JP5018351B2 - Droplet discharge head - Google Patents

Description

The present invention relates to a droplet ejection heads for ejecting liquid droplets.

  2. Description of the Related Art Conventionally, an ink jet recording head that discharges ink onto a recording medium such as a recording sheet is known as a droplet discharging head. As such an ink jet recording head, a cavity unit (flow path unit) provided with a plurality of pressure chambers communicating with a plurality of nozzles, an active portion (energy generating portion) for giving ejection energy to ink in each pressure chamber, and An actuator having an individual surface electrode for applying a voltage to the active portion, a plurality of individual bonding electrodes bonded to face the plurality of individual surface electrodes, and a wiring board having a plurality of wirings respectively connected to the individual bonding electrodes (Wiring member) and an integrated circuit (driving circuit) provided on a wiring board and connected to a plurality of wirings are known (for example, see Patent Document 1).

  In such an ink jet recording head, on the surface of the actuator, a plurality of individual surface electrodes are arranged along a predetermined direction corresponding to the plurality of nozzles, and are shifted in a direction perpendicular to the predetermined direction. In addition, the wiring board is formed by laminating the part where the individual bonding electrode corresponding to the individual surface electrode at one end of the wiring board is formed on the actuator, and the other end is pulled out in a direction perpendicular to the predetermined direction and connected to the external electrode. Has been. Each wiring on the wiring board extends from an individual junction electrode through a drive circuit in a direction orthogonal to a predetermined direction so that an external electrode and an actuator are electrically connected via the drive circuit. ing.

Japanese Patent Laying-Open No. 2005-161760 (FIG. 15)

  In such an ink jet recording head described in Patent Document 1, since the distance to the drive circuit is different between the adjacent individual junction electrodes, the wiring extending from the individual junction electrode to the drive circuit is different. The wiring length is different, the parasitic capacitance between adjacent wirings varies, the voltage response characteristics from the drive circuit to multiple individual surface electrodes vary, causing variations in the droplet discharge timing at each energy generation unit Yes. Further, when the heat generated in the drive circuit is large, the heat generated in the drive circuit is transferred to the flow path unit and the actuator via the wiring. At this time, the denser the wiring, the more heat is transferred to the flow path unit and actuator, which affects the ink in the flow path unit and affects the droplet discharge performance from each nozzle. was there.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a droplet discharge head that reduces adverse effects on droplet discharge performance caused by wiring length variation from a wiring drive circuit.

The droplet discharge head according to the present invention includes a plurality of energy generation units for discharging droplets, an actuator having a plurality of individual surface electrodes for applying voltages to the plurality of energy generation units on the surface, One end portion is overlapped on the surface of the actuator, and a wiring member that is parallel to the surface and drawn out in one direction is provided. On one surface of the wiring member , a plurality of corresponding surface electrodes correspond to the plurality of individual surface electrodes. An individual bonding electrode is provided, and a drive circuit for driving the actuator is mounted on the drawn-out side, and a plurality of first wiring patterns respectively connected to the plurality of individual bonding electrodes include the one wiring pattern. extends along the direction, the other surface of the wiring member has a plurality of the second wiring pattern corresponding to the one-to-one to the plurality of first wiring pattern is formed Cage, liquid the first and second wiring patterns to each other, that the wiring member are conductive through a through hole passing through and joined the in correspondence with said individual bonding electrode and the individual surface electrode corresponding to each other In the droplet discharge head, the plurality of individual surface electrodes are arranged at predetermined intervals along a direction orthogonal to the one direction, with the plurality of individual surface electrodes being shifted in the one direction on the surface . The total wiring length of the first and second wiring patterns is substantially the same as the total wiring length of any of the other first and second wiring patterns corresponding to each other .

According to the droplet discharge head of the present invention, the total wiring length of the first and second wiring patterns corresponding to each other is substantially the same for any of the first and second wiring patterns corresponding to each other. Therefore, the parasitic capacitance between adjacent wiring patterns is almost the same. Then, the voltage response characteristics from the drive circuit to the plurality of individual electrodes become uniform, and variations in droplet discharge timing and the like in each energy generation unit can be reduced.

  In addition, a flow path unit including a plurality of nozzles that discharge liquid droplets and a plurality of pressure chambers that store liquid corresponding to the plurality of energy generation units respectively communicating with the plurality of nozzles, It is preferable that the actuator is arranged so that the plurality of pressure chambers and the plurality of energy generation units face the flow path unit. According to this, voltage response characteristics from the drive circuit to the plurality of individual electrodes become uniform, and variations in droplet discharge performance such as droplet diameter and droplet discharge speed at each nozzle can be reduced.

In the present invention, the second wiring pattern may be arranged so as to overlap the first wiring pattern when viewed from a direction orthogonal to the one surface of the wiring member. The through hole may be arranged closer to the drive circuit than the individual surface electrode, and the second wiring pattern may extend so as to approach the individual surface electrode in the one direction.

  A holding member that fixes the flow path unit and at least a part of which is formed of a conductive member is attached to the upper surface of the flow path unit, and the end of the wiring member opposite to the drive circuit The part is preferably connected to the holding member by an insulating material. According to this, the heat generated when the active part is driven by the drive circuit is transmitted to the holding member through the plurality of wiring patterns and the insulating material, and the heat to the physical properties such as the viscosity of the liquid in each pressure chamber due to the heat. The variation in influence can be further reduced, and the variation in the droplet discharge performance of each nozzle can be further reduced.

  Further, the actuator has an outer shape smaller than the holding member, and the holding member is formed with a through-hole so that the actuator is exposed and accommodated. It is preferable that the insulating material is filled between the inner walls of the through holes. According to this, when the actuator and the flow path unit can be attached to the holding member, and when the active portion is driven by the drive circuit via the insulating material filled between each side surface of the actuator and the inner wall of the through hole, Since the generated heat is transferred to the holding member, it is possible to further reduce the variation in the thermal influence on the physical properties such as the viscosity of the liquid in each pressure chamber due to the heat, and further reduce the variation in the droplet discharge performance of each nozzle. can do.

  Moreover, it is preferable that a member having excellent thermal conductivity is disposed on at least a surface of the wiring member overlapping the actuator. According to this, the heat generated when the active part is driven by the drive circuit is more uniformly transmitted to the actuator and the flow path unit, and the variation of the thermal influence on the physical properties such as the viscosity of the liquid in each pressure chamber due to the heat is further increased. This can reduce the variation in droplet discharge performance of each nozzle.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an exploded perspective view of an ink jet head of an ink jet printer apparatus as an example of a droplet discharge head of the present invention. FIG. 2 is an exploded perspective view showing a state in which the inkjet head is mounted on the head holder.

  The ink jet printer apparatus provided with the ink jet head 1 of the present invention is not only a single printer apparatus but also a printer function (recording function) of a multi-function device (MFD: Multi Function Device) having a copy function, a scanner function, a facsimile function and the like. Part).

  In an ink jet printer apparatus (not shown), a substantially box-shaped head holder 60 (see FIG. 2) that functions as a carriage is attached to a guide shaft installed in the main body so as to be able to scan along the guide shaft. Is mounted with an inkjet head 1 that records ink on recording paper by ejecting ink from nozzles 11 formed on its lower surface.

  The head holder 60 performs recording in a direction (sub-scanning direction: Y direction in FIG. 1) perpendicular to the main scanning direction while reciprocally scanning along the recording paper in the width direction (main scanning direction: X direction in FIG. 1). Printing is performed by transporting the paper and ejecting ink from the nozzles 11 of the inkjet head 1.

  The head holder 60 has a substantially box-like bottom plate 20c on a lower surface side of the bottom plate 20c via a reinforcing frame 91 described later, and the inkjet head 1 exposes the surface where the nozzles 11 are opened downward to be substantially parallel to the bottom plate 60c. To be fixed. A damper device 61 is mounted on the upper surface side of the bottom plate 60c of the head holder 60, and inks of various colors, for example, black, cyan, magenta, and yellow ink cartridges (not shown) that are stationary in the ink jet printer main body. The ink inside is supplied to and stored in a plurality of ink chambers partitioned inside the ink tube 62. An opening 60d is formed through the bottom plate 60c of the head holder 60. Inside the opening 60d, an ink outlet (not shown) of the damper device 61 and an ink supply port 31a to be described later of the inkjet head 1 are provided. To 31d are connected via ink supply ports 91a to 91d (see FIG. 1) of the reinforcing frame 91 and an elastic seal member (not shown), and the ink is independent from the damper device 61 to the inkjet head 1 for each color. Supplied.

As shown in FIG. 1, the inkjet head 1 according to the present embodiment has a flow path unit 10 having a nozzle surface on the lower surface formed by exposing a plurality of nozzles 11a (see FIG. 1) to the lower surface.
A piezoelectric actuator 12 that selectively applies discharge pressure to the ink in the flow path unit 10 is bonded via an adhesive sheet, and a drive signal is output to the piezoelectric actuator 12 on the upper surface thereof. A wiring material (wiring member) (FPC: Flexible Printed Circuit) 40 is electrically connected by laminating one end thereof to the actuator 12. The other end of the flexible wiring member 40 is pulled out in the X direction in parallel with the surface thereof, and a driver IC 102 having a driving circuit is mounted in the middle of the drawing. The driver IC 102 converts print data serially transferred from an external device, for example, a control board of the printing apparatus main body including the inkjet head 1, into parallel data corresponding to each nozzle 11 a and a predetermined voltage corresponding to the print data. The waveform signal is generated and output to each wiring pattern 79 described later.

  The flow path unit 10 and the piezoelectric actuator 11 both have a flat shape that is substantially rectangular in plan view, but the outer shape of the flow path unit 10 is formed slightly larger than the outer shape of the piezoelectric actuator 11. The piezoelectric actuator 11 is stacked substantially at the center of the back surface of the flow path unit 10, and the four ink supply ports 37 provided near one side parallel to the Y-axis direction of the flow path unit 10 are exposed on the back surface side. It is supposed to be.

  In addition, the inkjet head 1 has a reinforcing frame 91 (holding member) that is laminated so as to surround the piezoelectric actuator 11 on the back surface of the flow path unit 10. The reinforcing frame 91 is made of a material having rigidity (for example, a metal plate such as SUS), and is a flat plate member having a B-shape in plan view in which a through hole 91a is formed in the vicinity of the center of the plan view shape of the reinforcing frame 91. Thus, the outer shape is formed to be slightly larger than the flow path unit 10, and the piezoelectric actuator 12 is formed so as to be substantially larger than the planar shape of the piezoelectric actuator 12 so that the piezoelectric actuator 12 is exposed from the through hole 91e. Four ink supply ports 91a to 91d are formed side by side for each ink color near one side parallel to the Y-axis direction in the frame portion 91f. The ink supply ports 91 a to 91 d are formed to correspond to the ink supply ports 31 a to 31 d of the flow path unit 10, and are arranged so as to be separated from each other along the short direction of the reinforcing frame 91. The ink supply ports 91 a to 91 d have the same shape as the ink supply ports 31 a to 31 d formed in the flow path unit 10.

  The reinforcement frame 15 is for increasing the rigidity of the flow path unit 10, and the reinforcement frame 91 is previously placed on the back surface (upper surface) of the flow path unit 10 with the piezoelectric actuator 12 exposed from the through hole 91 a. By fixing the adhesive to the bottom plate 60c of the head holder 60 with an adhesive, deformation and distortion of the thin flat channel unit 10 (head holder 60) can be prevented.

  The ink jet head 1 has a front frame 92 disposed on the front surface (nozzle surface) side of the flow path unit 10. The front frame 92 is a flat plate having a U-shape in plan view, and is fixed to the front surface of the front frame 92 in order to eliminate a step between the nozzle surface of the flow path unit 10 and the periphery of the head holder 60 (see FIG. 2 and FIG. 3).

  The inkjet head 1 has a rigid member 81 having a rectangular shape in plan view, which is laminated at a position corresponding to the piezoelectric actuator 11 on the back surface (upper surface in FIG. 2) of the flexible wiring material 12. The rigid member 81 is formed of flat aluminum having substantially the same size as the upper surface of the piezoelectric actuator 12, and is made of a material having higher rigidity than the flexible wiring member 40 and having excellent thermal conductivity. For example, in addition to aluminum, a metal plate such as copper or SUS is applied. The rigid member 81 can uniformly transmit heat generated when an active portion described later by the driver IC 102 is driven to the piezoelectric actuator 12 and the flow path unit 10, and has rigidity, so that it can be assembled. Easy handling.

  The inkjet head 1 is formed by laminating and bonding a flow path unit 10, a piezoelectric actuator 12, and a flexible wiring member 40, and a reinforcing frame 91 is bonded to the upper surface and a front frame 92 is bonded to the lower surface. The region of the piezoelectric actuator 12 and the flexible wiring member 40 that overlaps the piezoelectric actuator 12 is accommodated in a through hole 91e formed in the reinforcing frame 91, and the flexible wiring member 40 extends from the overlapping region (one end). The part (the other end) is drawn out on the through hole 91e. The other end of the flexible wiring member 40 drawn out is inserted into a slit 60f provided in the bottom plate 60c of the head holder 60, drawn upward along the side wall 60a, and joined to a circuit board (not shown). And electrically connected to an external signal source of the ink jet printer apparatus.

  The peripheral portion of the piezoelectric actuator 12 on the upper surface of the flow path unit 10 and the lower surface of the reinforcing frame 91 are bonded together with an adhesive such as an adhesive sheet. As a result, the upper surface of the flexible wiring member 40 is exposed upward from the through hole 91e of the reinforcing frame 91. Further, the front frame 92 is bonded to the lower surface of the reinforcing frame 91 in a state where the flow path unit 10 is surrounded by a U-shape of the front frame 92. That is, the nozzle 11a formed in the flow path unit 10 is exposed downward from the U-shaped inner region.

  The ink supply ports 31a to 31d are aligned and arranged so as to communicate with the ink supply ports 91a to 91d when the reinforcing frame 91 and the flow path unit 10 are bonded to each other. As will be described later, the gap between the side surface of the piezoelectric actuator 12 and the flexible wiring member 40 and the side surface (inner wall) of the through hole 91e of the reinforcing frame 91 is made of a thermosetting resin such as silicon for preventing ink leakage. Further, a potting agent 98 (insulating material) having an insulating property is filled (see FIG. 6). As described above, the flow path unit 10, the piezoelectric actuator 12, and the flexible wiring member 40 are fixed by the reinforcing frame 91 and the front frame 92.

  Here, details of the flow path unit 10 will be described with reference to FIGS. 3 and 4. FIG. 3 is an exploded perspective view of the flow path unit. FIG. 4 is a partially enlarged view of FIG.

  As shown in FIG. 3, the flow path unit 10 includes a nozzle plate 11, a cover plate 15, a damper plate 16, two manifold plates 17 and 18, two spacer plates 19 and 20, and a base plate 21 in order from the lower layer. Eight flat plates are laminated and bonded with an adhesive. Each plate has a thickness of about 40 to 150 μm, the nozzle plate 11 is made of synthetic resin such as polyimide, and the other plates 15 to 21 are made of 42% nickel alloy steel plate.

  The nozzle plate 11 is provided with a large number of nozzles 11a having a minute diameter (about 20 μm). The nozzles 11a are arranged in a staggered arrangement along the Y direction, and five nozzle rows are formed with a predetermined interval in the X direction. FIG. 3 shows the first row N1, the second row N2, and the third row N3 among the five nozzle rows along the Y direction, and the fourth row and the fifth row are not shown. Among the nozzle rows, cyan ink from the nozzle 11a in the first row N1, yellow ink from the nozzle 11a in the second row N2, magenta ink from the third row N3 nozzle 11a, fourth row and fifth row (not shown). Black ink is ejected from each nozzle 11a. Since black ink is used frequently, it is ejected from two rows of nozzles.

  The base plate 21 has a plurality of pressure chambers 23 corresponding to the nozzles 11a. The pressure chambers 23 are arranged in a staggered arrangement along the Y direction in the same manner as the nozzles 11a, and five pressure chamber rows are formed with an interval in the X direction. In FIG. 3, reference numbers 23-1, 23-2, 23-3, 23-4, and 23-5 are assigned to five pressure chamber rows along the Y direction, respectively. As shown in FIG. 4, the pressure chambers 23 included in each row are arranged via partition walls 24 in the Y direction, and are shifted by a half pitch in the Y direction with respect to the pressure chambers 23 included in adjacent rows, so-called staggered. Are arranged in a shape. Each pressure chamber 23 has an elongated shape in plan view in the X direction, one end in the longitudinal direction is a communication hole 29 formed in the spacer plate 20, and the other end is a cover plate 15, a damper plate 16, a manifold plate. The nozzles 11a communicate with the nozzles 11a through communication passages 25 formed in the spacer plates 17 and 18, respectively.

  As shown in FIG. 3, the base plate 21 has four ink supply ports 31 formed in the vicinity of one end in the Y direction. In FIG. 3, reference numbers 31a, 31b, 31c, and 31d are assigned to four ink supply ports 31 that are formed at appropriate intervals in the X direction. The spacer plates 19 and 20 are formed with ink supply passages 32 communicating with the respective ink supply ports 31. A filter body for removing foreign matters in the ink is collectively attached to the ink supply port 31 of the base spray 21 with an adhesive or the like.

  In the manifold plates 17 and 18, an ink passage extending in the Y direction is formed below each row of the pressure chambers 23, and five common ink chambers 26 are formed by stacking the plates 17 and 18. Is done. One end of each common ink chamber 26 communicates with the ink supply passage 32 and the ink supply port 31. In FIG. 3, reference numbers 26a, 26b, 26c, 26d, and 26e are assigned to five common ink chambers. The common ink chambers 26a, 26b, and 26c communicate with the ink supply ports 31a, 31b, and 31c through the ink supply passages 32 formed in the spacer plates 19 and 20, respectively, and the common ink chambers 26d and 26e are both inks. It communicates with the supply port 31d.

  A damper chamber 27 having a shape coinciding with each common ink chamber 26 in a plan view is recessed on the lower surface of the damper plate 16, and the damper plate 16 and the cover plate 15 are stacked to form a sealed damper chamber. 27 is formed. As a result, the pressure fluctuation that has propagated to the common ink chamber 26 among the pressure waves acting on the pressure chamber 23 is absorbed by the thin wall of the upper plate of the damper chamber 27 that vibrates freely due to elastic deformation, thereby causing crosstalk. Occurrence can be suppressed.

  As shown in FIG. 4, a narrowed narrow portion 28 is recessed in the X direction on the upper surface of the spacer plate 19. The throttle portions 28 respectively correspond to the pressure chambers 23. One end of each throttle portion 28 communicates with the corresponding common ink chamber 26, and the other end communicates with the pressure chamber 23 through a communication hole 29 formed in the spacer plate 20.

  The ink supplied to each ink supply port 31 flows into the corresponding common ink chamber 26 and is distributed into each pressure chamber 23 through the throttle portion 28 and the communication hole 29, and then communicated from each pressure chamber 23. The nozzle 11 a corresponding to the pressure chamber 23 is reached through the passage 25. Cyan ink is supplied to the ink supply port 31a, yellow ink is supplied to the ink supply port 31b, magenta ink is supplied to the ink supply port 31c, and black ink is supplied to the ink supply port 31d. From the ink supply port 31d to which black ink is supplied, the ink chambers 27 and 27 for two rows of black ink are branched and flowed, and two nozzle rows for discharging black ink are set. Each of the three ink supply ports is supplied with each ink individually. As described above, in the flow path unit 10, the ink flows from the ink supply port 37 through the connection port 38 to the common ink chamber 34, reaches the pressure chamber 31 through the connection flow path 33 and the communication hole 32, and An ink flow path reaching the nozzle 4 through the through path 35 is formed.

  Next, the details of the piezoelectric actuator 12 will be described with reference to FIG. FIG. 5 is an exploded perspective view of the piezoelectric actuator.

  As shown in FIG. 5, the piezoelectric actuator 12 is formed by laminating insulating sheets 33 and 34 and a plurality of piezoelectric sheets 35 and 36 in the same manner as a known actuator disclosed in Japanese Patent Application Laid-Open No. 2002-254634. Is formed. The piezoelectric sheet is an appropriate number of sheets among a plurality of piezoelectric ceramic material sheets (green sheets) formed by mixing ceramic powder, binder and solvent into a flat shape so that the thickness of each sheet is about 30 μm. An electrode layer is formed on the surface with a conductive paste by a printing method or the like, and the green sheet is laminated and baked to form a piezoelectric sheet. Thereby, each green sheet becomes a ceramic sheet of a sintered body. On the upper surface of the piezoelectric sheet 36, a plurality of individual electrodes 37 are arranged in five rows in a staggered manner along the Y direction of the piezoelectric sheet 36 corresponding to the arrangement of the pressure chambers 23 in the flow path unit 10. Each individual electrode 37 is formed in an elongated shape in the X direction of the piezoelectric sheet 36 as a whole. In addition, each individual electrode 37 has a lead-out portion 37 a that extends from either one end portion in the Y direction of the piezoelectric sheet 36. In addition, any drawer | drawing-out part 37a is pulled out to the position facing the partition 24 which divides each pressure chamber 23. FIG.

  On the upper surface of the piezoelectric sheet 35, a common electrode 38 is provided across the plurality of pressure chambers 23. In the common electrode 38, a plurality of non-formation regions 39 where the piezoelectric sheet 35 is exposed are formed, and a hole 40 penetrating in the thickness direction of the piezoelectric sheet 35 is formed in each non-formation region 39. Each non-formation region 39 is formed at a position facing the lead portion 37 a of the corresponding individual electrode 37.

  On the upper surface of the uppermost insulating sheet 33 (the upper surface of the piezoelectric actuator 12), there are provided individual surface electrodes 50 corresponding to the plurality of individual electrodes 37 and common surface electrodes 51 corresponding to the common electrodes 38, respectively. The individual surface electrodes 50 are arranged at positions facing the partition walls 24 that partition the pressure chambers 23, and are arranged in five staggered rows along the Y direction of the piezoelectric actuator 12 corresponding to the individual electrodes 37. ing. The common surface electrode 51 extends along the X direction of the piezoelectric actuator 12 on one end of the insulating sheet 33. Each of the surface electrodes 50 and 51 is aligned and electrically connected to an individual bonding electrode 78 (described later) formed on the flexible wiring member 40.

  A plurality of continuous holes 41 penetrating in the thickness direction of the insulating sheets 33, 34 are formed in the insulating sheets 33, 34 in regions facing the individual surface electrodes 50 and the lead portions 37 a and facing the holes 40. Is formed. In this state, with the holes 40 and the continuous holes 41 aligned, the two insulating sheets 33 and 34 and the plurality of piezoelectric sheets 35 are stacked, so that the piezoelectric actuator 12 has a plurality of upper sheets. A plurality of through holes penetrating the sheets 33 to 35 are formed. These through holes are filled with a conductive member in order to electrically connect the individual surface electrode 50 and the individual electrode 37 when the piezoelectric actuator 12 is manufactured. In addition, the insulating sheets 33 and 34 have three continuous holes 42 penetrating in the thickness direction of the insulating sheets 33 and 34 in the region where the common surface electrode 51 and the common electrode 38 face each other in the X direction of the insulating sheets 33 and 34. Are spaced apart from each other. These continuous holes 42 are also filled with a conductive member in order to electrically connect the common surface electrode 51 and the common electrode 38 when the piezoelectric actuator 12 is manufactured.

  Such a piezoelectric actuator 12 is provided alternately in the stacking direction with the electrode layer of the individual electrode 37, the electrode layer of the common electrode 38 and the piezoelectric sheet interposed therebetween, and the individual electrodes 37 and the common electrode 38 in the piezoelectric sheets 35 and 36 are provided. A portion sandwiched between the two becomes an active portion (energy generating portion) by applying a voltage between the individual electrode 37 and the common electrode 38. That is, the active part is disposed so as to face the pressure chamber 23 formed in the flow path unit 10. As a result, distortion due to the piezoelectric longitudinal effect occurs in the stacking direction in the active portion corresponding to the individual electrode 37 applied by the drive signal applied to the piezoelectric actuator 12 from the flexible wiring member 40. Then, due to the distortion, a pressure wave is generated in the pressure chamber 23 corresponding to the active portion, and ink is ejected from the nozzle 11 a communicating with the pressure chamber 23 to perform printing on the paper.

The individual surface electrodes 50 are arranged in rows extending along the X axis direction corresponding to the pressure chambers 23 (individual electrodes 37), arranged in five rows in the Y axis direction, and the pressure chambers 23 (individual electrodes 37). ) And the same long and narrow shape along the Y-axis direction, and on the upper surface of one end in the longitudinal direction, the connection terminal 50a (made of conductive material) is shorter and wider than the individual surface electrode 50. ) Is formed. The connection terminals 50a are electrically joined to correspond to individual joint electrodes 78 described later of the flexible wiring member 40. In the connection terminal 50a, the individual joint electrodes 78 of the flexible wiring member 40 are arranged with high density and the wiring is routed. Therefore, the adjacent individual joint electrodes 78 terminal electrodes are arranged in the X-axis direction in order to increase the interval between them. Are arranged in a staggered pattern. Therefore, in order to make a distance as large as possible between the corresponding connection terminals 50a, the connection terminals 50a provided in a staggered manner along the X-axis direction, that is, one end side in the longitudinal direction of the individual surface electrode 50, and the other end The connection terminals 50a provided on the side are arranged so as to be alternately arranged along the X-axis direction. Further, the connection terminals 50a are arranged so as not to be adjacent to each other in the Y axis direction even between the individual surface electrodes 50a adjacent to each other in the Y axis direction.

  The common surface electrode 51 is formed in a wide band shape along one (or both) sides parallel to the Y-axis direction of the piezoelectric actuator 11, and has a rectangular shape in plan view with an appropriate space on the upper surface thereof. A connection terminal 51a is formed. The connection terminals 50a and 51a are made by depositing a conductive material on the surface electrodes 50 and 51 by printing or plating in order to improve the bondability between the surface electrodes 50 and 51 and the bumps 54 of the flexible wiring member 40 described later. It is a thing.

  Next, the configuration of the flexible wiring member 40 will be described with reference to FIGS. 6 and 7. FIG. 6 is a schematic schematic plan view of the ink jet head. Further, the rigid member 81 arranged and fixed on the flexible wiring member 40 is indicated by a dotted line, and for the sake of description, the rigid member 81 and a protective layer 101 to be described later are transmitted to clearly show the wiring pattern 37 on the flexible wiring member 40. Shows the state. 7 is a cross-sectional view taken along line VI-VI in FIG. Note that the wiring intervals of the wiring patterns formed on the flexible wiring member 40 in FIG. 6 and the positions of the individual bonding electrodes are schematically shown for simplicity. Actually, the number of individual joining electrodes is larger, and the wiring interval of the wiring pattern is narrower.

As shown in FIGS. 6 and 7, the flexible wiring member 40 has a belt-like shape as a whole, is elongated in the X direction, and one end in the longitudinal direction is disposed and fixed on the upper surface of the piezoelectric actuator 12. A region overlapping the piezoelectric actuator 12 at one end of the flexible wiring member 40 is exposed from a through hole 91e formed in the reinforcing frame 91, and a continuous flexible portion from the overlapping region toward the other end is reinforced. It is pulled out in the X direction from the upper side of the through hole 91e of the frame 91 (the side opposite to the piezoelectric actuator 12). A driver IC 102 is mounted in the middle in the longitudinal direction of the flexible portion, and the sides on both sides in the Y direction and the X direction are filled with the potting agent 98 so as to fill a gap formed when combined with the rigid member 81. In addition, the influence of ink leakage or the like is prevented. The side of the potting agent 98 near the driver IC 102 in the Y direction is bonded to the potting agent 98 from the top of the flexible wiring material. Although not shown, the back side of the flexible wiring material (the side bonded to the actuator) In this case, the potting agent may be used to seal the necessary amount between the rigid member 81 and the ink so as not to leak. The other end of the flexible wiring member 40 is connected to an external signal source, and a drive signal sent from the signal source is output to the piezoelectric actuator 12 via the driver IC 102. The driver IC 102 has a rectangular shape that is long in the width direction (Y direction) of the flexible wiring member 40, and has a wiring pattern 79 a from each electrode of the flexible wiring member 40 and an external signal source for each input and output terminal. The wiring pattern 79b is connected. The driver IC 102 mounted on the flexible portion is brought into contact with a heat sink 65 provided near the side plate 60a of the head holder 60, so that the heat generated by the driver IC 102 is dissipated by the heat sink 65 (FIG. 2).

  The flexible wiring member 40 has a base material 100 made of a synthetic resin material (for example, polyimide resin, polyester resin, polyamide resin) having electrical insulation and flexibility, and an electrode forming surface 100 a that is the upper surface of the base material 100. Includes a wiring pattern 79 (79a, 79b) formed of a conductive material (copper foil or the like) with a photoresist or the like, and further, an electrically insulating and flexible synthetic resin material (covering the wiring pattern 79). For example, a protective layer 101 made of a polyimide resin, a polyester resin, or a polyamide resin is coated. The above-described rigid member 81 is disposed on the upper surface of the protective layer 101 above the flexible wiring member 40. The wiring pattern 79 includes a common bonding electrode (not shown) bonded to the common surface electrode 51, a plurality of individual bonding electrodes 78 respectively bonded to the individual surface electrodes 50, a common bonding electrode, and each individual bonding. An output wiring pattern 79 a that electrically connects the electrode 78 to the driver IC 102 is formed, and an input wiring pattern 79 b that connects the driver IC 102 to the external electrode is formed. Note that FIG. 7 does not show a wiring pattern for electrically connecting the common junction electrode to the driver IC 102.

  The individual bonding electrodes 78 are arranged at predetermined intervals along the Y direction in a state where the adjacent individual bonding electrodes 78 are shifted in the X direction so as to face the individual surface electrodes 50 formed on the upper surface of the piezoelectric actuator 12. Has been placed. In FIG. 6, the arrangement of the individual bonding electrodes 78 is schematically shown, but actually, like the individual surface electrodes 50, they are arranged in five rows in a staggered manner along the Y direction.

  Further, as shown in FIG. 7, the individual bonding electrode 78 has a plurality of penetrations penetrating in the thickness direction of the base material 100 at positions overlapping the connection terminals 50 a of the individual surface electrodes 50 of the piezoelectric actuator 12 in the base material 100. A part of the wiring pattern 79 is exposed from the hole, and a bump 54 made of a heat-meltable conductive material (for example, solder) is provided on the individual bonding electrode 78 toward the individual surface electrode 50. It is provided to protrude. The bumps 54 are bonded to the connection terminals 50a of the individual surface electrodes 50, whereby the individual bonding electrodes 78 and the individual surface electrodes 50 are electrically connected. Similarly, the common surface electrode 51 and the common bonding electrode are connected via the bumps 54.

  Each wiring pattern 79a extending in the X direction of the base material 100 is provided in the same number as the pressure chambers 23 and the individual bonding electrodes 78, one end of which is connected to the driver IC 102, and the other end of each wiring pattern 79a. The base material 100 extends to the end opposite to the side where the driver IC 102 is provided via the bonding electrode 78. In other words, all the wiring patterns 79a that are electrically connected to the individual bonding electrodes 78 and the driver IC 102 all extend from the driver IC 102 to the end of the base material 100 opposite to the side where the driver IC 102 is provided. Therefore, the wiring length from the driver IC 102 is almost the same.

  As shown in FIG. 7, the end of each wiring pattern 79a opposite to the driver IC 102 is exposed to the outside from the end face side of the base material 100, and is connected to the potting agent 98 via the exposed portion. Yes. Thereby, the heat generated when the active part is driven by the driver IC 102 is transmitted to the reinforcing frame 91 via the plurality of wiring patterns 79 and the potting agent 98, and the viscosity of the ink in each pressure chamber 23 due to the heat, etc. Variations in the thermal influence on the physical properties can be reduced, and variations in the droplet discharge performance of each nozzle 11a can be reduced. Note that the potting agent 98 filled in the gap between the inner wall of the reinforcing frame 91 and the piezoelectric actuator 12 is not filled, that is, the generated heat can be radiated to the air layer. It is desirable to have 98.

  According to the inkjet head 1 described above, since the plurality of wiring patterns 79a drawn from the driver IC 102 have the same wiring length, the parasitic capacitance between the adjacent wiring patterns 79 is substantially the same. Then, the voltage response characteristics from the driver IC 102 to the plurality of individual surface electrodes 50 become uniform, and variations in the droplet discharge timing and the like in each active portion can be reduced. Then, there is no variation in the ink ejection speed, the droplet diameter, etc. from each nozzle 11a, and the variation in the droplet ejection performance in each nozzle 11a can be reduced.

  In addition, since the plurality of wiring patterns 79 extend to the position of the individual joint electrode 78 that is farthest from the driver IC 102 in the X direction, the plurality of wiring patterns 79 are even on the flexible wiring material 40. Is distributed. Therefore, the heat generated when the active part is driven by the driver IC 102 is uniformly transmitted to the piezoelectric actuator 12 and the flow path unit 10 via the wiring pattern 79, and the viscosity of the ink in each pressure chamber 23 due to the heat, etc. Variations in the thermal influence on the physical properties can be reduced, and variations in the droplet discharge performance of each nozzle 11a can be further reduced.

  Furthermore, since the plurality of wiring patterns 79 extend to the end of the flexible wiring material 40 on the side opposite to the driver IC 102, for example, in the manufacturing process, the wiring pattern 79 is formed on the base material 100 by an appropriate length. The flexible wiring material 40 on which the desired wiring pattern 79 is printed can be easily formed simply by pattern printing and cutting out the base material 100 with a predetermined length of the wiring pattern 79. In addition, it is possible to easily conduct a continuity test for searching for a defect due to a short circuit between the wiring patterns 79 in the product completion stage or the shipping stage with the wiring pattern 79 formed up to the end thereof.

  In addition, since the rigid member 81 is disposed on the surface of the flexible wiring member 40, heat generated by driving the driver IC 102 is more uniformly transmitted to the piezoelectric actuator 12 and the flow path unit 10, and each pressure due to heat is transmitted. Variations in the thermal influence on the ink in the chamber 23 can be further reduced, and variations in ejection performance at each nozzle 11a can be further reduced.

  Next, a method for joining the flexible wiring member 40 and the piezoelectric actuator 12 will be described.

  When the flexible wiring member 40 and the piezoelectric actuator 12 are connected, a conductive material bump is formed on the terminal electrode on the wiring pattern 79a exposed from the through hole previously formed in the base material 100 by printing or the like. The individual bonding electrode 78 is positioned so as to face the individual surface electrode 50, and the flexible wiring member 40 is arranged on the surface of the piezoelectric actuator 12 opposite to the flow path unit 10. When the flexible wiring member 40 and the piezoelectric actuator 12 are arranged and heated while pressing from the upper surface of the flexible wiring member 40 to the piezoelectric actuator 12 side by a heater or the like, the bumps 54 are melted and solidified, and the individual bonding electrodes 78 are melted. It is electrically and mechanically joined to the individual surface electrode 50 via a conductive member. As a result, the flexible wiring member 40 and the piezoelectric actuator 12 are electrically and mechanically joined. The common junction electrode and the common surface electrode are connected in the same manner.

  Here, as described above, since the plurality of wiring patterns 79 having the same wiring length extend on the flexible wiring material 40 to the position of the individual bonding electrode 78 farthest from the driver IC 102, the flexible wiring material 79 is flexible. When the wiring member 40 is joined to the piezoelectric actuator 12, heat is uniformly transmitted to the surface of the flexible wiring member 40 via the wiring pattern 79, and the entire rigidity of the flexible wiring member 40 becomes uniform. Warpage is reduced, and the flexible wiring member 40 and the piezoelectric actuator 12 are uniformly joined without deviation. Furthermore, since the warpage is reduced, peeling of the wiring pattern 79 due to residual stress is reduced.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various design changes can be made as long as they are described in the claims.

  In the above-described embodiment, the plurality of wiring patterns 79a extend to the end of the flexible wiring material 40 on the side opposite to the driver IC 102. However, if the wiring lengths of the plurality of wiring patterns 79a are substantially the same, It does not have to extend to the end of the flexible wiring member 40. For example, the plurality of wiring patterns 79a may extend to the position of the individual bonding electrode 78 that is farthest from the driver IC 102 in the X direction. In FIG. 8A, a double-sided flexible wiring material is adopted as the flexible wiring material. In this way, since layers for providing wiring patterns can be arranged on both the upper and lower surfaces of the base material 100, the plurality of wiring patterns 179 a extend from the driver IC 102 to the corresponding individual bonding electrodes 78. As shown in FIG. 8B, a wiring pattern 279 is formed on the opposite surface of the flexible wiring material 40 through the through hole 180 by the length of the difference from the wiring pattern 179a having the longest wiring length. May be. Furthermore, the wiring pattern is not limited to a straight line, and depending on how the wiring pattern is routed, if the wiring length is substantially the same, it extends outward at both ends of the flexible wiring material 40 in the Y direction. May be.

  In this embodiment, the rigid member 81 is disposed on the upper surface of the flexible wiring member 40. However, when the heat generated by driving the driver IC 102 is very small, the rigid member 81 may not be provided.

  Further, in the present embodiment, the flow path unit 10, the piezoelectric actuator 12, and the flexible wiring material 40 are fixed by the reinforcing frame 91 and the front frame 92, but the flow path unit 10, the piezoelectric actuator 12 and the flexible wiring material 40 are used. When the frame is fixed firmly enough only by adhesion, the reinforcing frame 91 and the front frame 92 may not be provided. At this time, since the reinforcing frame 91 is not provided, a gap between the side surface of the piezoelectric actuator 12 and the flexible wiring member 40 and the side surface of the through hole 91e of the reinforcing frame 91 is not formed, and the potting agent 98 is not filled.

  In addition, in the present embodiment, the piezoelectric actuator 12 is driven to generate a pressure wave serving as ejection energy in the ink in the pressure chamber 23. However, the pressure wave is not limited to the piezoelectric type, and a thermal type or the like. The driving method may be adopted.

  In addition, although the present embodiment has been described as an example applied to an ink jet head, various liquids such as a head other than a liquid, such as a head for applying a colored liquid to manufacture a color filter of a liquid crystal display device, are discharged. It can be applied to the head.

It is a disassembled perspective view of the inkjet head which concerns on this embodiment. It is a disassembled perspective view which shows the state by which the inkjet head was mounted in the head holder. It is a disassembled perspective view of a flow path unit. FIG. 4 is a partially enlarged view of FIG. 3. It is a disassembled perspective view of a piezoelectric actuator. It is a typical schematic plan view of the inkjet head except a rigid member. It is sectional drawing along the VI-VI line of FIG. It is a figure which shows the modification of the wiring pattern printed on the flexible wiring material.

DESCRIPTION OF SYMBOLS 1 Inkjet head 10 Flow path unit 11a Nozzle 12 Piezoelectric actuator 23 Pressure chamber 50 Individual surface electrode 78 Individual joining electrode 79 Wiring pattern 81 Rigid member 91 Reinforcement frame 91e Through-hole 98 Potting agent 102 Driver IC

Claims (7)

An actuator having a plurality of energy generating parts for discharging droplets, and a plurality of individual surface electrodes for applying a voltage to the plurality of energy generating parts on the surface thereof;
One end portion is overlaid on the surface of the actuator, and the wiring member is drawn in one direction in parallel with the surface,
On one surface of the wiring member , a plurality of individual joint electrodes are provided corresponding to the plurality of individual surface electrodes, and a drive circuit for driving the actuator is mounted on the drawn side. A plurality of first wiring patterns respectively connected to the plurality of individual joining electrodes extend along the one direction;
A plurality of second wiring patterns corresponding to the plurality of first wiring patterns are formed on the other surface of the wiring member,
The first and second wiring patterns corresponding to each other are electrically connected through a through hole penetrating the wiring member,
In the droplet discharge head in which the individual surface electrode and the individual bonding electrode are bonded in correspondence with each other,
The plurality of individual surface electrodes are arranged at predetermined intervals along a direction orthogonal to the one direction in a state shifted in the one direction on the surface,
The total wiring length of the first and second wiring patterns corresponding to each other is substantially the same as the total wiring length of any of the other first and second wiring patterns corresponding to each other. Droplet discharge head. 2. The liquid according to claim 1, wherein the second wiring pattern is disposed so as to overlap the first wiring pattern when viewed from a direction orthogonal to the one surface of the wiring member. Drop ejection head.   The through hole is disposed closer to the drive circuit than the individual surface electrode,
The droplet discharge head according to claim 1, wherein the second wiring pattern extends so as to approach the individual surface electrode in the one direction. A flow path unit including a plurality of nozzles each discharging liquid droplets, and a plurality of pressure chambers communicating with each of the plurality of nozzles and containing liquid corresponding to the plurality of energy generation units,
The actuator relative to the channel unit, in any one of claims 1-3, wherein the plurality of pressure chambers and a plurality of energy generating portion is characterized in that it is arranged so as to face The droplet discharge head described. On the upper surface of the flow path unit, the flow path unit is fixed, and a holding member at least partially formed of a conductive member is attached.
End opposite to the drive circuit in the wiring member, the liquid droplet ejection head according to any one of claims 1 to 4, characterized in that it is connected with the holding member and the insulating material. The actuator has an outer shape smaller than the holding member,
A through hole is formed in the holding member so that the actuator is exposed and accommodated,
The liquid droplet ejection head according to claim 5, wherein the insulating material is filled between each side surface of the actuator and an inner wall of the through hole.   The droplet discharge head according to claim 6, wherein a member having excellent thermal conductivity is disposed on at least a surface of the wiring member that overlaps the actuator.

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