JP2010012724A - Liquid droplet discharge head, image forming apparatus, and method for manufacturing liquid droplet discharge head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive liquid droplet discharge head with a simple structure while avoiding a fault caused by the expansion and contraction of FPC, and to assure a high reliability of an electrode connection, and to make the head long by connecting piezoelectric elements. <P>SOLUTION: The liquid droplet discharge head 10 is composed of a head part 100, the piezoelectric element 200 and a three-dimensional wiring substrate 300. In this case, an external individual electrode 230 and external common electrode 240 of the piezoelectric element 200 are arranged on two surfaces intersecting perpendicularly each other, and an individual contact part 341 and common contact part 351 of the three-dimensional wiring substrate 300 are arranged on two surfaces confronting the rectangular surface of the piezoelectric element 200, and the piezoelectric element 200 and the three-dimensional wiring substrate 300 are combined. The external individual electrode 230 and the individual contact part 341 are contacted while the external common electrode 240 and the common contact part 351 being contacted, and then they are joined by solders 370 and 380, respectively. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a droplet discharge head, an image forming apparatus, and a method for manufacturing a droplet discharge head, and in particular, by driving a piezoelectric element arranged corresponding to a pressurized liquid chamber to which a nozzle communicates, The present invention relates to a droplet discharge head that ejects droplets from a nozzle by pressurizing a liquid, an image forming apparatus including the droplet discharge head, and a method of manufacturing the droplet discharge head.

An ink jet apparatus used as an image forming apparatus such as a printer, a facsimile machine, a copying apparatus, or a plotter has a nozzle that ejects ink droplets and a liquid chamber (an ink flow path, a discharge chamber, a pressure chamber, a pressurized liquid chamber, And a droplet discharge head including a drive unit (pressure generation unit) for pressurizing the ink in the liquid chamber. As a driving means for such a droplet discharge head, there is provided a piezoelectric body, in particular, a piezoelectric element in which piezoelectric layers and internal electrodes are alternately laminated, and an elastically deformable diaphragm that forms the wall surface of the liquid chamber by the displacement of the piezoelectric element. A so-called piezoelectric type is known in which ink droplets are ejected by changing the volume / pressure inside the liquid chamber.
The piezoelectric element has a structure provided with a plurality of columnar members that are divided into comb teeth by slitting or the like in order to drive a portion corresponding to the nozzle. In such a piezoelectric element, the internal electrode is drawn out to the external electrode formed on the outer surface of the piezoelectric element, individual electrodes are provided corresponding to the columnar portions, and further, common electrodes are provided at both ends of the individual electrode array. Is provided.

For example, Patent Document 1 discloses an FPC (flexible FPC) in which a drive IC is mounted by depositing an individual electrode and a common electrode at both ends thereof by performing vapor deposition on the outer surface of the piezoelectric element through a mask member and slitting the piezoelectric element. A circuit board or TAB terminal electrode) is connected via a bonding member such as solder or an anisotropic conductive film. That is, in Patent Document 1, the piezoelectric element forming member is electrically independent of the adjacent piezoelectric elements divided by a plurality of slits on the side opposite to the fixed substrate of the fixed portion, which is a portion joined to the fixed substrate. The piezoelectric element unit can be reduced in size by arranging the individual external electrodes to be the individual electrodes to be arranged in parallel and the common external electrodes to be electrically common to the adjacent piezoelectric elements on both sides of the parallel arrangement direction. It can be made.
Further, in Patent Document 2, an inkjet recording head is provided at a portion facing an end surface electrode formed on an end surface of a ceramic substrate on which a drive circuit is mounted and an end surface of a ceramic substrate of a multilayer piezoelectric element on which the ceramic substrate is placed. A configuration in which the formed common signal external electrodes and individual signal external electrodes are connected by solder fillets is described.
Further, in Patent Document 3, a piezoelectric element is bonded to a base, a PCB substrate is bonded to the base in a direction orthogonal to the bonding surface with the piezoelectric element, and an individual external electrode of the piezoelectric element is further bonded. And a PCB substrate are directly connected by wire bonding with a wire.
Patent Document 4 discloses a nozzle hole for ejecting ink droplets, a pressure liquid chamber communicating with each of the nozzle holes, a vibration plate constituting at least one wall of the pressure liquid chamber, and driving the vibration plate. In a droplet discharge head having a thin plate laminated structure of piezoelectric elements, the piezoelectric element is connected onto the conductive member, the common electrode is drawn, and the conductive member is a circuit. A circuit board is mounted and the circuit board electrode and the piezoelectric element signal electrode are connected.
Japanese Patent Laid-Open No. 2003-17770 JP 2001-88302 A JP 2003-118106 A JP 2007-55021 A

By the way, in recent years, an ink jet recording apparatus is required to have high image quality and high speed, and the nozzles of the ink jet head, which is a droplet discharge head, are arranged with high density, or the number of nozzles is increased by increasing the length of the ink jet head. The device is made to increase. For example, an inkjet head that has conventionally been about 20 mm long has a length of about 30 to 40 mm when considering about 400 nozzles at 300 dpi.
As the mounting structure of the piezoelectric element, the structure in which the electrode of the piezoelectric element and the electrode of the FPC are connected is the most general. However, due to the moisture absorption of the FPC and the expansion and contraction during the thermocompression bonding, the piezoelectric element electrode and the FPC electrode are connected. There is a problem that a pitch shift occurs, the connection reliability is significantly reduced, and further, a column collapse of the piezoelectric element occurs. This problem becomes conspicuous as the nozzle density increases and the head length increases.
In addition, as a method of increasing the length of the inkjet head and increasing the number of nozzles, connecting the piezoelectric elements in the longitudinal direction is performed, but in the terminal structure in which the common electrodes are arranged at both ends of the individual electrodes of the piezoelectric elements, No nozzles can be provided in the common electrode portion, and it is necessary to arrange separate heads or piezoelectric elements in a staggered manner, resulting in a complicated structure.
As a mounting structure that does not use an FPC, the one described in Patent Document 2 uses a ceramic substrate as a base plate, patterning electrodes on the base plate and the side surfaces, and dividing the piezoelectric element by a slit process. The electrodes are connected with solder fillets. However, since the electrodes of the piezoelectric element are formed by patterning, the cost is higher than that described in Patent Document 1. Moreover, since the thing of patent document 2 has connected the side electrode of the base substrate and the terminal electrode provided in the non-slit part of the piezoelectric element with the solder fillet, the fine pitch of the electrode corresponding to the high density of a nozzle is made. Is difficult. Moreover, since the common electrode is arrange | positioned at the both ends of the individual electrode of a piezoelectric element, lengthening by connection of a piezoelectric element is difficult. Furthermore, since the vibration of the piezoelectric element causes the base substrate to resonate, there is also a problem that the jetting characteristics are likely to deteriorate.

Further, the device described in Patent Document 3 bonds a piezoelectric element to a base and wire-bonds a PCB electrode bonded to the base to a surface perpendicular to the bonding surface with the piezoelectric element and an external electrode of the piezoelectric element. By connecting the base and PCB separately, the jetting characteristics are good, but in wire bonding, it takes time to connect as the number of electrodes to be connected increases, so a long high-density head with a large number of nozzles Application to is unsuitable.
In consideration of these, Patent Document 4 uses a three-dimensional wiring board in which conductor wiring is formed on the surface of a molded body, and connects the piezoelectric elements by adopting a structure in which individual electrodes and common electrodes are drawn out on different surfaces of the three-dimensional wiring board. It is possible to do. However, since the individual electrodes of the piezoelectric element and the electrodes of the three-dimensional wiring board are connected by the conductive paste wiring, the wiring resistance is high, and it is necessary to form a surface connecting member at the connecting portion of the piezoelectric element and the three-dimensional wiring board There was a high cost.
The present invention has been made in view of the above problems, avoids problems due to expansion and contraction of the FPC, has a high reliability of the electrode connection portion, enables the head to be elongated by connecting the piezoelectric elements, and An object of the present invention is to provide an inexpensive droplet discharge head having a simple structure.

In order to solve the above-mentioned problem, the present invention of claim 1 is provided with columnar members each formed corresponding to a plurality of pressurized liquid chambers communicating with corresponding nozzles and made of a plurality of piezoelectric material layers, and each of the columnar members. The first and second internal electrodes are disposed in the piezoelectric material layer disposed on the first and second inner electrodes in order to apply individual drive signals to the columnar members, and are individually connected to the first inner electrodes. A piezoelectric element having an external common electrode connected to all of the electrode and the second internal electrode on the surface thereof, and arranged in combination with the piezoelectric element, and connected to the external individual electrode of the piezoelectric element on the outer surface thereof And a three-dimensional wiring board having a common contact portion connected to the external common electrode on the surface thereof, wherein the piezoelectric element includes a first electrode forming surface portion and a second electrode surface that are substantially orthogonal to each other. The electrode forming surface portion, The external individual electrode portion is disposed on the first electrode formation surface portion, the external common electrode portion is disposed on the second electrode formation surface portion, and the three-dimensional wiring board is substantially orthogonal and the first and second of the piezoelectric element A first contact installation surface portion facing the electrode forming surface portion; and a second contact installation surface portion, wherein the individual contact portion is installed on the first contact installation surface portion, and the common contact portion is connected to the second contact ground. It is a droplet discharge head characterized by being disposed on a surface portion.
The present invention of claim 2 is characterized in that a plurality of piezoelectric elements are arranged side by side.
The present invention according to claim 3 is characterized in that the three-dimensional wiring board is mounted with a circuit element for controlling the driving of the piezoelectric element.
According to a fourth aspect of the present invention, corner portions formed by the first and second electrode forming surface portions of the piezoelectric element are chamfered, and the individual electrodes connected to the common electrode and a plurality of piezoelectric materials are individually connected. The electrodes are separated from each other.

The present invention of claim 5 is characterized in that the wiring board is formed of a material having a linear expansion coefficient of 10E-6 / ° C. or less.
The present invention of claim 6 is characterized in that the wiring board is insert-molded with an insertion member having a linear expansion coefficient of 10E-6 / ° C. or less.
According to a seventh aspect of the present invention, an external common electrode is formed on the electrode arrangement surface portion of the piezoelectric element, and the external common electrode is connected to a common contact portion of the three-dimensional wiring board via a conductive member. The conductive member is made of a material having a linear expansion coefficient of 10E-6 / ° C. or less.
The present invention of claim 8 is characterized in that at least one of the external individual electrode and the external common electrode of the piezoelectric element, and at least one contact part of the individual contact part and the common contact part disposed on the wiring board, Are connected by solder, and the solder has a fillet portion.
The present invention of claim 9 is arranged on the three-dimensional wiring board, and the individual electrodes and the common electrode are partly buried in a molded body constituting the three-dimensional wiring board. And
According to a tenth aspect of the present invention, there is provided an image forming apparatus comprising the droplet discharge head.
The present invention of claim 11 is an image forming apparatus characterized in that the wiring of the three-dimensional wiring board is formed by transfer.

According to the droplet discharge head according to the present invention, since the piezoelectric element can be connected to the drive IC as the drive means without using the FPC, problems due to the expansion and contraction of the FPC can be avoided, and the reliability of the electrode connection portion can be increased. .
In addition, since the common electrode is not formed on both ends of the individual electrode, the electrode structure of the piezoelectric element can be simplified, and the end of the piezoelectric element can be used as the vibrating portion.
Furthermore, according to the manufacturing method of the droplet discharge head according to the present invention, since the wiring of the three-dimensional wiring board is formed by transfer, an epoxy resin having a low linear expansion coefficient can be used as a molded body of the three-dimensional wiring board. In addition to the wide choice of molding materials, all wirings can be transferred simultaneously, so that the number of wirings is large, and even if the wiring pitch is small, the cost is not high, which is suitable as a method for manufacturing a three-dimensional wiring board for a droplet discharge head.

The best mode for carrying out the present invention will be described below with reference to the drawings.
1A and 1B show a droplet discharge head according to an embodiment, wherein FIG. 1A is a cross-sectional view in a short direction of a piezoelectric element portion, FIG. 1B is a cross-sectional view in a longitudinal direction of a piezoelectric element portion, and FIG. FIG. 3 is a perspective view showing a piezoelectric element of a droplet discharge head.
The droplet discharge head 10 according to this example includes a head unit 100, a piezoelectric element 200, and a three-dimensional wiring board 300. The head unit 100 includes a flow path substrate (liquid chamber substrate) 110 formed of a single crystal silicon substrate, a vibration plate 120 bonded to the lower surface of the flow path substrate 110, and an ink droplet bonded to the upper surface of the flow path substrate 110. And a nozzle plate 130 on which nozzles 131 for discharging are formed. The head unit 100 includes a pressurized liquid chamber 141 that is a flow path (ink liquid chamber) that communicates with the nozzle plate 130 via an ink communication path by the flow path substrate 110, the vibration plate 120, and the nozzle plate 130. A common liquid chamber 143 that supplies ink to the liquid chamber 141 via an ink supply path 142 serving as a fluid resistance portion is formed.
The flow path substrate 110 is a through-hole that becomes each pressurized liquid chamber by anisotropically etching a single crystal silicon substrate having a crystal plane orientation (110) using an alkaline etching solution such as an aqueous potassium hydroxide solution (KOH). A groove portion serving as an ink supply path and a through hole serving as a common liquid chamber are formed.

The diaphragm 120 is formed from a nickel metal plate, for example. The diaphragm 120 can be formed of a resin member or a laminated member of a resin member and a metal member. The diaphragm 120 is bonded to the flow path substrate 110 with an adhesive. The diaphragm 120 is adhesively bonded to a frame 150 having an ink supply path (not shown) connected to an external ink tank (not shown).
The nozzle plate 130 is formed with nozzles 131 having a diameter of 10 to 30 μm corresponding to the pressurized liquid chambers 141, and is bonded to the flow path substrate 110 with an adhesive. The nozzle plate 130 may be made of a metal such as stainless steel or nickel, a combination of a metal and a resin such as a polyimide resin film, silicon, or a combination thereof. Further, a water repellent film is formed on the nozzle surface (surface in the ejection direction: ejection surface) by a known method such as plating or water repellent coating in order to ensure water repellency with ink.

As shown in FIG. 2, the piezoelectric element 200 is configured as a substantially cubic member having an upper surface 261, a lower surface 262, and hanging surfaces 263 and 264, and the lower surface 262 and the hanging surface 264 are substantially perpendicular to each other. The portion formed is chamfered at a portion corresponding to the side where the lower surface 262 and the hanging surface 264 are in contact with each other. In this example, two piezoelectric elements 200 are arranged below the diaphragm 120, and these two piezoelectric elements 200 are mounted on one three-dimensional wiring board 300.
The piezoelectric element 200 individually drives a portion corresponding to each pressurized liquid chamber 141 of the vibration plate 120. Therefore, the piezoelectric element 200 is formed with a plurality of columnar members 260 that are divided and formed in a comb-like shape with the gap 270 interposed therebetween, as shown in FIGS. 1B and 3, by slit processing. ing. The diaphragm 120 is joined to the piezoelectric element 200 on the upper surface 261 of the columnar member 260. In FIG. 3, the individual electrode 221 and the common electrode 222 are not shown.
Each columnar member 260 of the piezoelectric element 200 is formed by alternately laminating piezoelectric material layers 210 and internal electrodes 220. The internal electrode 220 includes an individual electrode 221 that is a first internal electrode for applying a separate drive signal to the columnar member 260 and a common electrode 222 that is a second internal electrode.

In the slit processing of the piezoelectric element 200, the piezoelectric element 200 in which the internal electrode 220 is disposed can be processed by dicing or a wire saw, and the dicing processing using a diamond wheel enables higher density processing. The slit processing of the piezoelectric element 200 may be performed either before or after mounting the piezoelectric element 200 on the three-dimensional wiring board 300. In the figure, for the sake of simplicity, an example in which eight columnar members 260 are provided is shown, but actually, several hundred members are provided.
Each columnar member 260 of the piezoelectric element 200 is configured by alternately stacking piezoelectric material layers 210 and internal electrodes 220. As described above, the internal electrode 220 includes the individual electrode 221 that is a first internal electrode for applying a separate drive signal to the columnar member 260 and the common electrode 222 that is a second internal electrode.
The individual electrodes 221 are individually connected to the drive IC 400 via the external individual electrodes 230 disposed on the respective hanging surfaces 264 of the columnar member 260. The external individual electrode 230 is composed of a conductive thin film disposed on the surface of the hanging surface 264.

The common electrode 222 is connected to the drive IC 400 through the external common electrode 240 disposed from the bottom surface 263 to the bottom surface 262 of the columnar member 260. The external common electrode 240 includes a drooping portion 240 a disposed on the drooping surface 263 of the columnar member 260 and a horizontal portion 240 b disposed on the bottom surface 262. The drooping portion 240a of the external common electrode 240 is formed for each columnar member 260 in the same manner as the common electrode 222, and there is a gap between the plurality of drooping portions 240a so as to be in an insulating state. The horizontal portion 260b of the external common electrode 240 is in a state where a plurality of hanging portions 240a are connected, and the common electrode 222 is integrated from the hanging portion 240a of the external common electrode 240 by the horizontal portion 240b and connected to the driving IC 400. . The horizontal portion 240b is formed up to both ends in the longitudinal direction of the lower surface 262 of the piezoelectric element 200, and is connected to a common contact portion 351 of the three-dimensional wiring board 300 described later.
In this example, the case where the ink in the pressurized liquid chamber 141 is pressurized using the displacement in the d33 direction as the piezoelectric direction of the piezoelectric element 200 is taken as an example, but the pressurized liquid chamber is used using the displacement in the d31 direction as the piezoelectric direction. The ink in the ink 141 may be configured to be pressurized. In this example, the external individual electrode 230 and the external common electrode 240 of the piezoelectric element 200 are formed by sputtering or vapor-depositing a metal material on three surfaces in the longitudinal direction of the piezoelectric element 200, and corners (corners) between the lower surface 262 and the drooping surface 264. A C chamfered portion 250 is formed on the surface. Thereby, the individual electrode 221 and the common electrode 222 are separated, and the plurality of individual electrodes 221 are separated from each other. As the metal material, chromium, nickel, copper, gold, alloys thereof, and the like can be used, and these can be stacked and used. As a method of forming the electrodes separately, a method of masking at the time of electrode formation and a method of partial etching after the electrode formation can be used, but the cost is higher than that of this embodiment in which the entire surface is formed and chamfered. .
Further, in this example, in order to increase the density of the nozzles, two piezoelectric elements 200 are arranged symmetrically in the short direction as shown in FIG. can do.

Next, the three-dimensional wiring board 300 will be described. FIG. 4 is an enlarged perspective view showing a part of the three-dimensional wiring board. First, as shown in FIGS. 1 and 4, the three-dimensional wiring board 300 is formed of a substantially rectangular parallelepiped base 310 and the same number of standing portions 320 as the columnar members 260 disposed on the top surface of the base 310. As shown in FIG. 4, the standing portion 320 is slit-processed in a comb-like shape at the same pitch as the columnar member 260 of the piezoelectric element 200, and is disposed with a plurality of slit portions 330 interposed therebetween. In addition, a drive IC 400 that is a circuit element for driving the piezoelectric element 200 is disposed on the side surface portion 311 of the base 310 (see FIG. 1).
The side surface portion 321 of the standing portion 320 includes a predetermined number of individual contact portions 341 that come into contact with the external individual electrodes 230 of the piezoelectric element 200. These individual contact portions 341 are connected to the drive IC 400 via a predetermined number of individual electrode wires 340. The individual electrode wiring 340 reaches the driving IC 400 through the side surface portion 321 of the standing portion 320, the upper surface portion 312 of the base 310, and the side surface portion 311.
Common contact portions 351 are formed on the upper surface portion 312 of the base 310 and at both ends in the longitudinal direction where the individual electrode wiring 340 is not disposed. The common contact portion 351 is connected to the drive IC 400 via the common electrode wiring 350. The common electrode wiring 350 reaches the driving IC 400 through a portion where the individual electrode wiring 340 on the upper surface portion 312 and the side surface portion 311 is not disposed.

Further, in the portion of the upper surface portion 312 of the substrate 310 where the individual electrode wiring 340 is formed, as shown in FIG. 4, an insulating material made of a synthetic resin film is provided so as to cover the individual electrode wiring 340. A solder resist 360 is arranged.
In this example, an epoxy resin for thermosetting semiconductor is used as a molding material for the three-dimensional wiring board 300. Specifically, EME-760 manufactured by Sumitomo Bakelite Co., Ltd. was used. This material contains a silica filler and has a linear expansion coefficient of 9E-6 / ° C. Thereby, moisture absorption and expansion / contraction at the time of connection between electrodes are small, and peeling of the electrode connection portion between the piezoelectric element and the three-dimensional wiring board and column collapse of the piezoelectric element can be prevented. Note that the linear expansion coefficient may be 10E-6 / ° C. or less, and any material that has low moisture absorption and expansion / contraction upon connection between electrodes may be used.

Further, the individual electrode wiring 340 and the common electrode wiring 350 of the three-dimensional wiring board 300 are formed using copper wiring. Thereby, compared with wire bonding and conductive paste wiring, wiring resistance can be made low. The individual contact portion 341 and the common contact portion 351 are formed by coating nickel and gold on the copper wiring. Thereby, the connection reliability between electrodes can be improved. In addition to the electrode part, nickel or gold may be formed, or a solder resist may be formed. In this example, the individual electrode wiring 340 is disposed so as to be partially embedded in the base 310 (see FIG. 9B). As a result, the adhesion between the individual electrode wiring 340 and the substrate 310 can be increased, and the individual electrode wiring 340 can be prevented from peeling off from the substrate 310.
Further, in this example, a driving IC 400 that controls driving of the piezoelectric element 200 is mounted on the side surface portion 311 of the three-dimensional wiring board 300. As a result, the number of connection electrodes between the three-dimensional wiring board 300 and an external board (not shown) can be reduced, and the connection between the three-dimensional wiring board 300 and the external board is FFC (flexible flat cable: not shown). Will be able to do it. The individual electrode wiring 340 and the common electrode wiring 350 of the three-dimensional wiring board 300 can be connected to the driving IC 400 by a bump 410 made of gold, solder, or the like, an anisotropic conductive film, or the like. Moreover, it can replace with the bump 410 and the connection by wire bonding can be performed.
In this example, the external individual electrode 230 of the piezoelectric element 200 and the individual contact part 341 of the three-dimensional wiring board 300 are connected by solder 370, and the external common electrode 240 and the common contact part 351 are similarly connected by solder 380. Connected with. As these connection members, a conductive adhesive and an anisotropic conductive film can be used in addition to solder. Solder is suitable as a connection member because of its low connection resistance and high reliability. The connecting member is printed on the electrode of the piezoelectric element or the electrode of the three-dimensional wiring board by screen printing, nozzle printing, transfer method, etc., and the piezoelectric element is mounted on the three-dimensional wiring board while aligning the electrode, and the connection part is heated. Thereby, the electrode of a piezoelectric element and the electrode of a three-dimensional wiring board can be connected.

As described above, in the droplet discharge head 10 according to the present invention, the external individual electrode 230 and the external common electrode 240 connected to the internal electrode 220 of the piezoelectric element 200 are connected to the perpendicular lower surface 264 and the lower surface 262 that are orthogonal to each other. The individual electrode wiring 340 and the common electrode wiring 350 of the three-dimensional wiring board 300 are formed on the side surface portion 321 of the upright portion 320 and the upper surface portion 312 of the base 310 that are orthogonal to each other. Since the individual electrode wiring 340, the external common electrode 240 and the common electrode wiring 350 are directly connected, the piezoelectric element 200 and the three-dimensional wiring board 300 can be connected without using the FPC. Various problems caused by expansion and contraction can be avoided, and the reliability of the electrode connecting portion can be increased.
Further, since the driving IC 400 for controlling the driving of the piezoelectric element 200 is mounted on the three-dimensional wiring board 300, the three-dimensional wiring board 300 and the external board can be connected by FFC, and the FPC can be connected to the external board. Therefore, it is possible to avoid problems caused by expansion and contraction of the FPC.
In addition, the external individual electrode 230 and the external common electrode 240 of the piezoelectric element 200 are formed by forming a conductive film on the three surfaces of the lower surface 262 and the hanging surfaces 263 and 264, and chamfering the corners formed by the hanging surface 264 and the lower surface 262. Thus, the external individual electrode 230 and the external common electrode 240 are separated from each other, and further, the piezoelectric element 200 is slit to separate the external individual electrode 230 in each columnar member 260. Compared with the method of forming an electrode by masking or etching, the manufacturing cost relating to electrode production can be reduced.

Further, since the linear expansion coefficient of the three-dimensional wiring board 300 is 10E−6 / ° C. or less, the difference in the linear expansion coefficient between the piezoelectric element 200 and the three-dimensional wiring board 300 can be reduced. Peeling of the electrode connection part and column collapse of the piezoelectric element can be prevented.
Further, a part of the wiring of the three-dimensional wiring board in the thickness direction can be buried in the molded body. By doing in this way, the adhesive force of a molded object and wiring can be made high and it can prevent that a wiring peels from a molded object.
In the above example, the external individual electrode 230 is formed on the hanging surface 264 and the external common electrode 240 is formed on the hanging surface 263 and the bottom surface 262. However, the external individual electrode 230 is formed on the hanging surface 263 and the bottom surface 262, and the external common electrode 240 is formed. The individual contact portion 341 and the common contact portion 351 provided on the three-dimensional wiring board 300 may be provided on the surface corresponding to each common electrode, as provided on the hanging surface 264.

Next, a second embodiment of the droplet discharge head according to the present invention will be described. FIG. 5 is a longitudinal sectional view of the piezoelectric element portion of the droplet discharge head according to the second embodiment. The droplet discharge head 510 according to this example connects three piezoelectric elements 520, 530, and 540 having the same length as the piezoelectric element 200 of the droplet discharge head 10 according to the first example in the longitudinal direction. Are arranged. In this example, the flow path substrate, the vibration plate, the head portion 550 including the nozzle plate, and the three-dimensional wiring substrate 560 are integrally formed with a length three times that according to the first example. The number of connected piezoelectric elements is not limited to three, but may be two, or four or more.
According to the droplet discharge head 510 according to this example, the external individual electrode and the external common electrode are formed on the orthogonal surfaces of the piezoelectric elements 520, 530, and 540 that are not covered by the multilayer head portion. When the elements 520, 530, and 540 are connected in the longitudinal direction, the external individual electrode 230 and the external common electrode 240 can be connected to the individual contact part and the common contact part in an exposed state, and the ends of all the piezoelectric elements can be connected. Up to the portion can be used for driving the diaphragm. For this reason, the nozzle intervals can be arranged at equal pitches up to the respective joint portions of the adjacent piezoelectric elements, and it is not necessary to arrange the piezoelectric elements in a staggered manner, and the droplet discharge head can be miniaturized.
In this case, the slit processing of the piezoelectric element is desirably performed after the piezoelectric element is mounted on the three-dimensional wiring board. As a result, even if the piezoelectric element is displaced, the columnar member is not displaced, and a droplet discharge head having a correct pitch can be manufactured.
As described above, according to the liquid droplet ejection head according to the present embodiment example, the piezoelectric elements are disposed adjacent to each other in the longitudinal direction and the other members are formed as an integrated type. The length of the droplet discharge head can be increased. Thereby, even with a long head, it is possible to avoid a problem due to expansion and contraction of the FPC of the piezoelectric element electrode portion, and to provide a droplet discharge head with high reliability of the electrode connection portion.

Next, a droplet discharge head according to a third embodiment will be described. FIG. 6 is a cross-sectional view in the short-side direction of the piezoelectric element portion of the droplet discharge head according to the third embodiment. In the droplet discharge head 600 of this example, an insert member 620 having a linear expansion coefficient of 10E-6 / ° C. or less is insert-molded on a three-dimensional wiring board 610. Since other configurations are the same as those of the droplet discharge head 10 according to the first embodiment, the same members are denoted by the same reference numerals, and detailed description thereof is omitted. As the insert member 620, a 42Ni—Fe material having a linear expansion coefficient of about 7E-6 / ° C. has a shape obtained by substantially reducing the shape of the three-dimensional wiring board 610. As a material of the insert member 620, a member having a linear expansion coefficient of 10E-6 / ° C. or less such as PZT, alumina, silica glass, or the like can be used.
According to this embodiment, even if a member having a linear expansion coefficient of 10E-6 / ° C. or higher is used as the molding resin that is the material of the three-dimensional wiring board 610, the difference in thermal expansion between the piezoelectric element and the three-dimensional wiring board is reduced. In addition, it is possible to prevent peeling of the electrode connection portions between the piezoelectric element and the three-dimensional wiring board and column collapse of the piezoelectric element. As a material of the three-dimensional wiring board 610, for example, a liquid crystal polymer (Vectra C820 manufactured by Sumitomo Bakelite Co., Ltd.) having a linear expansion coefficient of about 32E-6 / ° C. could be used. In the case where the member having a linear expansion coefficient of 10E-6 / ° C. or less was not insert-molded, the piezoelectric element collapsed when the piezoelectric element and the three-dimensional wiring board were connected.
In this example, since a member having a linear expansion coefficient of 10E-6 / ° C. or less is insert-molded in the three-dimensional wiring board, a resin having a linear expansion coefficient of 10E-6 / ° C. or more is used as a molding resin for the three-dimensional wiring board. Even in such a case, it is possible to provide a droplet discharge head in which the electrode connection portion has high reliability.

Next, a droplet discharge head according to a fourth embodiment will be described. FIG. 7 is a cross-sectional view in the short-side direction of the piezoelectric element portion of the droplet discharge head according to the fourth embodiment. A droplet discharge head 700 according to this example includes a piezoelectric element 800 and a three-dimensional wiring board 900. The piezoelectric element 800 has substantially the same comb-tooth structure as the piezoelectric element 200 according to the first embodiment, and the upper surface 811, the lower surface 812, and the drooping surfaces 813 and 814 are formed on the piezoelectric element 800. In this example, an external common electrode 820 is formed on the lower surface 812 of these surfaces, and an external individual electrode 830 is formed on the hanging surface 814.
The three-dimensional wiring board 900 includes a base portion 910 and standing portions 920 disposed on both sides of the base portion 910 and has a substantially concave shape. The driving IC 400 is provided on the outer surface 930 of the three-dimensional wiring substrate 900. In addition to the arrangement, the individual electrode wiring 940 is arranged from the outer surface 930 to the inside of the standing portion 920. A common electrode wiring 950 is disposed on the upper side 911 of the base 910. A solder resist layer 960 is disposed outside the individual electrode wiring 940.
In this example, the external common electrode 820 is connected to the common electrode wiring 950 by solders 981 and 982 via a conductive member 970 provided on the upper side surface 911 of the base 910 of the three-dimensional wiring board 900. Here, the common electrode wiring 950 is a member having a linear expansion coefficient of 10E−6 / ° C. or less.
The external individual electrode 830 is connected to the individual electrode wiring 940 via the solder 983 inside the standing portion 920. In this embodiment, two piezoelectric elements are arranged in the short direction, and the external individual electrode 830 is formed on the frame 150 side.
Here, the conductive member 970 is preferably a metal. By using the conductive member 970 as a metal, connection resistance can be reduced, and heat storage due to self-heating of the piezoelectric element 800 can be prevented. As the number of channels of the piezoelectric element increases, the temperature rises to near 100 ° C. due to self-heating, and the bonding reliability decreases. Further, due to self-heating, the temperature inside the head increases, and the ink temperature rises. However, when the ink temperature rises, the ink viscosity decreases, and the ejection characteristics are greatly affected. Therefore, by using a conductive member as a metal, it is possible to prevent not only a decrease in connection resistance but also a decrease in bonding reliability and a deterioration in jetting characteristics.

As described above, in this example, a member having a linear expansion coefficient of 10E-6 / ° C. or less is used as the conductive member. When the linear expansion coefficient of the conductive member is large, when an adhesive is used to connect the piezoelectric element and the conductive member, the piezoelectric element and the conductive member may be peeled off at high or low temperatures. That is, in the past, since the total length of the piezoelectric element was not long, there was almost no problem that the piezoelectric element and the conductive member were peeled off due to a temperature difference due to environmental fluctuations, but the length of about 30 to 40 mm having about 400 nozzles at 300 dpi. This problem became apparent by using the piezoelectric element. Therefore, it is preferable to use a material having a linear expansion coefficient of 10E-6 / ° C. or less as the conductive member. By setting the linear expansion coefficient within the range, the connection interface with the piezoelectric element is peeled off due to a temperature difference due to environmental fluctuations. Can be prevented. In particular, it has been confirmed that if all the linear expansion coefficients of the parts connected to the piezoelectric element are 10E-6 / ° C. or less, it is very effective against peeling of the connection interface.
As a specific material of the conductive member, an alloy such as 42Ni—Fe can be used, and gold can be formed on the surface of the conductive member.
As the connection member between the conductive member and the electrode of the piezoelectric element or the electrode of the three-dimensional wiring board, solder, a conductive adhesive, or an anisotropic conductive film can be used, and solder is desirable because of its low connection resistance and high reliability. .

Further, the conductive member can be insert-molded in the molded body with the surface exposed, and can be connected to the wiring on the surface.
Further, in this example, two piezoelectric elements are arranged in the short direction, and by forming the individual electrodes on the frame side, the common electrode is drawn out on the surface opposite to the diaphragm of the piezoelectric element. The connection area can be increased, and the connection reliability can be improved. Moreover, since the heat dissipation characteristics of the piezoelectric element are also improved, it is possible to prevent a decrease in bonding reliability and a deterioration in jetting characteristics.
According to this example, the common electrode is drawn out to the surface opposite to the diaphragm of the piezoelectric element and connected to the three-dimensional wiring board via the conductive member having a linear expansion coefficient of 10E-6 / ° C. or less. The difference in thermal expansion is small, and the reliability of the connection portion of the common electrode can be increased.

Next, a fifth embodiment will be described. FIG. 8 is a cross-sectional view showing the piezoelectric element of the droplet discharge head and the electrode connection portion of the three-dimensional wiring board according to the fifth embodiment. In this example, the piezoelectric element 1200 has an upper surface 1211, a lower surface 1212, and hanging surfaces 1213 and 1214. An external common electrode 1220 is disposed from the hanging surface 1214 to the lower surface 1212, and an external individual electrode 1220 is disposed on the hanging surface 1213. Has been. The three-dimensional wiring board 1300 includes a base portion 1310 and a standing portion 1320, and a common electrode 1330 is disposed on the upper surface of the base portion 1310, and an individual electrode 1340 is disposed on the standing portion 1320. Here, the individual electrode 1340 is disposed in a bowl shape (¬ shape) having a horizontal portion 1341 and a hanging portion 1342 and is installed on the shoulder portion of the base portion 1310.
In this example, the external common electrode 1220 is connected to the common electrode 1330 and the external individual electrode 1230 is connected to the individual electrode 1340 with solder 1350 and 1360, respectively, but the solder 1360 between the external individual electrode 1230 and the individual electrode 1340 is A fillet portion 1370 is formed. Here, the fillet portion is formed on the solder 1360 for connection to the individual electrode 1340, but the fillet portion can be similarly formed on the common electrode 1330 side by making the electrode shape into a bowl shape.
As described above, according to this example, since the electrodes of the piezoelectric element 1200 and the electrodes of the three-dimensional wiring board 1300 are connected while forming the fillet portion with solder, the reliability of the connecting portion between the piezoelectric element and the three-dimensional wiring board is high. Can be.

Next, a sixth embodiment will be described. This example relates to a method of manufacturing a droplet discharge head. In this example, the three-dimensional wiring board of the droplet discharge head forms the wiring by transfer so that a part of the wiring thickness is buried in the molded body. As a manufacturing method capable of forming the finest wiring in the conventional manufacturing method of a three-dimensional wiring board, there is a method according to the following procedure. The outline of this construction method is shown below.
1. Copper is vapor-deposited or sputtered on the surface of a resin or ceramic such as polyphthalamide or liquid crystal polymer whose surface has been activated.
2. The copper is etched by scanning with a laser along the outline of the wiring.
3. Electrolytic copper plating is performed on the wiring portion to thicken the wiring.
4). Copper is soft etched (thin film portions other than wiring are removed).
5). Perform electrolytic nickel and gold plating on the wiring.
In this method, it is possible to form wiring up to a pitch of 60 μm (about 400 dpi).
However, it is necessary to perform an activation process for increasing the adhesion between the wiring and the molded body, and the process cannot be applied to the low-expansion epoxy resin for thermosetting semiconductor employed in Example 1. For example, the linear expansion coefficient is 10 to 25E-6 / ° C for polyphthalamide and 15 to 150E-6 / ° C for a liquid crystal polymer. Further, since the outline of the wiring is scanned with a laser, if the number of wirings is large and the wiring pitch is small, the number of steps is increased and the cost is increased.
For this reason, the manufacturing method of the three-dimensional wiring board of the droplet discharge head is not optimal. Therefore, in this example, wiring is formed in a mold for molding a molded body of a three-dimensional wiring board, and the wiring is transferred to the molded body when the molded body is released from the mold. At this time, the three-dimensional wiring board is formed so that a part of the wiring thickness is buried in the molded body.

Hereinafter, an embodiment of a method for manufacturing a droplet discharge head will be described. FIG. 8 illustrates a method for manufacturing a three-dimensional wiring board of a droplet discharge head according to an eighth embodiment. FIG. 8A is a cross-sectional view of a mold-resin contact portion (wiring portion) during molding. (B) is a wiring cross-sectional view after mold release. First, an insulating film is formed on a contact surface with a resin of a mold for forming a molded body of a three-dimensional wiring board. As the mold, various steel materials such as stainless steel (SUS304 or the like) can be used, and nickel or the like may be formed on the surface. A stainless film or the like can also be used to improve the releasability.
As the insulating film, various insulating films such as a polyimide film and an insulating diamond-like carbon film can be used as long as they can withstand the following steps. The film thickness is preferably about 0.5 to 10 μm depending on the insulating properties of the film and film thickness variations, but may be thick as long as it can withstand the following steps. Here, 2 μm of polyimide film was formed. As a forming method, various methods such as printing, dipping, vapor deposition, and adhesion can be used.
Next, the wiring equivalent part of the insulating film is etched. In this treatment, a resist was formed on the insulating film, patterned by photolithography, and the wiring equivalent part of the insulating film was etched by RIE to form an opening pattern in the insulating film. The narrowest part of the opening pattern was set to a 60 μm pitch.
Next, wiring is formed in the opening. In this treatment, electrolytic copper plating was performed on the opening to form a copper wiring with a thickness of 10 μm. Since this electrolytic copper plating is thicker than the film thickness of the insulating film, the wiring cross-sectional shape becomes a mushroom shape.
Next, a surface modification process is performed on the wiring. In this treatment, the surface modification treatment was performed by immersing the wiring portion in a chemical: copper bond (manufactured by Sugawara Eugleite). By this surface treatment, the adhesion between the wiring and the resin could be secured. By this surface modification, the conductor wiring film thickness was slightly reduced to about 8 μm.

Next, resin molding is performed using a mold in which wiring is formed. In this process, a mold having wiring formed thereon and other molds are set in a molding machine, and as shown in FIG. 9A, a thermosetting semiconductor sealing epoxy resin (EME-760 manufactured by Sumitomo Bakelite Co., Ltd.). ) And transfer molding. After the mold release, the wiring formed on the mold was transferred to the surface of the molded body as shown in FIG. The wiring thickness embedded in the molding resin was about 8 μm, and the wiring thickness of about 2 μm was exposed. When the surface treatment was not performed on the wiring, a part of the wiring was lifted from the molded body, and the adhesion between the wiring and the resin was weak.
Next, nickel and gold plating are performed on the wiring. This is preferably performed in order to improve the connection reliability with the electrodes of the piezoelectric element, and in the case where plating is not performed, it is preferable to perform a copper anti-oxidation treatment. Specifically, electro nickel plating and electroless gold plating were performed, and the wiring film thickness was about 10 μm.
Next, a solder resist is formed as necessary. Specifically, it can be formed by printing by screen printing, nozzle printing, transfer method, etc., and thermosetting.
In the manufacturing method of the droplet discharge head according to this example, since the wiring is formed by transfer, an epoxy resin having a low linear expansion coefficient can be used as a molded body of the three-dimensional wiring board. Moreover, since all the wirings can be transferred simultaneously, the number of wirings is large, and even if the wiring pitch is small, the cost is not high.

Moreover, since it forms so that a part of wiring thickness may be embedded in a molded object, the adhesive force of a molded object and wiring can be made high, and it can prevent that a wiring peels from a molded object. Further, even if the wiring is thickened, the adhesion force between the molded body and the wiring is not lowered, but on the contrary, the wiring can be thickened, and the wiring resistance can be reduced even if the wiring becomes finer.
As described above, according to the droplet discharge head according to the present invention, the individual electrodes of the external electrode and the common electrode are formed on the surfaces perpendicular to each other, and the electrodes formed on the surfaces perpendicular to each other of the three-dimensional wiring board Can be connected to the drive IC without using the FPC. Thereby, the malfunction by expansion / contraction of FPC can be avoided and the reliability of an electrode connection part can be made high. In addition, since the common electrode is not formed on both ends of the individual electrode, the electrode structure of the piezoelectric element can be simplified, and the end of the piezoelectric element can be used as the vibrating portion.
Further, according to the droplet discharge head according to the present invention, since the piezoelectric elements are arranged in a row in the longitudinal direction, unlike the conventional piezoelectric element in which a common electrode is formed at both ends of the individual electrode, Since the piezoelectric elements in which the common electrodes are formed on the surfaces perpendicular to each other are connected in series, the end of the piezoelectric element can be used for driving the diaphragm. However, the nozzles can be arranged at an equal pitch. That is, it is not necessary to form a single piezoelectric element with a long length, and a conventional short piezoelectric element can be used. Further, even when the piezoelectric elements are arranged and lengthened, it is not necessary to arrange the piezoelectric elements in a staggered manner as in the prior art, and the piezoelectric elements can be arranged adjacent to each other in series, and the head can be miniaturized. In addition, according to the present invention, the piezoelectric elements are arranged adjacent to each other in the longitudinal direction, and the diaphragm, the three-dimensional wiring board, and the like are integrally formed, so that the droplet discharge head can be lengthened without using the FPC. Is possible. Thereby, even with a long head, problems due to expansion and contraction of the FPC of the piezoelectric element electrode portion can be avoided, and the reliability of the electrode connection portion can be increased.

In addition, according to the droplet discharge head according to the present invention, since the IC for controlling the driving of the piezoelectric element is mounted on the three-dimensional wiring board, the number of connection electrodes with the external substrate of the three-dimensional wiring board can be reduced, In addition, since the connection between the three-dimensional wiring board and the external board can be performed by FFC, it is not necessary to use the FPC for the connection to the external board, and a problem due to the expansion and contraction of the FPC can be avoided.
Further, according to the droplet discharge head according to the present invention, one side of the surface opposite to the diaphragm of the piezoelectric element is chamfered, and the individual electrode, the common electrode, and the individual electrodes are separated from each other. There is no need to use a method or a method of partial etching after electrode formation, the electrodes can be easily separated from each other, and the cost can be reduced.
In addition, according to the liquid droplet ejection head according to the present invention, since the linear expansion coefficient of the three-dimensional wiring board is 10E-6 / ° C. or less, the difference between the linear expansion coefficients of the piezoelectric element and the three-dimensional wiring board can be reduced. Further, peeling of the electrode connection portion of the three-dimensional wiring board and column collapse of the piezoelectric element can be prevented.
Further, according to the droplet discharge head according to the present invention, a member having a linear expansion coefficient of 10E-6 / ° C. or less is insert-molded on the three-dimensional wiring board, so that the linear expansion coefficient is 10E-6 as a molding resin for the three-dimensional wiring board. A resin at / ° C. or higher can be used, and even in that case, the reliability of the electrode connecting portion can be increased.

Further, according to the liquid droplet ejection head according to the present invention, the common electrode is formed on the opposite surface of the piezoelectric element from the diaphragm, and the common electrode and the conductive member having a linear expansion coefficient of 10E-6 / ° C. or less Since the member and the electrode of the three-dimensional wiring board are connected, the difference in thermal expansion between the piezoelectric element and the conductive member is small, and the reliability of the connection portion of the common electrode can be increased.
Further, according to the droplet discharge head according to the present invention, since the external electrode of the piezoelectric element and the electrode of the three-dimensional wiring board are connected by the solder fillet, the reliability of the connection portion between the piezoelectric element and the three-dimensional wiring board can be increased. .
In addition, according to the droplet discharge head according to the present invention, since a part of the wiring thickness of the wiring of the three-dimensional wiring board is buried in the molded body, the adhesion between the molded body of the three-dimensional wiring board and the wiring can be increased, It is possible to prevent the wiring from being peeled from the molded body. Further, even if the wiring is thickened, the adhesion force between the molded body and the wiring is not lowered, but on the contrary, the wiring can be thickened, and the wiring resistance can be reduced even if the wiring becomes finer.
And, according to the manufacturing method of the droplet discharge head according to the present invention, since the wiring of the three-dimensional wiring board is formed by transfer, an epoxy resin having a low linear expansion coefficient can also be used as a molded body of the three-dimensional wiring board. Wide choice of molding materials. In addition, since all the wirings can be transferred simultaneously, the number of wirings is large and the wiring pitch is small, so that the cost is not high.

1 shows a droplet discharge head according to an embodiment, where (a) is a cross-sectional view in the short-side direction of the piezoelectric element portion, and (b) is a cross-sectional view in the longitudinal direction of the piezoelectric element portion. FIG. 2 is an enlarged cross-sectional view of the droplet discharge head shown in FIG. It is a perspective view which shows the piezoelectric element of a droplet discharge head. It is a perspective view which shows the wiring pattern of the three-dimensional wiring board of a droplet discharge head. It is a longitudinal direction sectional view of a piezoelectric element part of a droplet discharge head concerning the example of a 2nd embodiment. It is a transversal direction sectional view of the piezoelectric element part of the droplet discharge head concerning the example of a 3rd embodiment. It is a transversal direction sectional view of the piezoelectric element part of the droplet discharge head concerning the example of a 4th embodiment. It is sectional drawing which shows the piezoelectric element of the droplet discharge head which concerns on the example of 5th Embodiment, and the electrode connection part of a three-dimensional wiring board. 8A and 8B illustrate a method for manufacturing a three-dimensional wiring board of a droplet discharge head according to an eighth embodiment, wherein FIG. 5A is a cross-sectional view of a mold-resin contact portion (wiring portion) during molding, and FIG. FIG. 4 is a cross-sectional view of the wiring after release.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Droplet discharge head, 100 head part, 110 Flow path substrate (liquid chamber substrate), 120 Vibration plate, 130 Nozzle plate, 131 Nozzle, 141 Pressurized liquid chamber, 142 Ink supply path, 150 frame, 200 Piezoelectric element, 210 Piezoelectric material layer, 220 internal electrode, 221 individual electrode, 222 common electrode, 230 external individual electrode, 240 external common electrode, 240a hanging portion, 240b horizontal portion, 250 C chamfered portion, 260 columnar member, 260b horizontal portion, 261 top surface 262 Lower surface, 263, 264 Hanging surface, 264 Hanging surface, 263, 264 Hanging surface, 270 Gap portion, 300 Three-dimensional wiring board, 310 Base, 311 Side surface portion, 312 Upper surface portion, 320 Standing portion, 321 Side surface portion, 330 Slit, 340 Individual electrode wiring, 341 Individual contact, 350 Common Electrode for wiring, 351 common contact portion, 360 solder resist, 370, 380 solder, 400 driving IC, 410 bump, 510 droplet discharge head, 520, 530, 540 piezoelectric element, 550 head portion, 560 three-dimensional wiring board, 600 liquid Droplet discharge head, 610 Three-dimensional wiring board, 620 Insert member, 700 Droplet discharge head, 800 Piezoelectric element, 811 Upper surface, 812 Lower surface, 813, 814 Hanging lower surface, 820 External common electrode, 830 External individual electrode, 900 Three-dimensional wiring substrate, 910 Base, 911 Upper side, 920 Standing part, 930 Outer side, 940 Individual electrode wiring, 950 Common electrode wiring, 960 Solder resist layer, 970 Conductive member, 981, 982, 983 Solder, 1200 Piezoelectric element, 1211 Upper surface, 1212 Lower surface, 1 13, 1214 Hanging surface, 1220 External common electrode, 1230 External individual electrode, 1300 Solid wiring board, 1310 Base, 1320 Standing portion, 1330, 1340 Common electrode, 1341 Horizontal portion, 1342 Hanging portion, 1350, 1360 Solder, 1370 Fillet Part

Claims (11)

Each of the columnar members includes a columnar member that is arranged corresponding to each of the plurality of pressurized liquid chambers that communicate with the corresponding nozzle, and that includes a plurality of piezoelectric material layers. First and second internal electrodes are arranged to apply individual drive signals, and are connected to all of the external individual electrodes and the second internal electrodes individually connected to the first internal electrodes. A piezoelectric element having an external common electrode on its surface;
Three-dimensional wiring that is arranged in combination with the piezoelectric element and has on its surface an individual contact portion connected to the external individual electrode of the piezoelectric element on its outer surface and a common contact portion connected to the external common electrode A substrate, and
The piezoelectric element includes a first electrode forming surface portion and a second electrode forming surface portion that are substantially orthogonal to each other, wherein the external individual electrode portion is formed on the first electrode forming surface portion, and the external common electrode portion is formed on the second electrode. Placed on the face,
The three-dimensional wiring board includes a first contact placement surface portion and a second contact placement surface portion that are substantially orthogonal to each other and face the first and second electrode formation surface portions of the piezoelectric element. A droplet discharge head, wherein the droplet contact head is installed on one contact installation surface portion, and the common contact portion is arranged on the second contact grounding surface portion.   The droplet discharge head according to claim 1, wherein a plurality of piezoelectric elements are arranged side by side.   3. The liquid droplet ejection head according to claim 1, wherein the three-dimensional wiring board is mounted with a circuit element that controls driving of the piezoelectric element.   The corners formed by the first and second electrode forming surface portions of the piezoelectric element are chamfered to separate the individual electrodes from the common electrode and the individual electrodes connected to the plurality of piezoelectric materials. The droplet discharge head according to any one of claims 1 to 3, wherein   5. The droplet discharge head according to claim 1, wherein the wiring board is formed of a material having a linear expansion coefficient of 10E−6 / ° C. or less.   6. The liquid droplet ejection head according to claim 1, wherein an insertion member having a linear expansion coefficient of 10E-6 / [deg.] C. or less is insert-molded on the wiring board. An external common electrode is formed by being drawn out on the electrode arrangement surface portion of the piezoelectric element, and the external common electrode is connected to a common contact portion of the three-dimensional wiring board via a conductive member,
The droplet discharge head according to claim 1, wherein the conductive member is made of a material having a linear expansion coefficient of 10E−6 / ° C. or less.   At least one of the external individual electrode and the external common electrode of the piezoelectric element, and at least one contact part of the individual contact part and the common contact part disposed on the wiring board are connected by a solder part, The droplet discharge head according to claim 1, wherein the solder includes a fillet portion.   9. The device according to claim 1, wherein the individual electrode and the common electrode are disposed on the three-dimensional wiring board, and a part of a thickness direction of the individual electrode and the common electrode is embedded in a molded body constituting the three-dimensional wiring board. The droplet discharge head according to any one of the above.   An image forming apparatus comprising the droplet discharge head according to claim 1.   10. The method for manufacturing a droplet discharge head according to claim 1, wherein the wiring of the three-dimensional wiring board is formed by transfer.

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