JP2014151584A - Method for manufacturing liquid discharge device, and method for manufacturing piezoelectric actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce variation in discharge speed of ink from nozzles between liquid discharge devices and the like.SOLUTION: For manufacturing an inkjet head, a laminate 55 of piezoelectric layers 42, 43 and a common electrode 44 is manufactured, and in parallel with this, a laminate 56 of a channel unit 21 and an ink separation layer 41 is manufactured. Next, the laminate 55 and the laminate 56 are bonded by a thermosetting adhesive 50. Then, an individual electrode 45 is formed on an upper surface of the piezoelectric layer 43 at a part overlapping with a pressure chamber 10. At this time, the individual electrode 45 is formed on the upper surface of the piezoelectric layer 43 at a part shifted from a part overlapping with a central part of the pressure chamber 10 by a shift amount E depending on a contraction amount D of the piezoelectric layers 42, 43 after bonding of the laminate 55 and the laminate 56 with respect to those of before the bonding.

Description

  The present invention relates to a method for manufacturing a liquid discharge device that discharges liquid from a nozzle, and a method for manufacturing a piezoelectric actuator used in the liquid discharge device and the like.

  In Patent Document 1, in order to manufacture a liquid discharge head, a plurality of green sheets serving as piezoelectric layers are screen-printed with a conductive paste serving as an individual electrode or a common electrode, and a plurality of sheets formed with the conductive paste are formed. Laminate green sheets on each other. And the piezoelectric actuator is produced by baking the laminated body of the green sheet in which the electrically conductive paste was formed. Subsequently, the produced piezoelectric actuator and the separately produced flow path unit are joined with a thermosetting adhesive.

JP 2012-179800 A

  Here, in Patent Document 1, the flow path unit is formed by laminating a plurality of plates made of a metal material, and these plates usually have a linear expansion coefficient higher than that of the piezoelectric layer. high. On the other hand, in Patent Document 1, the piezoelectric actuator and the flow path unit are heated when the piezoelectric actuator and the flow path unit are joined with a thermosetting adhesive. Therefore, the piezoelectric layer of the piezoelectric actuator after being joined to the flow path unit is not bonded to the flow path unit due to a difference in linear expansion coefficient between the piezoelectric layer and the plate to be joined to the piezoelectric layer of the flow path unit. Is shrinking. Further, the contraction amount of the piezoelectric layer at this time varies between the liquid discharge heads. Here, when the contraction amount of the piezoelectric layer is different, the deformation amount of the piezoelectric layer when the drive potential is applied to the individual electrode varies, and the ejection speed of the liquid from the nozzle varies. Specifically, the greater the amount of contraction of the piezoelectric layer, the smaller the amount of deformation of the piezoelectric layer when a drive potential is applied to the individual electrode, and the slower the liquid ejection speed from the nozzle. When the amount of contraction of the piezoelectric layer varies between the liquid ejection heads, the liquid ejection speed from the nozzles varies between the liquid ejection heads.

  An object of the present invention is to provide a method for manufacturing a liquid ejection device in which variations in the liquid ejection speed are unlikely to occur regardless of the amount of contraction of the piezoelectric layer, and a piezoelectric in which drive characteristics are less likely to vary regardless of the amount of contraction of the piezoelectric layer. It is to provide a method for manufacturing an actuator.

  According to a first aspect of the present invention, there is provided a liquid ejecting apparatus comprising: a nozzle; a pressure chamber communicating with the nozzle; a piezoelectric layer disposed so as to overlap the pressure chamber; and a surface of the piezoelectric layer opposite to the pressure chamber. A method of manufacturing a liquid ejection device comprising a driving electrode formed in a portion overlapping with the pressure chamber, wherein the first member including the piezoelectric layer and a material having a higher linear expansion coefficient than the piezoelectric layer A joining step of joining the second member having the pressure chamber with a thermosetting adhesive, and the pressure chamber on the surface opposite to the pressure chamber of the piezoelectric layer after the joining step An electrode forming step of forming the driving electrode in a portion opposing the pressure chamber, and in the electrode forming step, the bonding is applied to a portion of the surface opposite to the pressure chamber of the piezoelectric layer facing the pressure chamber. Shrinkage of the piezoelectric layer after the process with respect to before the bonding process Forming the drive electrodes of the embodiments according to.

  According to a ninth aspect of the present invention, there is provided a piezoelectric actuator in which a first member including a piezoelectric layer and a second member including a portion made of a material having a higher linear expansion coefficient than the piezoelectric layer are bonded with a thermosetting adhesive. And an electrode forming step of forming a driving electrode on the surface of the piezoelectric layer opposite to the second member after the joining step, and in the electrode forming step, the second of the piezoelectric layer The driving electrode is formed on the surface opposite to the member in a manner corresponding to the amount of contraction of the piezoelectric layer after the joining process before the joining process.

  When the first member and the second member are joined with the thermosetting adhesive, the first member and the second member are heated, so that the piezoelectric layer and the portion of the second member having a higher linear expansion coefficient than the piezoelectric layer Due to the difference in coefficient of linear expansion, stress remains in the bonded piezoelectric layer. Then, the piezoelectric layer after the joining process is contracted in the surface direction with respect to the pre-joining process due to the residual stress. At this time, the larger the amount of contraction of the piezoelectric layer, the smaller the amount of deformation of the piezoelectric layer when a voltage is applied to the drive electrode.

  In the first and ninth inventions, the driving electrode having a mode corresponding to the amount of contraction of the piezoelectric layer after the bonding process before the bonding process is formed. Thus, in the first invention, for example, between the liquid ejection devices, when the piezoelectric layer is piezoelectrically deformed by applying a predetermined potential to the driving electrode, the variation in the deformation amount of the piezoelectric layer, that is, from the nozzle Variations in the liquid ejection speed can be reduced. In the ninth invention, variation in the deformation amount of the piezoelectric layer, that is, variation in drive characteristics when the piezoelectric layer is piezoelectrically deformed by applying a predetermined potential to the driving electrode between piezoelectric actuators, for example, is reduced. be able to.

  The liquid ejection device according to a second aspect of the present invention is the liquid ejection device according to the first aspect, wherein, in the electrode forming step, a predetermined reference that overlaps the pressure chamber on a surface of the piezoelectric layer opposite to the pressure chamber. The driving electrode is formed in a portion shifted from the portion in a predetermined direction by an amount corresponding to the contraction amount.

  According to the present invention, the driving electrode is formed on a portion of the surface opposite to the pressure chamber of the piezoelectric layer that is displaced in a predetermined direction by an amount corresponding to the contraction amount of the piezoelectric layer from the predetermined reference portion overlapping the pressure chamber. Therefore, for example, it is possible to reduce variations in the discharge speed of the liquid from the nozzles between the liquid discharge apparatuses.

  A liquid ejection apparatus according to a third aspect is the liquid ejection apparatus according to the second aspect, wherein the liquid ejection apparatus includes a plurality of the nozzles and the pressure chambers, and the piezoelectric layer is disposed in the plurality of pressure chambers. A plurality of the drive electrodes are formed on a portion of the surface of the piezoelectric layer opposite to the pressure chambers that overlaps the plurality of pressure chambers, the electrode forming step. In this case, the driving layer has a portion shifted in the predetermined direction by the same amount corresponding to the contraction amount from the reference portion corresponding to each pressure chamber on the surface of the piezoelectric layer opposite to the pressure chamber. An electrode is formed.

  According to the present invention, when a plurality of driving electrodes are formed in one piezoelectric layer, the piezoelectric layer is subjected to the contraction amount of the piezoelectric layer from the reference portion corresponding to each pressure chamber on the surface opposite to the pressure chamber of the piezoelectric layer. In addition, by forming the driving electrodes in the portions shifted in the predetermined direction by the same amount, the liquid discharge speed of the nozzles can be reduced between the liquid discharge devices in which a plurality of drive electrodes are formed in one piezoelectric layer. Variations can be reduced.

  According to a fourth aspect of the present invention, there is provided the liquid ejection device according to the second or third aspect, wherein the liquid ejection device includes a plurality of the piezoelectric layers separated from each other and overlapping the different pressure chambers. In the electrode forming step, the smaller the piezoelectric layer, the smaller the piezoelectric layer, the portion of the surface of the piezoelectric layer opposite to the pressure chamber is greatly displaced in the predetermined direction from the reference portion. A drive electrode is formed, and the reference portion applies a predetermined potential to the drive electrode in a region overlapping the pressure chamber on the surface of the piezoelectric layer opposite to the pressure chamber, thereby piezoelectrically moving the piezoelectric layer. This is the portion where the amount of deformation of the piezoelectric layer when it is deformed is the largest.

  The greater the deviation of the driving electrode from the reference portion in the predetermined direction, the slower the ink ejection speed from the nozzle. On the other hand, the greater the amount of contraction of the piezoelectric layer, the slower the ink ejection speed from the nozzle. Therefore, in the present invention, when the liquid ejection device includes a plurality of piezoelectric layers, a piezoelectric layer having a smaller shrinkage amount is formed with a plurality of driving electrodes in a portion largely deviating from the reference portion in a predetermined direction. Variation in the discharge speed of the liquid from the nozzle in the liquid discharge apparatus including the piezoelectric layer can be reduced.

  According to a fifth aspect of the present invention, in the liquid ejection device according to the fourth aspect of the present invention, in the electrode forming step, the reference portion of the piezoelectric layer having the largest amount of contraction among the plurality of piezoelectric layers. The driving electrode is formed.

  According to the present invention, it is possible to suppress a decrease in the liquid discharge speed from the nozzle as much as possible by shifting the driving electrode in order to reduce the variation in the liquid discharge speed from the nozzle.

  The liquid ejection device according to a sixth aspect of the present invention is the liquid ejection device according to the fourth or fifth aspect of the invention, wherein the pressure chamber has the pressure chamber from the stacking direction of the first member and the second member. When viewed from the stacking direction, the predetermined direction is a direction orthogonal to the longitudinal direction of the pressure chamber.

  According to the present invention, by setting the predetermined direction to be a direction orthogonal to the longitudinal direction of the pressure chamber, it is possible to increase the amount of fluctuation in the liquid ejection speed from the nozzle when the drive electrode is shifted.

  According to a seventh aspect of the present invention, there is provided the liquid ejecting apparatus according to any one of the second to sixth aspects, wherein the liquid ejecting apparatus further includes an inspection space different from the pressure chamber. A layer extends across the pressure chamber and the inspection space, and an inspection electrode overlapping the inspection space is further formed on a surface of the piezoelectric layer opposite to the pressure chamber, In the electrode forming step, the driving electrode is formed on the surface of the piezoelectric layer opposite to the pressure chamber, and the inspection electrode having a portion longer than the inspection space in the predetermined direction is formed. .

  When the inspection space and the inspection electrode are formed, by applying an alternating voltage to the inspection electrode and changing the frequency of the alternating voltage, the resonance frequency of the portion of the piezoelectric layer that overlaps the inspection space can be detected. . Based on the detected resonance frequency, it can be determined whether or not the liquid ejection device has a predetermined performance. Here, for example, a mask on which a pattern corresponding to the driving electrode and the inspection electrode is formed is disposed on the surface of the piezoelectric layer opposite to the pressure chamber, and the pressure layer on the opposite side of the pressure chamber of the piezoelectric layer on which the mask is disposed. When the driving electrode and the inspection electrode are formed on the surface by screen printing at a time, the driving electrode is formed in a portion shifted in a predetermined direction from the reference portion of the surface opposite to the pressure chamber of the piezoelectric layer. Then, the inspection electrode is formed so as to be shifted in the predetermined direction by the same amount as the driving electrode. On the other hand, if the portion of the inspection space where the inspection electrode overlaps varies, the detected resonance frequency varies, and it is determined whether or not the liquid ejection device has a predetermined performance. May not be able to be performed normally. In the present invention, since the inspection electrode has a portion longer than the inspection space in the predetermined direction, it protrudes from the inspection space in the predetermined direction. Therefore, even when the inspection electrode is formed so as to be shifted in a predetermined direction, the portion of the inspection space that overlaps the inspection electrode hardly changes. Thereby, it is possible to normally determine whether or not the liquid ejection device has a predetermined performance.

  The liquid ejection device according to an eighth invention is the liquid ejection device according to any one of the first to seventh inventions, wherein the surface of the piezoelectric layer opposite to the pressure chamber is provided before the joining step. Measuring a distance between the pair of markers after the marker forming step and before the joining step after forming the pair of markers arranged across the region where the driving electrode is formed A pre-joining measurement step, a post-joining measurement step for measuring a distance between the pair of markers after the joining step, a distance between the pair of markers measured in the post-joining measurement step, and the pre-joining measurement. A contraction amount acquisition step of acquiring the contraction amount from a difference between the distance between the pair of markers measured in the step, and in the electrode formation step, the contraction amount acquired in the contraction amount acquisition step. Applicable aspects To form the driving electrodes.

  According to the present invention, the amount of contraction of the piezoelectric layer after the joining process before the joining process can be acquired based on the difference in distance between the pair of markers before and after the joining process.

  According to the present invention, it is possible to reduce variation in the deformation amount of the piezoelectric layer when the piezoelectric layer is piezoelectrically deformed by applying a predetermined potential to the driving electrode, for example, between liquid ejection devices or piezoelectric actuators. it can.

1 is a schematic configuration diagram of a printer according to a first embodiment. It is a top view of the inkjet head of FIG. It is the III-III sectional view taken on the line of FIG. It is the IV-IV sectional view taken on the line of FIG. It is a flowchart which shows the manufacture procedure of an inkjet head. It is a figure which shows the state in each step of manufacture of an inkjet head. FIG. 9 is a diagram corresponding to FIG. FIG. 10 is a diagram corresponding to FIG. FIG. 10 is a diagram corresponding to FIG. 12 is a plan view of a mask used for electrode formation in Modification 3. FIG. FIG. 10 is a diagram corresponding to FIG. FIG. 10 is a diagram corresponding to FIG. FIG. 10 is a diagram corresponding to FIG.

  Hereinafter, preferred embodiments of the present invention will be described.

  As shown in FIG. 1, the printer 1 according to the present embodiment includes a carriage 2, an inkjet head 3, a paper transport roller 4, and the like. The carriage 2 reciprocates in the scanning direction along the guide rail 5. The inkjet head 3 is mounted on the carriage 2 and ejects ink from a plurality of nozzles 15 formed on the lower surface thereof. The paper transport rollers 4 are disposed on both sides of the ink jet head 3 in the paper feed direction orthogonal to the scanning direction, and transport the recording paper P in the paper feed direction.

  In the printer 1, printing is performed on the recording paper P by ejecting ink from the inkjet head 3 that reciprocates in the scanning direction together with the carriage 2 while transporting the recording paper P in the paper feeding direction by the paper transporting roller 4. . Further, the recording paper P for which printing has been completed is discharged by the paper transport roller 4.

  Next, the inkjet head 3 will be described in more detail. As shown in FIGS. 2 to 4, the inkjet head 3 applies pressure to the ink in the pressure chamber 10 and the flow path unit 21 in which the ink flow paths such as the nozzle 15 and the pressure chamber 10 described later are formed. The piezoelectric actuator 22 is provided.

  The flow path unit 21 is formed by joining four plates 31 to 34 stacked on each other with a thermosetting adhesive. The plates 31 to 33 are made of a metal material such as stainless steel. The plate 34 is made of a synthetic resin material such as polyimide. Alternatively, the plate 34 may be made of the same metal material as the plates 31 to 33.

  A plurality of pressure chambers 10 are formed in the plate 31. The plurality of pressure chambers 10 have a substantially elliptical planar shape whose longitudinal direction is the scanning direction. The plurality of pressure chambers 10 are arranged at equal intervals in the paper feeding direction to form a pressure chamber row 9. The plate 31 has two pressure chamber rows 9 arranged in the paper feed direction. In the plate 32, a plurality of substantially circular through holes 12 and 13 are formed in portions overlapping with both longitudinal ends of the plurality of pressure chambers 10, respectively.

  Two manifold channels 11 corresponding to the two pressure chamber rows 9 are formed in the plate 33. The two manifold channels 11 extend in the paper feeding direction, and overlap the substantially outer half in the scanning direction of the plurality of pressure chambers 10 constituting the corresponding pressure chamber row 9. The two manifold channels 11 are connected to each other at the downstream end in the paper feeding direction. Ink is supplied to the two manifold channels 11 from the ink supply ports 8 provided in the mutually connected portions. In addition, a plurality of substantially circular through holes 14 are formed in the plate 33 so as to overlap the plurality of through holes 13. In the plate 34, a plurality of nozzles 15 are formed in portions overlapping with the plurality of through holes 14.

  In the flow path unit 21, the manifold flow path 11 communicates with the plurality of pressure chambers 10 through the through holes 12. Further, each pressure chamber 10 communicates with the corresponding nozzle 15 through the through holes 13 and 14. That is, a plurality of individual ink channels are formed in the channel unit 21 from the outlet of the manifold channel 11 to the nozzle 15 via the pressure chamber 10.

  The piezoelectric actuator 22 includes an ink separation layer 41, piezoelectric layers 42 and 43, a common electrode 44, and a plurality of individual electrodes 45. The ink separation layer 41 is made of a metal material such as stainless steel, and is disposed on the upper surface of the plate 31 so as to cover the plurality of pressure chambers 10. The ink separation layer 41 and the plate 31 are joined by a thermosetting adhesive. The ink separation layer 41 is for preventing the ink in the pressure chamber 10 from coming into contact with the piezoelectric layer 42.

  The piezoelectric layer 42 is made of a piezoelectric material mainly composed of lead zirconate titanate, which is a mixed crystal of lead titanate and lead zirconate. The piezoelectric layer 42 is bonded to the upper surface of the ink separation layer 41 by a thermosetting adhesive 50. In FIGS. 3 and 4, illustration of the thermosetting adhesive other than the thermosetting adhesive 50 between the plates 31 to 34 and between the plate 31 and the ink separation layer 41 is omitted. . The piezoelectric layer 43 is made of the same piezoelectric material as the piezoelectric layer 42 and is disposed on the upper surface of the piezoelectric layer 42.

  The common electrode 44 is formed over almost the entire area between the piezoelectric layer 42 and the piezoelectric layer 43. The common electrode 44 is always held at the ground potential by a driver IC (not shown). The plurality of individual electrodes 45 have a substantially elliptical planar shape that is slightly smaller than the pressure chamber 10. The plurality of individual electrodes 45 are formed in portions overlapping the plurality of pressure chambers 10 on the upper surface of the piezoelectric layer 43. Thereby, the plurality of individual electrodes 45 are arranged in a substantially rectangular region R on the upper surface of the piezoelectric layer 43. Each of the plurality of individual electrodes 45 is selectively given either a ground potential or a predetermined drive potential by a driver IC (not shown).

  Corresponding to the formation of the common electrode 44 and the plurality of individual electrodes 45 so as to sandwich the piezoelectric layer 43, the portion of the piezoelectric layer 43 sandwiched between the common electrode 44 and the plurality of individual electrodes 45 is , Polarized in the thickness direction.

  Further, markers 51 a to 51 d are formed on the upper surface of the piezoelectric layer 43 at portions located outside the four corners of the region R where the plurality of individual electrodes 45 are arranged. The markers 51a to 51d are made of the same metal material as that of the individual electrode 45, for example.

  Here, a method for driving the piezoelectric actuator 22 to eject ink from the nozzle 15 will be described. In the piezoelectric actuator 22, the potentials of all the individual electrodes 45 are previously held at the ground potential by a driver IC (not shown). In order to eject ink from a certain nozzle 15, the potential of the individual electrode 45 corresponding to the nozzle 15 is switched from the ground to the driving potential. Then, due to the potential difference between the individual electrode 45 and the common electrode 44, an electric field parallel to the polarization direction is generated in a portion sandwiched between the individual electrode 45 and the common electrode 44 of the piezoelectric layer 43. Due to this electric field, the portion of the piezoelectric layer 43 contracts in the horizontal direction orthogonal to the polarization direction due to piezoelectric deformation, and the portion overlapping the pressure chamber 10 of the ink separation layer 41 and the piezoelectric layers 42 and 43 as a whole is the pressure chamber 10. Deforms so that it is convex to the side. As a result, the volume of the pressure chamber 10 decreases, the pressure of the ink in the pressure chamber 10 increases, and ink is ejected from the nozzle 15 communicating with the pressure chamber 10.

  Next, the manufacturing method of the inkjet head 3 is demonstrated using the flowchart of FIG. 5, and FIG. In order to manufacture the inkjet head 3, first, as shown in FIG. 6A, a laminated body 55 of piezoelectric layers 42 and 43 and a common electrode 44 is manufactured (step S101, hereinafter simply referred to as S101). ). Specifically, for example, a conductive paste that becomes the common electrode 44 is formed on the upper surface of the green sheet of the piezoelectric material that becomes the piezoelectric layer 42. In addition, conductive paste that becomes the markers 51 a to 51 d is formed on the upper surface of the green sheet of the piezoelectric material that becomes the piezoelectric layer 43. Then, these green sheets on which the conductive paste is formed are stacked on each other and fired at a temperature of about 800 to 1000 ° C., for example. At this stage, the individual electrode 45 is not formed on the upper surface of the piezoelectric layer 43. And after producing the laminated body 55, while measuring the distance of the marker 51a and the marker 51c which pinches | interposes the area | region R diagonally among the four markers 51a-51d, and the distance of the marker 51b and the marker 51d, respectively. These average values are calculated (S102).

  In parallel with S101 and S102, as shown in FIG. 6B, a laminated body 56 of the flow path unit 21 and the ink separation layer 41 is produced (S103). Specifically, for example, the plates 31 to 34 that form the flow path unit 21 and the ink separation layer 41 are stacked, and these are bonded by a thermosetting adhesive or the like.

  Then, as shown in FIG.6 (c), the produced laminated body 55 and the laminated body 56 are mutually joined by the thermosetting adhesive 50 (S104). In addition, the heating temperature at the time of joining by the thermosetting adhesive in S103 or S104 is about 150-250 degreeC, for example. And after joining the laminated body 55 and the laminated body 56, while measuring again the distance of the marker 51a and the marker 51c, and the distance of the marker 51b and the marker 51d, these average values are calculated (S105). ).

  Subsequently, by taking the difference between the average value of the distance between the markers measured in S102 and the average value of the distance between the markers measured in S105, the process of S104 of the piezoelectric layers 42 and 43 after the process of S104. A shrinkage amount D in the surface direction with respect to the front is calculated (S106). Then, based on the shrinkage amount D calculated in S105, a plurality of individual electrodes 45 are formed in a portion overlapping the plurality of pressure chambers 10 on the upper surface of the piezoelectric layer 43 (S107). More specifically, the shift amount E as shown in Table 1 is determined according to the contraction amount D. Then, as shown in FIG. 6 (d), from the portion overlapping the central portion of the plurality of pressure chambers 10 on the upper surface of the piezoelectric layer 43 to the portion shifted by the shift amount E in the direction orthogonal to the longitudinal direction of the pressure chamber 10. A plurality of individual electrodes 45 are formed. Here, K1, K2, and K3 in Table 1 have a relationship of K1 <K2 <K3, and E1 and E2 have a relationship of E1> E2. At this time, the individual electrode 45 may be shifted to either side in the direction orthogonal to the longitudinal direction of the pressure chamber 10.

  That is, in the present embodiment, as the contraction amount D is smaller, the individual electrode 45 is formed in a portion that is largely deviated from a portion overlapping the central portion of the pressure chamber 10 on the upper surface of the piezoelectric layer 43. Further, when the contraction amount D is larger than K3, the product obtained by joining the laminated body 55 and the laminated body 56 is discarded as a defective product or sent to a recycling process.

  In this embodiment, as shown in Table 1, the shift amount E of the individual electrode 45 is determined in three stages of E1, E2, and 0 according to the contraction amount D, but according to the contraction amount D, The shift amount E may be determined in two stages or a plurality of stages of four or more. Alternatively, the shift amount E may be continuously changed according to the contraction amount D.

  A specific method for forming the plurality of individual electrodes 45 will be described. For example, first, a mask on which a pattern corresponding to the plurality of individual electrodes 45 is formed is disposed on the upper surface of the piezoelectric layer 43. At this time, by adjusting the positional relationship between the mask and the piezoelectric layer 43, the mask is shifted from the position where the individual electrode 45 is formed in a portion overlapping the central portion of the pressure chamber 10 on the upper surface of the piezoelectric layer 43. It is arranged at a position shifted by an amount E. Then, a plurality of individual electrodes 45 are formed on the upper surface of the piezoelectric layer 43 on which the mask is arranged by screen printing. Accordingly, the plurality of individual electrodes 45 are formed on the upper surface of the piezoelectric layer 43 at a portion shifted by the same shift amount E from the portion overlapping the central portion of the corresponding pressure chamber 10 according to the contraction amount D. Here, when the individual electrode 45 is formed by screen printing, the individual electrode 45 needs to be baked after the screen printing. At this time, the heating temperature is between the plates 31 to 34 and between the plate 31 and the ink. The temperature is set so low that the thermosetting adhesive does not thermally decompose so that the bonding between the layer 41, the ink separation layer 41, and the piezoelectric layer 42 is not released. Specifically, for example, when the temperature at which the thermosetting adhesive is thermally decomposed is about 250 to 400 ° C., the heating temperature during firing of the individual electrode 45 is set to about 100 ° C. Further, instead of performing screen printing, the individual electrode 45 may be formed by evaporating a conductive material. In this case, firing of the individual electrode 45 is not necessary.

  Here, a metal material such as stainless steel forming the ink separation layer 41 has a higher linear expansion coefficient than the piezoelectric material forming the piezoelectric layers 42 and 43. Therefore, when the laminated body 55 and the laminated body 56 are joined in S104, the laminated body 55 and the laminated body 56 are joined in a state where the ink separation layer 41 is expanded more than the piezoelectric layers 42 and 43 due to heating during joining. . When the stacked bodies 55 and 56 are cooled after the stacked body 55 and the stacked body 56 are joined, the ink separation layer 41 contracts more than the piezoelectric layers 42 and 43. Therefore, after the laminate 55 and the laminate 56 are joined, the piezoelectric layers 42 and 43 have a stress that causes the piezoelectric layers 42 and 43 to contract in the surface direction.

  On the other hand, when the individual electrode 45 is formed in the same portion overlapping the pressure chamber 10 on the upper surface of the piezoelectric layer 43, the drive potential is applied to the individual electrode 45 as the contraction amount of the piezoelectric layers 42 and 43 increases. The deformation amount of the piezoelectric layers 42 and 43 and the ink separation layer 41 when applied is reduced. That is, the greater the amount of contraction of the piezoelectric layers 42 and 43, the slower the ink ejection speed from the nozzle 15.

  From the above, when manufacturing a plurality of ink jet heads 3, unlike this embodiment, in S 107, for example, a piezoelectric layer such as a portion that always overlaps the central portion of the pressure chamber 10 on the upper surface of the piezoelectric layer 43. If the individual electrodes 45 are formed on the same portion of the upper surface of 43, the ink ejection speed from the nozzles 15 varies between the inkjet heads 3.

  On the other hand, when the pressure chamber 10 has a substantially elliptical planar shape and the individual electrode 45 has a substantially elliptical shape that is slightly smaller than the pressure chamber 10, the piezoelectric layer can be used if the other conditions are the same. When the individual electrode 45 is formed in a portion of the upper surface of 43 that overlaps the central portion of the pressure chamber 10, the deformation amount of the piezoelectric layers 42 and 43 and the ink separation layer 41 when the driving potential is applied to the individual electrode 45 is the largest. Thus, the ink ejection speed from the nozzle 15 is the fastest. The deformation amount of the piezoelectric layers 42 and 43 and the ink separation layer 41 becomes smaller as the individual electrode 45 is formed on the portion of the upper surface of the piezoelectric layer 43 that is largely deviated from the portion overlapping the central portion of the pressure chamber 10. The discharge speed of ink from 15 becomes slow.

  Therefore, in the present embodiment, as described above, the central portion of the pressure chamber 10 on the upper surface of the piezoelectric layer 43 becomes smaller as the contraction amount D of the piezoelectric layers 42 and 43 after the step of S104 is smaller than that before the step of S104. The individual electrode 45 is formed in a portion that is greatly deviated from the overlapping portion. Thereby, the dispersion | variation in the discharge speed of the ink from the nozzle 15 between the inkjet heads 3 can be reduced.

  In the present embodiment, as described above, the contraction amount D of the piezoelectric layers 42 and 43 can be acquired based on the difference between the distance between the markers measured in S102 and the distance between the markers measured in S105. it can. At this time, the distance between the markers 51a and 51c that sandwich the region R diagonally and the distance between the markers 51b and 51d are the distance between the markers 51a and 51b that sandwich the region R in the paper feed direction and the markers 51c and 51d. , The distance between the markers 51a and 51d that sandwich the region R in the scanning direction, and the distance between the markers 51b and 51c. Therefore, as in the present embodiment, in S102 and S105, when the distance between the markers 51a and 51c and the distance between the markers 51b and 51d are measured and the average value thereof is calculated, the marker 51a and The distance between 51b and the distance between the markers 51c and 51d are measured, and the average value of these is calculated, or the distance between the markers 51a and 51d and the distance between the markers 51b and 51c is measured, and the average is calculated. Compared to the case, the contraction amount D calculated in S106 becomes larger. As a result, the influence of the measurement error when measuring the distance between the markers in S102 and S105 on the contraction amount D calculated in S106 can be reduced. Therefore, the contraction amount D accurately corresponds to the degree of contraction of the piezoelectric layers 42 and 43. Further, since the average value is calculated as described above in S102 and S105, and the contraction amount D is calculated from the difference between the average values in S106, the contraction amount D is surely the extent of contraction of the entire piezoelectric layers 42 and 43. It will be compatible.

  Further, in the present embodiment, the pressure chamber 10 has a substantially elliptical planar shape, and the individual electrode 45 has a substantially elliptical planar shape that is slightly smaller than the pressure chamber 10. In such a case, when the individual electrode 45 is formed at a portion shifted by a shift amount E in a direction orthogonal to the longitudinal direction of the pressure chamber 10 from a portion overlapping the central portion of the pressure chamber 10 on the upper surface of the piezoelectric layer 43. In addition, the piezoelectric layers 42, 43, and 47 are formed more than when the individual electrode 45 is formed in a portion shifted from the portion overlapping the central portion of the pressure chamber 10 on the upper surface of the piezoelectric layer 43 by the shift amount E in the longitudinal direction of the pressure chamber 10. The deformation amount of the ink separation layer 41 changes greatly. In the present embodiment, since the individual electrode 45 is shifted in a direction orthogonal to the longitudinal direction of the pressure chamber 10, the deformation amount of the piezoelectric layers 42 and 43 and the ink separation layer 41 when the piezoelectric actuator 22 is driven is set to a certain amount. The shift amount of the individual electrode 45 necessary for the fluctuation can be reduced.

  In the present embodiment, the inkjet head 3 corresponds to the liquid ejection apparatus according to the present invention. The individual electrode 45 corresponds to the driving electrode according to the present invention. The laminated body 55 corresponds to the first member according to the present invention. Moreover, the laminated body 56 is corresponded to the 2nd member which concerns on this invention. Further, the step of forming the markers 51a to 51d in S101 corresponds to the marker forming step according to the present invention. The process of S104 corresponds to the joining process according to the present invention. Moreover, the process of S102 corresponds to the pre-joining measurement process according to the present invention. The process of S105 corresponds to a post-joining measurement process according to the present invention. The process of S106 corresponds to the contraction amount acquisition process according to the present invention. Further, the step S107 corresponds to the electrode forming step according to the present invention. Moreover, the part which overlaps with the center part of the pressure chamber 10 of the upper surface of the piezoelectric layer 43 is equivalent to the reference | standard part which concerns on this invention. Further, the driving potential applied to the individual electrode 45 corresponds to the predetermined potential according to the present invention. Further, the paper feeding direction orthogonal to the longitudinal direction of the pressure chamber 10 corresponds to the predetermined direction according to the present invention.

  Next, modified examples in which various changes are made to the present embodiment will be described. However, description of components having the same configuration as in this embodiment will be omitted as appropriate.

  In the above-described embodiment, the piezoelectric layers 42 and 43 extend continuously across all the pressure chambers 10 of the inkjet head 3, but are not limited thereto. In one modification (Modification 1), as shown in FIG. 7, four pressure chamber rows 9 are formed in the flow path unit 21 in the scanning direction. The piezoelectric layers 42 and 43 are provided individually for the four pressure chamber rows 9. That is, in the first modification, a plurality of piezoelectric layers 42 and 43 separated from each other are provided so as to overlap with the pressure chambers 10 constituting the different pressure chamber rows 9.

  In S102 and S105, the distance between the markers 51a and 51c and the distance between the markers 51b and 51d are individually measured for each piezoelectric layer 42 and 43 corresponding to each pressure chamber row 9, and the measurement is performed. Calculate the average value. In S106, the contraction amount D is calculated individually for each of the piezoelectric layers 42 and 43 corresponding to each pressure chamber row 9. In S107, the individual electrode 45 is formed in a portion overlapping the central portion of the pressure chamber 10 on the upper surface of the piezoelectric layer 43 having the largest shrinkage amount D calculated in S106. For the other piezoelectric layers 43, the individual electrodes 45 are formed in portions where the piezoelectric layer 43 having a smaller contraction amount D is greatly deviated from the portion overlapping the central portion of the pressure chamber 10 on the upper surface of the piezoelectric layer 43.

  In this case, the variation in the deformation amount of the piezoelectric layers 42 and 43 and the ink separation layer 41 when the drive potential is applied to the individual electrode 45 between the pressure chamber rows 9, that is, the ejection speed of the ink from the nozzle 15. Variations can be reduced.

  In the first modification, as described above, the individual electrode 45 is formed in a portion overlapping the central portion of the pressure chamber 10 on the upper surface of the piezoelectric layer 43 having the largest shrinkage amount D. That is, the shift amount E is set to 0 for the piezoelectric layer 43 having the largest shrinkage amount D. In accordance with this, the shift amount E of the individual electrode 45 formed on the other piezoelectric layer 43 is determined. Therefore, the shift amount E of the individual electrode 45 in each piezoelectric layer 43 can be minimized. Accordingly, it is possible to suppress the decrease in the ink discharge speed from the nozzle 15 as much as possible by shifting the individual electrode 45 in order to reduce the variation in the ink discharge speed from the nozzle 15.

  In the first modification, the individual electrode 45 is formed in a portion overlapping the central portion of the pressure chamber 10 on the upper surface of the piezoelectric layer 43 having the largest shrinkage amount D, but is not limited thereto. In the first modification, the individual electrodes 45 may be formed on all the piezoelectric layers 43 at portions shifted from the portion overlapping the central portion of the pressure chamber 10 on the upper surface of the piezoelectric layer 43.

  In the above-described embodiment, the inkjet head 3 is a so-called serial head that ejects ink from the nozzle 15 while reciprocating in the scanning direction, but is not limited thereto. In another modification (Modification 2), a line head 70 is provided in the printer 1 instead of the inkjet head 3, as shown in FIG. The line head 70 includes four head units 71 and a holding member 72. The head unit 71 includes a flow path unit in which an ink flow path such as the nozzle 15 and the pressure chamber 10 is formed, as in the flow path unit 21, and an ink separation layer 41, piezoelectric layers 42 and 43, similar to the piezoelectric actuator 22. And a piezoelectric actuator having a common electrode 44 and an individual electrode 45. The four head units 71 are arranged in such a direction that the plurality of nozzles 15 are arranged along the scanning direction, and are arranged in a staggered manner over the substantially entire length of the recording paper P along the scanning direction. The holding member 72 is a substantially rectangular member whose longitudinal direction is the scanning direction, and holds four head units 71.

  In this case, the portions other than the individual electrodes 45 of the four head units 71 are respectively produced in the same procedure as S101 to S106, and the contraction amounts D of the piezoelectric layers 42 and 43 in each head unit 71 are calculated. . In S107, among the four head units 71, for the head unit 71 having the largest contraction amount D calculated in S106, the individual electrode 45 is provided in a portion overlapping the central portion of the pressure chamber 10 on the upper surface of the piezoelectric layer 43. Form. For the other head units 71, the individual electrode 45 is formed in a portion that is largely displaced because the head unit 71 having a smaller contraction amount D overlaps with the central portion of the pressure chamber 10 on the upper surface of the piezoelectric layer 43. Then, the line head 70 is completed by attaching the four manufactured head units 71 to the holding member 72.

  In this case, the variation in the deformation amount of the piezoelectric layers 42 and 43 and the ink separation layer when the drive potential is applied to the individual electrode 45 between the head units 71, that is, the variation in the ejection speed of the ink from the nozzle 15. Can be reduced.

  In the second modification, as described above, in the head unit 71 having the largest contraction amount D, the individual electrode 45 is formed in a portion overlapping the central portion of the pressure chamber 10 on the upper surface of the piezoelectric layer 43. That is, the shift amount E is set to 0 for the head unit 71 having the largest contraction amount D. In accordance with this, the shift amount E of the individual electrode 45 in the other head unit 71 is determined. Therefore, the shift amount E of the individual electrode 45 in each head unit 71 can be minimized. Accordingly, it is possible to suppress the decrease in the ink discharge speed from the nozzle 15 as much as possible by shifting the individual electrode 45 in order to reduce the variation in the ink discharge speed from the nozzle 15.

  In the second modification, in the head unit 71 having the largest shrinkage D, the individual electrode 45 is formed on the upper surface of the piezoelectric layer 43 overlapping the central portion of the pressure chamber 10, but this is not limitative. In the second modified example, the individual electrodes 45 may be formed in all the head units 71 at portions shifted from the portions overlapping the central portion of the pressure chamber 10 on the upper surface of the piezoelectric layer 43.

  In the second modification, the line head 70 corresponds to the liquid ejection apparatus according to the present invention.

  The present invention is also applicable to the case where an electrode other than the individual electrode 45 for driving the piezoelectric actuator 22 is provided on the upper surface of the piezoelectric layer 43. For example, in another modified example (Modified Example 3), as shown in FIG. 9, each of the pressure chamber rows 9 of the plate 31 has a substantially circular shape arranged in the paper feed direction at the outer portion in the scanning direction. A plurality of inspection spaces 81 are formed. The ink separation layer 41 is disposed so as to cover the plurality of pressure chambers 10 and the plurality of inspection spaces 81. The piezoelectric layers 42 and 43 extend continuously across the plurality of pressure chambers 10 and the plurality of inspection spaces 81. On the upper surface of the piezoelectric layer 43, in addition to the plurality of individual electrodes 45 and the markers 51a to 51d, a plurality of inspection electrodes 82 and a plurality of pads 83 corresponding to the plurality of inspection spaces 81 are formed.

  The inspection electrode 82 is arranged so as to overlap each inspection space 81. Further, the inspection electrode 82 is longer than the inspection space 82 in the paper feeding direction orthogonal to the longitudinal direction of the pressure chamber 10 and protrudes from the inspection space 81 on both sides in the paper feeding direction. The pad 83 has a larger area than the inspection electrode 82 and is disposed on the inner side in the scanning direction of each inspection electrode 82. The inspection electrode 82 and the pad 83 corresponding to each other are connected to each other by a connecting portion 84 provided therebetween.

  In this case, in S107, for example, on the upper surface of the piezoelectric layer 43, as shown in FIG. 10, a pattern 86a corresponding to the plurality of individual electrodes 45, a plurality of inspection electrodes 82, a plurality of pads 83, and a plurality of connections. A mask 86 on which a pattern 86b corresponding to the portion 84 is formed is disposed, and a plurality of individual electrodes 45, a plurality of inspection electrodes 82, a plurality of pads 83, and a plurality of pads 83 are formed by screen printing on the upper surface of the piezoelectric layer 43 on which the mask 86 is disposed. A plurality of connecting portions 84 are formed simultaneously.

  When the inkjet head 3 is provided with the inspection space 81, the inspection electrode 82, the pad 83, and the connection portion 84, after manufacturing the inkjet head 3, a probe that outputs an alternating voltage is applied to the pad 83, An AC voltage is applied to the inspection electrode 82 and an output current from the common electrode 44 is detected. Then, the frequency of the AC voltage applied to the inspection electrode 81 is sequentially changed. Then, when the frequency of the AC voltage applied to the inspection electrode 82 becomes the resonance frequency of the portion overlapping the inspection space 81 of the piezoelectric actuator 22, the output current from the common electrode 44 has a peak value. Using this fact, the frequency of the AC voltage applied to the inspection electrode 82 when the output current from the common electrode 44 reaches the peak value is detected as the resonance frequency. Then, for example, by comparing the detected resonance frequency with the designed resonance frequency, it is possible to inspect whether or not the piezoelectric actuator 22 of the inkjet head 3 has a predetermined performance.

  Here, as described above, the individual electrode 45 and the inspection electrode 82 are formed at a time using the mask 86 in which the pattern 86a corresponding to the individual electrode 45 and the pattern 86b corresponding to the inspection electrode 82 are formed. In this case, when the individual electrode 45 is formed in a portion shifted in the paper feed direction from the portion overlapping the central portion of the pressure chamber 10 on the upper surface of the piezoelectric layer 43, the inspection electrode 82 is also in the paper feed direction as much as the individual electrode 45. They will be formed out of alignment. On the other hand, when the portion of the inspection space 81 where the inspection electrode 82 overlaps varies, the resonance frequency detected by the inspection also varies.

  In the modified example 3, as described above, the inspection electrode 82 protrudes from the inspection space 81 on both sides in the direction orthogonal to the longitudinal direction of the pressure chamber 10, that is, on both sides in the direction in which the individual electrode 45 is shifted. Therefore, even if the inspection electrode 82 is displaced in a direction perpendicular to the longitudinal direction of the pressure chamber 10, the portion of the inspection space 81 where the inspection electrode 82 overlaps hardly changes. Therefore, it can be normally inspected whether or not the piezoelectric actuator 22 of the inkjet head 3 has a predetermined performance.

  Further, in the above-described embodiment, the individual electrode 45 is shifted in the direction orthogonal to the longitudinal direction of the pressure chamber 10, but is not limited thereto. The individual electrode 45 may be shifted in another predetermined direction such as the longitudinal direction of the pressure chamber 10.

  In the above-described embodiment, the pressure chamber 10 has a substantially elliptical planar shape, and the individual electrode 45 has a substantially elliptical shape that is slightly smaller than the pressure chamber 10. The shape of the electrode 45 is not limited to this. When the shapes of the pressure chamber 10 and the individual electrode 45 are different, the piezoelectric layer when a driving potential is applied to the individual electrode 45 in the portion overlapping the pressure chamber 10 on the upper surface of the piezoelectric layer 43 according to these shapes. The reference portion may be a portion where the amount of deformation of 42 and 43 and the ink separation layer 41 is the largest. Then, the individual electrode 45 may be formed on a portion of the upper surface of the piezoelectric layer 43 that is shifted from the reference portion by a shift amount E corresponding to the contraction amount D.

  Further, in the above-described embodiment, the portion overlapping the central portion of the pressure chamber 10 on the upper surface of the piezoelectric layer 43 is used as the reference portion. That is, of the portion overlapping the pressure chamber 10 on the upper surface of the piezoelectric layer 43, the portion where the amount of deformation of the piezoelectric layers 42 and 43 and the ink separation layer 41 when the drive potential is applied to the individual electrode 45 is the largest as the reference portion. Yes. However, it is not limited to this. For example, the portion of the upper surface of the piezoelectric layer 43 shifted from the central portion of the pressure chamber 10 by a predetermined shift amount is used as a reference portion, and the individual electrode 45 is connected to the pressure chamber 10 as the contraction amount D of the piezoelectric layers 42 and 43 increases. You may shift from a reference | standard part so that it may approach a center part.

  In the above-described embodiment, in S102 and S105, the distance between the markers 51a and 51c and the distance between the markers 51b and 51d that sandwich the region R where the plurality of individual electrodes 45 are arranged diagonally are measured. Although the average value of these was calculated, it is not limited to this. For example, in S102 and S105, the distance between the markers 51a and 51b that sandwich the region R in the paper feed direction and the distance between the markers 51c and 51d may be measured, and the average value thereof may be calculated. Alternatively, in S102 and S105, the distance between the markers 51a and 51d that sandwich the region R in the scanning direction and the distance between the markers 51b and 51c may be measured, and the average value thereof may be calculated.

  Moreover, it is not restricted to taking the average value as mentioned above. For example, only two markers sandwiching the region R where the plurality of individual electrodes 45 are arranged may be provided on the upper surface of the piezoelectric layer 43, and the distance between these two markers may be measured in S102 and S105.

  Furthermore, the distance between the markers formed on the upper surface of the piezoelectric layer 43 is measured, and the contraction amount D of the piezoelectric layers 42 and 43 is calculated from the measurement result. For example, the contraction amount may be measured by a method other than measuring the marker distance, such as directly measuring the lengths of the piezoelectric layers 42 and 43.

  In the above-described embodiment, the laminate 56 of the ink separation layer 41 and the flow path unit 21 is manufactured in S103, and the laminate 55 and the laminate 56 are joined in S104. I can't. For example, in S103, a laminate of the ink separation layer 41 and a part of the plates 31 to 34 forming the flow path unit 21 including the plate 31 is produced, and in S104, the laminate 55 and S103 are produced. The laminated body may be joined. In this case, the laminated body of the ink separation layer 41 and the part of the plates 31 to 34 including the plate 31 corresponds to the second member according to the present invention. In this case, after S104, a step of joining the remaining plates among the plates 31 to 34 to the stacked body formed in S104 is required.

  Alternatively, the stacked body 55 and the ink separation layer 41 that is not bonded to the plates 31 to 34 may be bonded in S104 without producing the stacked body in S103. In this case, a step of bonding the plates 31 to 34 to the ink separation layer 41 is required after S104 and before the formation of the individual electrode 45 in S107. In this case, the combination of the step of bonding the laminate 55 and the ink separation layer 41 and the step of bonding the plates 31 to 34 to the ink separation layer 41 corresponds to the bonding step according to the present invention. To do.

  In this case, the plates 31 to 34 may be joined to the ink separation layer 41 after the formation of the individual electrodes in S107.

  Further, as described above, when the ink separation layer 41 and the plates 31 to 34 are joined to the laminated body 55 in a plurality of times, the distance between the markers immediately before the individual electrode 45 is formed and the plurality of times of joining. The contraction amount D is calculated based on the difference from the distance between the markers in the stage before the first joining. Alternatively, the contraction amount D may be calculated based on the difference between the distance between the markers immediately before forming the individual electrode 45 and the distance between the markers immediately before the second and subsequent bondings among the plurality of bondings. .

  In the above-described embodiment, the ink separation layer 41 is disposed between the plate 31 and the piezoelectric layer 42. However, the present invention is not limited to this. For example, in another modification (Modification 4), as shown in FIG. 11, the piezoelectric layer 42 is directly bonded to the upper surface of the plate 31 of the flow path unit 21 by a thermosetting adhesive 50. In this case, the flow path unit 21 is produced in S103, and the laminate 55 and the flow path unit 21 are joined with the thermosetting adhesive 50 in S104.

  In this case, due to the difference in linear expansion coefficient between the piezoelectric layers 42 and 43 and the plate 31, the piezoelectric layers 42 and 43 after joining the laminated body 55 and the flow path unit 21, as in the above-described embodiment, Shrinks before joining. However, in the modified example 4 as well, in the above-described S107, the amount of shift according to the contraction amount of the piezoelectric layers 42 and 43 from the portion of the upper surface of the piezoelectric layer 43 that overlaps the central portion of the pressure chamber 10 in S107. The individual electrode 45 is formed at a portion shifted by this amount. Therefore, as in the case of the above-described embodiment, it is possible to reduce variations in the ejection characteristics of ink from the nozzles 15 between the inkjet heads 3. In Modification 4, the flow path unit 21 corresponds to the second member according to the present invention.

  In the above example, the piezoelectric layer 42 and the ink separation layer 41 and the plate 31 made of a material having a higher linear expansion coefficient than the piezoelectric layer 42 are directly bonded by the thermosetting adhesive 50. It is not limited to. A layer such as another thin film may be interposed between the piezoelectric layer 42 and the ink separation layer 41 or the plate 31.

  Further, in the above-described embodiment, the plurality of individual electrodes 45 capable of individually switching the potential are formed in the portion overlapping the plurality of pressure chambers 10 on the upper surface of the piezoelectric layer 43. However, the present invention is not limited to this. . In another modification (Modification 5), a common electrode 91 is formed on the upper surface of the piezoelectric layer 43 as shown in FIGS. The common electrode 91 has a plurality of driving portions 91a and connecting portions 91b. The plurality of drive units 91 a have substantially the same elliptical planar shape as the individual electrodes 45 (see FIG. 2), and are disposed so as to overlap the plurality of pressure chambers 10. The connecting part 91b is electrically connected to each other by connecting a plurality of driving parts 91a. Further, in Modification 5, a plurality of individual electrodes 92 having substantially the same elliptical planar shape as the individual electrodes 45 are formed in portions overlapping the plurality of pressure chambers 10 between the piezoelectric layers 42 and 43. .

  In this case, in S101, a laminated body of the piezoelectric layers 42 and 43 and the plurality of individual electrodes 92 is formed. In S107, the common electrode 91 is formed on the upper surface of the piezoelectric layer 43. At this time, for example, the common electrode 91 is formed in a portion shifted by a shift amount E corresponding to the contraction amount D calculated in S106 from a portion overlapping the central portion of the pressure chamber 10 corresponding to the plurality of drive portions 91a.

  Even in this case, as in the above-described embodiment, it is possible to reduce variations in the ejection speed of ink from the nozzles 15 in the inkjet head 3. In Modification 5, the common electrode 91 corresponds to the driving electrode according to the present invention. Further, the ground potential applied to the common electrode 91 corresponds to the predetermined potential according to the present invention.

  The present invention can also be applied to the manufacture of an inkjet head including a piezoelectric actuator having a configuration different from that described above, and the manufacture of a piezoelectric actuator constituting the inkjet head. For example, the present invention can be applied to the manufacture of an ink jet head and the manufacture of a piezoelectric actuator as described in JP 2010-233428 A. In this case, the upper electrode formed on the upper surface of the upper piezoelectric layer is formed in a portion shifted from the portion overlapping the central portion of the pressure chamber by a shift amount corresponding to the contraction amount of the piezoelectric layer.

  Further, in the above-described embodiment, the shift amount of the individual electrode 45 is changed according to the contraction amount D of the piezoelectric layers 42 and 43, but is not limited thereto. For example, aspects other than the position of the individual electrode 45 such as the size and shape of the individual electrode 45 may be changed according to the contraction amount D of the piezoelectric layers 42 and 43.

  Moreover, although the example which applied this invention to manufacture of the inkjet head which discharges an ink from a nozzle, and manufacture of the piezoelectric actuator used for an inkjet head was demonstrated above, it is not restricted to this. The present invention can also be applied to the manufacture of a liquid discharge apparatus other than an ink jet head that discharges liquid other than ink, and the manufacture of a piezoelectric actuator used in the liquid discharge apparatus. The present invention can also be applied to the manufacture of piezoelectric actuators used in devices other than liquid ejection devices.

3 Inkjet Head 10 Pressure Chamber 15 Nozzle 21 Channel Unit 22 Piezoelectric Actuator 31 Plate 41 Ink Separation Layer 42, 43 Piezoelectric Layer 45 Individual Electrode 81 Inspection Space 82 Inspection Electrode 91 Common Electrode

Claims (9)

A nozzle,
A pressure chamber communicating with the nozzle;
A piezoelectric layer disposed to overlap the pressure chamber;
A driving electrode formed on a portion of the surface of the piezoelectric layer opposite to the pressure chamber that overlaps the pressure chamber, and a manufacturing method of a liquid ejection device comprising:
A bonding step of bonding a first member including the piezoelectric layer and a second member including a portion made of a material having a higher linear expansion coefficient than the piezoelectric layer and having the pressure chamber with a thermosetting adhesive;
An electrode forming step of forming the driving electrode on a portion of the surface of the piezoelectric layer opposite to the pressure chamber opposite to the pressure chamber after the bonding step;
In the electrode forming step, the portion of the surface opposite to the pressure chamber of the piezoelectric layer facing the pressure chamber is in a form according to the contraction amount of the piezoelectric layer after the bonding step with respect to the bonding step. A method of manufacturing a liquid ejection apparatus, comprising forming a drive electrode.   In the electrode forming step, the driving layer is formed on a portion of the surface of the piezoelectric layer opposite to the pressure chamber that is shifted in a predetermined direction by an amount corresponding to the contraction amount from a predetermined reference portion overlapping the pressure chamber. The method of manufacturing a liquid ejection device according to claim 1, wherein an electrode is formed. The liquid ejection device includes:
A plurality of the nozzles and the pressure chambers are provided,
The piezoelectric layer extends continuously across the plurality of pressure chambers;
A plurality of the driving electrodes are formed on a portion of the surface of the piezoelectric layer opposite to the pressure chamber, which overlaps the plurality of pressure chambers,
In the electrode forming step, on the surface of the piezoelectric layer opposite to the pressure chamber, from the reference portion corresponding to each pressure chamber, to a portion shifted in the predetermined direction by the same amount according to the contraction amount, respectively. The method for manufacturing a liquid ejection apparatus according to claim 2, wherein the driving electrode is formed. The liquid ejection device includes:
A plurality of the piezoelectric layers separated from each other, which overlap with different pressure chambers,
In the electrode forming step, the driving electrode is formed on a portion of the surface of the piezoelectric layer opposite to the pressure chamber on the side opposite to the pressure chamber, which is largely deviated from the reference portion in the predetermined direction, as the shrinkage amount is smaller And
The reference portion includes the piezoelectric layer when the piezoelectric layer is piezoelectrically deformed by applying a predetermined potential to the driving electrode in a region overlapping the pressure chamber on the surface of the piezoelectric layer opposite to the pressure chamber. 4. The method of manufacturing a liquid ejection apparatus according to claim 2, wherein the deformation amount of the layer is the largest.   5. The liquid ejection apparatus according to claim 4, wherein, in the electrode forming step, the driving electrode is formed on the reference portion of the piezoelectric layer having the largest contraction amount among the plurality of piezoelectric layers. Manufacturing method. The liquid ejection device includes:
The pressure chamber has a long shape when viewed from the stacking direction of the first member and the second member,
6. The method of manufacturing a liquid ejection apparatus according to claim 4, wherein the predetermined direction is a direction orthogonal to a longitudinal direction of the pressure chamber when viewed from the stacking direction. The liquid ejection device includes:
Further comprising an inspection space separate from the pressure chamber;
The piezoelectric layer extends across the pressure chamber and the inspection space;
An inspection electrode that overlaps the inspection space is further formed on the surface of the piezoelectric layer opposite to the pressure chamber,
In the electrode forming step, the driving electrode is formed on the surface of the piezoelectric layer opposite to the pressure chamber, and the inspection electrode having a portion longer than the inspection space in the predetermined direction is formed. The method of manufacturing a liquid ejection device according to claim 2, wherein Before the joining step, a marker forming step of forming a pair of markers disposed on the surface of the piezoelectric layer opposite to the pressure chamber with a region where the driving electrode is formed,
After the marker forming step and before the joining step, a pre-joining measurement step for measuring a distance between the pair of markers,
After the joining step, a post-joining measurement step for measuring a distance between the pair of markers,
A contraction amount acquisition step of acquiring the contraction amount from a difference between a distance between the pair of markers measured in the post-joining measurement step and a distance between the pair of markers measured in the pre-joining measurement step; Further comprising
The liquid ejection apparatus according to claim 1, wherein, in the electrode formation step, the driving electrode is formed in a mode corresponding to the contraction amount acquired in the contraction amount acquisition step. Production method. A bonding step of bonding a first member including a piezoelectric layer and a second member including a portion made of a material having a higher linear expansion coefficient than the piezoelectric layer with a thermosetting adhesive;
An electrode forming step of forming a driving electrode on a surface opposite to the second member of the piezoelectric layer after the bonding step;
In the electrode forming step, the driving electrode is formed on the surface of the piezoelectric layer opposite to the second member in a manner corresponding to the amount of contraction of the piezoelectric layer after the bonding step with respect to the bonding step. A method for manufacturing a piezoelectric actuator.

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