JP2008143011A - Droplet discharge head and its manufacturing method, and droplet discharge device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a droplet discharge head such as an inkjet head which is improved in reliability for connecting a piezoelectric element with a wiring board by effectively preventing cracks from being generated in the piezoelectric element electrically connected to the wiring board, and its manufacturing method, and to provide a droplet discharge device. <P>SOLUTION: Electrode bumps 12b in a flexible printed wiring board (FPC) 12 are composed of effective bumps 12b1 arranged in an effective discharge area as an area discharging droplets from nozzles 2a, and noneffective bumps 12b2 arranged in a noneffective discharge area other than the discharge area and not contributing directly to electrical connection with the piezoelectric element 8. The noneffective bump 12b2 is higher than the effective bump 12b1 in height and has height permitting connection with the electrodes 8a and 8b of the effective bump 12b1 which has been hindered by contact with the vibrating plate 7 side of the noneffective bump 12b2 by reduction in height by the thermal melting of the noneffective bump 12b2 itself before being electrically connected. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a droplet discharge head, a manufacturing method thereof, and a droplet discharge apparatus. More specifically, a droplet discharge head such as an ink jet head in which the occurrence of cracks and the like is effectively prevented in a piezoelectric element electrically connected to a wiring board and the connection reliability between the piezoelectric element and the wiring board is excellent, and its manufacture The present invention relates to a method and a droplet discharge device.

  In an inkjet head that records information by deforming a piezoelectric element by a drive signal supplied to an electrode and ejecting ink from the nozzle in the form of fine droplets, a plurality of nozzles are used to increase the density of the head. And the structure which arranged the piezoelectric element in the matrix form is employ | adopted. In this case, a flexible printed circuit board (FPC) is used as an electrical connection means for supplying drive signals to the electrodes of the piezoelectric element, and electrode bumps are connected to the conductive pattern of the flexible substrate (FPC) at predetermined positions of the electrodes of the piezoelectric element. Has been disclosed (see Patent Document 1). Specifically, FPC electrode bumps are placed opposite to the piezoelectric element electrodes, and the heater is heated after directly pressing the heater against the surface opposite to the surface on which the FPC electrode bumps are installed. Thus, the solder of the FPC electrode bumps is thermally melted, and the FPC electrode bumps and the electrodes of the piezoelectric elements are joined by soldering. The invention disclosed in Patent Document 1 configured as described above can easily and accurately perform electrical connection with high density and high reliability.

  Here, a nozzle that discharges ink, a pressure generation chamber, an ineffective (dummy) pressure generation chamber that does not discharge ink to a region (ineffective discharge region) outside the matrix region (effective discharge region) of the piezoelectric element, and an ineffective (dummy) ) The piezoelectric elements are arranged at the same size and the same pitch as in the effective ejection region. This is to make the ink ejection characteristics at the outermost periphery of the effective ejection area the same as the ink ejection characteristics in the adjacent part on the inside. In other words, the electrode bumps of the FPC are configured such that there are effective bumps connected to the piezoelectric elements in the effective discharge region and dummy bumps connected to the dummy piezoelectric elements.

Although different from the present invention in the technical idea, the invention using the positioning solder electrode bump (see Patent Document 2), the size of the electrode pad are common inventions in terms of the shape of the electrode bump. An invention in which the sheath shape is different (see Patent Document 3), an invention in which the area of the corner electrode pad is increased (see Patent Document 4), and the like are disclosed.
JP 2003-69103 A Japanese Patent Laid-Open No. 10-74792 JP-A-7-307410 Japanese Patent Laid-Open No. 11-233926

  However, in the case of the invention disclosed in Patent Document 1, the effective bumps and the dummy bumps are approximately the same size, and there is no difference in size between them, but there are various variations in the size of other components, For example, when the electrode bumps are formed due to variations in the size of the solder balls placed on the electrode bumps, variations in the thickness of the electrodes of the piezoelectric elements, variations in the amount of solder paste applied, etc. Therefore, when soldering the FPC electrode bump to the electrode of the piezoelectric element, the FPC electrode bump should contact the electrode of the piezoelectric element before the solder is melted due to the relative variation in the height of the electrode bump. There may be no contact with the location. Compared with the case where the electrode bumps of the FPC are few in contact, the case where most of the electrode bumps of the FPC are in contact, or the case where all the electrode bumps are in contact with each other, The contact pressure becomes high, and if this pressure becomes too high, there is a problem that the piezoelectric element cracks. The effective piezoelectric elements in the effective ejection region and the dummy piezoelectric elements in the non-effective ejection region have a larger number of effective piezoelectric elements, so that the possibility of cracks occurring in the effective piezoelectric elements in the effective ejection region is increased.

  The present invention has been made in view of the above-described problems, and the occurrence of cracks or the like is effectively prevented in the piezoelectric element electrically connected to the wiring board, and the connection reliability between the piezoelectric element and the wiring board is improved. It is an object of the present invention to provide an excellent droplet discharge head such as an inkjet head, a manufacturing method thereof, and a droplet discharge device.

  In order to achieve the above object, according to the present invention, there are provided the following droplet discharge head, manufacturing method thereof, and droplet discharge apparatus.

[1] A flow path member having a plurality of nozzles and pressure generation chambers communicated with each other by a flow path structure, a vibration plate disposed on the opposite side of the flow path member from the nozzle, and a vibration plate disposed on the vibration plate The electrode has an electrode, is deformed when a drive signal is supplied to the electrode, changes the volume in the pressure generating chamber, and discharges the liquid stored in the pressure generating chamber as droplets from the nozzle. A plurality of piezoelectric elements, a conductive pattern that supplies the drive signal to the electrodes of the piezoelectric element, and a plurality of electrodes that are electrically connected by thermally melting the electrodes of the piezoelectric element and the conductive patterns themselves A wiring board having a bump, wherein the wiring board is disposed as an electrode bump in an effective ejection area that is an area for ejecting the liquid droplet from the nozzle. Directly connected to the electrical connection between the electrode of the piezoelectric element and the conductive pattern, which is disposed in a non-effective discharge area where the droplet is not discharged from the nozzle other than the discharge area. And non-effective bumps that do not contribute, and at least three of the non-effective bumps before the electrical connection between the electrode and the conductive pattern by the effective bumps. The contact of the effective bump with the electrode, which has a height higher than the effective bump and is hindered by the contact of the ineffective bump with the diaphragm side, is caused by the thermal melting of the ineffective bump itself. A droplet discharge head characterized by having a height that can be achieved by reducing the height of the droplet.

[2] The piezoelectric element directly contributes to the electrical connection between the effective electrode disposed in the effective ejection region and the conductive pattern disposed in the ineffective ejection region as the electrode. The non-effective bumps in the non-effective bumps are electrically connected to the effective electrodes of the piezoelectric element and the conductive pattern by the effective bumps. Before, the contact of the effective bump with the effective electrode, which has a height higher than the effective bump and is prevented by the contact of the non-effective bump with the non-effective electrode, The droplet discharge head according to [1] above, which has a height that can be achieved by a reduction in height due to heat melting.

[3] The ineffective bump in the wiring board is disposed in the ineffective ejection area located in the outermost peripheral portion of the effective ejection area in which the effective bump is disposed. ] The droplet discharge head according to any one of the above.

[4] The [2], wherein the non-effective electrode in the piezoelectric element is disposed in the non-effective discharge region located at an outermost peripheral portion of the effective discharge region in which the effective electrode is disposed. ] The droplet discharge head according to any one of the above.

[5] The electrode bump in the wiring board is characterized in that a core made of a refractory metal having a higher melting point than the heat-fusible metal is coated with an outer peripheral part made of a heat-fusible metal. The droplet discharge head according to [1].

[6] A flow path member having a plurality of nozzles and pressure generation chambers communicated with each other by a flow path structure, a vibration plate disposed on the opposite side of the flow path member from the nozzle, and a vibration plate disposed on the vibration plate. The electrode has an electrode, is deformed when a drive signal is supplied to the electrode, changes the volume in the pressure generating chamber, and discharges the liquid stored in the pressure generating chamber as droplets from the nozzle. A plurality of piezoelectric elements, a conductive pattern that supplies the drive signal to the electrodes of the piezoelectric element, and a plurality of electrodes that are electrically connected by thermally melting the electrodes of the piezoelectric element and the conductive patterns themselves A method of manufacturing a droplet discharge head including a wiring substrate having a bump, wherein the effective discharge region is a region for discharging the droplet from the nozzle as the electrode bump on the wiring substrate. It contributes directly to the electrical connection between the electrode of the piezoelectric element and the conductive pattern in the non-effective discharge area which is an area where the droplet is not discharged from the nozzle other than the discharge area. Non-effective bumps are disposed, and among the non-effective bumps, the non-effective bumps at least at three-point support positions are formed at a height higher than the effective bumps, and the diaphragm of the non-effective bumps A first step of forming contact with the electrode of the effective bump, which has been hindered by contact with a side, by a reduction in height due to thermal melting of the ineffective bump itself; The wiring board obtained in the first step and the piezoelectric element are opposed to each other and heated and pressed to bring the ineffective bumps into contact with the vibration plate side, and then the ineffective bumps are thermally melted. A second step of bringing the effective bumps that have been thermally melted into contact with the electrode of the piezoelectric element and electrically connecting the electrode of the piezoelectric element and the conductive pattern due to a decrease in thickness. A manufacturing method of a droplet discharge head characterized by the above.

[7] In the first step, first, as the wiring board, a wiring board with bumps in which the effective bumps and the ineffective bumps are all formed at a uniform height is prepared, and then the wiring board with bumps is prepared. The height of the non-effective bump is adjusted to be higher than the effective bump, and the effective bump can be brought into contact with the electrode by reducing the height of the non-effective bump by heat melting. The method of manufacturing a droplet discharge head according to [6] above, wherein the adjustment is performed.

[8] In the first step, first, a bumpless wiring board in which only the conductive pattern is disposed is prepared as the wiring board, and then the effective bump and the ineffective are provided on the wiring board without bump. Bumps are made such that the ineffective bumps are higher in height than the effective bumps, and the effective bumps can be brought into contact with the electrodes by reducing the height of the ineffective bumps themselves by thermal melting. The method for manufacturing a droplet discharge head according to [6], wherein the droplet discharge head is formed so as to be adjusted to a height.

[9] The ineffective bumps in the wiring board are formed by coating a core portion made of a refractory metal having a higher melting point than the heat meltable metal with an outer peripheral portion made of a heat meltable metal. The method for producing a droplet discharge head according to [6], which is characterized in that

[10] The height of the ineffective bump is adjusted in the first step by further disposing a heat-meltable metal on the ineffective bump of the wiring board with bumps. [7] The method of manufacturing a droplet discharge head according to claim 7.

[11] In the first step, by disposing a larger amount of hot-melt metal than the portion where the effective bump is formed in the portion where the ineffective bump is formed in the wiring board without bumps, The method for manufacturing a droplet discharge head according to [8], wherein the height of the ineffective bump is adjusted.

[12] In the liquid droplet ejection apparatus including a plurality of liquid droplet ejection heads that eject liquid as liquid droplets from a plurality of nozzles toward a surface to be ejected by driving a plurality of piezoelectric elements, the liquid droplet ejection head Is a flow path member having a plurality of nozzles and pressure generation chambers that are communicated with each other by a flow path structure, a diaphragm disposed on the opposite side of the nozzle of the flow path member, and disposed on the diaphragm The electrode has an electrode, is deformed when a drive signal is supplied to the electrode, changes the volume in the pressure generating chamber, and discharges the liquid stored in the pressure generating chamber as droplets from the nozzle. A plurality of piezoelectric elements, a conductive pattern for supplying the drive signal to the electrodes of the piezoelectric elements, and a plurality of electrodes electrically connected by thermally melting the electrodes of the piezoelectric elements and the conductive patterns And a wiring board having a bump, wherein the wiring board is disposed in an effective ejection area, which is an area for ejecting the liquid droplets from the nozzle, as the electrode bump. And an electrical connection between the electrode of the piezoelectric element and the conductive pattern disposed in an ineffective ejection area that is an area where the liquid droplets are not ejected from the nozzle other than the ejection area. The non-effective bumps that do not contribute, and the non-effective bumps at least at the three-point support position among the non-effective bumps before the electrodes and the conductive pattern are electrically connected by the effective bumps. The contact of the effective bumps with the electrodes has a height higher than that of the effective bumps and is hindered by the contact of the non-effective bumps with the diaphragm side. The droplet discharge device, characterized in that the droplet discharge head having the potential to become high by the reduction in height due to ineffective bumps own hot melt.

  The droplet discharge head according to claim 1 of the present invention effectively prevents the occurrence of cracks in the piezoelectric element electrically connected to the wiring board, and ensures excellent connection reliability between the piezoelectric element and the wiring board. Is done.

  With the droplet discharge head according to the second aspect of the present invention, the above-described effects are more remarkably exhibited.

  With the liquid droplet ejection head according to claims 3 to 4 of the present invention, the above-described effects can be more easily and reliably exhibited.

  With the liquid droplet ejection head according to claim 5 of the present invention, the above-described effect can be more reliably exhibited.

  According to the manufacturing method of the droplet discharge head according to the sixth aspect of the present invention, generation of cracks and the like is effectively prevented in the piezoelectric element electrically connected to the wiring board, and excellent connection reliability between the piezoelectric element and the wiring board is achieved. Therefore, a liquid droplet ejection head in which the property is ensured is efficiently manufactured.

  By the method for manufacturing a droplet discharge head according to the seventh to eighth aspects of the present invention, the above-described effects are more remarkably exhibited.

  By the method for manufacturing a droplet discharge head according to the ninth aspect of the present invention, the above-described effect can be more reliably exhibited.

  By the method for manufacturing a droplet discharge head according to the tenth to eleventh aspects of the present invention, the above-described effects can be achieved more easily.

  High-definition image information is provided by the droplet discharge device according to claim 12 of the present invention.

[First Embodiment]
(Configuration of droplet discharge head)
FIG. 1 is a cross-sectional view showing a droplet discharge head according to a first embodiment of the present invention, FIG. 2 shows a piezoelectric element portion and a flexible printed wiring board portion before bonding, and FIG. (B) is a partially enlarged view of part A in (a), (c) is a sectional view taken along line BB in (b), and FIG. 3 is a diagram before joining the flexible printed wiring board part. The piezoelectric element part is shown, (a) is a plan view, (b) is a partially enlarged view of part C in (a), and (c) is a sectional view taken along the line DD in (b).

  As shown in FIGS. 1 to 3, the droplet discharge head 1 includes a flow path member S having a plurality of nozzles 2 a and pressure generation chambers 3 a communicated with each other by a flow path structure, and a nozzle 2 a of the flow path member S. Has a diaphragm 7 disposed on the opposite side, an electrode (individual electrode 8a, common electrode 8b) and a piezoelectric element member 8c disposed on the diaphragm 7, and a drive signal is supplied to the electrodes 8a and 8b. As a result, the piezoelectric element 8 is deformed, the volume in the pressure generating chamber 3a is changed, and the liquid stored in the pressure generating chamber 3a is ejected as droplets from the nozzle 2a. A wiring board (flexible printed circuit board) having a conductive pattern 12a to be supplied to the electrodes 8a and 8b and a plurality of electrode bumps 12b that are electrically connected by thermally melting the electrodes 8a and 8b of the piezoelectric element 8 and the conductive pattern 12a themselves. A droplet discharge head 1 including a printed wiring board (hereinafter referred to as “FPC”) 12, and the FPC 12 is disposed as an electrode bump 12b in an effective discharge region that is a region for discharging droplets from the nozzle 2a. Electrical connection between the electrodes 8a and 8b of the piezoelectric element 8 and the conductive pattern 12a disposed in the effective bump 12b1 thus formed and the non-effective discharge area where the droplets are not discharged from the nozzle 2a other than the discharge area The non-effective bumps 12b2 that do not directly contribute to the non-effective bumps 12b2 and the non-effective bumps 12b2 of the non-effective bumps 12b2 at least at the three-point support positions connect the electrodes 8a and 8b and the conductive pattern 12a to the effective bumps 12b1 Before the electrical connection is made, the height of the effective bump 12b1 is higher and the non-effective bump 12b2 is in contact with the diaphragm 7 side. Effective bump 12b1 electrode 8a that has been hampered by the contact with the 8b is configured to have the potential to become high by the reduction of the non-effective bump 12b2 height by its hot melt.

  In the present embodiment, as shown in FIG. 2, the non-effective bump 12b2 in the FPC 12 is disposed in the non-effective discharge area located at the outermost peripheral portion of the effective discharge area where the effective bump 12b1 is disposed. . Next, the configuration of each unit will be described.

(Diaphragm)
As shown in FIG. 1, the diaphragm 7 is disposed between the flow path member S and the piezoelectric element 8. The diaphragm 7 has conductivity and elasticity, for example, a metal material such as SUS, a composite material of different metals, a composite material of metal and resin, and a surface treatment material in which a metal film is formed on the surface of the resin by sputtering or vapor deposition. Etc. can be used.

(Flexible printed circuit board)
As shown in FIG. 2, the FPC 12 supplies a drive signal to a plurality of individual electrodes 8a of the piezoelectric element 8 (see FIG. 3), and the conductive pattern 12a drawn to the input side of the drive signal and the individual of the piezoelectric elements 8 are supplied. The electrode 8a and the conductive pattern 12a are disposed in a predetermined region E and have a plurality of electrode bumps 12b that are electrically connected.

  The conductive pattern 12a is disposed on the base film 12d and is covered with a cover layer 12c. The conductive pattern 12a is electrically connected to the individual electrode 8a of the piezoelectric element 8 through the electrode bump 12b disposed on the bump pad 12f (see FIG. 4B). As the conductive pattern 12a, one made of a metal such as copper can be suitably used. Moreover, as the base film 12d, a film made of a polyimide resin having excellent heat resistance can be suitably used. Further, as the cover layer 12c, a polyester resin such as a polyethylene terephthalate (PET) resin, which is widely used as a film material, or a material composed of a polyimide resin or the like when heat resistance is required can be suitably used. . The conductive pattern 12a may have a single layer structure or a two layer structure. The wiring board is not limited to the FPC, and may be a rigid printed wiring board (PWB) represented by a glass epoxy base material, a glass board, or a ceramic board.

(Piezoelectric element)
As shown in FIG. 3, a plurality of piezoelectric elements 8 are arranged in the effective discharge region and the non-effective discharge region located at the outermost peripheral portion of the effective discharge region. The piezoelectric element 8 includes, for example, a piezoelectric element member 8c composed of lead zirconate titanate (piezoelectric element) and the like, and electrodes (individual electrode 8a and common electrode 8b). The electrodes (individual electrode 8a and common electrode 8b) are formed by sputtering or the like, and the individual electrode 8a formed on the upper surface side is driven from the conductive pattern 12a of the FPC 12 (see FIG. 2) via the electrode bump 12b. Is electrically connected to the conductive pattern 12a, and the common electrode 8b formed on the lower surface side is electrically connected to the diaphragm 7 by a conductive adhesive. Is grounded. The piezoelectric element 8 is individually joined to the position of the diaphragm 7 corresponding to the pressure generating chamber 3a.

(Other configurations)
For example, the nozzle plate 2 constituting the flow path member S is made of, for example, a self-bonding type polyimide resin from the viewpoint of ink resistance, heat resistance, etc., and the laminated plate 3 is made of ink resistance. It is made of a metal such as SUS.

  As described above, in the present embodiment, among the ineffective bumps 12b2, the ineffective bumps 12b2 at least at the three-point support position electrically connect the electrodes 8a and 8b and the conductive pattern 12a by the effective bumps 12b1. The contact with the electrodes 8a and 8b of the effective bump 12b1 that has a height higher than that of the effective bump 12b1 and is obstructed by the contact of the non-effective bump 12b2 with the vibration plate 7 side is the ineffective bump 12b2 itself. It is configured to have a height that can be achieved by reducing the height due to thermal melting of the material. The relationship between the height of such an ineffective bump 12b2 and the height of other components is expressed by the following equation.

  Hd> Hj + Tp and S ≧ Hd−Hj−Tp

  In the above formula, Hd represents the height of the ineffective bump 12b2, Hj represents the height of the effective bump 12b1, Tp represents the thickness of the piezoelectric element 8, and S represents the amount of decrease in height due to thermal melting of the ineffective bump 12b2. .

(Liquid flow)
The flow of the liquid will be described with reference to FIG. When a drive signal is supplied to the individual electrode 8 a of the piezoelectric element 8 disposed on the diaphragm 7, the piezoelectric element 8 is deformed and the volume in the pressure generation chamber 3 a of the laminated plate 3 is reduced via the diaphragm 7. The liquid that is changed and supplied to the supply hole (not shown) of the vibration plate 7 causes the liquid stored in the pressure generation chamber 3 a of the laminated plate 3 to be ejected as droplets from the nozzle 2 a of the nozzle plate 2.

(Method for manufacturing droplet discharge head)
4A to 4F are cross-sectional views illustrating a process of forming an FPC in the manufacturing method of the droplet discharge head according to the first embodiment.

(Formation of conductive pattern)
As shown in FIG. 4A, a conductive film 12a is formed by patterning a copper-clad film having a copper foil on a base film 12d by etching. The conductive pattern 12a may be formed by plating a copper foil on the base film 12d so as to have the shape of the conductive pattern 12a.

(Formation of cover layer)
As shown in FIG. 4B, the polyimide film is etched on the conductive pattern 12a formed on the base film 12d to form a cover layer 12c having bump pads 12f. The cover layer 12c may be formed by exposing and developing a photoresist and patterning bump lands and the like.

(Formation of electrode bumps)
As shown in FIG. 4C, solder bumps are applied to the bump pads 12f to form electrode bumps 12b having a uniform height.

(Formation of bumped FPC)
As shown in FIG. 4D, external processing, inspection, and the like are performed to form the FPC 12x with bumps. The electrode bumps 12b in this case all have a uniform height.

(Adjustment of bump height)
As shown in FIG. 4E, solder 12g is applied to the electrode bumps 12b in the non-effective discharge area. Examples of the solder 12g include solder paste and the like, but thread solder may be supplied by manual soldering. Examples of the application means include screen printing, dispensing, and manual soldering (including robots). In this case, the application amount of the solder 12g is such that the non-effective bump 12b2 has a higher height than the effective bump 12b1, and the effective bump 12b1 that has been hindered by the contact of the non-effective bump 12b2 with the diaphragm 7 side. The height of the non-effective bump 12b2 is adjusted to be a height that can be contacted with the individual electrode 8a by reducing the height of the non-effective bump 12b2.

(FPC completed)
As shown in FIG. 4F, the solder 12g is melted and hardened, and the height of the non-effective bump 12b2 is made higher than the height of the effective bump 12b1, thereby completing the FPC. Examples of the solder melting method include reflow soldering, hot air, a heater, a light beam, and a soldering iron.

  5A to 5C are cross-sectional views showing a process of joining the FPC part and the piezoelectric element part after the process shown in FIG. 4 in the method of manufacturing the droplet discharge head according to the first embodiment. FIG.

(Alignment)
As shown in FIG. 5A, the piezoelectric element 8 and the FPC 12 obtained in the step shown in FIG. Although there is no restriction | limiting in particular as an alignment method, For example, the method of aligning with an FPC alignment mark and the electrode pad of a piezoelectric element, the method of aligning with an alignment mark, the method of aligning with a positioning hole, etc. can be mentioned. FIG. 5A shows a case where the piezoelectric element 8 is not disposed in a region where the ineffective bump 12b2 faces.

(Lamination)
As shown in FIG. 5B, the FPC 12 and the piezoelectric element 8 are bonded together. The non-effective bumps 12b2 are in contact with the diaphragm 7 which is the upper surface of the flow path member S, but the effective bumps 12b1 are not in contact with the individual electrodes 8a of the piezoelectric element 8.

(Joining)
As shown in FIG. 5C, the heater 13 is pressed from the opposite surface (the surface of the base film 12 d) of the piezoelectric element 8 of the FPC 12 and heated while being pressurized by the heater 13. The ineffective bumps 12b2 and the effective bumps 12b1 made of solder are heated and melted to reduce the height, and the FPC 12 settles to the piezoelectric element 8 side. Thereafter, the effective bumps 12b1 come into contact with the individual electrodes 8a of the piezoelectric elements 8. However, since the effective bumps 12b1 are thermally melted, the joining by soldering is completed without causing cracks in the piezoelectric elements 8 in the effective discharge region. Can be made.

[Modification of First Embodiment]
6A to 6F are cross-sectional views illustrating a process of forming an FPC in the manufacturing method of the droplet discharge head according to the modification of the first embodiment.

  As shown in FIG. 6, in this modification, as an electrode bump 12b in the FPC 12, a high melting point metal (for example, copper, silver, etc.) having a melting point higher than that of the solder 12g is formed by the outer peripheral portion made of the solder 12g which is a heat melting metal. Etc.) is the same as in the case of the first embodiment, except that the core 12h made of the same is used. In this case, in the bonding step, as shown in FIG. 5, when heating is performed while applying pressure with the heater 13, the non-effective bumps 12b2 and the effective bumps 12b1 are thermally melted, and the FPC 12 settles to the piezoelectric element 8 side, and the electrode bumps 12b. The core 12h comes into contact with the piezoelectric element 8 and stops. The effective bumps 12b1 come into contact with the individual electrodes 8a of the piezoelectric element 8 during the sedimentation of the FPC 12. However, since the effective bumps 12b1 are melted by heat, the piezoelectric elements 8 in the effective discharge area are not cracked and are soldered. Joining can be completed.

  In the case of the droplet discharge head obtained in this modification, the relationship between the height of the non-effective bump 12b2 and the height of other components is expressed by the following equation.

  Hd> Hj + Tp and S ≧ Hd−Hj−Tp and Hd−S ≧ D + Tp

  In the above formula, Hd is the height of the ineffective bump 12b2, Hj is the height of the effective bump 12b1, Tp is the thickness of the piezoelectric element 8, S is a decrease in height due to thermal melting of the ineffective bump 12b2, and D is The diameter of the core 12h of the electrode bump 12 is shown respectively.

[Second Embodiment]
7A to 7D are cross-sectional views illustrating a process of forming an FPC in the manufacturing method of the droplet discharge head according to the second embodiment.

(Formation of conductive pattern)
As shown in FIG. 7A, a copper-clad film in which a copper foil is disposed on the base film 12d is patterned by etching to form a conductive pattern 12a. The conductive pattern 12a may be formed by plating a copper foil on the base film 12d so as to have the shape of the conductive pattern 12a.

(Formation of cover layer)
As shown in FIG. 7B, the polyimide film is etched on the conductive pattern 12a formed on the base film 12d to form a cover layer 12c having bump pads 12f. The cover layer 12c may be formed by exposing and developing a photoresist and patterning bump lands and the like.

(Formation of FPC without bump)
As shown in FIG. 7C, external processing, inspection, and the like are performed to form a bumpless FPC 12y.

(Effective and ineffective bump formation)
As shown in FIG. 7D, an effective bump 12b1 and an ineffective bump 12b2 are placed on the bump pad 12f of the bumpless FPC 12y so that the ineffective bump 12b2 is higher than the effective bump 12b1. The height of the non-effective bump 12b2 is prevented from coming into contact with the individual electrode 8a, which has been hindered by the contact of the non-effective bump 12b2 with the diaphragm 7 side. Adjust to form. A method for adjusting the height of the electrode bump 12b will be described later.

  FIGS. 8A to 8C are cross-sectional views showing one specific example of the method for adjusting the height of the electrode bump 12b shown in FIG. 7D.

(Application of flux and solder paste)
As shown in FIG. 8A, the flux 12i is applied to the position where the effective bump 12b1 in the effective ejection area of the FPC 12y without bumps is formed, and the position where the ineffective bump 12b2 in the ineffective ejection area is formed. Solder paste 12j is applied. Examples of the application means include screen printing, dispensing, and manual soldering (including robots).

(Mounting of solder balls)
As shown in FIG. 8B, solder balls 12k having the same size are mounted on the flux 12i and the solder paste 12j.

(Effective and ineffective bump formation)
As shown in FIG. 8C, the solder (solder paste 12j and solder ball 12k) is thermally melted by heating, and bumps are formed by cooling and hardening to form effective bumps 12b1 and ineffective bumps 12b2. Unlike the flux 12i, the non-effective bump 12b2 having a height higher than the effective bump 12b1 is formed by the solder paste 12j that contributes to the formation of the height. Examples of the solder melting method include reflow soldering, hot air, and a light beam.

  FIGS. 9A to 9D are cross-sectional views showing other specific examples of the method for adjusting the height of the electrode bump 12b shown in FIG. 7D.

  As shown in FIGS. 9A and 9B, the solder paste 12j is applied to the bumpless FPC 12y by a screen printing method using a screen 12m and a squeegee 12p. At this time, the ineffective bump 12b2 in the non-effective discharge area is formed so that the opening area of the opening 12n for applying the solder paste 12j on the screen 12m is larger than the position where the effective bump 12b1 in the effective discharge area is formed. Widen the position. As a result, the amount of the solder paste 12j applied at the position where the non-effective bump 12b2 in the non-effective discharge area is formed is larger than the position where the effective bump 12b1 in the effective discharge area is formed.

  The steps shown in FIGS. 9C to 9D are the same as those shown in FIG.

  10A to 10C are cross-sectional views showing still another specific example of the method for adjusting the height of the electrode bump 12b shown in FIG. 7D.

  As shown in FIG. 10A, a solder paste 12j is applied to a bumpless FPC 12y by a dispenser 12q having a nozzle 12r. In this case, the application amount of the solder paste 12j is made larger at the position where the non-effective bump 12b2 in the non-effective discharge area is formed than at the position where the effective bump 12b1 in the effective discharge area is formed.

  The steps shown in FIGS. 10B to 10C are the same as those shown in FIG.

[Third Embodiment]
FIGS. 11A to 11C are cross-sectional views showing a process of joining the FPC portion and the piezoelectric element portion in the method of manufacturing the droplet discharge head according to the third embodiment.

  As shown in FIG. 11C, the piezoelectric element 8 in the droplet discharge head according to the third embodiment includes an effective piezoelectric element 8A (effective individual electrode 8a1, effective common electrode 8b1, Non-effective piezoelectric element 8B (non-effective individual electrode 8a2, non-effective common electrode) that does not directly contribute to the electrical connection between the effective piezoelectric element member 8c1) and the conductive pattern 12a disposed in the non-effective discharge area 8b2, an ineffective piezoelectric element member 8c2), and among the ineffective bumps 12b2, the ineffective bumps 12b2 at least at the three-point support positions connect the effective individual electrodes 8a1 and the conductive patterns 12a of the piezoelectric elements 8 to the effective bumps 12b1. Before being electrically connected to the non-effective individual electrode 8a2 of the non-effective bump 12b2 and having a height higher than that of the effective bump 12b1. In the first embodiment, the effective bump 12b1 that has been hindered from contacting the effective individual electrode 8a1 has a height that can be achieved by reducing the height of the non-effective bump 12b2 by heat melting. It is different from the case.

  In this case, the non-effective individual electrode 8a2 in the piezoelectric element 8 is disposed in the non-effective discharge region located at the outermost peripheral portion of the effective discharge region where the effective individual electrode 8a1 is disposed.

  The relationship between the height of such an ineffective bump 12b2 and the height of other components is expressed by the following equation.

  Hd> Hj and S ≧ Hd−Hj

  In the above formula, Hd represents the height of the ineffective bump 12b2, Hj represents the height of the effective bump 12b1, and S represents the amount of decrease in height due to thermal melting of the ineffective bump 12b2.

  Hereinafter, a step of joining the FPC portion and the piezoelectric element portion in the manufacturing method of the droplet discharge head according to the third embodiment will be described.

(Alignment)
As shown in FIG. 11A, the piezoelectric element 8 and the FPC 12 obtained in the process shown in FIG. 4 are opposed to each other and are aligned by visual observation or automatic image recognition. Although there is no restriction | limiting in particular as an alignment method, For example, the method of aligning with an FPC alignment mark and the electrode pad of a piezoelectric element, the method of aligning with an alignment mark, the method of aligning with a positioning hole, etc. can be mentioned. In FIG. 11A, an ineffective piezoelectric element 8B is disposed in a region where the ineffective bump 12b2 faces.

(Lamination)
As shown in FIG. 11B, the FPC 12 and the piezoelectric element 8 are bonded together. The non-effective bump 12b2 contacts the non-effective piezoelectric element 8B, but the effective bump 12b1 does not contact the effective piezoelectric element 8A of the piezoelectric element 8.

(Joining)
As shown in FIG. 11 (c), the heater 13 is pressed from the opposite surface (the surface of the base film 12 d) of the piezoelectric element 8 of the FPC 12 and heated while being pressurized by the heater 13. The ineffective bumps 12b2 and the effective bumps 12b1 made of solder are heated and melted to reduce the height, and the FPC 12 settles to the effective piezoelectric element 8A and the ineffective piezoelectric element 8B side. Thereafter, the effective bumps 12b1 come into contact with the effective individual electrodes 8a1 of the piezoelectric element 8. However, since the effective bumps 12b1 are thermally melted, they are joined by soldering without causing cracks in the effective piezoelectric elements 8A in the effective discharge region. Can be completed.

[Modification of Third Embodiment]
12A to 12C are cross-sectional views illustrating a process of joining the FPC portion and the piezoelectric element portion in the manufacturing method of the droplet discharge head according to the modified example of the third embodiment.

  As shown in FIG. 12, in this modification, the electrode bump 12b in the FPC 12 has a high melting point metal (for example, copper, silver, etc.) having a melting point higher than that of the solder 12g due to the outer peripheral portion made of the solder 12g that is a heat melting metal. Etc.) is the same as in the case of the second embodiment, except that the core 12h made of the same is used. In this case, when heated while being pressurized by the heater 13, the ineffective bump 12b2 and the effective bump 12b1 are melted by heat, the FPC 12 settles to the effective piezoelectric element 8A and the ineffective piezoelectric element 8B side, and the core 12h of the electrode bump 12b The effective piezoelectric element 8A and the non-effective piezoelectric element 8B are contacted and stopped. While the effective bumps 12b1 come into contact with the effective individual electrodes 8a1 of the effective piezoelectric element 8A during the sedimentation of the FPC 12, the effective bumps 12b1 are thermally melted without causing cracks in the effective piezoelectric elements 8A in the effective discharge area. Joining by soldering can be completed.

  In the case of the droplet discharge head obtained in this modification, the relationship between the height of the non-effective bump 12b2 and the height of other components is expressed by the following equation.

  Hd> Hj and S ≧ Hd−Hj and Hd−S ≧ D

  In the above formula, Hd is the height of the ineffective bump 12b2, Hj is the height of the effective bump 12b1, S is the amount of decrease in height due to thermal melting of the ineffective bump 12b2, and D is the diameter of the core 12h of the electrode bump 12. Each is shown.

[Fourth Embodiment]
(Color printer configuration)
FIG. 13 is a configuration diagram of a color printer to which the liquid droplet ejection apparatus according to the fourth embodiment of the present invention is applied. This color printer 100 has a substantially box-shaped casing 101, a paper feed tray 20 for storing paper P in the lower part of the casing 101, and a recorded paper P in the upper part of the casing 101. Each of the discharged paper discharge trays 21 is disposed, main conveyance paths 31a to 31e from the paper supply tray 20 via the recording position 102 to the paper discharge tray 21, and from the paper discharge tray 21 side to the recording position 102 side. A transport mechanism 30 that transports the paper P along the reverse transport path 32 is provided.

  At the recording position 102, a plurality of droplet discharge heads 1 shown in FIG. 1 are arranged in parallel to form a droplet discharge head unit. The four droplet discharge head units are respectively yellow (Y) and magenta (M). As a droplet discharge head unit 41 (41Y, 41M, 41C, 41K) that discharges ink droplets of each color of cyan, (C), and black (K), a droplet discharge head array is configured by arranging in the paper P transport direction. is doing. Details of the arrangement will be described later.

  In addition, the color printer 100 includes a charging roll 43 as an adsorbing unit that adsorbs the paper P, a platen 44 disposed to face the droplet discharge head units 41Y, 41M, 41C, and 41K via the endless belt 35. The maintenance unit 45 disposed in the vicinity of the droplet discharge head units 41Y, 41M, 41C, and 41K and each part of the color printer 100 are controlled, and the droplet discharge head units 41Y, 41M, 41C, A control unit (not shown) that records a color image on the paper P by applying a driving voltage to the piezoelectric element 8 of the droplet discharge head 1 constituting 41K, discharging ink droplets from the nozzles 2a, is provided.

  The droplet discharge head units 41 </ b> Y, 41 </ b> M, 41 </ b> C, and 41 </ b> K have an effective print area that is equal to or larger than the width of the paper P. In addition, although the piezoelectric method was used as a method for discharging droplets, there is no particular limitation, and for example, a widely used method such as a thermal method can be appropriately used.

  Ink tanks 42Y, 42M, 42C, and 42K that store inks corresponding to the droplet discharge head units 41Y, 41M, 41C, and 41K are disposed above the droplet discharge head units 41Y, 41M, 41C, and 41K. is doing. From each ink tank 42Y, 42M, 42C, 42K, it is comprised so that ink may be supplied to each droplet discharge head 1 via piping which is not shown in figure.

  The ink stored in the ink tanks 42Y, 42M, 42C, and 42K is not particularly limited, and for example, commonly used inks such as water-based, oil-based, and solvent-based inks can be appropriately used.

  The transport mechanism 30 is disposed in each part of the pick-up roll 33 that takes out the paper P one by one from the paper feed tray 20 and supplies it to the main transport path 31a, the main transport paths 31a, 31b, 31d, 31e, and the reverse transport path 32. A plurality of transport rolls 34 that transport the paper P, an endless belt 35 that is provided at the recording position 102 and transports the paper P in the direction of the paper discharge tray 21, a drive roll 36 on which the endless belt 35 is stretched, and a follower A roll 37 and a drive motor (not shown) that drives the transport roll 34 and the drive roll 36 are provided.

(Color printer operation)
Next, the operation of the color printer 100 will be described. The transport mechanism 30 drives the pickup roll 33 and the transport roll 34 under the control of the control unit, takes out the paper P from the paper feed tray 20, and transports it along the main transport paths 31a and 31b. When the paper P reaches the vicinity of the endless belt 35, electric charge is applied to the paper P by the electrostatic attraction force of the charging roll 43, and the paper P is attracted to the endless belt 35.

  The endless belt 35 is rotated by the drive of the drive roll 36, and when the paper P is conveyed to the recording position 102, a color image is recorded by the droplet discharge head units 41Y, 41M, 41C, 41K.

  The paper P on which the color image is recorded is discharged to the paper discharge tray 21 by the transport mechanism 30 via the main transport path 31d.

  When the duplex recording mode is set, the paper P once discharged to the paper discharge tray 21 returns to the main transport path 31e again, passes through the reverse transport path 32, and again passes through the main transport path 31b. Then, the color image is recorded on the surface opposite to the surface of the paper P recorded last time by the droplet discharge head units 41Y, 41M, 41C, and 41K.

  The present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the invention.

  The liquid droplet discharge head, the manufacturing method thereof, and the droplet discharge apparatus of the present invention are various industrial fields in which high-definition image information patterns are required to be formed by discharging droplets, such as polymer films. Ink is ejected onto the glass surface using an ink jet method to form a color filter for display, solder paste is ejected onto the substrate to form bumps for component mounting, and circuit board wiring is formed. It is effectively used in the electrical / electronic industry fields such as the medical field for producing biochips for inspecting the reaction with a sample by discharging a reaction reagent onto a glass substrate or the like.

1 is a cross-sectional view showing a droplet discharge head according to a first embodiment of the present invention. The piezoelectric element part and the flexible printed wiring board part before joining are shown, (a) is a plan view, (b) is a partially enlarged view of part A in (a), and (c) is B- in (b). It is B line sectional drawing. The flexible printed wiring board part and the piezoelectric element part before joining are shown, (a) is a plan view, (b) is a partially enlarged view of part C of (a), and (c) is a D- It is D line sectional drawing. (A)-(f) is sectional drawing which shows the process of forming FPC among the manufacturing methods of the droplet discharge head of 1st Embodiment. (A)-(c) is sectional drawing which shows the process of joining the FPC part and a piezoelectric element part after the process shown in FIG. 4 among the manufacturing methods of the droplet discharge head of 1st Embodiment. is there. (A)-(f) is sectional drawing which shows the process of forming FPC among the manufacturing methods of the droplet discharge head of the modification of 1st Embodiment. (A)-(d) is sectional drawing which shows the process of forming FPC among the manufacturing methods of the droplet discharge head of 2nd Embodiment. (A)-(c) is sectional drawing which shows one specific example of the method of adjusting the height of the electrode bump 12b shown in FIG.7 (d). (A)-(d) is sectional drawing which shows the other specific example of the method of adjusting the height of the electrode bump 12b shown in FIG.7 (d). (A)-(c) is sectional drawing which shows the other specific example of the method of adjusting the height of the electrode bump 12b shown in FIG.7 (d). (A)-(c) is sectional drawing which shows the process of joining an FPC part and a piezoelectric element part among the manufacturing methods of the droplet discharge head of 3rd Embodiment. (A)-(c) is sectional drawing which shows the process of joining an FPC part and a piezoelectric element part among the manufacturing methods of the droplet discharge head of the modification of 3rd Embodiment. It is a block diagram of the head unit of the color printer to which the droplet discharge apparatus which concerns on the 4th Embodiment of this invention is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Droplet discharge head 2 Nozzle plate 2a Nozzle 3 Laminated plate 3a Pressure generating chamber 7 Diaphragm 8 Piezoelectric element 8a Individual electrode 8a1 Effective individual electrode 8a2 Ineffective individual electrode 8b Common electrode 8b1 Effective common electrode 8b2 Ineffective common electrode 8c Piezoelectric element Member 8c1 Effective piezoelectric element member 8c2 Ineffective piezoelectric element member 12 Flexible printed circuit board (FPC)
12a Conductive pattern 12b Electrode bump 12b1 Effective bump 12b2 Ineffective bump 12c Cover layer 12d Base film 12f Bump pad 12g Solder 12h Core 12i Flux 12j Solder paste 12k Solder ball 12m Screen 12n Opening 12p Squeegee 12q Dispenser 12r Nozzle 13 Heater 20 Supply Paper tray 21 Paper discharge tray 30 Transport mechanisms 31a to 31e Main transport path 32 Reverse transport path 33 Pickup roll 34 Transport roll 35 Endless belt 36 Drive roll 37 Followed rolls 41Y, 41M, 41C, 41K Droplet discharge head units 42Y, 42M, 42C, 42K Ink tank 43 Charging roll 44 Preten 45 Maintenance unit 100 Color printer 101 Housing 102 Recording position P Paper S Channel Wood

Claims (12)

A flow path member having a plurality of nozzles and pressure generation chambers communicated with each other by a flow path structure;
A diaphragm disposed on the opposite side of the flow path member from the nozzle;
The electrode is disposed on the diaphragm, has an electrode, is deformed when a drive signal is supplied to the electrode, changes the volume in the pressure generating chamber, and stores the liquid stored in the pressure generating chamber A plurality of piezoelectric elements ejected as droplets from a nozzle;
A conductive pattern that supplies the drive signal to the electrode of the piezoelectric element, and a wiring board having a plurality of electrode bumps that are electrically connected by thermally melting the electrode of the piezoelectric element and the conductive pattern; A liquid droplet ejection head comprising:
The wiring board includes, as the electrode bumps, effective bumps disposed in an effective discharge region that is a region for discharging the droplets from the nozzle, and regions that do not discharge the droplets from the nozzles other than the discharge region. A non-effective bump that is disposed in the non-effective discharge region and does not directly contribute to the electrical connection between the electrode of the piezoelectric element and the conductive pattern, and
Among the non-effective bumps, the non-effective bumps at least at the three-point support position have a height higher than the effective bumps before electrically connecting the electrode and the conductive pattern by the effective bumps. The height of the ineffective bump, which has been hindered by contact with the diaphragm side of the ineffective bump, can be reduced by reducing the height of the ineffective bump due to thermal melting. A droplet discharge head characterized by that.   The piezoelectric element is not effective as the electrode and does not directly contribute to the electrical connection between the effective electrode disposed in the effective ejection region and the conductive pattern disposed in the ineffective ejection region. The non-effective bumps at least at the three-point support position among the non-effective bumps before electrically connecting the effective electrode of the piezoelectric element and the conductive pattern by the effective bumps. The contact between the effective bump and the effective electrode, which has a height higher than the effective bump and is prevented by the contact of the non-effective bump with the non-effective electrode, is due to the thermal melting of the non-effective bump itself. The droplet discharge head according to claim 1, wherein the droplet discharge head has a height that can be achieved by a reduction in height.   The ineffective bump in the wiring board is disposed in the ineffective discharge area located at an outermost peripheral portion of the effective discharge area in which the effective bump is disposed. Droplet discharge head.   The ineffective electrode in the piezoelectric element is disposed in the ineffective discharge region located at an outermost peripheral portion of the effective discharge region in which the effective electrode is disposed. Droplet discharge head.   The electrode bump in the wiring board is formed by coating a core made of a refractory metal having a higher melting point than the heat-fusible metal with an outer peripheral part made of a heat-fusible metal. 2. A droplet discharge head according to 1. A flow path member having a plurality of nozzles and pressure generating chambers communicated with each other by a flow path structure, a vibration plate disposed on the opposite side of the flow path member from the nozzle, and disposed on the vibration plate, A plurality of electrodes that are deformed when a drive signal is supplied to the electrodes, change a volume in the pressure generation chamber, and discharge liquid stored in the pressure generation chamber as droplets from the nozzle; A piezoelectric element; a conductive pattern that supplies the drive signal to the electrode of the piezoelectric element; and a plurality of electrode bumps that electrically connect the electrode of the piezoelectric element and the conductive pattern by thermally melting them. A method of manufacturing a droplet discharge head including a wiring board,
As the electrode bumps on the wiring board, effective bumps are applied to an effective discharge area which is an area for discharging the liquid droplets from the nozzle, and non-effective areas which are areas other than the discharge area where the liquid droplets are not discharged from the nozzle. An ineffective bump that does not directly contribute to the electrical connection between the electrode of the piezoelectric element and the conductive pattern is disposed in the ejection region, and the ineffective bump at least at the three-point support position among the ineffective bumps. The bump is formed at a height higher than that of the effective bump, and the contact of the ineffective bump with the electrode that has been hindered by the contact of the ineffective bump with the diaphragm side is caused by the ineffective bump itself. A first step of forming to a height that is made possible by a reduction in height due to thermal melting;
The wiring substrate obtained in the first step and the piezoelectric element are opposed to each other and heated and pressed to bring the non-effective bumps into contact with the diaphragm side, and then the high-efficiency due to thermal melting of the non-effective bumps. A second step of bringing the effective bumps that have been thermally melted into contact with the electrode of the piezoelectric element and electrically connecting the electrode of the piezoelectric element and the conductive pattern due to a decrease in thickness. A manufacturing method of a droplet discharge head characterized by the above.   In the first step, first, a wiring board with bumps in which the effective bumps and the ineffective bumps are all formed at a uniform height is prepared as the wiring board, and then the non-bumping in the wiring board with bumps is prepared. The effective bump is adjusted to a height that is higher than the effective bump, and the height of the non-effective bump itself is adjusted to a height that enables contact of the effective bump with the electrode due to thermal melting. The method of manufacturing a droplet discharge head according to claim 6.   In the first step, first, as the wiring substrate, a bumpless wiring substrate in which only the conductive pattern is disposed is prepared, and then, the effective bump and the ineffective bump are provided on the wiring substrate without bump. The height of the non-effective bump is higher than that of the effective bump, and the height of the non-effective bump can be contacted with the electrode by reducing the height of the non-effective bump by heat melting. The method of manufacturing a droplet discharge head according to claim 6, wherein the droplet discharge head is formed so as to be adjusted.   The ineffective bump in the wiring board is characterized in that a core portion made of a refractory metal having a higher melting point than the heat meltable metal is coated with an outer peripheral portion made of a heat meltable metal. A method for manufacturing a droplet discharge head according to claim 6.   The height of the non-effective bump is adjusted in the first step by further disposing a heat-meltable metal on the non-effective bump of the wiring board with bumps. 8. A method for manufacturing a droplet discharge head according to item 7.   In the first step, the ineffective bump is formed by disposing a larger amount of hot-melt metal than the portion where the effective bump is formed in the portion where the ineffective bump is formed in the wiring board without bump. The method of manufacturing a droplet discharge head according to claim 8, wherein the height of the bump is adjusted. In a droplet discharge device including a plurality of droplet discharge heads that discharge liquid as droplets from a plurality of nozzles toward a discharge target surface by driving a plurality of piezoelectric elements,
The droplet discharge head is
A flow path member having a plurality of nozzles and pressure generating chambers communicated with each other by a flow path structure, a vibration plate disposed on the opposite side of the flow path member from the nozzle, and disposed on the vibration plate, A plurality of electrodes that are deformed when a drive signal is supplied to the electrodes, change a volume in the pressure generation chamber, and discharge liquid stored in the pressure generation chamber as droplets from the nozzle; A wiring having a piezoelectric element, a conductive pattern that supplies the drive signal to the electrode of the piezoelectric element, and a plurality of electrode bumps that are electrically connected by thermally melting the electrode of the piezoelectric element and the conductive pattern A droplet discharge head comprising a substrate,
The wiring board, as the electrode bump, an effective bump disposed in an effective discharge area that is an area for discharging the liquid droplet from the nozzle, and an area that does not discharge the liquid droplet from the nozzle other than the discharge area A non-effective bump that is disposed in the non-effective discharge region and does not directly contribute to the electrical connection between the electrode of the piezoelectric element and the conductive pattern, and
Among the non-effective bumps, the non-effective bumps at least at the three-point support position have a height higher than the effective bumps before electrically connecting the electrode and the conductive pattern by the effective bumps. The height of the ineffective bump, which has been hindered by contact with the diaphragm side of the ineffective bump, can be reduced by reducing the height of the ineffective bump due to thermal melting. A droplet discharge apparatus, which is a droplet discharge head.

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