JP2009083242A - Liquid drop delivery head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid drop delivery head including a wiring unit and a thermally conductive plate, structured so that the two members are joined together through a liquid adhesive so as to secure the thermal conductivity between the two members sufficiently, nevertheless capable of preventing the surplus portion of the liquid adhesive from leaking out through the gap between the them. <P>SOLUTION: The thermally conductive plate 13 of this liquid drop delivery head 6 is adhered through the liquid adhesive 70 to the top surface of the wiring unit 12 having an area approximately the same as that of a piezoelectric unit and joined in lamination with the piezoelectric unit, wherein that surface of the wiring unit 12 which is confronting the plate 13 is furnished with a trap groove 16 for seizing the liquid adhesive 70 along the peripheral edge of the piezoelectric unit viewed on the plan in such a manner as to be open toward the plate 13. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a droplet discharge head that discharges droplets.

  As an example of a liquid droplet ejection apparatus using an ink jet printer apparatus, a flow path unit having a liquid flow path to a nozzle hole for ejecting liquid droplets inside, and a nozzle by applying a discharge pressure to the liquid in the liquid flow path Some include a droplet discharge head formed by laminating a piezoelectric unit for discharging droplets from a hole and a wiring unit that outputs a signal to drive the piezoelectric unit (for example, see Patent Document 1). .

More specifically, as disclosed in Patent Document 1, in this type of droplet discharge head, a piezoelectric element having an outer dimension smaller than that of the channel unit is formed on the upper surface of the channel unit having a rectangular shape in plan view. The units are laminated and bonded, and one end of a flexible band-like wiring unit is laminated and bonded to the upper surface of the piezoelectric unit. In a series of operations in which the piezoelectric unit is driven to discharge droplets from the nozzle holes of the flow path unit, the piezoelectric unit generates heat by the drive, and the generated heat is transmitted to the liquid in the flow path unit. In some cases, the heat generated by the drive may affect the discharge, for example, due to a thickening of the liquid in the liquid or a variation in the drive heat generation that causes heat transfer, resulting in a variation in discharge characteristics or defective discharge. Therefore, a heat conductive plate material made of aluminum or the like is laminated and bonded to the upper surface of the wiring unit, and heat generated when the piezoelectric unit is driven is dissipated through the wiring unit to the plate material, and the temperature distribution of the entire piezoelectric unit is By achieving uniformity, the influence of the discharge characteristics of the droplet discharge device due to the thermal effect is suppressed.
JP 2006-44196 A (refer in particular to paragraph 0030 and FIG. 3)

  By the way, it is conceivable to use a double-sided tape or a liquid adhesive for bonding the wiring unit and the plate material. However, when a double-sided tape is used, there is a variation in the method of sticking and a partial lift occurs. In some cases, the thermal conductivity between the wiring unit and the plate material may not be sufficient due to the fact that the double-sided tape has a relatively large thickness and high thermal resistance. In addition, when a liquid adhesive is used, there is a merit that the above-described floating can be prevented and the thickness dimension of the adhesive layer can be reduced to reduce the thermal resistance, but the application amount is not easily adjusted. For this reason, the surplus may leak to the outside through the gap between the wiring unit and the plate material. This excess liquid adhesive penetrates between the wiring unit and the piezoelectric unit and solidifies, so that the solidified portion is constrained to the piezoelectric unit. This restricts and inhibits discharge, which may affect discharge characteristics.

  Therefore, the present invention is configured to join the two through the liquid adhesive so as to sufficiently secure the thermal conductivity between the wiring unit and the heat conductive plate material, and the surplus liquid adhesive has a gap between the two. An object of the present invention is to provide a droplet discharge head that can prevent leakage from the outside to the outside.

  The present invention has been made in view of the circumstances as described above, and the droplet discharge head according to the present invention is a flow path unit by driving based on signals to a plurality of drive electrodes provided on one surface. A piezoelectric unit that applies discharge pressure to the liquid in the liquid flow path, and a plurality of power supply terminals corresponding to the drive electrodes, and the power supply terminals and the drive electrodes are opposed to the piezoelectric unit. A droplet discharge head comprising: a wiring unit to be stacked; and a thermally conductive plate material stacked on the opposite side of the piezoelectric unit in the wiring unit, wherein the thermally conductive plate material is the piezoelectric in plan view It has substantially the same dimensions as the unit and is bonded to the wiring unit via a liquid adhesive. At least one of the facing surfaces of the wiring unit and the thermally conductive plate material has a front surface. Trap groove for capturing excess liquid adhesive is formed so as to be opened toward the other.

  By adopting such a configuration, the excess liquid adhesive can be captured by the trap groove, and the excess liquid adhesive leaks to the outside through the gap between the wiring unit and the thermally conductive plate material. Can be prevented. In addition, it is possible to suppress the influence of the liquid unit on the discharge characteristics by restricting the driving of the piezoelectric unit, such as leakage of the liquid adhesive between the piezoelectric unit and the wiring unit and solidifying it. A reliable droplet discharge head can be provided.

  Further, the trap groove may be formed at an outer position than a region where the plurality of drive electrodes are disposed in a plan view. With this configuration, the trap groove can capture excess adhesive, and the piezoelectric unit can be driven to handle a plurality of drive electrodes in a plan view that applies discharge pressure to the liquid in the flow path unit. A heat conductive plate material adheres to the wiring unit to effectively dissipate or equalize the heat in the region to be processed.

  Moreover, the said trap groove | channel may be extended along the peripheral part of the said heat conductive plate material by planar view. By adopting such a configuration, it is possible to ensure a relatively wide adhesive region by the liquid adhesive between the heat conductive plate material and the wiring unit. Can be reduced. In addition, since the trap groove is formed along the peripheral edge of the thermally conductive plate material, it is possible to prevent leakage of excess liquid adhesive on all sides, providing a highly reliable droplet discharge head it can.

  In addition, the wiring unit has a sheet-like base material that has an insulating property and the power supply terminal is disposed on one surface thereof, and the other surface of the base material that covers the other surface of the heat conductive plate. An intermediate layer that is opposed to the material, and the intermediate layer includes the trap groove that is cut out or penetrated to open on the surface side of the intermediate layer and the thermal layer. The conductive plate material may be connected via the liquid adhesive. By adopting such a configuration, it is only necessary to arrange an intermediate layer in which a trap groove is newly formed on the other surface of the base material of the wiring unit that has been conventionally used for electrical connection with the actuator. In addition, there is no need for means and a configuration for separately preparing a member, aligning and bonding, and such a process, and it can be realized easily and at low cost. In addition, since the trap groove is formed in the intermediate layer, the degree of freedom in selecting the shape of the trap groove (plan view size, depth size, arrangement, etc.) is improved.

  In addition, an insulating covering material that covers the other while exposing the power supply terminal through the opening is laminated on one surface of the base member of the wiring unit, and is exposed through the opening in the power supply terminal. The portion may be provided with a bump, and the power supply terminal and the drive electrode may be electrically connected via the bump. With such a configuration, the above-described droplet discharge head can be realized by using the wiring unit used for electrical connection with the conventional actuator.

  The intermediate layer may be made of a photosensitive resist. Such a configuration facilitates patterning of the trap groove, so that a desired position and shape can be easily formed even if the trap groove has a complicated shape in plan view.

  According to the liquid droplet ejection head according to the present invention, the liquid adhesive is configured to join both of them via the liquid adhesive so as to sufficiently ensure the thermal conductivity between the wiring unit and the heat conductive plate material. Can be prevented from leaking outside through the gap between the two.

  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 is applied to an inkjet head that discharges ink of an inkjet printer as a droplet discharge head. The ink jet printer of the present invention can be applied not only as a single printer device but also as a printer of a multi-function device (MFD) having a copy function, a scanner function, a facsimile function, and the like.

  An ink jet printer (not shown) is configured such that a carriage 1 on which an ink jet head is mounted is mounted across two guide shafts (not shown) and can be reciprocated (scanned) in the left-right direction in FIG. The inkjet head reciprocates in the scanning direction together with the carriage 1, and is conveyed to the back side of the paper surface of FIG. 1 from a nozzle provided on its lower surface (lower side of the paper surface in FIG. 1) by a conveyance motor of a paper conveyance mechanism (not shown). Ink droplets are ejected onto a recording sheet. As a result, desired characters and images are recorded on the recording paper.

  As shown in FIG. 1, the carriage 1 includes, for example, a liquid tank 3 that supplies inks (liquids) of each color such as cyan, magenta, yellow, and black independently to a flow path unit 10 described later, A holder case 4 that accommodates and holds the liquid tank 3 and an inkjet head 6 that is attached to a lower portion of the holder case 4 via a support frame 5 are provided. The inkjet head 6 has a plate-type piezoelectric unit 11 laminated and bonded to the upper surface of the flow path unit 10 having a plurality of plates laminated and bonded and having a liquid flow path 10a (see FIG. 2) inside. A wiring unit (chip on film) 12 used for electrical connection with an external device is further joined to the upper surface of the piezoelectric unit 11, and a heat conductive plate material 13 is laminated and bonded to the upper surface of the wiring unit 12. ing. A driver IC 51, which is 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 based on print data from the main body side.

  2 is an enlarged cross-sectional view of the inkjet head 6 provided in the carriage 1 shown in FIG. 1. FIG. 3 shows the flow path unit 10, the piezoelectric unit 11, the wiring unit 12, the heat conductive plate material 13, and the 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, and a first common liquid, each of which has a rectangular plate shape. The chamber plate 24, the second common liquid chamber plate 25, the damper plate 26, the cover plate 27, and the nozzle plate 28 are arranged in this order from above 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 21 to 27 are metal plates such as 42% nickel alloy steel plate (42 alloy), and each has a rectangular shape in plan view. , Each has a thickness of about 50 to 150 μm. In each of the plates 20 to 27, an opening or a concave portion constituting each liquid flow path (channel) 10a is formed by electrolytic etching, laser processing, plasma jet processing, or the like.

  In the lowermost nozzle plate 28 in the flow path unit 10, a large number of nozzle holes 28 a for discharging ink droplets having a minute diameter (about 20 μm) are formed at minute intervals, and the nozzle holes 28 a are formed on the nozzle plate 28. 5 rows are arranged in a row extending along the long side direction (X-axis direction in FIG. 3). The pressure chamber plate 20 located in the uppermost layer in the flow path unit 10 is provided with five rows of pressure chamber holes 20a in a row along the X-axis direction corresponding to the row of nozzle holes 28a. The pressure chamber hole 20a has an elongated hole shape in plan view along the short side direction (Y-axis direction in FIG. 3) of the pressure chamber plate 20, and is formed so as to penetrate the pressure chamber plate 20 in the thickness direction. The longitudinal direction (Y-axis direction) is arranged along the direction orthogonal to the row of nozzle holes 28a. And this pressure chamber hole 20a forms the pressure chamber 31 which has internal space by laminating | stacking the piezoelectric unit 11 from upper direction and laminating | stacking the 1st spacer plate 21 from the downward direction.

  The first spacer plate 21 is formed with a communication hole 21a that communicates with one end of the pressure chamber hole 20a, the second spacer plate 23 is formed with a communication hole 23a, and is further interposed between these plates 21 and 23. The aperture plate 22 is formed with an aperture 22a having a long hole shape. One end of the throttle hole 22 a communicates with the communication hole 21 a of the first spacer plate 21, and the other end communicates with the communication hole 23 a of the second spacer plate 23. These communication holes 21a and 23a and the throttle hole 22a form a throttle passage 33 that allows the pressure chamber 31 to communicate with a common liquid chamber 35 described later.

  The other end of each pressure chamber hole 20a is formed in the first spacer plate 21, the throttle plate 22, the second spacer plate 23, the two manifold plates 25 and 26, the damper plate 26, and the cover plate 27. The small-diameter communication holes communicated with the nozzle holes 28a of the nozzle plate 28 through nozzle passages 36 communicating with each other.

  In the first common liquid chamber plate 24 and the second common liquid chamber plate 25 located below the second spacer plate 23, a lower position corresponding to the position where the pressure chamber holes 20a are arranged in the column direction (X-axis direction). Thus, common liquid chamber holes 24a and 25a extending along the column direction (X-axis direction) are formed through the plates 24 and 25 in the thickness direction. The common liquid chamber holes 24a and 25a are provided in a total of five rows (not shown) for each ink color corresponding to the nozzle rows and the pressure chamber rows. Two common liquid chamber plates 24 and 25 are stacked, and the upper surface thereof is covered with the second spacer plate 23 and the lower surface thereof is covered with the damper plate 26, whereby the common liquid chamber 35 is formed.

  In addition, four liquid supply paths 34 are perforated for each ink color, corresponding to the upper and lower positions at one end in the longitudinal direction (X direction) of each plate of the second spacer plate 23 from the pressure chamber plate 20. When the ink jet head is mounted on the carriage 1, the ink from the ink cartridges of each color communicating with the liquid tank 3 and stationary on the ink jet printer main body (not shown) is supplied to the liquid tank 3 and the liquid supply. Ink is supplied into the flow path unit 10 by being supplied to one end of the common liquid chamber 35 in the longitudinal direction via the path 34. Further, each common liquid chamber hole 24 a communicates with the pressure chamber 31 via the throttle passage 33. Note that there are five nozzle rows, pressure chamber rows, and five common ink chambers in the Y direction, but there are four ink supply ports for black ink that is frequently used. This is because ink is supplied to the two common ink chamber rows, the pressure chamber row, and the nozzle row.

  The damper plate 26 is a surface on the opposite side to the surface facing the common liquid chamber 35, and the portions corresponding to the positions of the common liquid chambers 35 are formed in a thin shape by being recessed from below. A damper wall 26a is provided. A cover plate 27 is laminated and bonded to the damper plate 26 from below, so that a damper space 26 b is formed between the plates 26 and 27. In addition, a nozzle plate 28 having a plurality of nozzle holes 28a is laminated and bonded to the cover plate 27 from below.

  By laminating and bonding such plates 20 to 28, a flow path unit 10 as shown in FIG. 2 is configured. In the flow path unit 10, a liquid flow path 10 a extending from the liquid supply path 34 communicating with the liquid tank 3 to the nozzle hole 28 a via the common liquid chamber 35, the throttle path 33, the pressure chamber 31, and the nozzle path 36. Is formed.

  On the other hand, as shown in FIG. 2, the piezoelectric unit 11 is configured by laminating a large number of piezoelectric sheets 40 to 45 and an insulating top sheet 46 (which becomes a constraining layer). 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 arranged in a row along the X-axis direction so as to correspond to each row formed by the pressure chambers 31, and are printed and formed so that this row becomes five rows in the Y-axis direction. 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 connected to the top of each of the piezoelectric sheets 40 to 45 and the top sheet 46 through a relay wiring (filled or coated with a conductive adhesive) (not shown) provided on the side end surfaces or through holes (not shown). The surface electrode 49 (see also FIG. 3) provided on the upper surface of the sheet 46 is electrically connected. The piezoelectric unit 11 is bonded and fixed to each other with the individual electrodes 47 and the pressure chambers 31 of the flow path unit 10 facing each other.

  The surface electrode 49 has an individual surface electrode (drive electrode) 49a that is conducted to the individual electrode by a through hole. The individual surface electrode 49a has an elongated shape along the X-axis direction in a plan view, and the piezoelectric unit 11 The uppermost piezoelectric sheet 46 is provided so as to overlap the pressure chamber 31, and is arranged in a row along the X-axis direction corresponding to the pressure chamber 31. Five rows are formed in the direction. The surface electrode 49 includes a common surface electrode 49b formed in a band shape along both ends (short sides) in the X-axis direction so as to sandwich a set of a plurality of individual surface electrodes 49a on the upper surface of the piezoelectric sheet 46. Have. The common surface electrode 49b is electrically connected to the common electrode 48 through a through hole, and is grounded. Such a surface electrode 49 is screen-printed using an Ag-pd conductive material.

  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 at one end thereof, a plurality of power supply terminals 50 are formed corresponding to each surface electrode 49 on the upper surface of the piezoelectric unit 11, and an individual corresponding to the individual surface electrode 49a. The power supply terminals are arranged in a row along the X-axis direction, and five rows are formed in the Y-axis direction. The power supply terminals are shared at appropriate positions in the Y-axis direction at positions corresponding to the strip-shaped common surface electrodes 49b. A power supply terminal is provided. Then, each power supply terminal 50 is aligned with each surface electrode 49, one end of the wiring unit 12 is laminated and joined to the actuator, and the other end is a direction perpendicular to the column direction of the power supply terminals 50 (Y-axis) Direction). In the middle of the wiring unit 12 being pulled out, a driver IC 51 (see FIG. 3) including a drive circuit is mounted. Although not shown, the wiring unit 12 is provided with a plurality of conductive wires along the drawn-out direction (Y-axis direction), and a conductive wire for inputting a drive signal from the main body side to the driver IC 51 is provided in the wiring unit 12. The other end of the terminal is connected to the driver IC 51, and from the driver IC 51, another conducting wire that outputs to each power feeding terminal 50 is connected to each power feeding terminal 50. As will be described later, solder bumps 52 are attached to the power supply terminals 50, and the piezoelectric units 11 and the wiring units 12 stacked on the upper surface thereof are connected to the power supply terminals 50 and the drive electrodes 49 via the solder bumps 52. Are electrically connected.

  Further, as will be described in detail later, a thermally conductive plate material 13 is laminated and bonded to the upper surface of the wiring unit 12 via a liquid adhesive 70 (see FIG. 4). The thermally conductive plate material 13 is a rectangular flat plate material that is substantially the same area as the piezoelectric unit in the Y direction and is long in the Y direction, and is made of a material that is higher in rigidity than the wiring unit and excellent in thermal conductivity. For example, a metal plate such as aluminum, copper, or SUS is applied.

  The droplet discharge head 6 having such a configuration operates as follows and discharges liquid from the nozzle hole 28a. That is, the liquid supplied from the liquid tank 3 through a filter (not shown) is filled in the liquid flow path 10 a including the liquid supply path 34, the common liquid chamber 35, the throttle path 33, the pressure chamber 31, and the nozzle path 36. ing. In this state, when a drive signal (drive potential) is selectively applied from the driver IC 51 to the piezoelectric unit 11 and the plurality of individual electrodes 47 are selectively set to a predetermined potential, the individual electrodes 47 and the common electrode 48 to which the potentials are applied A potential difference is generated between them, and an electric field acts on the active portions of the piezoelectric sheets 41 to 44 to cause 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 part is deformed in this way, the lowermost piezoelectric sheet 40 protrudes into the corresponding pressure chamber 31, so that the internal pressure of the pressure chamber 31 rises, and the liquid inside passes through the nozzle passage 36 from the nozzle hole 28 a. It is discharged to the outside.

  Further, the pressure wave generated by the increase in the internal pressure of the pressure chamber 31 is attenuated by the throttle passage 33 having a smaller cross-sectional area than the surroundings, and the remaining pressure wave is absorbed by elastic deformation of the damper wall 26a. The This suppresses the pressure wave generated in one pressure chamber 31 from reaching the other pressure chamber 31 via the common liquid chamber 35.

  Further, heat is generated from the individual electrodes 47 (and the individual surface electrodes 49a) of the piezoelectric unit 11 that is driven when the liquid is discharged, and this heat is transmitted to the thermally conductive plate material 13 through the wiring unit 12 that is laminated. And is dissipated from the thermally conductive plate member 13 to the outside. Further, a part of this heat is diffused in the heat conductive plate material 13 so that the temperature of the piezoelectric unit 11 is made uniform.

  Further, such a droplet discharge head 6 is supported on 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 has a larger outer shape than the flow path unit 10, and a frame is formed by forming an opening 5 a in the central portion of a plate member that is rectangular in plan view. It has a shape. The opening 5a is formed so as to have an opening area slightly larger than the outer dimension of the piezoelectric unit 11, and the support frame 5 has the other end of the wiring unit drawn out from the opening 5a, and the piezoelectric unit 11 is placed in the opening 5a. The upper surface 10a of the flow path unit 10 and the support frame 5 are bonded and fixed so as to be positioned.

  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. Then, a liquid sealing agent 66 (see FIG. 2) is injected into the gap path 60 to seal the joint portion between the support frame 5 and the flow path unit 10. A liquid supply hole 5c is formed at one end in the longitudinal direction of the support frame 5 corresponding to the liquid supply path 34 of the flow path unit 6, and the liquid from the liquid tank 3 It is introduced into the liquid supply path 34 of the flow path unit 6 through 5c. 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. 1).

  FIG. 4 is an enlarged cross-sectional view of the inkjet head 6 described above, and mainly shows the configuration of the piezoelectric unit 11, the wiring unit 12, and the heat conductive plate material 13, and FIGS. 5 (a) and 5 (b). ) Is a plan view of the inkjet head 6, and the thermal conductive plate 13 is indicated by a two-dot chain line, and for the sake of explanation, the thermal conductive plate material 13 and the wiring unit 12 are shown in a transparent state.

  As shown in FIG. 4, the wiring unit 12 has a flexible belt-like base sheet 12a (thickness: 38 μm) made of polyimide or the like. A conductive material layer made of copper foil is provided on one surface (the lower surface in FIG. 4) of the base sheet 12a, and each drive electrode 49 disposed on the upper surface of the piezoelectric unit 11 by this conductive material layer. A plurality of power supply terminals 50 corresponding to 1 and conductive wires (not shown) connected to the power supply terminals 50 are formed (see also FIG. 5).

  In addition, an insulating covering material 14 made of a photosensitive resist is laminated from below on one surface (the lower surface in FIG. 4) of the conductive material layer so as to cover almost the entire surface of the conductive wire layer. Each power supply terminal 50 is partially exposed through the hole 14a. Bumps 52 made of a conductive bonding member such as solder are formed on each power supply terminal 50 that is partially exposed. Then, each power supply terminal 50 and each drive electrode 49 are aligned so as to correspond to each other, and heated and pressurized with a bar heater or the like from above the wiring unit 12 to melt the wiring unit 12 and the piezoelectric unit 11. Are connected and joined. The solder is formed by screen printing, and bumps are formed by cooling after the reflow process.

  Further, an intermediate layer 15 having a rectangular shape in a plan view made of a photosensitive resist is laminated on the other surface (upper surface in FIG. 4) of the base sheet 12a. As shown in FIG. 5A, the intermediate layer 15 has a rectangular shape having substantially the same area and shape as the piezoelectric unit 11 in plan view. The intermediate layer 15 has a trap groove 16 that is linear in a plan view on the surface thereof (on the side opposite to the base sheet 12a and on the side of the heat conductive plate 13), and the piezoelectric unit 11 (or the heat conductive plate 13). Are formed independently at four locations along each side in the vicinity of the outer peripheral edge. The trap groove 16 is formed by cutting out the intermediate layer 15 so as to open toward the heat conductive plate material 13 as shown in FIG. 4, and in the case shown in FIG. It penetrates from the back to the back side. The intermediate layer 15 is a photosensitive resist similar to the above-described insulating coating material 14, and the above-described coating material 14 is laminated on one surface of the base sheet 12 a on which the conductive wire layer is disposed. When part of the power supply terminal 50 is partially exposed by removing the portion with photoresist or the like, the intermediate layer 15 is laminated on the other surface of the base sheet 12a and a part thereof is removed with photoresist or the like. A trap groove 16 is formed. A known method may be used as a specific method of exposure. However, when the trap groove 16 is formed using a photosensitive resist, the trap groove 16 can be easily patterned and the shape in plan view is complicated. Can also be formed easily. The solder bump 52 is preferably formed after the intermediate layer and the trap layer are formed.

  Then, the liquid adhesive 70 is partially applied to the surface of the intermediate layer 15 thus formed or the lower surface of the heat conductive plate member 13 and pressed between the wide surfaces facing each other. The liquid adhesive 70 spreads along the direction and is bonded and fixed. At this time, when the liquid adhesive 70 spreads to the formation region of the trap groove 16, the liquid adhesive 70 enters and is held in the trap groove 16. In other words, the liquid adhesive 70 spreads between the upper surface of the intermediate layer 15 and the lower surface of the heat conductive plate material 13 in the inner region surrounded by the trap grooves 16 and bonds and fixes both of them. (Refer to the liquid adhesive 70 shown by a two-dot chain line in FIG. 5).

  According to the ink jet head 6 as described above, the liquid adhesive 70 spreads to the region where the trap groove 16 is formed, and the reached liquid adhesive 70 is held by the trap groove 16. The adhesive fixing between the plate material 13 and the wiring unit 12 is ensured, and when there is a surplus liquid adhesive 70, the surplus adhesive 70 can be captured by the trap groove 16, and the wiring unit It is possible to prevent excess from leaking out from the gap between the heat conductive plate material 13 and the heat conductive plate material 13. Further, since the trap groove 16 is provided along the outer peripheral portion of the piezoelectric unit 11 (or the heat conductive plate material 13), the bonding area between the piezoelectric unit 11 and the heat conductive plate material 13 may be wide. Not only can the leakage of excess liquid adhesive 70 be prevented more reliably. In addition, since the adhesive area is wide, the liquid adhesive 70 spreads in a wide region along the surface direction between the opposing surfaces, so that the amount of excess liquid adhesive 70 that actually reaches the trap groove 16 is reduced. be able to. Since the excess liquid adhesive 70 is held and trapped in the trap groove 16 in this way, the liquid adhesive 70 leaks out and enters between the piezoelectric unit 11 and the wiring unit 12 to be solidified. Since the driving of the unit 11 is not hindered, a highly reliable ink jet head 6 can be provided.

  Further, as shown in FIG. 5B, the trap groove 16 may be provided outside the region where the individual surface electrode 49 a of the piezoelectric unit 11 is disposed in the intermediate layer 15 in plan view. In FIG. 5B, the trap grooves 16 are extended so as to surround the individual surface electrodes 49a arranged in a row in the XY direction from the outside. As described above, the individual surface electrode 49a of the piezoelectric unit 11 is selectively driven based on the drive signal from the driver IC 51 to be deformed into the pressure chamber 31. Therefore, the individual surface electrode 49a is driven in the vicinity of the individual surface electrode 49a. The calorific value is large. Therefore, by providing a trap groove outside the arrangement area of the individual surface electrode 49a to be driven, the liquid adhesive 70 described above is held and captured to prevent leakage of excess, and a thermally conductive plate material The heat propagation area to 13 can be adhered correspondingly, and the driving heat can be effectively dissipated. In this case, in the intermediate layer 15, the trap groove 16 is disposed in a region corresponding to the installation region of the strip-shaped common surface electrode 49 b provided on both end sides sandwiching the individual surface electrode 49 a of the piezoelectric unit 11 in plan view. However, since the common surface electrode 49b is grounded to the ground potential, the common surface electrode 49b is not affected by the heat generated by the drive, and thus does not affect the heat dissipation effect.

  Further, the trap groove 16 only needs to be provided with the intermediate layer 15 with respect to the wiring unit 12 conventionally used for connecting the piezoelectric unit 11 and the external power source, and the trap groove 16 can be easily formed. In addition, there is no need for means or a structure for newly preparing a member, aligning and bonding, and such a process, and it can be realized easily and at low cost.

  In the above-described example, the configuration in which the linear trap grooves 16 are arranged so as not to communicate with each other along each side of the heat conductive plate material 13 is described. However, the present invention is limited to such a configuration. It is not something.

  FIG. 6 is a drawing showing another variation of the trap groove 16. As shown in FIG. 6, it may be a series of trap grooves 16 that circulate along each side of the thermally conductive plate material 13 (see FIG. 6A), and the surface side without penetrating the intermediate layer 15. It may have a concave cross-sectional shape that opens to the top. The dent shape or the thickness, width dimension, shape, and the like of the through hole can be appropriately changed. (See FIG. 6 (b)). Further, as shown in FIG. 6C, a concave trap groove 16 may be formed on the lower surface of the heat conductive plate material 13 (the surface facing the wiring unit 12), as shown in FIG. 6D. In addition, the trap groove 16 may be provided on both the lower surface of the thermally conductive plate material 13 and the intermediate layer 15.

  FIG. 7 is an enlarged sectional view of the inkjet head 6 showing still another variation of the trap groove 16. The trap groove 16 shown in FIG. 7 is substantially the same as that shown in FIG. 4, but has a partition wall 16a projecting from the bottom surface of the trap groove 16 (two in FIG. 7). The partition wall 16 a partitions the cross-sectional area of the trap groove 16 into a plurality of small cross-sectional areas, and extends along the trap groove 16.

  When such a partition wall 16a is provided, when the excess liquid adhesive 70 enters a part of the trap groove 16, the liquid adhesive 70 is guided in the extending direction of the trap groove 16 by capillary action. Can be expected. Therefore, particularly when the viscosity of the liquid adhesive 70 to be used is small, the surplus portion can be captured so as not to overflow outward from the trap groove 16, and the entire volume of the trap groove 16 can be effectively utilized. it can. Although the height dimension of the partition wall 16a may be approximately the same as the depth dimension of the trap groove 16, in order to utilize capillary action, the width dimension of the space partitioned by the partition wall 16a in the trap groove 16 It is preferable that it is below the same level. Needless to say, only one partition wall 16a may be provided, or a plurality of partition walls 16a may be provided. Moreover, you may provide such a trap groove | channel 16 in the heat conductive plate material side.

  The present invention is configured to join the two through the liquid adhesive so as to sufficiently ensure the thermal conductivity between the wiring unit and the heat conductive plate material, while the excess of the liquid adhesive is from the gap between the two. The present invention can be applied to a droplet discharge head that can prevent leakage to the outside.

It is sectional drawing of a carriage provided with the inkjet head which concerns on this Embodiment which makes an inkjet printer head an example. 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 inkjet head is disassembled into a flow path unit, a piezoelectric unit, a wiring unit, a heat conductive plate material, and a support frame. It is an expanded sectional view of an ink jet head, and mainly shows composition of a piezoelectric unit, a wiring unit, and a heat conductive plate material. It is a top view of an inkjet head. It is a top view which shows the other structure of an inkjet head. It is drawing which shows the other variation of a trap groove | channel. It is drawing which shows the other variation of a trap groove | channel. It is drawing which shows the other variation of a trap groove | channel. It is drawing which shows the other variation of a trap groove | channel. It is an expanded sectional view of the inkjet head which shows other variation of a trap groove | channel.

Explanation of symbols

6 Inkjet Head 10 Channel Unit 10a Liquid Channel 11 Piezoelectric Unit 12 Wiring Unit 12a Base Sheet 13 Thermal Conductive Plate Material 14 Insulating Cover Material 15 Intermediate Layer 16 Trap Groove 16a Partition Wall 49 Drive Electrode 50 Feed Terminal 52 Solder Bump 70 Liquid adhesive

Claims (6)

A piezoelectric unit that applies discharge pressure to the liquid in the liquid flow path of the flow path unit by driving based on signals to the plurality of drive electrodes provided on one surface, and a plurality of power supplies corresponding to the drive electrodes A wiring unit that has a terminal and is stacked on the piezoelectric unit so that the power supply terminal and the drive electrode face each other, and a thermally conductive plate material that is stacked on the opposite side of the piezoelectric unit in the wiring unit; A droplet discharge head comprising:
The thermally conductive plate material has substantially the same dimensions as the piezoelectric unit in plan view, and is bonded to the wiring unit via a liquid adhesive,
A trap groove for capturing the liquid adhesive is formed on at least one of the opposing surfaces of the wiring unit and the thermally conductive plate material so as to open toward the other. A droplet discharge head that is characterized.   The droplet discharge head according to claim 1, wherein the trap groove extends along an outer peripheral edge portion of the piezoelectric unit in a plan view.   3. The droplet discharge head according to claim 1, wherein the trap groove is formed at an outer position than a region where the plurality of drive electrodes are disposed in a plan view.   The wiring unit has a sheet-like base material having insulation and the power supply terminal disposed on one surface, and the surface of the base material covering the other surface of the base material is the heat conductive plate material. And the intermediate layer has the trap groove cut out or penetrated so as to open on the surface side, and the intermediate layer and the thermally conductive plate. The droplet discharge head according to claim 1, wherein a material is connected via the liquid adhesive.   On one surface of the base member of the wiring unit, an insulating covering material that covers the other while exposing the power supply terminal through an opening is laminated, and an exposed portion of the power supply terminal through the opening is stacked. The droplet discharge head according to claim 4, wherein a bump is provided, and the power supply terminal and the drive electrode are electrically connected through the bump.   6. The droplet discharge head according to claim 4, wherein the intermediate layer is made of a photosensitive resist.

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