JP2010149371A - Method of manufacturing liquid transfer device - Google Patents

Abstract

Deformation of a diaphragm caused by aerosol spraying in a piezoelectric layer forming process is suppressed.
First, a filter plate 36 is disposed in a recess 85 of a reinforcing frame 84, and the reinforcing frame 84, the filter plate 36, and a diaphragm 70 are stacked and heated to a predetermined temperature (for example, 1000 ° C.). Pressurize and join by metal diffusion bonding (joining process). Next, the piezoelectric layer 71 is formed by spraying aerosol on the surface of the vibration plate 70 to deposit particles of the piezoelectric material (piezoelectric layer forming step). Thereafter, the piezoelectric layer 71, the filter plate 36, and the reinforcing frame 84 are heated to a predetermined temperature, and heat treatment is performed on the piezoelectric layer 71 (annealing process). Next, the vibration plate 70, the filter plate 36, the reinforcing frame 84, and the eight plates constituting the flow path unit 31 are laminated and bonded with an adhesive or the like.
[Selection] Figure 7

Description

  The present invention relates to a method for manufacturing a liquid transfer device that forms a piezoelectric layer of a piezoelectric actuator that applies pressure to a liquid by spraying aerosol onto a diaphragm to deposit particles of piezoelectric material.

  Conventionally, as a liquid transfer device for transferring a liquid, a flow path unit in which a liquid flow path including a pressure chamber is formed, a diaphragm covering the pressure chamber, and a piezoelectric element disposed on the surface of the vibration plate opposite to the pressure chamber There is known a piezoelectric actuator having a layer and a piezoelectric actuator configured to apply pressure to a liquid in a pressure chamber.

  Here, various methods are conventionally known as a method for forming a piezoelectric layer of a piezoelectric actuator. Among them, aerosol containing particles of a piezoelectric material and a carrier gas is sprayed on a diaphragm at high speed. A method of forming a piezoelectric layer by depositing particles of piezoelectric material (aerosol deposition method: AD method) is known. In the film formation by the AD method, if the diaphragm is thin, the diaphragm may be deformed by the collision energy when the aerosol sprayed at a high speed collides with the diaphragm. On the other hand, in order not to deform the diaphragm, it is necessary to increase the rigidity of the diaphragm by increasing the thickness of the diaphragm. However, if the diaphragm is thickened, the deformation of the diaphragm during driving of the piezoelectric actuator is reduced, and as a result, the pressure necessary for liquid transfer cannot be applied to the liquid. Therefore, the diaphragm itself has a relatively thin thickness so as to be easily deformed with low rigidity, and when spraying aerosol onto the diaphragm, a thick member such as a flow path unit is previously joined to the diaphragm. Rigidity is being increased. For example, in the ink jet head described in Patent Document 1, a flow path unit is joined to a vibration plate, and a piezoelectric layer is formed on the upper surface of the vibration plate by an AD method.

JP 2006-054442 A (FIG. 3)

  However, if the thickness of the flow path unit is not sufficient even if the piezoelectric layer is formed by AD method after joining the flow path unit to the diaphragm like the inkjet head described in Patent Document 1, The diaphragm is not sufficiently reinforced, and the diaphragm is deformed when the aerosol collides with the diaphragm.

  Therefore, an object of the present invention is to provide a method for manufacturing a liquid transfer device that suppresses deformation of the diaphragm due to the spraying of aerosol in the piezoelectric layer forming step.

  The method for manufacturing a liquid transfer device of the present invention includes a flow path unit in which a liquid flow path including a pressure chamber is formed, a diaphragm joined to one surface of the flow path unit so as to cover at least the pressure chamber, A piezoelectric actuator including a piezoelectric layer bonded to the opposite side of the diaphragm to the pressure chamber, and a reinforcement bonded to the diaphragm in order to suppress the deflection of the flow path unit that is thicker than the flow path unit. A liquid transfer device manufacturing method comprising: a frame; a bonding step of bonding the diaphragm and the reinforcing frame; and a bonding surface of the diaphragm with the flow path unit after the bonding step; A piezoelectric layer forming step of forming a piezoelectric layer by spraying an aerosol containing particles of the piezoelectric material and a carrier gas to deposit the particles of the piezoelectric material on the opposite surface.

  According to the manufacturing method of the liquid transfer device of the present invention, the rigidity of the reinforcing frame provided to suppress the bending of the thin channel unit is fulfilled, and this rigidity is applied in the joining step before the piezoelectric layer forming step. By joining the high reinforcing frame to the diaphragm, it is possible to prevent the diaphragm from being deformed by the aerosol being sprayed in the piezoelectric layer forming step.

  Moreover, it is preferable that only the reinforcing frame is bonded to the diaphragm during the piezoelectric layer forming step. In the piezoelectric layer forming step, the diaphragm is bonded only to the reinforcing frame and not bonded to the flow path unit. Therefore, there is no possibility that particles of the piezoelectric material that have been sprayed on the diaphragm in the piezoelectric layer forming process but have not accumulated on the diaphragm will enter the liquid channel formed in the channel unit. A step of removing particles in the liquid flow path such as a cleaning step performed when particles enter the channel is not necessary.

  Furthermore, it is preferable that the diaphragm and the reinforcing frame are made of a metal material, and in the joining step, the diaphragm and the reinforcing frame are joined by metal diffusion joining in a stacked state. Since metal diffusion bonding is performed by using atomic diffusion, the reliability of bonding can be improved as compared with bonding using an adhesive. Furthermore, it can join, without using intermediate materials with low rigidity, such as an adhesive agent, a diaphragm and a reinforcement frame can be integrated, rigidity can be made high, and it can suppress that a diaphragm deform | transforms more.

  In addition, after the piezoelectric layer forming step, an annealing treatment step for heating the piezoelectric layer is further provided. Originally, metal diffusion bonding is a bonding method that utilizes atomic diffusion by pressing metals to be bonded together at a high temperature. Therefore, even if heat treatment is performed on the piezoelectric layer formed on the diaphragm bonded to the reinforcing frame by metal diffusion bonding during the annealing process, the bonding state between the diaphragm and the reinforcing frame is not affected.

  Further, the flow path unit has a supply port communicating with the liquid flow path, and in the joining step, in addition to the diaphragm and the reinforcing frame, a filter made of a metal material and covering the supply port It is preferable to join the formed filter plates by metal diffusion bonding in a laminated state. According to this, by joining the filter plate to the vibration plate or the reinforcing frame by metal diffusion bonding, the reliability of the bonding can be improved, and the liquid can be prevented from leaking out from the bonding portion.

  Further, the filter plate is configured by laminating at least two plates each having a plurality of through holes, and when the at least two plates are laminated, the through holes of the respective plates are In plan view, it is preferable that some of them overlap each other, and in the joining step, the at least two plates are joined in a laminated state. According to this, by forming the filter plate by laminating at least two plates, the thickness of the filter is increased, the volume of the through hole is increased, and even if dust or the like is accumulated, the through hole is not easily blocked. The number of usable years is extended. Further, by increasing the thickness of the filter, it is possible to maintain the collection performance of foreign matters and bubbles as a filter without increasing the projected area as compared with the case where the thickness of the filter is thin.

  In addition, in the joining step, it is preferable that the filter plate is laminated between the diaphragm and the reinforcing frame and joined by metal diffusion joining. The outer shape of the filter is smaller than that of the diaphragm or the reinforcing frame. Therefore, it can join reliably by laminating | stacking between a diaphragm and a reinforcement frame, and joining by metal diffusion joining.

  The reinforcing frame is attached to a holder that holds the liquid transfer device. According to this, the reinforcing frame prevents the flow path unit from being bent, suppresses the deformation of the diaphragm in the piezoelectric layer forming step, and also functions as an attachment frame for holding the liquid transfer device on the holder.

  It is possible to prevent the diaphragm from being deformed by spraying aerosol in the piezoelectric layer forming step.

  Next, a preferred embodiment of the present invention will be described. The present embodiment is an example in which the present invention is applied to an inkjet head as a liquid transfer device that discharges ink from a nozzle while transferring ink to the nozzle in an ink flow path.

  FIG. 1 is a plan view illustrating a schematic configuration of a printer 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, a head unit 80 mounted on the carriage 2, sub tanks 4a to 4d, and ink. Ink cartridges 6a to 6d are provided.

  The printer 1 includes two guide frames 17a and 17b that extend in parallel in one horizontal direction (left and right direction in FIG. 1: scanning direction) and are spaced apart from each other in the paper feeding direction orthogonal to the scanning direction. The carriage 2 is attached to the two guide frames 17a and 17b. The carriage 2 is reciprocated in the scanning direction by the carriage drive mechanism 12 while being guided by the two guide frames 17a and 17b. In the present embodiment, the carriage drive mechanism 12 includes an endless belt 18 connected to the carriage 2 and a carriage drive motor 19 that travels the endless belt 18. The carriage drive motor 19 travels the endless belt 18. By driving, the carriage 2 is moved in the left-right direction.

  A head unit 80 and four sub tanks 4a to 4d are mounted on the carriage 2. The head unit 80 reciprocates in the scanning direction together with the carriage 2, and the nozzles 54 (see FIG. 3 and FIG. 3) provided on the lower surface of the ink jet head 3 described later provided on the head unit 80. 4), ink is ejected toward the recording paper P conveyed in the paper feeding direction (downward in FIG. 1) by a paper conveyance mechanism (not shown). As a result, desired characters and images are recorded on the recording paper P.

  The four sub tanks 4a to 4d are arranged side by side along the scanning direction. These four sub tanks 4a to 4d are integrally provided with a tube joint 11. The four sub tanks 4a to 4d and the four ink cartridges 6a to 6d are connected to each other via flexible tubes 5a to 5d connected to the tube joints 11, respectively.

  The four ink cartridges 6a to 6d store four colors of black, yellow, cyan, and magenta, respectively, and these ink cartridges 6a to 6d are detachably mounted on the cartridge mounting portion 10. Yes. 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 head unit 80.

  Next, the head unit 80 will be described. FIG. 2 is an exploded perspective view of the head unit. As shown in FIG. 2, the head unit 80 is fixed to the head holder 81 formed in a box shape with a synthetic resin material, the inkjet head 3 fixed to the lower surface of the head holder 81, and the upper surface of the head holder 81. A damper device 82 and an exhaust valve means 83.

  The head holder 81 accommodates a damper device 82 and an exhaust valve means 83 in a recess opened upward. The damper device 82, the head holder 81, and the inkjet head 3 are aligned with a mounting hole 82 a of the damper device 82 and a screw hole 84 b of a reinforcement frame 84 (to be described later) of the inkjet head 3, and are screwed with screws (not shown). An ink outlet (not shown) of the damper device 82 and the ink supply hole 84c of the reinforcing frame 84 are in close contact with each other and fastened to each other. At this time, the head holder 81 is closely attached between the damper device 82 and the reinforcing frame 84, and an adhesive is injected into the adhesive hole 81a, so that the head holder 81 and the reinforcing frame 84 are firmly fixed. As will be described in detail later, the reinforcing frame 84 is joined to the upper surface of the diaphragm 70 of the piezoelectric actuator 32 joined to the flow path unit 31, and the reinforcing frame 84 is joined to the head holder 81, The unit 31 and the piezoelectric actuator 32 are held by the head holder 81 via the reinforcing frame 84. That is, the reinforcing frame 84 functions as an attachment frame for holding the flow path unit 31 and the piezoelectric actuator 32 in the head holder 81 at the same time as connecting the damper device 82 and the ink flow path of the flow path unit 31.

  Next, the inkjet head 3 will be described in detail. FIG. 3 is an exploded perspective view of the inkjet head. FIG. 4 is a partial cross-sectional view of the inkjet head of FIG. In the following description of the inkjet head 3, the vertical direction (plate stacking direction) in FIG. 3 is defined as the vertical direction.

  As shown in FIGS. 3 and 4, the inkjet head 3 is disposed on the upper surface of the flow path unit 31 in which an ink flow path including a number of nozzles 54 and pressure chambers 53 is formed, A piezoelectric actuator 32 that applies pressure for causing the ink in the chamber 53 to be ejected from the nozzle 54, and a reinforcing frame 84 (which is disposed on the upper surface of the diaphragm 70 of the piezoelectric actuator 32, and suppresses the deflection of the flow path unit 31. 2) and the filter plate 36 disposed between the diaphragm 70 and the reinforcing frame 84.

  The channel unit 31 includes a total of eight plates 41 to 48 including a cavity plate 41, a base plate 42, an aperture plate 43, two manifold plates 44 and 45, a damper plate 46, a cover plate 47, and a nozzle plate 48. It consists of a laminate. Of the eight plates 41 to 48, the lowermost nozzle plate 48 is formed of a synthetic resin material such as polyimide, and the remaining seven plates 41 to 47 are each a metal plate such as a stainless steel plate. .

  The flow path unit 31 communicates with four ink supply holes 50a, 50b, and 50c connected to the four sub tanks 4a to 4d (see FIG. 1), respectively, and the four ink supply holes 50a to 50c. Manifold channels 51 (manifold forming holes 51a and 51b) are provided, and a plurality of individual ink channels branch from the manifold channel 51 and reach the nozzles 54 through the apertures 52 and the pressure chambers 53. Is provided.

  A plurality of pressure chambers 53 are formed through the cavity plate 41 located in the uppermost layer. Each pressure chamber 53 has a substantially elliptical planar shape with the scanning direction as a longitudinal direction, and the pressure chamber 53 is formed when the piezoelectric actuator 32 is laminated on the upper side and the base plate 42 is laminated on the lower side. . The plurality of pressure chambers 53 are arranged in the paper feeding direction to form five pressure chamber rows. Of the five pressure chamber columns, two are the pressure chambers 53 to which the most frequently used black ink is supplied, and the remaining three columns are cyan, yellow, and magenta three-color inks. Each is a row of pressure chambers 53 supplied. Further, four ink supply holes 50a for supplying the four colors of ink supplied from the sub tanks 4a to 4d to the manifold channel 51 are provided at one end of the cavity plate 41 in the paper feeding direction (the left end in FIG. 3). Are formed side by side in the scanning direction.

  The base plate 42 is formed with through holes 56 and 57 that communicate with both ends in the longitudinal direction of the pressure chamber 53 and an ink supply hole 50b that communicates with the ink supply hole 50a.

  The aperture plate 43 communicates with the through hole 56 of the base plate 42 and extends along the longitudinal direction of the pressure chamber 53. The aperture 52 as a throttle channel, the through hole 58 communicated with the through hole 57, and the ink supply hole Ink supply holes 50c communicating with 50b are respectively formed.

  Manifold formation holes 51 a and 51 b that extend in the paper feed direction and form a part of the manifold channel 51 are formed in the manifold plates 44 and 45, respectively, corresponding to the rows of pressure chambers 53. . Then, in the state where these two types of manifold forming holes 51a and 51b are vertically overlapped, the manifold channel 51 is formed by being blocked from both the upper and lower sides by the aperture plate 43 and the damper plate 46. Of the five manifold channels 51 provided in the channel unit 31, two correspond to the two pressure chamber columns for black ink, and the remaining three manifold channels 51 correspond to three for the color ink. Corresponds to the row of pressure chambers. As shown in FIG. 3, the two types of manifold forming holes 51a and 51b forming the manifold channel 51 are extended to a position overlapping with the ink supply hole 50c of the aperture plate 43, and communicated with the ink supply hole 50c. is doing. At this time, the two rows of manifold forming holes 51a and 51b for two black inks communicate with the same ink supply hole 50c. The two manifold plates 44 and 45 are formed with through holes 59 and 60 that are continuous with the through holes 58 of the aperture plate 43, respectively.

  Concave portions 61 are formed by half-etching at positions where the lower surface of the damper plate 46 overlaps the five manifold channels 51 in plan view. That is, the damper plate 46 is locally thin at the portion where the recess 61 is formed, and this thin portion functions as a damper portion that attenuates ink pressure fluctuations in the manifold channel 51. The damper plate 46 is also formed with a through hole 62 that is continuous with the through hole 60 of the manifold plate 45. The cover plate 47 is formed with a through hole 63 communicating with the through hole 62 of the damper plate 46.

  In the lowermost nozzle plate 48, nozzles 54 communicating with the through holes 63 of the cover plate 47 are arranged in the paper feed direction and arranged in five rows in the scanning direction. Then, droplets are ejected from each of the plurality of nozzles 54 toward the recording paper P facing the lower surface of the nozzle plate 48. Of the five nozzle rows, two are nozzle rows that discharge the most frequently used black ink, and the remaining three nozzle rows are three color inks (magenta, cyan, yellow). Each is a nozzle row that discharges.

  The eight plates 41 to 48 described above are bonded together with an adhesive or the like in a stacked state, whereby the ink flow path from the ink supply hole 50a to the manifold flow path 51 and the manifold flow are formed in the flow path unit 31. A plurality of individual ink flow paths are formed which branch from the path 51 and reach the nozzle 54 via the aperture 52 and the pressure chamber 53.

  Next, the piezoelectric actuator 32 will be described. As shown in FIG. 4, the piezoelectric actuator 32 includes a vibration plate 70, a piezoelectric layer 71, and a plurality of individual electrodes 72.

  The diaphragm 70 has the same outer shape as the eight plates 41 to 48 constituting the flow path unit 31, and is a metal plate such as a stainless steel plate like the seven plates 41 to 47. The diaphragm 70 is disposed on the upper surface of the cavity plate 41 and is grounded at a position not shown and held at the ground potential. At one end of the vibration plate 70 in the paper feeding direction (left side in FIG. 3), four filters 77 communicating with the four ink supply holes 50a formed in the cavity plate 41 are formed along the scanning direction. Each filter 77 includes a plurality of elongated through holes 77a formed by etching along the paper feed direction and arranged in the scanning direction.

  The piezoelectric layer 71 is a layer containing a piezoelectric material mainly composed of lead zirconate titanate, which is a mixed crystal of lead titanate and lead zirconate, and is formed on the upper surface (opposite to the pressure chamber 53) of the vibration plate 70. , And are continuously arranged across the plurality of pressure chambers 53. The piezoelectric layer 71 is previously polarized in the thickness direction.

  The plurality of individual electrodes 72 have a substantially oval planar shape that is slightly smaller than the pressure chamber 53, and are arranged on the upper surface of the piezoelectric layer 71 so as to overlap with the substantially central portions of the plurality of pressure chambers 53 in plan view. Has been. The individual electrode 72 is made of a conductive material such as platinum, palladium, gold, or silver. The end of the individual electrode 72 opposite to the nozzle 54 in the longitudinal direction extends to a portion that does not face the pressure chamber 53 in the scanning direction, and the tip thereof is connected to the flexible wiring board 87 (FPC: see FIG. 2). It is a connection terminal. A drive potential is applied to the individual electrode 72 via the FPC 87 by a driver IC 88 (see FIG. 2).

  Here, the operation of the piezoelectric actuator 32 during ink ejection will be described. When ink is ejected from a certain nozzle 54, a driving potential is applied from the driver IC 88 to the individual electrode 72 corresponding to the pressure chamber 53 communicating with the nozzle 54. Then, a potential difference is generated between the individual electrode 72 to which the driving potential is applied and the diaphragm 70 held at the ground potential, and an electric field parallel to the thickness direction is generated in the piezoelectric layer 71 sandwiched therebetween. Since the direction of the electric field coincides with the polarization direction of the piezoelectric layer 71, the piezoelectric layer 71 polarized in the thickness direction contracts in the horizontal direction orthogonal to the direction of the electric field (piezoelectric lateral effect). As a result, the portion of the diaphragm 70 facing the pressure chamber 53 is deformed so as to protrude toward the pressure chamber 53 (unimorph deformation). At this time, the volume of the pressure chamber 53 decreases, the pressure of the ink inside the pressure chamber 53 increases, and ink is ejected from the nozzle 54 communicating with the pressure chamber 53.

  Next, the filter plate 36 will be described. As shown in FIG. 3, the filter plate 36 has a substantially rectangular shape made of a metal material such as stainless steel, and covers the four filters 77 formed on the diaphragm 70. In the filter plate 36, four filters 37 communicating with the four filters 77 are formed along the scanning direction. Each filter 37 includes a plurality of elongated planar holes 37a formed by etching along the scanning direction and arranged in the paper feed direction.

  A flow path formed when the filter plate 36 and the diaphragm 70 are laminated will be described. FIG. 5 is a plan view when the filter plate is laminated on the diaphragm. As shown in FIG. 5, when the filter plate 36 and the diaphragm 70 are laminated, the planar plate-like through hole 37 a formed in the filter direction 36 and the diaphragm 70 are formed in a plan view. The elongated planar through-hole 77a intersects in the paper feeding direction. A certain through hole 37 a formed in the filter plate 36 overlaps and communicates with a part of the plurality of through holes 77 a formed in the diaphragm 70 in a plan view. By laminating the filter plate 36 and the diaphragm 70 in this way, a flow path having a small and three-dimensionally complicated structure is formed in each of a plurality of portions penetrating in a plan view. It is difficult in terms of etching technology to form a channel having a small area of each of the plurality of penetrating portions on a thick plate by etching. By laminating two plates to form a filter, it is possible to easily form a filter having a small area of each of a plurality of penetrating portions. Furthermore, the thickness of the filter increases, the volume of the flow path forming the filter becomes larger than that of the flat filter, and even if dust or the like is deposited on a part of the flow path forming the filter, the through hole is not easily blocked, The usable years as a filter are extended. Further, since the filter is thick, it is possible to maintain the collection performance of dust and bubbles such as foreign matters as a filter without increasing the projection area as compared with the case where the thickness is thin.

  Subsequently, the reinforcing frame 84 will be described. FIG. 6 is a side view of the reinforcing frame joined to the diaphragm. As shown in FIGS. 2 and 6, the reinforcing frame 84 is made of a metal material such as stainless steel, and is sufficiently thicker (for example, thicker) than the flow path unit 31 (for example, 0.6 mm thick). 1.2 mm) and the rigidity is high. The reinforcing frame 84 has an opening 84a, and the FPC 87 disposed on the upper surface of the piezoelectric actuator 32 is exposed from the opening 84a. The reinforcing frame 84 is bonded onto the diaphragm 70 of the piezoelectric actuator 32 that is bonded to the flow path unit 31, so that the flow path unit 31 is bent due to deformation of the piezoelectric actuator 32 when a droplet is discharged. Thus, the flow path unit 31 is reinforced so that the ejection direction of the ink from the nozzles 54 is not shifted. That is, the reinforcing frame 84 functions as an attachment frame for holding the flow path unit 31 and the piezoelectric actuator 32 on the head holder 81 and as a frame for suppressing the deflection of the flow path unit 31.

  A recess 85 is formed by half-etching in a region overlapping the filter plate 36 in plan view on the bottom surface of the reinforcing frame 84 (surface facing the vibration plate 70). The reinforcing frame 84 is joined by metal diffusion bonding in a state where the filter plate 36 is mounted in the recess 85 and is laminated with the diaphragm 70. Compared to the case where the diaphragm 70 and the reinforcing frame 84 are joined using an intermediate material having low rigidity such as an adhesive, the diaphragm 70 and the reinforcing frame 84 can be integrated to increase the rigidity. Therefore, it is possible to reduce so-called crosstalk in which deformation of the vibration plate 70 for ejecting liquid droplets from the nozzles 54 of a certain individual ink channel affects other individual ink channels.

  The filter plate 36 is also joined to the diaphragm 70 and the reinforcing frame 84 by metal diffusion bonding. The filter plate 36 has a smaller outer shape than the diaphragm 70 and the reinforcing frame 84. Therefore, it can join reliably by laminating | stacking between the diaphragm 70 and the reinforcement frame 84, and joining by metal diffusion joining. Moreover, when joining by metal diffusion joining compared with the case where it joins with an adhesive agent, the reliability of joining can be improved and it can prevent that ink leaks from a joining location.

  In addition, an ink supply hole 84c is formed at a position where one end of the reinforcing frame 84 (lower right portion in FIG. 2) overlaps the filter 37 of the filter plate 36 (the filter 77 of the diaphragm 70) in plan view. . After the ink introduced from the sub tanks 4 a to 4 d flows in the damper device 82, the flow path unit is passed through the ink supply hole 84 c of the reinforcing frame 84, the filter 37 of the filter plate 36, and the filter 77 of the diaphragm 70. Supplied to the ink flow path formed at 31.

  At this time, dust or bubbles mixed in the ink introduced from the sub tanks 4a to 4d are trapped by the filter flow path constituted by the filter 77 formed on the diaphragm 70 and the filter 37 formed on the filter plate 36. can do. In addition, a filter is formed on the downstream side closer to the flow path unit 31 than the reinforcing frame 84. The ink supply hole 84c of the reinforcement frame 84 has a larger flow path area than the ink flow path formed in the flow path unit 31, and the ink flow rate is slower in the ink supply hole 84c. Bubbles are difficult to move in the part where the flow rate of ink is slow. When bubbles are generated in the flow path, there is a possibility that a problem such as a droplet not being ejected from the nozzle 54 may occur. However, since the filter is configured on the downstream side closer to the flow path unit 31 than the reinforcing frame 84, there is no portion where the flow velocity is slow in the ink flow path downstream from the filter, and bubbles are generated on the flow path unit 31 side of the filter. It can reduce staying.

  Next, a method for manufacturing the inkjet head 3 will be described. 7A and 7B are diagrams illustrating a method for manufacturing an ink jet head, wherein FIG. 7A is a bonding process of a diaphragm, a filter, and a reinforcing plate, FIG. 7B is a piezoelectric layer forming process, and FIG. 7C is a flow path unit bonding process. .

  First, a plurality of through holes 77a are formed in the vibration plate 70, a plurality of through holes 37a are formed in the filter plate 36, and an opening 84a and an ink supply hole 84c are formed in the reinforcing frame 84 by etching. Further, the recess 85 is formed in the reinforcing frame 84 by half etching. Then, as shown in FIG. 7A, the filter plate 36 is disposed in the recess 85 of the reinforcing frame 84, and the reinforcing frame 84, the filter plate 36, and the diaphragm 70 are laminated, and a predetermined temperature (for example, 1000) is obtained. The pressure is applied while heating to (° C.), and bonding is performed by metal diffusion bonding (bonding process).

  Next, as shown in FIG. 7B, an aerosol is formed on the surface of the diaphragm 70 using a piezoelectric material mainly composed of lead zirconate titanate, which is a mixed crystal of lead titanate and lead zirconate. Piezoelectric layer 71 is formed by depositing particles of piezoelectric material by a deposition method (AD method) (piezoelectric layer forming step).

  In the AD method, the diaphragm 70, the filter plate 36, and the reinforcing frame 84 are held by fixing the four sides with a seal or the like on the stage 91 in the chamber 90 so that the surface of the diaphragm 70 on which the piezoelectric layer 71 is formed is downward. . Then, the inside of the chamber 90 is evacuated, and the aerosol chamber is caused by a pressure difference between an aerosol chamber (not shown) in which a mixture (aerosol) of particles (carrier gas) forming the chamber 90 and the piezoelectric layer 71 is enclosed. An aerosol is sprayed on the surface of the vibration plate 70 from a nozzle 93 communicating with the surface of the vibration plate 70, causing particles to collide with the vibration plate 70 at a high speed, and reciprocating the stage 91 in the horizontal direction to thereby apply piezoelectric material to the surface of the vibration plate 70. This is a film forming method for depositing particles.

  In the film formation by the AD method, when only the vibration plate 70 is held on the stage 91 and the aerosol is sprayed at a high speed, the thickness of the vibration plate 70 is so thin that the sprayed aerosol collides with the vibration plate 70. The diaphragm 70 may be deformed by the collision energy. In view of this, the diaphragm 70 is reinforced by bonding a sufficiently thick reinforcing frame 84 to the diaphragm 70 before film formation by the AD method. Thereby, the deformation of the diaphragm 70 due to the collision energy of the aerosol when the aerosol is sprayed at a high speed can be suppressed. Further, the reinforcing frame 84 is provided for the purpose of reinforcing the flow path unit 31, and in the piezoelectric layer process, the diaphragm 70 is reinforced to suppress deformation of the diaphragm 70, and the inkjet head. After the manufacture, the functions of the deflection of the flow path unit 31 and the bonding of the inkjet head 3 and the head holder 81, which are the original functions of the reinforcing frame 84, can be achieved. That is, a special member is not required, and an essential member provided to reinforce this separate member can also be used for reinforcing the diaphragm 70.

  In the case where the piezoelectric layer 71 is formed by the AD method, if the fine particles or lattice defects are generated in the piezoelectric layer 71, the piezoelectric characteristics necessary for deforming the diaphragm 70 cannot be obtained. Therefore, in order to grow grain crystals of the piezoelectric material and repair lattice defects in the crystals to improve the piezoelectric characteristics, the piezoelectric layer 71, the filter plate 36, and the reinforcing frame 84 are kept at a predetermined temperature (for example, 650 to 900 ° C.). ) And heat-treating the piezoelectric layer 71 (annealing process). At this time, even if the diaphragm 70, the filter plate 36, and the reinforcing frame 84 are subjected to heat treatment at a high temperature, the diaphragm 70, the filter plate 36, and the reinforcing frame 84 are bonded by utilizing atomic diffusion by applying pressure at a high temperature. Since bonding is performed by metal diffusion bonding, unlike the case of bonding by an adhesive, the bonding state of the diaphragm 70, the filter plate 36, and the reinforcing frame 84 is not affected. Thereafter, a plurality of individual electrodes 72 are respectively formed on the piezoelectric layer 71. The plurality of individual electrodes 72 are formed at a time by screen printing, vapor deposition, sputtering, or the like.

  Thereafter, the cavity plate 41, the base plate 42, the aperture plate 43, the two manifold plates 44 and 45, the damper plate 46, and the cover plate 47, which are metal plates among the plates constituting the flow path unit 31, are added to the pressure chamber 53 and A hole penetrating in the thickness direction constituting the ink flow path such as the manifold flow path 51 is formed. Since these plates 41 to 47 are made of a metal material, holes penetrating in the thickness direction constituting the ink flow path can be easily formed by etching. Further, the aperture 52 is formed in the aperture plate 43, and the recess 61 is formed in the damper plate 46 by half etching. A plurality of nozzles 54 are formed on a synthetic resin nozzle plate 48 by laser processing or the like.

  Then, as shown in FIG. 7C, the diaphragm 70, the filter plate 36, the reinforcing frame 84, and the eight plates 41 to 48 constituting the flow path unit 31 are laminated to form an adhesive or the like. The ink jet head 3 is completed.

  If the flow path unit 31 is joined to the vibration plate 70 before the piezoelectric layer forming step in order to reinforce the vibration plate 70, it was sprayed on the vibration plate 70 in the piezoelectric layer forming step. The particles of the piezoelectric material that have not been deposited in the ink flow into the ink flow path formed in the flow path unit 31. If the inkjet head 3 is completed with the particles remaining in the ink flow path, the remaining particles may clog the flow path. In addition, the remaining particles may be mixed with ink to cause a problem. However, in the piezoelectric layer forming process, it is the reinforcing frame 84 that is not formed with a liquid flow path or the like that is bonded to the vibration plate 70 for reinforcement. There is no problem.

  Furthermore, since the flow path unit 31 is bonded after the piezoelectric layer forming step, the particles do not enter the ink flow path, and a removal process for removing the particles by washing the ink flow path or the like becomes unnecessary. . In addition, since the reinforcement frame 84 is intended to suppress the deflection of the flow path unit 31, and has a thickness greater than that of the flow path unit 31, the diaphragm 70 is provided more than when the flow path unit 31 is joined. Reinforcement can be performed more efficiently, and deformation of the diaphragm 70 can be suppressed. In addition, when the diaphragm 70 is moved to the stage 91 of the chamber 90 in order to perform the AD method, the diaphragm 70 is bent because the thick reinforcing frame 84 is joined to the diaphragm 70. Easy to handle.

  Further, the vibration plate 70 is reinforced by the reinforcing frame 84 instead of the flow path unit 31, and after the annealing process in which the piezoelectric layer 71 formed on the vibration plate 70 is heat-treated at a high temperature, the vibration plate 70. Since the flow path unit 31 is joined to the diaphragm 70, the degree of freedom with respect to the joining method of the vibration plate 70 and the plurality of plates 41 to 48 constituting the flow path unit 31 is increased. For example, when the flow path unit 31 is bonded to the vibration plate 70 before the piezoelectric layer forming step for reinforcing the vibration plate 70, the bonding agent is thermally decomposed during the subsequent annealing treatment step if the bonding is performed using the adhesive. In some cases, it is difficult to maintain the joined state of the plurality of plates 41 to 48 and the diaphragm 70 constituting the flow path unit 31. On the other hand, when the plurality of plates 41 to 48 constituting the flow path unit 31 are subjected to metal diffusion bonding, a portion facing the manifold flow path 51 having a large opening is sufficient between the plates other than the manifold plates 44 and 45. A large pressing force cannot be ensured, resulting in insufficient metal diffusion between the plates, resulting in poor bonding. Specifically, metal diffusion between the base plate 42 and the aperture plate 43 and between the diaphragm 70 and the base plate 42 at a position overlapping the manifold channel 51 in plan view may be insufficient. Therefore, when a plate having a large opening portion is bonded, bonding with an adhesive is preferable. In the present embodiment, a desired joining method is applied in consideration of the above-described problems in order to join the vibration plate 70 and the plurality of plates 41 to 48 constituting the flow path unit 31 after the annealing process. Can do.

  Next, modified examples in which various changes are made to the present embodiment will be described.

  In this embodiment, the piezoelectric actuator 32 is provided with the vibration plate 70 that also serves as a common electrode on the lower surface of the piezoelectric layer 71, but an insulating layer is sandwiched between the lower surface of the piezoelectric layer 71 and the vibration plate 70. A common electrode may be arranged. In this case, after forming an insulating layer on the vibration plate 70, a common electrode is formed by a sputtering method or the like, and a piezoelectric layer is formed by an AD method.

  Further, in the present embodiment, the eight plates 41 to 48 constituting the flow path unit 31 and the vibration plate 70 are joined with an adhesive, but the plate formed of a metal material excluding the nozzle plate 48 is All may be bonded by metal diffusion bonding, and only the nozzle plate may be bonded by an adhesive.

  Further, in the present embodiment, the filter plate 36 is sandwiched and joined between the diaphragm 70 and the reinforcing frame 84, but communicates from the sub tanks 4 a to 4 d to the ink flow path formed in the flow path unit 31. For example, it may be joined to the upper surface of the reinforcing frame 84. The filter plate 36 may be joined in a process different from the process of joining the reinforcing frame 84 and the diaphragm 70.

  In addition, the reinforcing frame 84 for suppressing the deflection of the flow path unit 31 is a frame surrounding the flow path unit 31. However, if the thickness and material can be selected to reinforce the flow path unit 31. For example, it may be an elongated plate extending only in the longitudinal direction of the flow path unit 31.

  Furthermore, in the present embodiment, the filter 37 formed on the filter plate 36 and the filter 77 formed on the diaphragm 70 are stacked to form a flow path for collecting dust and the like. Is simply formed with through holes that do not function as filters, and there are a plurality of filter plates with a plurality of elongated through holes formed. When these filter plates are stacked, each filter plate A plurality of elongated through holes formed in the other filter plate and a plurality of elongated through holes formed in the other filter plate are stacked so that they partially overlap each other in plan view to form a filter flow path. Also good.

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

1 is a plan view illustrating a schematic configuration of a printer according to an embodiment. It is a disassembled perspective view of a head unit. It is a disassembled perspective view of an inkjet head. FIG. 4 is a partial cross-sectional view of the inkjet head of FIG. 3. It is a perspective view when a filter plate is laminated | stacked on the diaphragm. It is a side view of the reinforcement frame joined with the diaphragm. It is a figure which shows the manufacturing method of an inkjet head, (a) is a joining process of a diaphragm, a filter, and a reinforcement plate, (b) is a piezoelectric layer formation process, (c) is a joining process of a flow-path unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printer 3 Inkjet head 31 Flow path unit 32 Piezoelectric actuator 53 Pressure chamber 70 Diaphragm 71 Piezoelectric layer 84 Reinforcement frame

Claims (8)

A flow path unit in which a liquid flow path including a pressure chamber is formed, a vibration plate bonded to at least one surface of the flow path unit so as to cover the pressure chamber, and a vibration plate bonded to the opposite side of the pressure chamber Manufacturing of a liquid transfer device comprising: a piezoelectric actuator including a piezoelectric layer formed; and a reinforcing frame that is thicker than the flow path unit and is bonded to the diaphragm in order to suppress bending of the flow path unit. A method,
A joining step of joining the diaphragm and the reinforcing frame;
After the bonding step, the piezoelectric material particles are deposited on the surface of the diaphragm opposite to the bonding surface with the flow path unit by spraying an aerosol containing particles of the piezoelectric material and a carrier gas. And a piezoelectric layer forming step of forming a piezoelectric layer.   2. The method of manufacturing a liquid transfer device according to claim 1, wherein only the reinforcing frame is joined to the diaphragm during the piezoelectric layer forming step. The diaphragm and the reinforcing frame are made of a metal material,
3. The method of manufacturing a liquid transfer device according to claim 1, wherein, in the joining step, the diaphragm and the reinforcing frame are joined in a laminated state by metal diffusion joining.   The method for manufacturing a liquid transfer device according to claim 3, further comprising an annealing treatment step of heating the piezoelectric layer after the piezoelectric layer forming step. The flow path unit has a supply port communicating with the liquid flow path,
4. In the joining step, in addition to the diaphragm and the reinforcing frame, a filter plate made of a metal material and formed with a filter that covers the supply port is joined in a laminated state by metal diffusion joining. Or the manufacturing method of the liquid transfer apparatus of 4. The filter plate is configured by laminating at least two plates each having a plurality of through holes formed therein,
When the at least two plates are laminated, the through-holes of each plate overlap each other in plan view,
6. The method of manufacturing a liquid transfer device according to claim 5, wherein, in the joining step, the at least two plates are joined in a stacked state.   The method of manufacturing a liquid transfer device according to claim 5 or 6, wherein, in the joining step, the filter plate is laminated between the diaphragm and the reinforcing frame and joined by metal diffusion joining. The method of manufacturing a liquid transfer device according to claim 1, wherein the reinforcing frame is attached to a holder that holds the liquid transfer device.

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