to be the protective film 50, or the like.

  In addition to the steps of FIGS. 6A to 6D, as shown in FIG. 6E, the ink flow path (through holes 12 to 14,. Hole for forming the manifold channel 11 and the like, and the nozzle 15 is formed on the nozzle plate 24 made of a synthetic resin material by laser processing or the like, and the base plate 22, the manifold plate 23, and the nozzle plate 24 are stacked on each other and thermoset. Bonding with a conductive adhesive or the like (second part forming step).

  At this time, the through holes 12 to 14 and the like are small portions in the ink flow path formed in the flow path unit 31, but since the base plate 22 and the manifold plate 23 are made of a metal material, the small through holes 12 to 14 can be formed easily and accurately by etching.

  Then, as shown in FIG. 6F, the laminate of the cavity plate 21 and the piezoelectric actuator 32 and the laminate of the plates 22 to 24 are laminated to each other and joined together by a thermosetting adhesive or the like (joining). Process). At this time, as described above, since the warpage of the cavity plate 21 and the piezoelectric sheets 41 to 43 is reduced, misalignment hardly occurs between the electrodes 44 to 46 and the pressure chamber 10 when both are joined. . This prevents variations in the ink ejection characteristics from the nozzles 15. As described above, the ink jet head 3 is manufactured.

  Here, after the plates 22 to 24 having holes for forming ink flow paths are stacked and bonded together, the stacked body and the stacked body of the cavity plate 21 and the piezoelectric actuator 32 are stacked and bonded together. However, the plates 22 to 24 in which holes serving as ink flow paths are formed and the laminate of the cavity plate 21 and the piezoelectric actuator 32 may be stacked on each other and bonded together.

  According to the embodiment described above, since the piezoelectric sheets 41 to 43 and the green sheet to be the cavity plate 21 are stacked on each other, firing is performed, so that the total thickness of the piezoelectric sheets 41 to 43 and the cavity plate 21 is increased. Is as large as about 100 to 110 μm, and warpage of the fired piezoelectric sheets 41 to 43 and the cavity plate 21 is reduced.

  In addition, since the pressure chamber 10 is a relatively large portion of the ink flow path formed in the flow path unit 31, even when the cavity plate 21 is made of a piezoelectric material, the pressure chamber is formed by laser processing or the like. 10 can be easily formed.

  Further, since the cavity plate 21 that forms the side wall portion of the pressure chamber 10 and the piezoelectric sheets 41 to 43 that form the ceiling portion of the pressure chamber 10 are both made of a piezoelectric material, the piezoelectric actuator 32 is driven to perform piezoelectricity. Even if the ceiling portion of the pressure chamber 10 of the sheets 41 to 43 is deformed, cracks are unlikely to occur at the boundary portion between the side wall portion and the ceiling portion of the pressure chamber 10.

  Further, by forming a piezoelectric layer by laminating a plurality of piezoelectric sheets 41 to 43, the piezoelectric actuator 32 in which the electrodes 44 to 46 are disposed on the surfaces of the piezoelectric sheets 41 to 43 can be easily formed.

  In addition, since the protective film 50 is formed on the portion of the piezoelectric sheet 41 (piezoelectric layer) that serves as the ceiling surface of the pressure chamber 10 and the portion of the cavity plate 21 that serves as the side wall surface of the pressure chamber 10, Can be prevented from being eroded. Thereby, various kinds of ink can be used for the inkjet head 3, and the versatility of the inkjet head 3 becomes high.

  Further, since the base plate 22 and the manifold plate 23 constituting the flow path unit 31 are made of a metal material, an ink flow path including small through holes 12 to 14 and the like can be easily formed in the base plate 22 and the manifold plate 23 by etching. Can be formed with high accuracy.

  Next, modified examples in which various modifications are made to the above-described embodiment will be described. However, components having the same configurations as those of the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted as appropriate.

  In the above-described embodiment, the side wall of the pressure chamber 10 is formed by one cavity plate 21 made of a piezoelectric material. However, the present invention is not limited to this. In one modified example, as shown in FIG. 7, three piezoelectric sheets 61 to 63 are stacked and arranged instead of the cavity plate 21 (see FIG. 5). Then, the two piezoelectric sheets 61 and 62 except for the uppermost one of the three piezoelectric sheets 61 to 63 are placed in a position overlapping the pressure chamber 10 (see FIG. 5) in plan view. Through holes 61 a and 62 a having substantially the same size as the chamber 10 are formed. Of the three piezoelectric sheets 61 to 63, the uppermost piezoelectric sheet 63 is provided with a through hole 63 a that is slightly smaller than the pressure chamber 10 in a portion overlapping the pressure chamber 10 in plan view. The through hole 63a is located inside the through holes 61a and 62a in plan view. And the hole used as the pressure chamber 60 is formed because the through-holes 61a-63a mutually overlap (Modification 1). In Modification 1, the three piezoelectric sheets 61 to 63 correspond to the piezoelectric material portion according to the present invention.

  In this case, since the pressure chamber 60 has a structure in which a step is formed at the corner of the upper end portion, bubbles are less likely to accumulate at the corner of the pressure chamber 60. Further, in this case, the total thickness of the piezoelectric sheets 41 to 43 and the piezoelectric sheets 61 to 63 becomes large as in the case of the above-described embodiment (about 100 to 110 μm). The piezoelectric sheets 41 to 43 and the piezoelectric sheets 61 to 63 warped during firing by laminating and firing the piezoelectric material green sheets and the piezoelectric sheets 61 to 63, which are laminated. Can be reduced.

  Also in this case, since the pressure chamber 60 is a relatively large portion in the ink flow path formed in the flow path unit, the through holes 61a to 63a are formed in the piezoelectric sheets 61 to 63 made of a piezoelectric material by laser processing or the like. By forming, the pressure chamber 60 can be formed easily.

  In the above-described embodiment, the piezoelectric actuator has a structure in which the piezoelectric sheets 41 to 43 are stacked on each other and the electrodes 44 to 46 are arranged on the surfaces of the piezoelectric sheets 41 to 43. However, the present invention is not limited thereto. Absent. In another modification, as shown in FIGS. 8 and 9, a piezoelectric layer having the same thickness (about 60 μm) as the piezoelectric sheets 41 to 43 (see FIG. 4) are combined on the upper surface of the cavity plate 21. 71 is arranged. In addition, a plurality of recesses 71 a and 71 b are formed on the upper surface of the piezoelectric layer 71 at a portion facing the pressure chamber 10. The plurality of recesses 71a and 71b are arranged at substantially equal intervals in the paper feed direction (left and right direction in FIG. 9), thereby forming a row of recesses 71a and a row of recesses 71b. The rows of recesses 71b are alternately arranged at substantially equal intervals in the scanning direction.

  The plurality of recesses 71a and 71b are filled with a metal material paste or the like to form electrodes 72a and 72b, respectively. The electrode 72a is always held at the ground potential, and the potential of the electrode 72b is switched between the ground potential and the drive potential by a driver IC (not shown). Further, the portion of the piezoelectric layer 71 sandwiched between the electrodes 72a and 72b is polarized in the horizontal direction from the electrode 72b to the electrode 72a (Modification 2).

  In such a piezoelectric actuator, both the electrodes 72a and 72b are previously held at the ground potential, and when ejecting ink from the nozzle 15, the potential of the electrode 72b is set to one end drive potential, and after a predetermined time has elapsed, Return to ground potential. When the potential of the electrode 72b is changed to the drive potential, an electric field in the horizontal direction that is the same as the polarization direction is generated in the portion sandwiched between the electrodes 72a and 72b of the piezoelectric layer 71, and this portion of the piezoelectric layer 71 is moved horizontally. Elongate. On the other hand, in the portion below this portion of the piezoelectric layer 71, the above-described elongation does not occur. Therefore, the piezoelectric layer 71 is deformed so as to be convex on the opposite side of the pressure chamber 10 due to the difference in elongation between these two portions of the piezoelectric layer 71, thereby increasing the volume of the pressure chamber 10. Thereafter, when the potential of the electrode 72b is returned to the ground potential, the deformation of the piezoelectric layer 71 returns to the original, and the volume of the pressure chamber 10 decreases. As a result, the pressure of the ink in the pressure chamber 10 increases, and the ink is ejected from the nozzle 15 communicating with the pressure chamber 10.

  In this case, a piezoelectric material green sheet to be the piezoelectric layer 71 and a piezoelectric material green sheet to be the cavity plate 21 in which the through holes to be the pressure chambers 10 are formed are formed (piezoelectric layer forming step). , First part forming step), laminating them (lamination step), firing these laminates (piezoelectric material bodies) (firing step), and then forming recesses 71a and 71b in the piezoelectric layer 71 by laser processing or the like. Alternatively, instead of forming the recesses 71a and 71b after firing the piezoelectric layer 71, a green sheet to be the piezoelectric layer 71 having the recesses 71a and 71b formed by injection molding or the like may be formed ( Piezoelectric layer forming step). Then, the electrodes 72a and 72b are formed by filling the recesses 71a and 71b of the fired piezoelectric layer 71 with a conductive material (electrode formation step).

  Even in this case, as described above, the cavity plate 21 and the piezoelectric layer 71 generated during firing are obtained by laminating the cavity plate 21 made of the piezoelectric material and the piezoelectric layer 71 and then firing these laminates. Can be reduced.

  Moreover, in the above description, the part (cavity plate 21, piezoelectric sheets 61-63, that is, piezoelectric material part) which forms the pressure chamber 10 of a flow path unit, and the part (piezoelectric sheets 41-43) used as the piezoelectric layer of a piezoelectric actuator. However, the present invention is not limited to this. In another modification, as shown in FIG. 10, a piezoelectric material body 81 constituting the two portions (piezoelectric material portion and piezoelectric layer) is disposed on the upper surface of the base plate 22. The piezoelectric material body 81 has a concave portion 81a that becomes the pressure chamber 10 in a substantially lower half thereof, and concave portions 71a and 71b similar to those of the second modification are formed on the upper surface of the piezoelectric material body 81. In addition, electrodes 72a and 72b are formed in the recesses 71a and 71b, respectively (Modification 3).

  In this case, the piezoelectric material body 81 forms the recesses 71a, 71b, 81a by laser processing or the like after firing a green sheet of piezoelectric material formed by injection molding, or the recesses 71a, It is formed by firing the green sheets on which 71b and 81a are formed. However, since the piezoelectric material body 81 has a large thickness, warpage of the piezoelectric material body 81 that occurs during firing can be reduced. In this case, by forming a green sheet to be the piezoelectric material body 81 by injection molding, the piezoelectric layer forming step and the first partial forming step of the flow path unit 31 according to the present invention are performed simultaneously.

  In addition, the piezoelectric actuator is not limited to the above-described one, and the piezoelectric actuator has a thin piezoelectric layer, and if the green sheet that serves as the piezoelectric layer is fired, the piezoelectric layer may be warped greatly. The invention can also be applied.

  In the above-described embodiment, the protective film 50 is formed on the lower surface of the cavity plate 21 and the side wall surface of the pressure chamber 10, and on the lower surface of the piezoelectric sheet 41. However, as shown in FIG. The film 50 may not be formed (Modification 4). Even in this case, if the kind of ink that does not erode the piezoelectric material is used, the cavity plate 21 and the piezoelectric sheets 41 to 43 are not eroded by the ink.

  In the above-described embodiment, the plates 22 and 23 are made of a metal material. However, the present invention is not limited to this. For example, the plates 22 and 23 may be made of a silicon material. Even in this case, as in the case of being made of a metal material, the ink flow path including the small through holes 12 to 14 can be easily and accurately formed in the plates 22 and 23 by etching.

  In the above description, only the portion of the ink flow path formed in the flow path unit that forms the pressure chamber is made of piezoelectric material. For example, in addition to the cavity plate 21, the base plate 22 is also made of piezoelectric material. The flow path unit is composed of only a part of the piezoelectric material, and a portion other than the pressure chamber of the ink flow path is formed in the piezoelectric material portion formed of the piezoelectric material. And this piezoelectric material part may be integrated with the piezoelectric layer.

  In the above, an example in which the present invention is applied to an ink jet head that ejects ink from nozzles has been described. However, the present invention is not limited thereto, and the present invention is applied to a liquid transfer device that discharges liquid or transfers liquid other than ink. It is also possible to apply.

1 is a schematic configuration diagram of a printer according to an embodiment of the present invention. It is a top view of the inkjet head of FIG. FIG. 3 is a partially enlarged view of FIG. 2. It is the IV-IV sectional view taken on the line of FIG. It is the VV sectional view taken on the line of FIG. It is process drawing which shows the manufacture process of an inkjet head. FIG. 6 is a diagram corresponding to FIG. FIG. 6 is a diagram corresponding to FIG. FIG. 6 is a diagram corresponding to FIG. FIG. 6 is a diagram corresponding to FIG. FIG. 6 is a diagram corresponding to FIG.

Explanation of symbols

3 Inkjet head 10 Pressure chamber 12, 13, 14 Through hole 21 Cavity plate 22 Base plate 23 Manifold plate 31 Channel unit 32 Piezoelectric actuators 41-43 Piezoelectric sheet 44 Lower electrode 45 Intermediate electrode 46 Upper electrode 50 Protective film 60 Pressure chamber 61 63 Piezoelectric sheets 61a to 63a Through hole 71 Piezoelectric layer 72 Electrode 81 Piezoelectric material body

Claims (15)

A flow path unit in which a liquid transfer flow path including a pressure chamber is formed;
A piezoelectric layer, and an electrode for generating an electric field in the piezoelectric layer, and a piezoelectric actuator that applies pressure to the liquid in the pressure chamber,
A part of the flow path unit is made of a piezoelectric material, and a part of the liquid transfer flow path is formed in the piezoelectric material portion made of the piezoelectric material, and the piezoelectric material The part is integrated with the piezoelectric layer.   The liquid transfer device according to claim 1, wherein the pressure chamber is included in a part of the liquid transfer flow path formed in the piezoelectric material portion. The piezoelectric material portion forms a side wall portion of the pressure chamber,
The liquid transfer device according to claim 2, wherein the piezoelectric layer of the piezoelectric actuator forms a ceiling portion of the pressure chamber.   The liquid transfer device according to claim 3, wherein the piezoelectric layer and the piezoelectric material portion are stacked on each other.   The liquid transfer device according to claim 4, wherein the piezoelectric layer of the piezoelectric actuator is formed by laminating a plurality of piezoelectric sheets made of a piezoelectric material.   The liquid transfer device according to claim 4, wherein the piezoelectric material portion is formed by laminating a plurality of piezoelectric sheets made of a piezoelectric material. The portion forming the pressure chamber of the piezoelectric material portion is formed by laminating a plurality of the piezoelectric sheets in which holes to be the pressure chamber are formed,
The holes serving as the pressure chambers formed in the piezoelectric sheet disposed at the end on the piezoelectric actuator side with respect to the stacking direction of the plurality of piezoelectric sheets are formed in other piezoelectric sheets as viewed from the thickness direction of the plurality of piezoelectric sheets. The liquid transfer device according to claim 6, wherein the liquid transfer device is located inside a hole serving as the formed pressure chamber.   The liquid transfer device according to claim 1, wherein a portion of the flow path unit that is joined to the piezoelectric material portion is formed of metal or silicon.   A protective film for preventing the liquid in the liquid transfer flow path from contacting the piezoelectric layer and the piezoelectric material section on the portion of the piezoelectric layer and the piezoelectric material section that becomes the wall surface of the liquid transfer flow path. It is formed, The liquid transfer apparatus in any one of Claims 1-8 characterized by the above-mentioned. A flow path unit in which a liquid transfer flow path including a pressure chamber is formed;
A method for manufacturing a liquid transfer device, comprising: a piezoelectric layer; and an electrode for generating an electric field in the piezoelectric layer, and a piezoelectric actuator that applies pressure to the liquid in the pressure chamber,
A piezoelectric layer forming step of forming the piezoelectric layer of the piezoelectric actuator with a piezoelectric material;
A first part forming step of the flow path unit that forms a piezoelectric material portion that is a part that forms a part of the liquid transfer flow path in the flow path unit with the piezoelectric material;
An electrode forming step of forming the electrode;
A firing step of firing a piezoelectric material body in which the piezoelectric layer and the piezoelectric material portion are integrated;
A second portion forming step of the flow path unit for forming a portion other than the piezoelectric material portion of the flow path unit;
A method for manufacturing a liquid transfer device, comprising: a joining step for joining the piezoelectric material portion and a portion other than the piezoelectric material portion of the flow path unit after the firing step.   The liquid transfer device according to claim 10, further comprising a laminating step of forming the piezoelectric material body by laminating the piezoelectric layer and the piezoelectric material portion before the firing step. Production method.   12. The method for manufacturing a liquid transfer device according to claim 11, wherein in the piezoelectric layer step, the piezoelectric layer is formed by laminating a plurality of piezoelectric sheets made of a piezoelectric material.   The liquid transfer device according to claim 11 or 12, wherein, in the first part forming step, the piezoelectric material portion is formed by laminating a plurality of piezoelectric sheets made of a piezoelectric material.   The method for manufacturing a liquid transfer device according to claim 10, wherein the piezoelectric layer forming step and the first partial forming step are simultaneously performed by integrally forming the piezoelectric layer and the piezoelectric material portion. .   After the firing step, the liquid in the liquid transfer channel is prevented from coming into contact with the piezoelectric layer and the piezoelectric material part on the portion of the piezoelectric layer and the piezoelectric material part that becomes the wall surface of the liquid transfer channel. The method for producing a liquid transfer device according to claim 10, further comprising a protective film forming step of forming a protective film for the purpose.

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