JP2009241437A - Liquid droplet ejection head and wiring unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid droplet ejection head which prevents deformation of a piezoelectric layer from being hindered by adhesion of an excessive conductive material, prevents the occurrence of ion migration, can suppress enlargement of a driving electrode, and can further efficiently radiate heat, and to provide a wiring unit used for this. <P>SOLUTION: The liquid droplet ejection head 1 has through-holes 81a and 21c formed to a power supply terminal 50 and a sheetlike base 12a equipped in the wiring unit 12. The through-holes 81a and 12c penetrate from the surface of a piezoelectric unit side 11 to the surface of the opposite side. Recesses 87a-90a communicating with the through-holes 81a and 12c are formed to the surface of the opposite side to the piezoelectric unit 11 side in the sheetlike base 12a so that the excessive amount of the conductive material 52 is stored through the through-holes 81a and 12c at the time of stacking of the piezoelectric unit 11 and the sheetlike base 12a each other. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a wiring unit that has a plurality of power supply terminals electrically connected to a drive electrode through a conductive material and is stacked on one surface of a piezoelectric unit, and a droplet discharge head including the wiring unit About.

  In recent years, as a liquid droplet ejection head, for example, one mounted on an ink jet printer apparatus, there is a demand for a high density of flow paths (channels) that guide ink to nozzle holes. Here, there is a liquid droplet ejection head as disclosed in Patent Document 1, specifically, a flow path unit in which a plurality of flow paths for guiding ink to a plurality of nozzle holes are formed, Drive signals are sent to a plurality of drive electrodes arranged on the upper surface of the piezoelectric unit and a piezoelectric unit that is stacked on the upper surface of the flow channel unit and stacked with a piezoelectric layer to apply ejection pressure to the ink in the flow channel. And a wiring unit for output. Among these, each drive electrode of the piezoelectric unit is individually connected to the electrode portion corresponding to the pressure chamber provided in the middle of each flow path of the flow path unit and the plurality of power supply terminals of the wiring unit via the conductive material. It is comprised from the disk-shaped connection terminal connected. A conductive material such as solder is placed on the disk-shaped connection terminal.

By the way, the connection terminal of the drive electrode and the power supply terminal are connected by laminating the wiring unit and the piezoelectric unit through a conductive material such as solder. If the solder capacity is small, the solder height is sufficient. In other words, problems such as failure to join between the two terminals, or poor bonding when the solder placement area is narrow and the connection terminal and the power feeding terminal are misaligned and stacked are likely to occur. Also, the mechanical joint strength is weakened. For this reason, the capacity of the solder is set slightly larger. The solder does not flow out even if the solder is set slightly larger due to its surface tension. However, of the solder melted at the time of thermocompression bonding, when surplus flows out to the surroundings due to variations in applied pressure or variations in the amount of solder, the surplus solder adheres to the piezoelectric layer on the pressure chamber. When cured, the deformation of the piezoelectric layer is hindered, making it difficult to apply ejection pressure to the ink in the pressure chamber. Therefore, in Patent Document 1, even when surplus solder flows out of the connection terminal by disposing the connection terminal away from the region occupied by the pressure chamber when viewed in plan, the piezoelectric layer on the pressure chamber This prevents the piezoelectric layer from being hindered from being deformed.
Japanese Patent Laying-Open No. 2006-62211 (see FIG. 7)

  However, in the case of the configuration as in Patent Document 1, since the connection terminal is provided relatively far from the electrode portion, the size of each drive electrode becomes large, and the above-described demand for higher channel density is required. It becomes difficult to respond. Even when the pressure chamber is outside the region occupied by the conductive material, such as excess solder, flows out on the piezoelectric layer and hardens, there is a possibility that the deformation of the piezoelectric layer is hindered. Furthermore, if the surplus conductive material that has flowed out is close to another adjacent drive electrode, metal ions diffuse (ion migration) from the drive electrode over a long period of time in this state, and this is close to the drive electrode. There is a possibility of reaching the surplus conductive material. In this case, since the adjacent drive electrodes are in a conductive state, it becomes impossible to individually control the liquid in the flow path corresponding to these drive electrodes.

  In addition, apart from the situation due to the surplus of the conductive material as described above, in the droplet discharge head, heat generated by driving the piezoelectric unit or heat generated from a drive circuit (IC chip or the like) provided in the wiring unit is generated. There is also a desire to dissipate efficiently. Here, in the conventional droplet discharge head, a metal heat radiating plate is connected to the upper surface of the wiring unit (the surface opposite to the connection surface with the piezoelectric unit), and the heat described above is transferred from the heat radiating plate to the atmosphere. Is dissipated. However, such a heat radiating plate may have a relatively large thickness and increase in weight, or may not secure a sufficient adhesion area with the wiring unit and may not obtain a desired heat radiating effect.

  These circumstances are not limited to the droplet discharge heads included in the illustrated inkjet printer apparatus, and may also apply to those mounted in other apparatuses.

  Therefore, the present invention can prevent deformation of the piezoelectric layer due to the adhesion of surplus conductive material, prevent the occurrence of ion migration, suppress the increase in size of the drive electrode, and more efficiently. An object of the present invention is to provide a droplet discharge head that can dissipate heat and a wiring unit used therefor.

  A droplet discharge head according to the present invention includes a piezoelectric unit in which a plurality of drive electrodes are arranged close to one surface of a piezoelectric layer, a sheet-like base material, and the sheet-like base material provided on the drive electrode. A plurality of power supply terminals electrically connected via a conductive material, and a wiring unit stacked on the one surface of the piezoelectric unit, and based on an electrical signal from the power supply terminal to the drive electrode The piezoelectric unit is configured to discharge the liquid in the liquid channel of the channel unit stacked on the other surface of the piezoelectric unit to the outside by driving the piezoelectric unit. The material is formed with a through-hole penetrating from the surface on the piezoelectric unit side to the surface on the opposite side, and an excess portion of the conductive material is accommodated through the through-hole when the piezoelectric unit and the sheet-like base material are laminated. As much as possible The surface opposite to the piezoelectric unit side in the sheet-like base material, the recess communicating with the through-hole.

  By adopting such a configuration, the conductive material is interposed between the power supply terminal and the drive terminal, and the surplus conductive material is accommodated in the through hole or the recessed portion ahead of the conductive material. It is possible to reduce the surplus flowing out. Accordingly, it is possible to reduce the size of the drive electrode and increase the density of the flow path, and it is possible to prevent the deformation or the ion migration from adhering to and curing on the piezoelectric layer. Furthermore, the heat generated in the piezoelectric unit can be dissipated from the surface side of the sheet-like substrate via the drive electrode and the conductive material, and the heat generated from the drive circuit provided in the wiring unit can also be reduced by using the wiring and conductive material. Since it can dissipate from the surface side of a sheet-like base material via, it can thermally radiate efficiently.

  In addition, the wiring unit according to the present invention includes a sheet-like base material laminated on the one surface of the piezoelectric unit in which a plurality of drive electrodes are arranged close to one surface of the piezoelectric layer, and the sheet-like base material A plurality of power supply terminals that are electrically connected to each of the drive electrodes via a conductive material, and the power supply terminals and the sheet-like base material are opposite to the surface on the piezoelectric unit side. A through hole penetrating into the surface is formed, and a concave portion communicating with the through hole is provided on the surface of the sheet-like base material opposite to the piezoelectric unit side.

  By adopting such a configuration, as described above, it is possible to reduce the size of the drive electrode and increase the density of the flow path. Can be prevented. Furthermore, the heat generated in the piezoelectric unit and the heat generated from the drive circuit provided in the wiring unit can be efficiently dissipated from the surface side of the sheet-like substrate.

  Moreover, the said recessed part may be formed so that the opening of the said through-hole in the surface on the opposite side to the said piezoelectric unit side of the said sheet-like base material may be located inward. By setting it as such a structure, the excess electrically conductive material which reached the surface side of the sheet-like base material through the through-hole can be reliably accommodated in a recessed part. Moreover, the heat dissipation efficiency can be improved by making the opening of the recess larger than the through hole.

  The sheet-like base material may be provided with a coating layer that is laminated on a surface opposite to the piezoelectric unit side and covers the concave portion. By adopting such a configuration, it is possible to prevent excess conductive material reaching the concave portion from flowing out of the concave portion, and thus preventing the conductive materials in two adjacent concave portions from being connected and becoming conductive. can do.

  Further, the layer that forms the surface on the piezoelectric unit side of the sheet-like base material and the coating layer in the state where the power supply terminal is exposed are formed of the same material or a material having substantially the same coefficient of thermal expansion. Also good. In the sheet-like base material, the layer forming the surface on the piezoelectric unit side and the covering layer have substantially the same temperature due to the heat transmitted through the conductive material. Since the thermal expansion coefficient is the same or substantially the same, it is possible to prevent the wiring unit from being warped or distorted by heat.

  The conductive material may be solder. With such a configuration, even when a solder generally used for connecting the piezoelectric unit and the wiring unit is used as a conductive material, it can be electrically and mechanically reliably connected, and the above-described operational effects are expected. can do.

  According to the present invention, it is possible to prevent the deformation of the piezoelectric layer from being inhibited by the adhesion of an excessive conductive material, to prevent the occurrence of ion migration, and to suppress the increase in size of the drive electrode, and further to improve efficiency. In addition, it is possible to provide a droplet discharge head that can dissipate heat and a wiring unit used therefor.

  Hereinafter, a droplet discharge head according to an embodiment of the present invention will be specifically described with reference to the drawings.

  FIG. 1 is a cross-sectional view of a carriage on which a droplet discharge head according to this embodiment is mounted, and illustrates an inkjet head of an inkjet printer apparatus as the droplet discharge head. 1A shows a cross-sectional view of the ink jet head as viewed from one side, and FIG. 1B shows the ink jet head cut along line AA in FIG. 1A. FIG.

  As shown in FIG. 1, the carriage 1 includes, for example, an ink tank 3 that supplies inks (liquids) of each color such as cyan, magenta, yellow, and black independently to a flow path unit 10 described below, A holder case 4 that accommodates and holds the ink tank 3 and an inkjet head 6 that is attached to the lower portion of the holder case 4 via a support frame 5 are provided. In addition, as shown in FIGS. 2 and 3, which will be described later, the inkjet head 6 has a piezoelectric unit on the upper surface of a flow path unit 10 in which a plurality of plates are laminated and bonded to each other and has a liquid flow path 10a (see FIG. 2). 11 is laminated and bonded, and a wiring unit (chip-on-film) 12 is further laminated and bonded to the upper surface of the piezoelectric unit 11. A driver IC 51 (see FIG. 3) as a drive circuit is connected to the wiring unit 12, and the driver IC 51 outputs a drive signal for selectively driving the piezoelectric unit 11 based on print data from the main body side. . The carriage 1 having such an ink jet head 6 is configured to be movable in parallel with the paper surface of the recording paper, similarly to a known ink jet printer device, and by ejecting ink droplets from the ink jet head 6 while moving. An image can be formed on the paper.

  2 is an enlarged cross-sectional view of the inkjet head 6 provided in the carriage 1 shown in FIG. 1. FIG. 3 is an exploded view of the inkjet head 6 into a flow path unit 10, a piezoelectric unit 11, a wiring unit 12, and a support frame 5. FIG.

  As shown in FIG. 2, the flow path unit 10 of the inkjet head 6 includes a pressure chamber plate 20, a first spacer plate 21, a throttle plate 22, a second spacer plate 23, a first common liquid chamber plate 24, and a second common. The liquid chamber plate 25, the damper plate 26, the cover plate 27, and the nozzle plate 28 are arranged from above in this order and are laminated and bonded to each other.

  Among these, the nozzle plate 28 is a resin sheet such as polyimide, and the other plates 20 to 27 are 42% nickel alloy steel plate (42 alloy) or a metal plate such as stainless steel, and each has a rectangular shape in plan view. Each has a thickness of about 50 to 150 μm. Each of the plates 21 to 27 is formed with an opening or a recess constituting the liquid flow path (channel) 10a by etching, laser processing, plasma jet processing, or the like.

  The nozzle plate 28 in the lowermost layer of the flow path unit 10 is provided with a large number of nozzle holes 28a for discharging ink droplets having a minute diameter at minute intervals, and the nozzle holes 28a are arranged in the long side direction of the nozzle plate 28 ( It is arranged in a row extending along the X direction in FIG. 3, and five rows are provided in the short side direction (the Y direction in FIG. 3). Further, the pressure chamber plate 20 located in the uppermost layer in the flow path unit 10 is formed with a plurality of pressure chamber holes 20a to be a plurality of pressure chambers 31 penetrating the pressure chamber plate 20 in the thickness direction, and the nozzle Five rows are provided in the Y direction in a row along the X direction corresponding to the holes 28a. The pressure chamber hole 20a has an elongated shape in plan view that is long in the Y direction, and is arranged such that its longitudinal direction (Y direction) is along the direction (X direction) orthogonal to the row of nozzle holes 28a. The plurality of pressure chamber holes 20a form a plurality of pressure chambers 31 having an internal space by laminating the piezoelectric units 11 from above and laminating the first spacer plates 21 from below.

  Each opening from the first spacer plate 21 to the cover plate 27 is formed to penetrate each opening serving as a nozzle communication channel 36 that communicates with one end portion of each pressure chamber 31 and communicates with each nozzle hole 28a. The first spacer plate 21, the diaphragm plate 22, and the second spacer plate 23 are penetrated by openings 21 a and 23 a and a throttle hole 22 a that serve as a connection channel 33 that communicates the common ink chamber 35 and the other end of the pressure chamber 31. Is formed.

  Further, the two common liquid chamber plates 24 and 25 extend along the row direction (X direction) at a lower position corresponding to the position where the pressure chambers 31 are arranged in the row direction (X direction). The common ink chamber holes 24a and 25a to be the common ink chamber 35 are formed so as to penetrate the common liquid chamber plates 24 and 25 in the thickness direction, and are arranged in five rows in the short side direction (Y direction) of the flow path unit 10. Is provided. In addition, a damper wall 26 a in which a surface opposite to the surface facing the common liquid chamber 35 is formed in the damper plate 26 so as to be thin is formed corresponding to the shape of the common liquid chamber 35. The second spacer plate 23, the two manifold plates 24 and 25, the damper plate 26, and the cover plate 27 are stacked in this order, so that the common liquid chamber 35 and the damper space 26b are formed in five rows in the Y direction. It is formed. Further, a nozzle plate 28 having a plurality of nozzle holes 28a is laminated and bonded to the cover plate 27 from below.

  By laminating these plates 20 to 28, open holes and grooves communicated with each other are formed, and an ink flow path 10a through which ink flows is formed. That is, the ink flow path 10a includes the common ink chamber 35, the connection flow path 33, the pressure chamber 31, the nozzle communication flow path 36, and the nozzle 28a. With the above configuration, the ink supplied from the ink tank 3 (see FIG. 1) into the flow path unit 10 passes through the common ink chamber 35, the connection flow path 33, the pressure chamber 31, and the nozzle communication flow path 36 in order, 28a.

  The plates 20 to 23 from the pressure chamber plate 20 to the second spacer plate 23 correspond to four color inks by corresponding the upper and lower positions to one end in each longitudinal direction (X direction). Four ink supply ports 34 are formed (see FIG. 3). The four color inks from the ink tank 3 are independently supplied to the ink supply port 34. The ink supply port 34 communicates with one end in the longitudinal direction of the common liquid chamber 35 of the first and second common liquid chamber plates 24 and 25, and supplies each ink from the ink supply port 34 to the common liquid chamber 35. Is done. The ink supply port 34 into which black ink that is frequently used flows is formed larger than the other, and communicates with one end of the two common liquid chambers 35 in the X direction and is connected to the two ink flow paths 10a. Yes. The other ink supply ports 34 communicate with one end portion in the X direction of one common liquid chamber 35 independent of each other, and are connected with the remaining ink flow passage 10a. As described above, the flow path unit 10 has five ink flow paths, and the inkjet head 6 is configured to be able to eject four types of inks independently of each other.

As shown in FIG. 1, the ink supply port 34 is provided for each ink color of the ink tank 3 mounted on the holder case 4 when the inkjet head 6 is attached to the holder case 4 via the support plate 5. The ink outlets 3 a and the ink connection ports 5 c of the support plate 5 are connected in communication. (See Figs. 1 and 3)
On the other hand, as shown in FIG. 3, the piezoelectric unit 11 has a rectangular external shape that is long in the X direction in a plan view. Also, as shown in FIG. The piezoelectric sheets 40 to 45 and an insulating top sheet 46 are laminated. The piezoelectric sheets 40 to 45 are made of a lead zirconate titanate (PZT) ceramic material having a thickness of about 30 μm.

  Among the piezoelectric sheets 40 to 45, a large number of piezoelectric sheets 41 and 43 that are counted upward from the lowermost piezoelectric sheet 40 are arranged on the upper surface so as to individually correspond to the positions of the pressure chambers 31. The individual electrodes 47 are printed and formed in five rows so as to correspond to the respective rows formed by the pressure chambers 31. Further, on the upper surface of the odd-numbered piezoelectric sheets 40, 42, 44 counted upward from the lowermost piezoelectric sheet 40, a common electrode is arranged so as to cover all the individual electrodes 47 for each row when viewed in plan. 48 is printed. The individual electrode 47 and the common electrode 48 are a plurality of piezoelectric sheets 40 to 45 and a plurality of pieces provided on the top surface of the top sheet 46 via relay wiring (not shown) provided on the side end surfaces of the top sheet 46 or through holes (not shown). It is electrically connected to the drive electrode 49 (see also FIG. 3).

  The drive electrode 49 has an individual drive electrode 49a and a common drive electrode 49b. Among these, the individual drive electrodes (drive electrodes) 49a conducted to the individual electrodes 47 through the through holes are provided in a row so as to be elongated in the X direction and overlap the pressure chambers 20 in a plan view of the upper surface of the actuator. 5 rows corresponding to the pressure chambers 20 are formed. Further, the common drive electrode 49b is formed in a band shape along both ends (short sides) in the X direction across a set of a plurality of individual drive electrodes 49a. The common drive electrode 49b is electrically connected to the common electrode through a through hole and grounded. Has been. The electrodes 47 and 48 and the drive electrode 49 are screen-printed with an Ag—Pd-based conductive material.

  The piezoelectric unit 11 has a smaller outer shape than the flow path unit 10 and is disposed so as to expose the ink supply port 34 at one end of the flow path unit 10 in the X direction. 47 and the pressure chamber 31 of the flow path unit 10 are laminated and joined so as to face each other in a plan view.

  One end of the wiring unit 12 is joined to the upper surface of the piezoelectric unit 11. The wiring unit 12 is a flexible strip-shaped wiring member, and has a plurality of power supply terminals 50 corresponding to the drive electrodes 49 on the upper surface of the piezoelectric unit 11 at one end thereof. 12 is electrically connected to a driver IC 51 (see FIG. 3) provided at the other end of the twelve by a conducting wire 53a (see FIG. 4). Further, as will be described in detail later, solder 52 that is a conductive material is attached as a solder bump to the power supply terminal 50, and the piezoelectric unit 11 and the wiring unit 12 laminated on the upper surface thereof are heated by a bar heater or the like. The power supply terminal 50 and the drive electrode 49 are electrically connected to each other through the solder 52 that is pressurized and melted.

  The inkjet head 6 having such a configuration operates as follows, and ejects ink droplets from the nozzle holes 28a. That is, ink is supplied from the ink outlet 3 a of the ink tank 3 to the ink connection hole 5 c and the ink supply port 34 of the support plate 5. A filter (not shown) is attached to the ink supply port 34. The ink supplied from the ink supply port 34 into the flow path unit 10 is filled in the ink flow path 10 a including the common liquid chamber 35, the connection path 33, the pressure chamber 31, and the nozzle communication path 36. In this state, when the driver IC 51 selectively applies a driving potential from the wiring unit 12 to the piezoelectric unit 11 in accordance with the print data and selectively sets the plurality of individual electrodes 47 to a predetermined potential, the driver IC 51 is common to the individual electrodes 47 to which the potential is applied. A potential difference is generated between the electrodes 48 and an electric field acts on the active portions (energy generating portions) of the piezoelectric sheets 41 to 44 to generate strain deformation in the stacking direction. Here, the active portion refers to a portion sandwiched between the individual electrode 47 and the common electrode 48 in each of the piezoelectric sheets 41 to 44, and substantially refers to a portion where distortion deformation in the stacking direction as described above occurs. When the active portion is deformed in this manner, the piezoelectric sheet protrudes into the corresponding pressure chamber 31, so that the internal pressure of the pressure chamber 31 rises and the internal liquid is discharged from the nozzle hole 28 a to the outside through the nozzle passage 36. The

  Such an inkjet head 6 is supported by the holder case 4 (see FIG. 1) by a support frame 5 having a rectangular frame shape as shown in FIG. More specifically, as shown in FIG. 3, the support frame 5 is a plate member having a rectangular shape in plan view, and its outer shape in plan view is larger than that of the flow path unit 10 and is rectangular in plan view in the central portion. It has a frame shape with an opening 5a formed therethrough. In addition, four ink connection holes 5 c are formed through one end portion in the longitudinal direction (X direction) of the support frame 5 along the Y direction, so that the ink outlet 3 a of the ink tank 3 and the flow path unit 10 are provided. The ink supply port 34 is communicated. The opening 5a has an opening area that is slightly larger than the outer dimensions of the piezoelectric unit 11 in plan view, and the support frame 5 has the piezoelectric unit 11 to which one end of the wiring unit 12 is connected in the opening 5a, and the wiring unit. The other end portion of 12 is pulled out from the opening 5 a and is fixedly bonded to the upper surface 10 b of the flow path unit 10.

  At this time, a gap path 60 is formed between the inner peripheral part 5 b forming the opening 5 a in the support frame 5 and the outer peripheral part 11 a of the piezoelectric unit 11. The gap path 60 is filled with a liquid sealant 66 (see FIG. 2), and seals the joining boundary (gap) between the support frame 5, the flow path unit 10, and the piezoelectric unit 11.

  The support frame 5 is attached to the bottom of the holder case 4 with the adhesive 4a in a state where the support frame 5 is bonded and fixed to the flow path unit 10 in this way (see FIG. 1A). This adhesive 4a is applied over the entire circumference of the outer peripheral portion of the support frame 5, and the outside of the support frame 5 from the lower surface of the nozzle plate 28 of the flow path unit 10 (the surface on the side where the nozzle holes 28a open outward). A path that passes through the piezoelectric unit 11 through the adhesive 4a is closed by the adhesive 4a.

  Incidentally, as described above, the drive electrode 49 of the piezoelectric unit 11 and the power supply terminal 50 of the wiring unit 12 are electrically connected by the solder 53 that is a conductive material. If surplus flows out to the periphery, conduction between adjacent drive electrodes 49, 49 or between power supply terminals 50, 50 may occur, or excess solder 53 may adhere to the upper surface of the top sheet 46 and harden. There is a possibility that the deformation of the active part is inhibited. In addition, the inkjet head 6 according to the present embodiment has a configuration that can prevent the occurrence of such a situation caused by the excess solder 53. Hereinafter, such a configuration will be described.

Example 1
4 is a plan view of the wiring unit 12, FIG. 5 is a partially enlarged view showing the laminated piezoelectric unit 11 and the wiring unit 12 partially cut away, and FIG. 6 shows the piezoelectric unit 11 and the wiring unit 12 shown in FIG. It is sectional drawing when the wiring unit 12 is cut | disconnected by the VI-VI line. 6A shows a state where the piezoelectric unit 11 and the wiring unit 12 are opposed to each other and are not bonded, and FIG. 6B shows a state where both are bonded.

  As shown in FIGS. 4 to 6, the wiring unit 12 has a flexible belt-like sheet-like base material 12 a, and a conductive layer composed of a power supply terminal 50 and a conductive wire 53 is formed on the lower surface side of the base material 12 a. Yes. Further, a coating layer 70 made of polyimide, a photosensitive solder resist, or the like is laminated so as to cover the conductive layer and the sheet-like substrate 12a over substantially the entire surface of the sheet-like substrate 12a. Also, as shown in FIG. 4, the sheet-like base material 12a has one end side having the first region 121 joined to the piezoelectric unit 11 and extends in the Y direction to the other end side having the second region 122. A driver IC 51 (see also FIG. 3) is mounted in the second region 122.

  A plurality of power supply terminals 50 are disposed in the first region 121 of the conductive layer. More specifically, in both the first region 121 and the both ends of the sheet-like base material 12a in the width direction (X direction), a common electrode connected to the common electrode 48 of the piezoelectric unit 11 (common drive electrode) 49b is connected. The power supply terminals 50b are arranged in rows. In the region sandwiched between the common power supply terminals 50b at both ends, the individual power supply terminals 50a connected to the drive electrodes (individual drive electrodes) 49a connected to the individual electrodes 47 of the piezoelectric unit 11 are arranged in a plurality of rows. It is installed.

  A plurality of output conductors 53a connecting the individual power supply terminals 50a to the driver ICs 51 in the second region 122 through the adjacent individual power supply terminals 50a are drawn in the Y direction, and the driver ICs 51 in the second region 122 are drawn. The input lead wire 53b connected to a terminal (not shown) provided on the other end side is patterned on the sheet-like substrate 12a. In addition, at both ends in the width direction (X direction) of the wiring unit 12, a common electrode lead wire 53 c extending from the first region 121 to the second region 122 is formed in a strip shape extending to the other end along the Y direction. .

  These conducting wire layers are covered with an insulating covering layer 70, and individual power supply terminals 50a are partially formed by openings 70a (see 6) formed by partially removing the covering layer 70 at positions corresponding thereto. Is exposed to the piezoelectric unit 11 side. In addition, the common power supply terminal 50b has a part of the common electrode conductor 53c through an opening (not shown) formed by removing a part of the covering layer 70 that covers the wired strip-like common electrode conductor 53c. The common electrode terminal 50b is formed by being exposed to the piezoelectric unit 11 side. That is, the common power supply terminal 50b is the common electrode lead wire 53c itself.

  As shown in FIG. 5, a belt-like drive electrode 49 is disposed on the top surface of the top sheet 46 of the piezoelectric unit 11, and FIG. 5 shows the drive electrode 49a provided corresponding to the individual power supply terminal 50a. ing. The drive electrode 49a is formed in a strip corresponding to the pressure chamber 20 and extends in a predetermined direction (Y direction), and is provided at one end of the electrode portion 49c in the extending direction. A silver paste 80 is formed on the power receiving terminal 49d and protrudes in a dome shape in cross section. Such a drive electrode 49a is disposed so that the electrode portion 49c is positioned corresponding to the pressure chamber 31 of the flow path unit 10, and the adjacent drive electrodes 49a are positioned relatively close to each other. .

  The silver paste 80 is provided to improve electrical and mechanical connectivity between the power receiving terminal 49d and the individual power supply terminal 50a via a conductive material, and includes not only silver but also glass frit. Metal paste or the like may be used. Moreover, as long as it is a protrusion shape, it may be not only a dome shape in a sectional view but also a rectangular shape in a sectional view or an annular shape having a central portion penetrating or recessed. The drive electrode 49a has a narrow portion 49e that allows the electrode portion 49c and the power receiving terminal 49d to communicate with each other. The electrode portion 49c corresponds to the pressure chamber 20, and one end of the electrode portion 49c in the extending direction. If the power receiving terminal 49d located on the side corresponds to the individual power supply terminal 50a, the shape is not limited to this.

  As shown in FIG. 6, the individual power supply terminal 50a of the wiring unit 12 is disposed corresponding to the power reception terminal 49d of the drive electrode 49a. The individual power supply terminal 50 a has an annular shape in which a central portion of the disk member is cut out to form a through hole 81 a, and the peripheral portion thereof is covered with the coating layer 70. In other words, in the present embodiment, the annular individual power supply terminal 50a and the opening 70a of the covering layer 70 are positioned so that their centers substantially coincide with each other. The opening 70a has a tapered cross-sectional shape whose diameter is reduced from the surface on the piezoelectric unit side of the coating layer 70 (the surface opposite to the conductive layer) toward the conductive layer, and the solder 52 is not attached thereto. In the state, the individual power supply terminal 50a is exposed to the piezoelectric unit 11 side through the opening 70a having an opening diameter smaller than the outer diameter of the individual power supply terminal 50a. The exposed portion forms an annular exposed portion 81 that is exposed in an annular shape so as to face the power receiving terminal 49d.

  Solder 52 that is a conductive material is attached to the annular exposed portion 81, and the solder 52 also has an annular shape corresponding to the shape of the annular exposed portion 81. Further, as shown in FIG. 6A, the solder 52 attached to the annular exposed portion 81 is set so that the height dimension H1 from the sheet-like base material 12a is slightly larger than the thickness dimension H2 of the coating layer 70. Has been.

  As shown in FIG. 6B, when the piezoelectric unit 11 and the wiring unit 12 are laminated, heated and pressurized, the top of the annular solder 52 is bonded to the protruding silver paste 80, and individually. The power supply terminal 50a and the drive electrode 49 are electrically connected. In this case, since the central portion of the annular exposed portion 81 of the individual power supply terminal 50a is cut out to form a through hole 81a, the solder 52 is not provided in the through hole 81a. Therefore, the capacity of the solder 52 is small compared to the case where the solder 52 whose central portion is not cut is provided with respect to the exposed portion on the conventional disk. Accordingly, since the surplus portion of the solder 52 generated at the time of lamination bonding is reduced, the surplus portion of the solder 52 flows out from the annular exposed portion 81 and adheres and cures to the electrode portion 49c of the drive electrode 49 and the top sheet 26 of the piezoelectric unit 11. Can be suppressed, and the occurrence of ion migration can also be suppressed.

  Further, since it is possible to suppress the surplus of the solder 52 from adhering to and curing on the top sheet 26 as described above, the electrode portion of the drive electrode 49 is prevented from being hindered from inhibiting the deformation of the active portion of the piezoelectric unit 11. It is not necessary to provide the power receiving terminal 49d at a large distance from 49c. Therefore, it is possible to reduce the size of the drive electrode 49 by arranging the power receiving terminal 49d close to the electrode 49c.

  Further, since the outer dimension of the annular exposed portion 81 can be secured to the same level as the conventional one while reducing the capacity of the solder 52, the annular exposed portion 81 of the individual power supply terminal 50a when viewed from the piezoelectric unit 11 side. And a large area where the power receiving terminal 49d of the drive electrode 49 overlaps can be secured. In other words, since the arrangement area of the solder 52 is secured to the same extent as in the past, even if a slight misalignment occurs when the piezoelectric unit 11 and the wiring unit 12 are stacked, the annular exposed portion 81 is interposed via the solder 52. And the power receiving terminal 49d can be reliably connected. Further, since the solder 52 has an annular shape, when connected to the silver paste 80, the joining state becomes a fillet shape in a cross-sectional view, so that the mechanical connection strength is supplemented while the solder capacity is reduced. be able to. Furthermore, since the arrangement area of the solder 52 is secured to the same level as the conventional one, even if the solder capacity is reduced, the connection strength can be secured relatively large. Furthermore, since the solder height dimension from the surface of the annular exposed portion 81 can be relatively large while reducing the capacity of the solder 52, the annular exposure is performed when the piezoelectric unit 11 and the wiring unit 12 are stacked. The solder 52 on the portion 81 can be reliably connected to the power receiving terminal 49d.

  Further, since the silver paste 80 of the power receiving terminal 49d has a protruding shape, the bonding distance between the power receiving terminal 49d and the solder 52 on the individual power supply terminal 50a is shortened, and the solder 52 is easily crushed. can do. When the cross-sectional view shape of the silver paste 80 is a circular cross-sectional view with a central portion penetrating or recessed, the fillet portion is widened between the annular solder 52 and the mechanical portion because the fillet portion is wide. The strength can be supplemented.

(Example 2)
7A and 7B are diagrams showing another configuration of the wiring unit 12, in which FIG. 7A shows an enlarged plan view near the power supply terminal 50a, and FIG. 7B shows a side sectional view. 7 shows a mode in which the sheet-like base material 12a is disposed below the coating layer 70 and the wiring unit 12 is disposed below the piezoelectric unit 11. In this embodiment, the piezoelectric unit 11 and the wiring unit 12 in this embodiment are pressurized from above and below, and further heated and joined.

  The wiring unit 12 shown in FIG. 7 is different from that shown in FIG. 6 in that it has a solder accommodating portion 85 that accommodates the surplus portion of the solder 52. More specifically, as shown in FIG. 7, the sheet-like base material 12a of the wiring unit 12 is opened on the side facing the piezoelectric unit 11 so as to communicate with the through hole 81a of the individual power supply terminal 50a. A recess 12b is formed, and a solder accommodating portion 85 is constituted by the through hole 81a and the recess 12b.

  When the wiring unit 12 as described above is stacked on the piezoelectric unit 11 and heated and pressurized from the state shown in FIG. 7B, an annular solder is formed as in the case shown in FIG. 6B. The top of 52 adheres to the silver paste 80, and the individual power supply terminal 50a and the drive electrode 49 are electrically connected. In the case of the configuration shown in FIG. 7B, the solder 52 is accommodated in the solder accommodating portion 85 through the through hole 81a while being interposed between the individual power supply terminal 50a and the drive electrode 49. (See the arrow in the figure). Therefore, it is possible to more effectively suppress the surplus portion of the solder 52 from flowing out to the electrode portion 49c of the drive electrode 49 and the top sheet 26 of the piezoelectric unit 11.

  At this time, since the silver paste 80 has a protruding shape, it is easy to crush the solder 52 on the power supply terminal 50a, and it is easy to accommodate the surplus in the solder accommodating portion 85. As shown in FIG. 7B, when excess solder flows out from the individual power supply terminal 50a toward the electrode portion 49c on the surface of the coating layer 70 of the wiring unit 12, this flow out is caused by capillary force. In order to accommodate the solder, a solder accommodating groove 86 that is recessed from the surface of the coating layer 70 may be provided. The sectional view shape of the recess 12b is not limited to this shape, and may be a stepped shape having a wider cross-sectional area in the back than the opening surface of the recess 12b, or any one orthogonal to the depth direction. It may be eccentric in the direction. Since other configurations are the same as those already described in the first embodiment, a detailed description thereof is omitted here.

(Example 3)
8A and 8B are diagrams showing another configuration of the piezoelectric unit 11 and the wiring unit 12, wherein FIG. 8A shows an enlarged plan view near the power supply terminal 50a, and FIG. 8B shows a side sectional view. 8 also shows a mode in which the sheet-like base material 12a is disposed below the coating layer 70 and the wiring unit 12 is disposed below the piezoelectric unit 11. And the piezoelectric unit 11 and the wiring unit 12 in a present Example are pressurized from the up-down direction in such an arrangement state, and are further heated and joined.

  In the configuration shown in FIG. 8, the central axis 85a of the solder receiving portion 85 formed in the wiring unit 12 is eccentric to the electrode portion 49c side with respect to the center position C1 in the plan view of the power receiving terminal 49d of the drive electrode 49a. Is located. Further, the solder accommodating portion 85 has an opening width W2 that is substantially the same as the width dimension W1 of the narrow portion 49e on the electrode portion 49c side of the power receiving terminal 49d in the drive electrode 49a (see FIG. 8A). .

  Then, from the state shown in FIG. 8B, while maintaining the relative position as described above, when the wiring unit 12 is laminated on the piezoelectric unit 11 and heated and pressurized, the surplus portion of the molten solder 52 is The direction from the power receiving terminal 49d to the electrode portion 49c through the narrow width portion 49e can be suppressed. That is, since the solder accommodating portion 85 can supplement the narrow portion 49e on the way from the power receiving terminal 49d to the electrode portion 49c, it is possible to prevent the surplus portion from flowing into the electrode portion 49c side. it can. Since other configurations and various modifications are the same as those already described in the first and second embodiments, detailed description thereof is omitted here.

Example 4
9A and 9B are diagrams showing another configuration of the wiring unit 12, in which FIG. 9A shows an enlarged plan view near the power supply terminal 50a, and FIG. 9B shows a side sectional view. 9 also shows an aspect in which the sheet-like base material 12a is disposed below the coating layer 70 and the wiring unit 12 is disposed below the piezoelectric unit 11. And the piezoelectric unit 11 and the wiring unit 12 in a present Example are pressurized from the up-down direction in such an arrangement state, and are further heated and joined.

  The wiring unit 12 shown in FIG. 9 is different from the wiring unit 12 shown in FIG. 7 in that the concave portion 12b constituting the solder accommodating portion 85 forms a through hole 12c that penetrates the sheet-like base material 12a. The other configurations are the same as those in FIG.

  According to such a wiring unit 12, it is possible to secure a large capacity of the solder accommodating portion 85, and thus it is possible to accommodate more surplus from the solder 52 in the solder accommodating portion 85. Similarly, for the wiring unit 12 shown in FIG. 8, the concave portion 12b is formed as a through hole 12c that penetrates the sheet-like base material 12a, so that the surplus portion of the solder 52 from the power receiving terminal 49d toward the electrode portion 49c can be obtained. More can be captured by the narrow portion 49e on the way. Further, when joining the piezoelectric unit 11 and the wiring unit 12 according to the present embodiment, air is sucked from the sheet-like base material 12a side of the wiring unit 12 through the through hole 12c, and both are pressurized and heated to join. May be. If it does in this way, it will become easy to introduce the surplus part of solder into penetration hole 12c. In addition, the cross-sectional view shape of the through-hole 12c and the recessed part 12b is not restricted to this shape like the above-mentioned Examples 1-3. Further, in the case of the fourth embodiment, the solder receiving groove 86 in FIG. 7B may be a recess, but may penetrate through the wiring unit 12, and in that case, the solder receiving groove 86 together with the through hole 12c. Bonding may be performed while air suction is performed from the sheet-like base material 12a side. In this way, even after the excess solder flows out to the electrode portion 49c side, it can be sucked through the solder receiving groove 86, and the influence on the electrode portion 49c side can be reduced.

(Example 5)
FIG. 10 is a diagram showing another configuration of the wiring unit 12, and in (a) to (e) showing variations of the configuration, an enlarged plan view is shown in the upper stage and a side sectional view is shown in the lower stage. . In addition, in the side sectional view in FIG. 10, the wiring unit 12 in a state where the sheet-like base material 12 a is arranged below the coating layer 70 is shown.
Among these, in the case of the wiring unit 12 shown in FIG. 10A, the sheet is formed on the lower surface (the surface opposite to the surface facing the piezoelectric unit 11) of the sheet-like substrate 12a in the wiring unit 12 shown in FIG. The peripheral wall portion 87 is provided so as to surround the opening of the through hole 12c that penetrates the substrate 12a. A concave space 87a communicating with the through hole 12c is formed in the peripheral wall portion 87. In the configuration shown in FIG. 10A, the concave space 87a extends in a predetermined direction from the through 12c in a plan view. Is configured to do. The peripheral wall portion 87 has a relatively large width dimension W3 around the through hole 12c, and a relatively small width dimension W4 at a portion surrounding the space 87a apart from the through hole 12c.

  In the case of the wiring unit 12 shown in FIG. 10B, the peripheral wall portion 88 is provided on the lower surface of the sheet-like base material 12a so as to surround the opening of the through hole 12c. The peripheral wall portion 88 is configured concentrically with respect to the through hole 12c, and the through hole 12c is located near the center of the concave space 88a formed by the peripheral wall portion 88.

  In the case of the wiring unit 12 shown in FIG. 10C, a concave space 89a communicating with the through hole 12c is formed by forming a concave recess 89 directly on the lower surface of the sheet-like base material 12a. . The depression 89 has a circular outer shape when seen in a plan view, and is provided concentrically with the through hole 12c in the present embodiment.

  In the case of the wiring unit 12 shown in FIG. 10D, the peripheral wall 90 is formed outside the peripheral edge of the concave dent 89 so as to surround the dent 89 in the wiring unit 12 shown in FIG. Has been. A concave space 90 a having a relatively large capacity is formed by the recess 89 and the peripheral wall 90.

  In the case of the wiring unit 12 shown in FIG. 10 (e), in the wiring unit 12 shown in FIG. 10 (c), the concave depression 89 is covered from below so that a wide range (substantially) of the sheet-like substrate 12a is obtained. In the first area 121 (see FIG. 4), a covering sheet 91 is laminated. Due to this covering sheet 91, the concave space 89a in the recess 89 is a space closed toward the lower side of the sheet-like base material 12a. For example, the covering sheet 91 is polyimide.

  According to each wiring unit 12 shown in FIGS. 10A to 10E as described above, the surplus generated from the solder 52 at the time of joining to the piezoelectric unit 11 is passed through the through hole 12c of the sheet-like base material 12a. In addition to being able to be accommodated, more excess can be guided to the opposite side of the piezoelectric unit 11 through the through-hole 12c and accommodated in the concave spaces 87a to 90a formed on the upper surface of the sheet-like base material 12a. it can. Moreover, since each recessed space 87a-90a is formed in the surrounding wall part 87,88,90 or the hollow 89, the surplus part of the solder 52 accommodated here will go out of the recessed space 87a-90a. It can be prevented from flowing out.

  Further, when the wiring unit 12 shown in FIGS. 10A to 10D is joined to the piezoelectric unit 11, the air is sucked from the sheet-like base material 12 a side of the wiring unit 12 through the through-hole 12 c, and both of them are sucked. You may join by pressurizing and heating. If it does in this way, it will become easy to introduce the surplus part of solder into penetration hole 12c.

  Moreover, in the case of the wiring unit 12 shown to Fig.10 (a)-(d), the excess solder 52 will be exposed in air | atmosphere on the upper surface of the sheet-like base material 12a. Therefore, the heat generated in the piezoelectric unit 11 can be transmitted to the upper surface side of the sheet-like substrate 12a through the drive electrode 49, the power supply terminal 50, and the solder 52, and can be dissipated into the atmosphere here. Further, the heat generated in the driver IC 51 of the wiring unit 12 can also be transmitted to the upper surface side of the sheet-like substrate 12a through the wiring 53, the power supply terminal 50, and the solder 52, and can be dissipated into the atmosphere here. .

  On the other hand, in the case of the configuration shown in FIG. 10 (e), since the concave space 89a is covered with the covering sheet 91, it can be reliably prevented from flowing out along the upper surface of the sheet-like substrate 12a. Further, in the wiring unit 12 shown in FIG. 10 (d), since the large-capacity concave space 90 is formed by the recess 89 and the peripheral wall portion 90, a larger amount of surplus can be accommodated. Yes. In addition, in the wiring unit 12 shown in FIG.10 (e), the coating layer 70 which covers the lower surface of the sheet-like base material 12a, and the coating sheet 91 which covers the upper surface are formed of the same material or a material having substantially the same thermal expansion coefficient. Has been. For example, the same material of polyimide is used for the covering layer 70 and the covering sheet 91. Accordingly, since the coating layer 70 and the coating sheet 91 are similarly expanded and contracted by the heat transmitted by the excess solder 52, the wiring unit 12 can be prevented from warping due to the heat.

  As described above, according to the wiring unit 12 shown in FIGS. 10A to 10D, heat is generated in the piezoelectric unit 11 and the wiring unit 12 through the solder 52 extending from the front and back of the sheet-like base material 12a through the through hole 12c. Can be released into the atmosphere. Therefore, it is not necessary to provide a dedicated member for heat dissipation made of a metal plate or the like on the upper surface of the sheet-like substrate 12a. As a result, the problem of poor adhesion between the heat dissipation member and the sheet-like substrate 12a, which makes it difficult to make the temperature of the entire surface of the piezoelectric unit 11 uniform, is advantageous.

  The present invention prevents the deformation of the piezoelectric layer from being inhibited by the adhesion of surplus conductive material, prevents the occurrence of ion migration, can suppress the increase in size of the drive electrode, and more efficiently. The present invention can be applied to a heat-dissipating droplet discharge head and a wiring unit used therefor.

FIG. 4 is a cross-sectional view of a carriage on which the droplet discharge head according to the present embodiment is mounted, and illustrates an inkjet printer head as the droplet discharge head. (A) shows a cross-sectional view when the ink jet head is viewed from one side, and (b) shows a cross-sectional view when the ink jet head is cut along line AA in FIG. 1 (a). ing. It is an expanded sectional view of the inkjet head with which the carriage shown in FIG. 1 is provided. It is a perspective view when an ink jet head is disassembled into a channel unit, a piezoelectric unit, a wiring unit, and a support frame. 3 is a plan view of a wiring unit according to Embodiment 1. FIG. It is the elements on larger scale which cut and show partially the laminated piezoelectric unit and wiring unit. FIG. 6 is a cross-sectional view when the piezoelectric unit and the wiring unit shown in FIG. 5 are cut along a VI-VI line, where (a) shows a state in which the piezoelectric unit and the wiring unit are arranged opposite to each other and are not bonded; The state where both were adhered is shown, respectively. It is drawing which shows the structure of the wiring unit which concerns on Example 2, (a) shows the enlarged plan view of the electric power feeding terminal vicinity, (b) has shown side surface sectional drawing. It is drawing which shows the structure of the piezoelectric unit and wiring unit which concern on Example 3, (a) shows the enlarged plan view of the electric power feeding terminal vicinity, (b) has shown side surface sectional drawing. It is drawing which shows the structure of the wiring unit which concerns on Example 4, (a) shows the enlarged plan view of the electric power feeding terminal vicinity, (b) has shown side surface sectional drawing. FIG. 10 is a diagram illustrating a configuration of a wiring unit according to a fifth embodiment. In (a) to (e) showing variations of the configuration, an upper plan view is shown in the upper stage and a side sectional view is shown in the lower stage.

Explanation of symbols

1 Inkjet head (droplet discharge head)
DESCRIPTION OF SYMBOLS 10 Flow path unit 11 Piezoelectric unit 12 Wiring unit 12a Sheet-like base material 12b Recessed part 12c Through-hole 49, 49a, 49b Drive electrode 49c Electrode part 49d Power receiving terminal 50 Power feeding terminal 51 Driver IC
52 Solder (conductive material)
53a Conductor 70 Coating layer 80 Silver paste 81 Annular exposed part 85 Solder receiving part (conductive material containing part)
87a-90a Recessed space 91 Cover sheet

Claims (6)

A piezoelectric unit in which a plurality of drive electrodes are arranged close to one surface of the piezoelectric layer;
A sheet-like base material, and a plurality of power supply terminals provided on the sheet-like base material and electrically connected to the drive electrode via a conductive material, and stacked on the one surface of the piezoelectric unit With a wiring unit,
By driving the piezoelectric unit based on an electric signal from the power supply terminal to the drive electrode, the liquid in the liquid channel of the channel unit stacked on the other surface of the piezoelectric unit is discharged to the outside. And
Furthermore, a through-hole penetrating from the surface on the piezoelectric unit side to the surface on the opposite side is formed in the power feeding terminal and the sheet-like base material,
The through hole is formed on a surface of the sheet-like base material opposite to the piezoelectric unit side so that an excess portion of the conductive material is accommodated through the through-hole when the piezoelectric unit and the sheet-like base material are laminated. A liquid droplet ejection head, wherein a concave portion communicating with the liquid crystal is provided. A sheet-like base material laminated on the one surface of the piezoelectric unit in which a plurality of drive electrodes are arranged close to one surface of the piezoelectric layer; and each of the drive electrodes provided on the sheet-like base material A plurality of power supply terminals electrically connected through a conductive material,
A through hole penetrating from the surface on the piezoelectric unit side to the surface on the opposite side is formed in the power supply terminal and the sheet-like base material,
A wiring unit, wherein a concave portion communicating with the through hole is provided on a surface of the sheet-like base material opposite to the piezoelectric unit side.   The said recessed part is formed so that the opening of the said through-hole in the surface on the opposite side to the said piezoelectric unit side of the said sheet-like base material may be located inward. Wiring unit.   4. The wiring unit according to claim 2, further comprising a coating layer that is laminated on a surface of the sheet-like substrate opposite to the piezoelectric unit side and covers the concave portion.   The layer that forms the surface on the piezoelectric unit side of the sheet-like base material and the coating layer in the state where the power supply terminal is exposed are formed of the same material or a material having substantially the same coefficient of thermal expansion. 5. The wiring unit according to claim 4, wherein   The wiring unit according to claim 2, wherein the conductive material is solder.

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