JP2009149026A - Manufacturing method for liquid transfer device, and liquid transfer device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a thickness of adhesive from being uneven by suppressing deformation of a vibrating plate on a pressure chamber when piezoelectric layers and the vibrating plate integrated with a passage unit are joined with the adhesive. <P>SOLUTION: Firstly, the vibrating plate 60 in which a recess 70 corresponding to the pressure chamber 33 is formed, is integrated with the passage unit 22 having the pressure chamber 33. Next, while the adhesive 81 is interposed between the vibrating plate 60 and the piezoelectric layers 61 and 63, the piezoelectric layers 61 to 63 are set on the face of the vibrating plate 60, which face is opposite to the face jointed to the passage unit 22, so as to cover the recess 70. Then, the vibrating plate 60 or the set of piezoelectric layers 61 to 63 is pressed one against the other and thus the piezoelectric layers 61 to 63 are jointed to the vibrating plate 60 with the adhesive 81. At that time, the inside of the recess 70 covered with the piezoelectric layers 61 to 63 are evacuated, so that the portion of the vibrating plate 60, which is opposite to the pressure chamber 33 are attracted to the piezoelectric layers 61 to 63 side. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

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

  Liquid transfer devices used in various fields generally include an actuator for applying pressure to the liquid. Among such actuators, it has a piezoelectric layer made of a ferroelectric piezoelectric material such as lead zirconate titanate (PZT), and uses deformation (piezoelectric strain) of the piezoelectric layer when an electric field is applied. Piezoelectric actuators for driving are widely used.

  Patent Document 1 describes an ink jet head including a piezoelectric actuator that applies an ejection pressure to ink. The ink jet head disclosed in Patent Document 1 includes a flow path unit in which a nozzle, a pressure chamber communicating with the nozzle is formed, and a piezoelectric actuator joined to the flow path unit. The piezoelectric actuator includes a vibration plate joined to the flow path unit so as to cover the pressure chamber, a piezoelectric layer disposed on the opposite side of the pressure chamber of the vibration plate, and a portion of the piezoelectric layer facing the pressure chamber. And two electrodes (individual electrode and common electrode) provided to be sandwiched. The piezoelectric actuator includes a vibration plate that covers a pressure chamber by piezoelectric distortion generated in the piezoelectric layer when a voltage is applied between the two electrodes and an electric field is generated in a portion of the piezoelectric layer sandwiched between the two electrodes. It is configured to deform and apply an ejection pressure to the ink in the pressure chamber.

  When manufacturing such an ink jet head, a process of forming a piezoelectric layer on the vibration plate occurs. Various methods for forming the piezoelectric layer are known, and among them, a method of attaching a sheet-like piezoelectric layer (piezoelectric sheet) to the diaphragm with an adhesive is simple and widely used. ing.

JP 2006-166695 A

  By the way, when the method of adhering the sheet-like piezoelectric layer to the diaphragm is adopted as a method for forming the piezoelectric layer, (1) after first producing the piezoelectric actuator by adhering the piezoelectric layer to the diaphragm. There are two options: a method of joining the piezoelectric actuator to the flow path unit, and (2) a method of bonding only the diaphragm with the flow path unit and then bonding the piezoelectric layer to the diaphragm. .

  Here, the diaphragm is generally very thin so that the diaphragm can be greatly deformed according to the piezoelectric strain of the piezoelectric layer and pressure can be efficiently applied to the ink in the pressure chamber. It has become. Since handling of such a thin diaphragm has many difficult points such as easy breakage, it is preferable that handling of the diaphragm during the manufacture of the inkjet head be as small as possible. However, in the method (1), when the piezoelectric layer is bonded to the vibration plate, and when the vibration plate with the piezoelectric layer bonded is bonded to the flow path unit, the vibration plate alone or Similarly, it is necessary to handle the diaphragm in a state where the rigidity is low enough to bond the thin piezoelectric layer, and the diaphragm is easily damaged during handling. In addition, when two very thin layers such as a diaphragm and a piezoelectric layer are joined with an adhesive, it is impossible to apply a large pressing force, so it is very difficult to make the thickness of the adhesive uniform between the two. is there.

  From these viewpoints, the method (2), in which the diaphragm is first integrated with the flow path unit, is preferable. However, when this method (2) is adopted, another problem arises. Arise.

  When the method (2) is adopted, as shown in FIG. 9, a sheet is formed on the surface of the diaphragm 110 integrated with the flow path unit 101 so as to cover the pressure chamber 102 via an adhesive 103. After the piezoelectric layer 111 is installed, the piezoelectric layer 111 is pressed against the diaphragm 110. At this time, due to the force when the piezoelectric layer 111 is pressed, the vibration plate 110 is deformed in a convex shape toward the pressure chamber 102 in a region facing the hollow pressure chamber 102, and the adhesive 103 is cured in that state. May end up. In this case, the thickness of the adhesive 103 becomes non-uniform such that the thickness of the adhesive 103 increases in a region in which the vibration plate 110 is displaced in a convex shape toward the pressure chamber 102, and further, between the plurality of pressure chambers 102, There arises a problem that the amount of displacement of the diaphragm 110 varies.

  An object of the present invention is to suppress the deformation of the vibration plate on the pressure chamber and make the thickness of the adhesive non-uniform when the vibration plate integrated with the flow path unit and the piezoelectric layer are joined with the adhesive. It is to prevent.

According to a first aspect of the present invention, there is provided a liquid transfer device manufacturing method including a pressure chamber disposed on one surface of the liquid transfer device, wherein a liquid flow channel is formed, and the flow channel unit is configured to cover the pressure chamber. A liquid transfer device manufacturing method comprising: a diaphragm bonded to one surface; and a piezoelectric actuator including a piezoelectric layer stacked on the diaphragm,
A flow path unit manufacturing step for manufacturing the flow path unit, and facing the pressure chamber when the diaphragm is joined to the flow path unit on a surface opposite to the joint surface with the flow path unit. A recess forming step for forming a recess in a region to be formed, a diaphragm joining step for joining the diaphragm to the one surface of the channel unit so as to cover the pressure chamber, and the channel unit for the diaphragm. A piezoelectric layer installation step of installing the piezoelectric layer on the surface opposite to the bonding surface with the piezoelectric layer so as to cover the concave portion and with an adhesive interposed between the piezoelectric layer and the piezoelectric layer. A depressurizing step of depressurizing the inside of the covered concave portion, and an adhesion step of pressing one of the vibration plate and the piezoelectric layer against the other and bonding the piezoelectric layer to the vibration plate with the adhesive. It is characterized by.

  According to the method for manufacturing a liquid transfer device of the present invention, first, a recess is formed in a region of the vibration plate on the side opposite to the joint surface with the flow path unit and facing the pressure chamber. Then, after the diaphragm and the flow path unit are joined and integrated with each other, one of the piezoelectric layer and the diaphragm is pressed against the other, and the piezoelectric layer is joined to the diaphragm with an adhesive. Here, when the vibration plate and the piezoelectric layer are bonded, the pressure in the concave portion covered with the piezoelectric layer is reduced to draw the portion of the vibration plate facing the pressure chamber toward the piezoelectric layer side. This prevents the piezoelectric layer from being bonded in a state where the vibration plate is deformed to the pressure chamber side, so that the thickness of the adhesive layer between the vibration plate and the piezoelectric layer can be made uniform. Become.

  In addition, the concave portion of the diaphragm used for performing the pressure reducing process in the manufacturing stage of the liquid transfer device has a rigidity of the diaphragm in the region facing the pressure chamber after the completion of manufacturing (after the product is completed). Produces the effect of lowering. Therefore, in the liquid transfer device manufactured by the manufacturing method of the present invention, the diaphragm can be greatly deformed according to the piezoelectric strain of the piezoelectric layer, and the pressure can be efficiently applied to the liquid in the pressure chamber. Is possible.

  The method for producing a liquid transfer device according to a second aspect of the invention is characterized in that, in the first aspect of the invention, the pressure reduction step is performed simultaneously with the bonding step or after the bonding step.

  At the same time as or after bonding the diaphragm and the piezoelectric layer, the pressure in the recess formed in the diaphragm is reduced, so there is no gap between the piezoelectric layer and the diaphragm, and the piezoelectric layer and the diaphragm when the recess is decompressed. Inflow of air into the recess does not occur. Therefore, the pressure in the recess can be reduced efficiently, and the adhesive can be prevented from flowing into the recess due to the inflow of air from the outside. Furthermore, when the diaphragm and the piezoelectric layer are bonded simultaneously with the decompression or before the decompression, the positional deviation between the piezoelectric layer and the diaphragm, which may be caused by the decompression in the recess, is also suppressed.

  The method for manufacturing a liquid transfer device according to a third aspect of the invention is characterized in that, in the first or second aspect of the invention, the method further comprises a pressurizing step of pressurizing the pressure chamber after the diaphragm joining step. To do.

  Thus, after the diaphragm is joined to the flow path unit, the pressure chamber is pressurized, and the portion facing the pressure chamber of the diaphragm is expanded toward the piezoelectric layer, so that the diaphragm is deformed to the pressure chamber side. Thus, it is possible to reliably prevent the piezoelectric layer from being adhered.

According to a fourth aspect of the present invention, there is provided the method for manufacturing a liquid transfer device according to any one of the first to third aspects, wherein in the flow path unit manufacturing step, the flow path unit including a plurality of the pressure chambers is manufactured.
In the recess forming step, a plurality of the recesses respectively corresponding to the plurality of pressure chambers on a surface opposite to the joint surface of the diaphragm with the flow path unit, and a communication groove for communicating the plurality of recesses with each other. And one decompression port connected to the communication groove,
In the decompression step, the plurality of recesses are decompressed simultaneously by performing suction from the one decompression port.

  According to this configuration, the decompression in the plurality of recesses can be performed at a time by suction from one decompression port, so that the decompression process can be performed efficiently.

According to a fifth aspect of the present invention, there is provided a liquid transfer device including a plurality of pressure chambers disposed on one surface of the flow path unit in which a liquid flow path is formed and the flow path unit so as to cover the plurality of pressure chambers. A vibration plate joined to the one surface, and a piezoelectric actuator including a piezoelectric layer laminated on the vibration plate,
On the surface of the diaphragm opposite to the joint surface with the flow channel unit, a plurality of recesses respectively facing the plurality of pressure chambers, a communication groove for communicating the plurality of recesses with each other, and a connection to the communication groove An air communication port is formed.

  According to the liquid transfer device of the present invention, when the diaphragm and the piezoelectric layer are bonded with an adhesive, the thickness of the adhesive can be made uniform by suppressing the deformation of the diaphragm when the diaphragm and the piezoelectric layer are joined with the adhesive. The effect is obtained. In addition, since the concave portion is formed in the diaphragm, the rigidity of the diaphragm in the region facing the pressure chamber is locally reduced. The diaphragm can be greatly deformed according to the piezoelectric strain of the piezoelectric layer, and pressure can be efficiently applied to the ink in the pressure chamber.

  Further, a plurality of recesses for promoting deformation of the diaphragm communicate with the atmosphere via the communication groove and the atmosphere communication port. Therefore, the space in the recess can be respired (air can flow between the atmosphere) and the pressure in the recess can be kept at atmospheric pressure at all times. Accordingly, it is possible to prevent deformation of the diaphragm and the piezoelectric layer or generation of stress due to pressure fluctuations in the concave space.

  According to the present invention, when the piezoelectric layer is bonded to the vibration plate integrated with the flow path unit, the portion of the vibration plate facing the pressure chamber is reduced by reducing the pressure in the concave portion covered with the piezoelectric layer. Pull toward the piezoelectric layer. As a result, it is possible to prevent the diaphragm and the piezoelectric layer from being bonded while the diaphragm is deformed to the pressure chamber side, and the thickness of the adhesive layer between the diaphragm and the piezoelectric layer can be made uniform. It becomes.

  Next, an embodiment of the present invention will be described. In this embodiment, the present invention is applied to an ink jet head which is a kind of liquid transfer device that transfers ink to nozzles and ejects ink droplets from the nozzles.

  FIG. 1 is a plan view illustrating a schematic configuration of a printer including an inkjet head according to the present embodiment. As shown in FIG. 1, the printer 1 stores a carriage 2 configured to be reciprocally movable along one direction, an inkjet head 3 mounted on the carriage 2, sub tanks 4a to 4d, and ink. The ink cartridges 6a to 6d and the maintenance unit 7 for recovering the performance of the ink jet head 3 when the liquid droplet ejection performance is lowered are provided.

  The printer main body of the printer 1 has two guide frames 17a that extend in parallel to one horizontal direction (left and right direction in FIG. 1: scanning direction) and are spaced from each other in the paper feed direction perpendicular to the scanning direction. , 17b, and the carriage 2 is attached to these two guide frames 17a, 17b. An endless belt 18 is connected to the carriage 2. The endless belt 18 is driven by the carriage drive motor 19 so that the carriage 2 moves in the left-right direction as the endless belt 18 travels while being guided by the two guide frames 17a and 17b. It has become.

  An ink jet head 3 and four sub tanks 4 a to 4 d are mounted on the carriage 2. The ink jet head 3 reciprocates in the scanning direction together with the carriage 2, and conveys paper (not shown) from a number of nozzles 34 (see FIGS. 2 to 4) provided on the lower surface (the surface on the opposite side of the paper surface in FIG. 1). Ink droplets are ejected onto the printing paper P conveyed in the paper feeding direction (downward in FIG. 1) by the mechanism. As a result, desired characters, images, and the like are printed on the printing paper P.

  The four sub tanks 4a to 4d are arranged side by side in the scanning direction, and these four sub tanks 4a to 4d are respectively connected to four ink supply ports 30 (see FIG. 2) provided on the upper surface of the inkjet head 3. Has been. Moreover, the tube joint 21 is integrally provided in these four sub tanks 4a-4d. The four sub tanks 4a to 4d and the four ink cartridges 6a to 6d are connected to each other through flexible tubes 11a to 11d connected to the tube joint 21, respectively.

  The four ink cartridges 6 a to 6 d store four colors of black, yellow, cyan, and magenta, respectively, and these ink cartridges 6 a to 6 d are detachably mounted on the holder 10. The four color inks stored in the four ink cartridges 6a to 6d are temporarily stored in the sub tanks 4a to 4d and then supplied to the inkjet head 3.

  The maintenance unit 7 is arranged in an area outside the printing area facing the printing paper P (on the right side in FIG. 1) in the moving range of the carriage 2 in the scanning direction. This maintenance unit 7 is a suction purge for recovering the ejection performance when the droplet ejection performance of the inkjet head 3 is reduced due to ink thickening due to drying of the nozzles 34 or mixing of bubbles or dust into the ink. Is to do. The maintenance unit 7 includes a cap member 13 that can be brought into close contact with the lower surface of the inkjet head 3 that ejects droplets, and a suction pump 14 connected to the cap member 13.

  The cap member 13 includes a first cap portion 13a that covers a nozzle 34 that ejects black ink, and a second cap portion 13b that covers a nozzle 3440 that ejects three color inks (yellow ink, magenta ink, and cyan ink). And. The first cap part 13a and the second cap part 13b are connected to the suction pump 14 via the switching unit 15, and the communication unit of the suction pump 14 is connected to the first cap part 13a and the second cap by the switching unit 15. It can be switched between the parts 13b.

  When the inkjet head 3 has moved to a position facing the cap member 13 together with the carriage 2 due to the drop ejection performance, the cap member 13 is driven upward by a cap drive mechanism (not shown), and the inkjet head 3 The nozzle 34 arranged on the lower surface is covered. Then, when suction is performed by the suction pump 14 in a state where the nozzle 34 is covered with the cap member 13, the space in the cap member 13 is decompressed, and the ink in the inkjet head 3 is capped from the nozzle 34. It is discharged toward the member 13 (suction purge).

  Next, the inkjet head 3 (liquid transfer device) will be described. 2 is a plan view (top view) of the inkjet head 3 of FIG. 1, and FIG. 3 is a partially enlarged view of FIG. However, in order to make the drawing easy to understand, the detailed ink flow path such as the pressure chamber 33 shown in FIG. 3 is not shown in FIG.

  As shown in FIGS. 2 and 3, the inkjet head 3 applies pressure to the ink in the pressure chamber 33 and the flow path unit 22 in which the ink flow path including the nozzle 34 and the pressure chamber 33 is formed. Accordingly, a piezoelectric actuator 23 that discharges ink from the nozzle 34 of the flow path unit 22 is provided.

  First, the flow path unit 22 will be described. As shown in FIGS. 2 and 3, the flow path unit 22 communicates with the four ink supply ports 30 connected to the four sub tanks 4 (see FIG. 1) and the four ink supply ports 30, respectively. The four manifold channels 31 extending in the paper feed direction, the plurality of pressure chambers 33 connected to the manifold channel 31 via the apertures 32 (throttle channels), and the plurality of pressure chambers 33 communicate with each other. A plurality of nozzles 34.

  4 is a cross-sectional view taken along line IV-IV in FIG. As shown in FIG. 4, the flow path unit 22 includes a cavity plate 40, a base plate 41, an aperture plate 42, a supply plate 43, manifold plates 44 and 45, a cover plate 46, and a nozzle plate 47 that are stacked in order from the top. , And is composed of eight metal plates made of stainless steel or the like.

  In the cavity plate 40, four ink supply ports 30 and a number of pressure chambers 33 are formed. Each pressure chamber 33 has a substantially elliptical planar shape. The cavity plate 40 has a large number of pressure chambers 33 arranged in the paper feed direction. Further, two rows of pressure chambers 33 corresponding to one manifold channel 31 constitute one set, and one set and two rows of pressure chambers 33 are respectively connected to one manifold channel 31 and have the same color. Ink is supplied.

  The base plate 41 is formed with communication holes 50 and 51 communicating with both end portions of each pressure chamber 33. The aperture plate 42 is formed with apertures 32 and communication holes 52 corresponding to the pressure chambers 33. Two supply holes 53 and 54 corresponding to the pressure chambers 33 are formed in the supply plate 43.

  The two manifold plates 44 and 45 are formed with four manifold channels 31 and communication holes 55 and 56 corresponding to the pressure chambers 33. The four manifold channels 31 are supplied with four colors (black, yellow, cyan, magenta) of ink from the four sub tanks 4 through four ink supply ports 30 formed in the cavity plate 40, respectively. . Further, as shown in FIG. 3, each manifold channel 31 extends in the paper feed direction so as to overlap with a pair of two rows of pressure chambers 33 in plan view.

  A communication hole 57 corresponding to each pressure chamber 33 is formed in the cover plate 46. The nozzle plate 47 is formed with a number of nozzles 34 corresponding to the pressure chambers 33. As shown in FIGS. 2 and 3, the nozzles 34 are arranged in two rows along the paper feed direction on both sides of the corresponding manifold channel 31, and constitute a total of eight nozzle rows. Further, the same color ink is supplied from the manifold channel 31 through the pressure chamber 33 to the plurality of nozzles 34 constituting the two nozzle rows arranged on both sides of the single manifold channel 31. These nozzles 34 eject ink droplets of the same color.

  As shown in FIG. 4, in the flow path unit 22, the manifold flow path 31 that communicates with the ink supply port 30 communicates with the pressure chamber 33 via the communication hole 53, the aperture 32, and the communication hole 50. Further, the pressure chamber 33 communicates with the nozzle 34 via the communication holes 51 and 52 and the communication holes 54 to 57. That is, the flow path unit 22 is formed with a plurality of individual ink flow paths 58 from the outlet of the manifold flow path 31 to the nozzles 34 via the pressure chambers 33.

  Next, the piezoelectric actuator 23 will be described. The piezoelectric actuator 23 includes a vibration plate 60 disposed on the upper surface of the cavity plate 40 so as to cover the plurality of pressure chambers 33, three piezoelectric layers 61, 62, 63 stacked on the upper surface of the vibration plate 60, and 3 Individual electrodes 64 (64a, 64b) and common electrodes 65 (65a, 65b) are arranged so as to sandwich the piezoelectric layers 61, 62, 63 of the layers in the thickness direction.

  5 is a plan view of the diaphragm 60 in a state of being joined to the flow path unit 22, and FIG. 6 is a cross-sectional view taken along the line VI-VI in FIG. The diaphragm 60 is a metal plate made of an iron-based alloy such as stainless steel, a copper-based alloy, a nickel-based alloy, or a titanium-based alloy. As shown in FIGS. 4 and 5, the diaphragm 60 is joined to the cavity plate 40 in a state of being disposed on the upper surface of the cavity plate 40 so as to cover the plurality of pressure chambers 33.

  A plurality of recesses 70 are respectively formed in regions on the upper surface of the diaphragm 60 facing the central portions of the plurality of pressure chambers 33. The recess 70 has an elliptical planar shape that is slightly smaller than the pressure chamber 33. By forming such a recess 70, the rigidity of the diaphragm 60 is locally reduced in a region facing the pressure chamber 33, and the diaphragm 60 is easily deformed. A communication groove 71 is also formed on the upper surface of the diaphragm 60 so that the plurality of recesses 70 respectively corresponding to the plurality of pressure chambers 33 communicate with each other. Further, one communication port 72 is connected to the communication groove 71. In other words, the plurality of recesses 70 respectively corresponding to the plurality of pressure chambers 33 communicate with one atmosphere communication port 72 via the communication groove 71.

  The three piezoelectric layers 61 to 63 are made of a piezoelectric material mainly composed of lead zirconate titanate (PZT), which is a solid solution of lead titanate and lead zirconate and is a ferroelectric substance. These three piezoelectric layers 61 to 63 are bonded to the upper surface of the diaphragm 60 with an adhesive so as to cover the plurality of pressure chambers 33. However, as shown in FIG. 3, the atmosphere communication port 72 formed on the upper surface of the diaphragm 60 is not covered with the piezoelectric layers 61 to 63 and is always open to the atmosphere. Thereby, the spaces in the plurality of recesses 70 covered by the piezoelectric layers 61 to 63 are always in communication with the atmosphere via the atmosphere communication port 72.

  On the upper surface of the uppermost piezoelectric layer 61, individual electrodes 64 a respectively opposed to the central portions of the plurality of pressure chambers 33 are disposed. In addition, between the central piezoelectric layer 62 and the lowermost piezoelectric layer 63, individual electrodes 64 b that are respectively opposed to the central portions of the plurality of pressure chambers 33 are disposed. Each of these two types of individual electrodes 64 a and 64 b has an elliptical planar shape that is slightly smaller than the pressure chamber 33. The two types of individual electrodes 64a and 64b are electrically connected to each other through through holes penetrating the two upper piezoelectric layers 61 and 62 in a region not shown. Further, as shown in FIG. 3, in the individual electrode 64 a arranged on the upper surface of the uppermost piezoelectric layer 61, one end portion thereof (the end portion on the nozzle 34 side) is pulled out to a region not facing the pressure chamber 33. Thus, a contact portion 66 is formed. The contact portions 66 of the plurality of individual electrodes 64a are connected to a head driver (not shown) through a flexible printed circuit (FPC).

  Common electrodes 65a and 65b facing all of the plurality of pressure chambers 33 are disposed between the uppermost piezoelectric layer 61 and the intermediate piezoelectric layer 62 and on the lower surface of the lowermost piezoelectric layer 63, respectively. . These two types of common electrodes 65a and 65b are conducted in a region not shown, and are always held at the ground potential.

  Accordingly, the three piezoelectric layers 61 to 63 are sandwiched between the individual electrodes 64 (64a, 64b) and the common electrodes 65 (65a, 65b) alternately arranged in the thickness direction in the region facing the pressure chamber 33. It is in the state. Further, the three piezoelectric layers 61 to 63 are each polarized in the thickness direction at a portion sandwiched between the individual electrode 64 and the common electrode 65.

  The operation of the piezoelectric actuator 23 having the above configuration will be described. When pressure is not applied to the ink (when ink droplets are not ejected from the nozzles 34), the potentials of the plurality of individual electrodes 64 are held at a ground potential in advance by a head driver (not shown). In this state, when a predetermined drive potential is applied to any of the individual electrodes 64 by the head driver, a potential difference is generated between the individual electrode 64 to which the drive potential is applied and the common electrode 65 held at the ground potential. To do. Accordingly, in each of the three piezoelectric layers 61, 62, 63, an electric field in the same direction (thickness direction) as the polarization direction is generated in a portion sandwiched between the individual electrode 64 and the common electrode 65, and the piezoelectric layers 61-61 are arranged. Each 63 extends in the thickness direction and contracts in the surface direction. As the piezoelectric layers 61 to 63 are deformed (piezoelectric distortion), the diaphragm 60 is deformed so that a portion facing the pressure chamber 33 protrudes toward the pressure chamber 33 (unimorph deformation). At this time, since the volume of the pressure chamber 33 is reduced, the pressure of the ink inside the pressure chamber 33 is increased, and ink droplets are ejected from the nozzle 34 communicating with the pressure chamber 33.

  Here, as described above, since the concave portion 70 is formed in the region of the upper surface of the diaphragm 60 facing the pressure chamber 33, the rigidity of the diaphragm 60 is increased in the region facing the pressure chamber 33. It is locally reduced. Accordingly, when the drive potential is applied to the individual electrode 64 and piezoelectric distortion occurs in the piezoelectric layers 61 to 63, the displacement amount (deformation amount) of the diaphragm 60 toward the pressure chamber 33 becomes large. A pressure can be efficiently applied to the ink in the ink 33.

  Further, a plurality of recesses 70 provided on the upper surface of the diaphragm 60 corresponding to the plurality of pressure chambers 33 communicate with the atmosphere via the communication groove 71 and the atmosphere communication port 72. Therefore, the inside of the recess 70 can breathe (air can flow between the recess 70 and the atmosphere), and the pressure in the recess 70 is always kept at atmospheric pressure. Therefore, it is possible to prevent deformation and stress generation that occur in the diaphragm 60 and the piezoelectric layers 61 to 63 due to pressure fluctuation in the recess 70.

  Next, a method for manufacturing the inkjet head 3 will be described. FIG. 7 is an explanatory diagram showing a manufacturing process of the inkjet head 3 of the present embodiment. In FIG. 7, for the sake of simplicity, the individual electrodes 64a and 64b and the common electrodes 65a and 65b of the piezoelectric actuator 23 shown in FIG. 6 are not shown.

  As shown in FIG. 7A, first, a plurality of upper surfaces of the diaphragm 60, which is a metal plate (a surface opposite to the bonding surface with the flow path unit 22), are joined to the flow path unit 22. A plurality of recesses 70 are formed by etching, laser processing, or the like in a region that faces the pressure chamber 33 (recess formation step). At this time, on the upper surface of the diaphragm 60, there are also a communication groove 71 that allows the plurality of recesses 70 to communicate with each other, and one atmospheric communication port 72 (see FIGS. 2 and 3: decompression port) connected to the communication groove 71. Form it.

  On the other hand, in the eight metal plates 40 to 47 (see FIG. 4 for details) constituting the flow path unit 22, a plurality of nozzles 34, a plurality of pressure chambers 33, four manifold flow paths 31 and the like are etched. Etc. are formed. And after laminating | stacking these 8 plates 40-47 and the diaphragm 60 in which the several recessed part 70 was formed in the said recessed part formation process, a total of 9 plates are joined and production of the flow path unit 22 is carried out. And the diaphragm 60 are simultaneously joined to the flow path unit 22 (cavity plate 40) (flow path unit manufacturing process, diaphragm joining process). Here, as a method for joining the nine plates, for example, joining (adhesion) using a thermosetting epoxy adhesive, pressurization of the laminated plate under high temperature conditions, and metal at the plate boundary surface Metal diffusion bonding or the like that joins plates by diffusing atoms with each other can be employed.

  Next, as shown in FIG. 7B, a laminate 80 of three piezoelectric layers 61 to 63 is produced. Specifically, first, individual electrodes 64a and 64b or common electrodes 65a and 65b (see FIG. 6) are screen-printed or vapor-deposited on the surface of three green sheets to be the three piezoelectric layers 61 to 63. Formed by. Thereafter, the three green sheets are stacked so that the individual electrodes 64 and the common electrodes 65 are alternately arranged in the thickness direction, and then fired, whereby the stacked body 80 of the three piezoelectric layers 61 to 63 is formed. Make it.

  Next, an adhesive 81 containing an epoxy resin material as a main component is applied to a flat region on the upper surface of the diaphragm 60 where the plurality of recesses 70, the communication grooves 71, and the air communication port 72 are not formed. To do. And the laminated body 80 of the three piezoelectric layers 61-63 mentioned above is installed in the state aligned so that the several recessed part 70 might be covered on the upper surface of the diaphragm 60 to which the adhesive agent 81 was apply | coated (piezoelectric layer). Installation process). At this time, the laminated body 80 is not disposed in the region of the upper surface of the diaphragm 60 where the air communication port 72 is formed, so that the air communication port 72 is not covered with the piezoelectric layers 61 to 63 (see FIG. 3). The adhesive 81 is not necessarily applied to the vibration plate 60 and may be applied to the lower surface of the lowermost piezoelectric layer 63.

  After that, as shown in FIG. 7C, the laminated body 80 of the three piezoelectric layers 61 to 63 is pressed against the diaphragm 60 under a predetermined temperature condition where the adhesive 81 is cured (or the diaphragm 60 is moved). By pressing the laminated body 80), the laminated body 80 composed of the three piezoelectric layers 61 to 63 is adhered to the vibration plate 60 by the adhesive 81 (adhesion step).

  By the way, as described above, when one of the three piezoelectric layers 61 to 63 and the diaphragm 60 is pressed against the other in the bonding process, the portion of the diaphragm 60 facing the pressure chamber 33 is convex toward the pressure chamber 33 side. As a result, the adhesive 81 may be cured in a non-uniform thickness state.

  Therefore, the inside of the plurality of recesses 70 formed on the upper surface of the diaphragm 60 is decompressed using a suction pump 82 as a decompression source (decompression process). Accordingly, the vibration plate 60 is attracted to the piezoelectric layer 63 side in a region facing the pressure chamber 33 to prevent the vibration plate 60 from being deformed so as to be convex toward the pressure chamber 33 side. It becomes possible to make the thickness of the adhesive 81 between 63 uniform.

  A specific decompression method for the recess 70 in the present embodiment will be described. As described above, in the recess forming step, a plurality of recesses 70 are formed on the upper surface of the diaphragm 60, the communication groove 71 that allows the plurality of recesses 70 to communicate with each other, and the air communication port that communicates with the communication groove 71. 72 is formed at the same time. In addition, the atmosphere communication port 72 is not covered with the piezoelectric layers 61 to 63 disposed on the upper surface of the diaphragm 60 and is in an open state to the atmosphere.

  Then, a suction pump 82 is connected to the atmosphere communication port 72 on the upper surface of the diaphragm 60, and the suction pump 82 performs suction from one atmosphere communication port 72 (decompression port), thereby reducing the pressure in the plurality of recesses 70. At the same time. According to this, the pressure reduction in many recessed parts 70 can be performed at once by the suction from one pressure reduction opening 72, and a pressure reduction process can be performed efficiently.

  In addition, it is preferable to perform the pressure reduction process mentioned above simultaneously with the said adhesion process, or immediately after an adhesion process. In this case, since the gap between the lowermost piezoelectric layer 63 and the diaphragm 60 is almost eliminated by pressing in the bonding process, air from the gap between the piezoelectric layer 63 and the diaphragm 60 to the recess 70 is reduced during the decompression process. Inflow does not occur. Therefore, the pressure in the concave portion 70 can be efficiently reduced, and the inflow of the adhesive 81 into the concave portion 70 accompanying the inflow of air from the outside can be prevented. Further, when the diaphragm 60 and the piezoelectric layer 63 are bonded simultaneously with the decompression or prior to the decompression, the positional displacement between the piezoelectric layer 63 and the diaphragm 60 that may occur during the decompression in the recess 70. Is also suppressed.

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

  1] In the above-described embodiment, a plurality of plates such as the cavity plate 50 constituting the flow path unit 22 and the vibration plate 60 are joined at once, so that the manufacturing process of the flow path unit 22 and the flow path of the vibration plate 60 are performed. The joining process to the unit 22 is performed at the same time. First, the plates constituting the flow path unit 22 are joined together to produce the flow path unit 22, and then the diaphragm 60 is formed on the upper surface of the flow path unit 22. May be performed in separate steps such as joining.

  2] As shown in FIG. 8A, the pressure chamber 33 may be pressurized using the pressurizing pump 90 after the diaphragm 60 is joined to the flow path unit 22 (pressurizing step). The pressure pump 90 is connected to, for example, the ink supply port 30 of the flow path unit 22 shown in FIG. 2 and simultaneously pressurizes the inside of the plurality of pressure chambers 33 from the ink supply port 30 via the manifold flow path 31. Alternatively, it is possible to pressurize the pressure chamber 33 from the nozzle 34 side by connecting the pressurizing pump 90 to the plurality of nozzles 34. By pressurizing the inside of the pressure chamber 33 in this way, as shown in FIG. 8A, the portion of the vibration plate 60 facing the pressure chamber 33 swells upward (the piezoelectric layers 61 to 63 side).

  The step of joining the laminated body 80 of the piezoelectric layers 61 to 63 to the diaphragm 60 after the diaphragm 60 is expanded upward can be the same as that in the above embodiment. That is, as shown in FIG. 8B, the laminated body 80 is disposed in a state where the adhesive 81 is interposed on the upper surface of the vibration plate 60, and then the vibration plate 60 is pressed against the vibration plate 60. The inside of the concave portion 70 formed on the upper surface of the first is decompressed using a suction pump 82.

  As described above, after the diaphragm 60 is joined to the flow path unit 22, the inside of the pressure chamber 33 is pressurized and the portion facing the pressure chamber 33 of the diaphragm 60 is expanded upward, and then the piezoelectric layers 61 to 63 are attached. By bonding, it is possible to reliably prevent the piezoelectric layers 61 to 63 from being bonded in a state where the vibration plate 60 is deformed to the pressure chamber 33 side.

  As shown in FIG. 8, the piezoelectric layers 61 to 63 are disposed on the upper surface of the vibration plate 60 instead of pressurizing the pressure chamber 33 before the stacked body 80 of the piezoelectric layers 61 to 63 is disposed on the vibration plate 60. Then, when the laminated body 80 of the three piezoelectric layers 61 to 63 is pressed against the diaphragm 60, the pressure in the pressure chamber 33 may be simultaneously applied.

  4] In the modified embodiment described in the above 3], the diaphragm 60 is formed by performing both the pressurization in the pressure chamber 33 and the decompression in the recess 70 formed on the upper surface of the diaphragm 60. Although the piezoelectric layers 61 to 63 are prevented from being bonded in a state of being deformed to the pressure chamber 33 side, only the pressurization in the pressure chamber 33 may be performed, and the decompression in the recess 70 may be omitted. Further, in this case, since the recess 70 is not an essential configuration for bonding the piezoelectric layers 61 to 63, the step of forming the recess 70 in the diaphragm 60 can be omitted.

  3] The number of piezoelectric layers of the piezoelectric actuator is not limited to three, and the piezoelectric actuator may have one or two piezoelectric layers, or a large number of four or more piezoelectric layers. It may have a layer.

  4] In the above embodiment, the plurality of recesses 70 communicate with the atmosphere via the atmosphere communication port 72 so that the inside of the recesses 70 formed in the diaphragm 60 can breathe when the piezoelectric actuator 23 is operated. . However, if the recess 70 is always in communication with the atmosphere, foreign matter such as dust may enter the recess 70 from the outside, and the operation of the piezoelectric actuator 23 may be hindered. In consideration of this point, in the manufacturing stage, after the decompression process in the recess 70 is completed, the atmosphere communication port 72 may be closed, and the plurality of recesses 70 may be blocked from the atmosphere during use.

  In the embodiment described above, the present invention is applied to an ink jet printer that records an image or the like by ejecting ink onto printing paper. However, the application target of the present invention is not limited to such a printer. The present invention can be applied to various liquid transfer apparatuses that transfer various types of liquids according to their uses.

1 is a plan view illustrating a schematic configuration of a printer including an inkjet head according to an embodiment of the present invention. It is a top view of an inkjet head. FIG. 3 is a partially enlarged plan view of the inkjet head of FIG. 2. FIG. 4 is a sectional view taken along line IV-IV in FIG. 3. It is a top view of the diaphragm in the state joined to the flow path unit. FIG. 6 is a sectional view taken along line VI-VI in FIG. 4. It is a figure which shows the manufacturing process of an inkjet head, (a) is a figure which shows a recessed part formation process, a flow-path unit preparation process, and a diaphragm joining process, (b) is a figure which shows a piezoelectric layer installation process, (c) These are figures which show an adhesion process and a pressure reduction process. It is a figure which shows the manufacturing process of the inkjet head of a modified form, (a) is a figure which shows a pressurization process and a piezoelectric layer installation process, (b) is a figure which shows an adhesion process and a pressure reduction process. It is a figure for demonstrating the problem in the conventional inkjet head manufacturing method.

Explanation of symbols

3 Inkjet Head 22 Channel Unit 23 Piezoelectric Actuator 33 Pressure Chamber 60 Diaphragms 61, 62, 63 Piezoelectric Layer 70 Recess 71 Communication Groove 72 Air Communication Port 81 Adhesive

Claims (5)

A flow path unit in which a liquid flow path is formed, including a pressure chamber disposed on one surface thereof;
A method of manufacturing a liquid transfer device comprising: a vibration plate that is bonded to the one surface of the flow path unit so as to cover the pressure chamber; and a piezoelectric actuator that includes a piezoelectric layer laminated on the vibration plate. And
A flow path unit manufacturing step for manufacturing the flow path unit;
A recess forming step of forming a recess in a region of the vibration plate that faces the pressure chamber when bonded to the flow channel unit on a surface opposite to the bonding surface with the flow channel unit;
A diaphragm joining step of joining the diaphragm to the one surface of the flow path unit so as to cover the pressure chamber;
A piezoelectric layer in which the piezoelectric layer is installed on the surface of the diaphragm opposite to the joint surface with the flow path unit so as to cover the recess and with an adhesive interposed between the diaphragm and the diaphragm. Installation process;
A depressurizing step of depressurizing the inside of the recess covered with the piezoelectric layer;
An adhesion step of pressing one of the vibration plate and the piezoelectric layer against the other and bonding the piezoelectric layer to the vibration plate with the adhesive;
A method for producing a liquid transfer device, comprising:   The method for manufacturing a liquid transfer device according to claim 1, wherein the pressure reducing step is performed simultaneously with the bonding step or after the bonding step.   The method for manufacturing a liquid transfer device according to claim 1, further comprising a pressurizing step of pressurizing the pressure chamber after the diaphragm joining step. In the channel unit manufacturing step, the channel unit having a plurality of the pressure chambers is manufactured,
In the recess forming step, a plurality of the recesses respectively corresponding to the plurality of pressure chambers on a surface opposite to the joint surface of the diaphragm with the flow path unit, and a communication groove for communicating the plurality of recesses with each other. And one decompression port connected to the communication groove,
The method for manufacturing a liquid transfer device according to any one of claims 1 to 3, wherein in the pressure reducing step, the pressure in the plurality of recesses is simultaneously reduced by performing suction from the one pressure reducing port. A flow path unit in which a liquid flow path is formed, including a plurality of pressure chambers arranged on one surface thereof;
A vibration plate joined to the one surface of the flow path unit so as to cover the plurality of pressure chambers, and a piezoelectric actuator including a piezoelectric layer laminated on the vibration plate,
On the surface of the diaphragm opposite to the joint surface with the flow channel unit, a plurality of recesses respectively facing the plurality of pressure chambers, a communication groove for communicating the plurality of recesses with each other, and a connection to the communication groove A liquid transfer device characterized in that an air communication port is formed.

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