JP4507514B2 - Inkjet head - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ink jet head, and more specifically, driving walls and channel portions made of piezoelectric elements are alternately arranged in parallel, and outlets and inlets of channel portions are arranged on the front and rear surfaces, respectively, so as to face each other. The present invention relates to an ink jet head having a head chip in which a drive wall is subjected to shear deformation by applying a voltage to discharge ink in a channel portion.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an actuator for ejecting ink is used as a share mode type inkjet head in which a voltage is applied to a drive wall that partitions a channel portion to shear the drive wall to eject ink in the channel portion. The driving wall and the channel portion made of piezoelectric elements are alternately arranged side by side, and the so-called harmonica type head chip in which the outlet and the inlet of the channel portion are arranged opposite to each other on the front and rear surfaces, Inkjet heads with a large number of wafers taken from one wafer and extremely improved productivity are known (Patent Documents 1 to 3).
[0003]
The channel part of such an ink jet head is a straight type whose size and shape are almost the same in the length direction from the inlet to the outlet, and an ink supply chamber for supplying ink to the channel part is formed on the rear side. Since the ink manifold as the ink supply chamber forming member is fixed, it is difficult to electrically connect the wiring for applying a voltage to the drive electrode formed on each drive wall with the drive circuit.
[0004]
In particular, in recent years, in order to record higher-quality and higher-definition images, the density of nozzles has increased, and a plurality of nozzle walls can be formed on the nozzle surface by forming drive walls and channel portions in multiple stages in the vertical direction. Inkjet heads having a head chip structure in which a nozzle array is formed to increase the density are also considered. Particularly, in the case of a head chip configured in three or more stages in the vertical direction, each drive located in the middle thereof There has been a problem that it becomes increasingly difficult to electrically connect the wiring for applying a voltage to the electrode with the drive circuit.
[0005]
[Patent Document 1]
JP 2002-103612 A
[Patent Document 2]
JP 2002-103614 A
[Patent Document 3]
JP 2002-210955 A
[0006]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION An object of the present invention is to provide a highly productive and high-density inkjet head that can easily perform electrical connection between a drive electrode in each channel section and wiring from a drive circuit.
[0007]
Other problems of the present invention will become apparent from the following description of the present specification.
[0008]
[Means for Solving the Problems]
  According to the first aspect of the present invention, drive walls and channel portions made of piezoelectric elements are alternately arranged side by side, and outlets and inlets of the channel portions are respectively arranged on the front and rear surfaces so as to face each other, and the drive walls An upper substrate and a lower substrate formed longer than the length of the channel portion are respectively fixed to the upper surface and the lower surface of a head chip formed in a plurality of stages in the vertical direction with the channel portion. Extending to the rear side of
  Between the two substrates,For forming an ink supply chamber for supplying ink to each channel sectionFormed by the enclosure wallInk supply chamber forming member, So as to surround the rear surface of the head chipProvided,
  First wirings that are electrically connected to the drive electrodes of the respective channel portions are drawn out from the outer surface of the head chip,
  Of the first wirings,Each channel portion of the step located on the outermost side of the head chip and each channel portion of the step adjacent to this stepThe first wirings that are electrically connected to the drive electrodes of the two stages of the channel portions are distributed to the front surface and the rear surface of the head chip for each stage, and either the upper surface or the lower surface is interposed through the front surface and the rear surface. Pulled out to one side,
  The upper substrate or the lower substrate fixed to the upper surface or the lower surface of the head chip from which each of the first wirings is drawn is connected to each of the first wirings. Each wiring is formed,
  Of each of the second wirings, one end is electrically connected to the one of the first wirings that is drawn out through either the front surface or the rear surface of the head chip. The other end of the wiring is from the fixing surface with the head chipThe upper substrate or the lower substrate on which the second wiring is formedOne of the second wirings and one end of the second wirings which are led out through the other surface of the front surface or the rear surface of the head chip and the electric power. The other end of the second wiring to be connected to the rear side is the rear side on the fixing surface side with the head chip.To the endExtendAnd
  The ink supply chamber forming member is formed with a third wiring electrically connected to the other end of the second wiring, one end of which extends to the rear end on the fixing surface side to the head chip. And the second wiring has a protruding portion protruding rearward from the upper substrate or the lower substrate formed on both the outer surface and the fixing surface side of the head chip. And the other end of the third wiring is exposed to the head surface at the protruding portion.This is an inkjet head.
[0011]
  Claim2In the invention described in the above, the ink supply chamber forming member is formed by a wall portion provided so as to surround the rear surface of the head chip between the upper substrate and the lower substrate. The ink supply chamber is formed by a space surrounded by the wall portion.1It is an inkjet head of description.
[0012]
  Claim3The invention described in claim 1 is characterized in that an electrode protective film is formed on surfaces of the drive electrode, the first wiring facing the ink supply chamber, and the second wiring.Or 2It is an inkjet head of description.
[0013]
  Claim4In the described invention, at least one of the member other than the drive wall, the upper substrate, and the lower substrate in the head chip is selected from ceramics, piezoelectric materials, and liquid crystal polymers containing aluminum nitride as a component. It consists of the material of Claim 1 characterized by the above-mentioned.2 or 3It is an inkjet head of description.
[0014]
  Claim5In the described invention, the thermal expansion coefficient of at least one of the member other than the drive wall, the upper substrate, and the lower substrate in the head chip is ± 2 × 10 of the thermal expansion coefficient of the piezoelectric element.^-6/ ° C.4Any one of the inkjet heads.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0016]
1 is an exploded perspective view of an ink jet head according to the present invention, FIG. 2 is a longitudinal sectional view of the ink jet head taken along line (ii)-(ii) in FIG. 1, and FIG. 3 (a) is a front view of a head chip. (B) is a rear view of the head chip.
[0017]
In the figure, A is an inkjet head, 1 is a head chip, 2 is a nozzle plate fixed to the front surface of the head chip 1, 3 is an upper substrate fixed to the upper surface of the head chip 1, and 4 is fixed to the lower surface of the head chip 1. The lower substrate 5 is an ink supply chamber forming member.
[0018]
In the present specification, the side on which ink is ejected from the head chip is referred to as “front”, the opposite side is referred to as “rear”, and the respective surfaces are referred to as “front surface” and “rear surface”. Further, in this specification, the side to which the upper substrate is fixed as viewed from the head chip is “upper”, and the side to which the lower substrate is fixed is “lower”, and the channel portion arranged in parallel in the head chip is sandwiched. The upper and lower outer surfaces are called “upper surface” and “lower surface”, respectively.
[0019]
As shown in detail in FIG. 3, the head chip 1 includes a drive wall 14 (141 to 144) composed of a piezoelectric element 12 and a channel portion 15 between two upper and lower cover substrates 11, 11 constituting the head chip 1. (151 to 154) are alternately arranged in parallel in the horizontal direction in the figure, and a plurality of levels are formed in the vertical direction. In the illustrated example, four channel portions 15 and five drive walls 14 are formed in each step, and these are illustrated in four steps (a1 to a4) in the vertical direction. In addition, each channel part 151-154 has shifted | deviated by half pitch for every step a1-a4.
[0020]
As the piezoelectric material used for the piezoelectric element 12, a known piezoelectric material that is deformed by applying a voltage can be used, and examples thereof include a substrate made of an organic material and a non-metallic substrate. In particular, a non-metallic piezoelectric material substrate is preferable, and includes a piezoelectric ceramic substrate formed through processes such as molding and firing, or a substrate formed without requiring molding and firing.
[0021]
In a non-metallic piezoelectric material substrate, lead zirconate titanate (PZT) is preferable as the piezoelectric ceramic substrate formed through processes such as molding and firing. Furthermore BaTiO_Three, ZnO, LiNbO_ThreeLiTaO_ThreeEtc. may be used.
[0022]
As PZT, PZT (PbZrO_Three-PbTiO_Three) And third component added PZT. As a third component to be added, Pb (Mg_1/2Nb_2/3) O_Three, Pb (Mn_1/3Sb_2/3) O_Three, Pb (Co_1/3Nb_2/3) O_ThreeEtc.
[0023]
Moreover, as a board | substrate formed without requiring shaping | molding and baking in a nonmetallic piezoelectric material board | substrate, it can form by the sol-gel method, the laminated substrate coating method, etc., for example.
[0024]
The piezoelectric element 12 is formed by joining two piezoelectric material substrates 12a and 12b with polarization directions opposite to each other. Thus, by arranging a plurality of rows of grooves in the piezoelectric element 12, the drive wall 14 whose polarization directions are opposite to each other is formed.
[0025]
As means for joining the piezoelectric material substrates 12a and 12b, joining using an adhesive can be adopted, but is not particularly limited as long as joining is possible. When it joins using an adhesive agent, the range after hardening of the adhesive bond layer has the preferable range of 1-10 micrometers.
[0026]
Although not shown, instead of the cover substrate 11, one of the piezoelectric material substrates 12a or 12b is thick, and from the other piezoelectric material substrate 12a or 12b side to the middle part of the one piezoelectric material substrate 12a or 12b. The drive wall 14 similar to the above may be formed by forming a plurality of rows of parallel grooves.
[0027]
The shape of each channel portion 15 is such that both side walls face the vertical direction (up and down direction) and are parallel to each other. Moreover, it is a straight type whose size and shape are not substantially changed in the length direction from the inlet to the outlet. As described above, since the channel portion 15 is a straight type, it is possible to obtain an ink jet head that has good bubble removal, high power efficiency, low heat generation, and good high-speed response.
[0028]
On each drive wall 14, drive electrodes 16 (161 to 164) are formed facing the respective channel portions 15. The metal forming the drive electrode 16 includes Ni (nickel), Co (cobalt), Cu (copper), Al (aluminum), etc., and Ni and Cu are preferable, and Ni is particularly preferable.
[0029]
Examples of the formation of the drive electrode 16 include a method using a vacuum apparatus such as a vapor deposition method, a sputtering method, a plating method, a CVD (chemical vapor reaction method), and the like. Preferably it is formed. Electroless plating can form an electrode composed of a uniform and pinhole-free metal coating.
[0030]
In electrode formation by electroless plating, Ni-P (phosphorus) plating or Ni-B (boron) plating may be used alone, or Ni-P and Ni-B may be overlaid. Since Ni-P plating increases the electrical resistance as the P content increases, the P content is preferably about 1 to several percent. Since the B content of Ni-B plating is usually 1% or less, the Ni content is higher than that of Ni-P, the electrical resistance is lower, and the connection with external wiring is better. Although Ni-B is expensive, it is also preferable to combine Ni-P and Ni-B. Further, Ni—P plating or Ni—B plating may be used as a lower layer, and Au (gold) may be formed thereon by electrolytic plating or vapor deposition. The thickness of the plating film is preferably in the range of 0.5 to 5 μm.
[0031]
In the head chip 1, a first wiring 171 electrically connected to each driving electrode 16 formed on each driving wall 14 on the upper surface and the lower surface, that is, each fixing surface to the upper substrate 3 and the lower substrate 4. ˜174 are drawn.
[0032]
Each of the first wirings 171 to 174 is electrically connected to each drive electrode 16 of each of the two stages of the channel parts 15 adjacent to each other in the upper and lower sides of the head chip 1 composed of a plurality of stages, and the head chip 1 for each stage. Are distributed to the front surface and the rear surface, and are drawn out to the fixing surfaces of the upper substrate 3 and the lower substrate 4. In the illustrated example, the first wiring 171 electrically connected to the uppermost (a1) driving electrode 161 among the two driving electrodes 161 and 162 on the upper substrate 3 side (a1, a2) is as follows. The first wiring 172 drawn out to the upper surface through the rear end surface of the cover substrate 11 directly above the rear surface of the head chip 1 and electrically connected to the drive electrode 162 in the lower stage (a2) Is pulled out to the upper surface through the front end surface of each drive wall 141 in the upper stage (a1). Of the two-stage (a3, a4) drive electrodes 163 and 164 positioned on the lower substrate 4 side, the first wiring 174 that is electrically connected to the lowermost (a4) drive electrode 164 is the head. The first wiring 173 that is drawn out to the lower surface through the rear end surface of the cover substrate 11 immediately below the chip 1 on the rear surface of the chip 1 and is electrically connected to the drive electrode 163 on the upper stage (a3) is connected to the front surface of the head chip 1. Are drawn out to the lower surface through the front end surface of each drive wall 144 in the lower stage (a4).
[0033]
Conversely, the first wirings 172 and 173 may pass through the rear surface of the head chip 1, and the second wirings 171 and 174 may pass through the front surface of the head chip 1.
[0034]
Note that the first wirings 171 to 174 drawn to the upper surface and the lower surface through the front surface and the rear surface of the head chip 1 do not contact each other on the upper surface and the lower surface as shown in FIG. Are separated.
[0035]
The upper substrate 3 and the lower substrate 4 fixed to the upper surface and the lower surface of the head chip 1 are substantially the same width as the width of the head chip 1 (the length in the direction in which the channel portions 15 are arranged in parallel), and It is made of a substrate that is sufficiently longer than the length (the length from the front surface to the rear surface of the head chip 1), and the first wirings 171 to 171 drawn to the upper and lower surfaces of the head chip 1 are formed on the surface thereof. The second wirings 31, 32, 41, 42 are formed in parallel at the same pitch corresponding to 174.
[0036]
That is, in the upper substrate 3, the second wiring 31 electrically connected to the first wiring 171 is arranged on the lower surface (inner surface) of the upper substrate 3, which is the fixing surface side with the head chip 1. The second wiring 32 extending to the rear of the upper substrate 3 and extending to the rear end at the same number and pitch corresponding to the wiring 171 is electrically connected to the first wiring 172. The same number and the same pitch are formed on the lower surface (inner surface) of the upper substrate 3 as corresponding to the first wirings 171, which are drawn out to the upper surface through the front end surface of the upper substrate 3 and fixed to the head chip 1. Is extended to the rear of the upper surface (outer surface) of the upper substrate 3 which is the opposite surface side of the upper substrate 3 and is formed to the rear end.
[0037]
Further, in the lower substrate 4, the second wiring 41 electrically connected to the first wiring 173 is provided on the upper surface (inner surface) of the lower substrate 4, which is the fixing surface side with the head chip 1. Are formed at the same number and the same pitch corresponding to one wiring 173, and are drawn through the front end surface of the lower substrate 4 to the lower surface (outer surface) which is the opposite surface of the fixing surface to the head chip 1, The second wiring 42 that extends to the rear of the lower surface (outer surface) of the lower substrate 4 and extends to the rear end and is electrically connected to the first wiring 174 is also the upper surface ( The inner surface is formed behind the lower substrate 4 at the same number and pitch corresponding to each first wiring 174 and is formed up to the rear end.
[0038]
Each of the upper substrate 3 and the lower substrate 4 has its front end surface flush with the front surface of the head chip 1, and the second wirings 31, 32, 41, 42 are connected to the first chips of the head chip 1. Adhering to the upper surface and the lower surface of the head chip 1 so that the first wires 171 to 174 and the corresponding second wires 31, 32, 41, and 42 are electrically connected to each other. It is fixed using an agent or an anisotropic conductive film.
[0039]
As a result, the head chip 1 is sandwiched from above and below by the upper substrate 3 and the lower substrate 4 projecting to the rear side of the head chip 1, and each drive electrode is formed by the upper substrate 3 and the lower substrate 4. Wirings electrically connected to 161 to 164 are drawn from the head chip 1 to the rear side thereof.
[0040]
The nozzle plate 2 is fixed to the front side of the head chip 1 to which the upper substrate 3 and the lower substrate 4 are fixed. Nozzle holes 21 corresponding to the respective channel portions 15 are formed in the nozzle plate 2.
[0041]
The ink supply chamber forming member 5 is provided on the rear surface of the head chip 1 between the upper substrate 3 and the lower substrate 4, and ink supply for supplying ink to each channel portion 15 on the rear surface side of the head chip 1. Make up the room. Here, the ink supply chamber forming member 5 surrounds the rear surface of the head chip 1 between the upper substrate 3 and the lower substrate 4 with a high-functional resin or ceramic material called engineering plastic such as polyimide or polycarbonate. It is formed by the surrounding wall part (side wall 5a, 5b and rear wall 5c) which is provided so as to exhibit a substantially U shape in a plan view. Thus, the rear surface side of the head chip 1 is covered with the upper substrate 3 and the lower substrate 4 on the upper and lower sides, and the side surfaces are the side walls 5a and 5b and the rear wall 5c of the surrounding wall portion constituting the ink supply chamber forming member 5. Thus, a closed space is formed, and an ink supply chamber 51 for supplying ink to each channel portion 15 is configured by this space.
[0042]
Thus, the ink supply chamber 51 is constituted by the wall portion including the side walls 5a and 5b and the rear wall 5c provided so as to surround the rear surface of the head chip 1 between the upper substrate 3 and the lower substrate 4. As a result, the fixing part between the ink supply chamber forming member 5 and the head chip 1 has only a very small area between the front end surfaces of the side walls 5a and 5b and the both end parts of the head chip 1 to be fixed. There is.
[0043]
That is, in general, an ink supply chamber forming member (ink manifold) for constituting an ink supply chamber is a box-shaped member having an opening on one surface, and the opening surrounds the periphery of the channel portion on the rear surface of the head chip. Therefore, it is necessary to secure an allowance for the entire area including the upper and lower cover substrates that serve as the fixing surface. Therefore, in order to secure the adhesive margin, the cover substrate must be formed to be excessively large, and the head chip needs to be enlarged unnecessarily. Moreover, since it is necessary to apply the adhesive to a very small space corresponding to the thickness of the cover substrate so as not to reach the channel part, the application work is troublesome and the adhesive may even protrude into the channel part. .
[0044]
However, as shown in the present embodiment, the ink supply chamber 51 is formed by providing wall portions (side walls 5a, 5b and rear wall 5c) between the upper substrate 3 and the lower substrate 4, It is not necessary to apply the adhesive to the entire area of the cover substrate 11 around the channel portion 15, so that it is not necessary to form the head chip 1 unnecessarily large in order to form the ink supply chamber 51. The operation of applying the adhesive is almost unnecessary, and the productivity can be improved, which is a preferable aspect in the present invention.
[0045]
Reference numeral 52 denotes an inlet for allowing ink to flow into the ink supply chamber 51, whereby the ink supply chamber 51 functions as an ink manifold. Although not shown, the ink supply chamber 51 has a built-in filter to prevent inflow of dust.
[0046]
The ink supply chamber forming member 5 shown in the present embodiment shows a preferable mode in which the rear wall 5c protrudes rearward from the upper substrate 3 and the lower substrate 4 and the protruding portion 53 is formed. On the rear side of the ink supply chamber forming member 5, the same surface as the fixing surface to the upper substrate 3 and the lower substrate 4 protrudes from the upper substrate 3 and the lower substrate 4 and is partially exposed upward and downward. ing.
[0047]
One end of the ink supply chamber forming member 5 is the lower surface of the upper substrate 3 and the upper surface of the lower substrate 4 of the second wirings 31, 32, 41, 42, that is, the upper substrate 3 and the lower substrate 4. Each of the inner surfaces of the ink supply chambers is electrically connected to the second wirings 31 and 42 formed to extend to the rear end, and the other end is drawn to the surface exposed to the outside in the ink supply chamber forming member 5. Third wirings 541 and 542 are formed. Here, one third wiring 541 is formed in parallel with the same number and pitch as the second wiring 31 on the upper surface of the ink supply chamber forming member 5, and the protruding portion 53 of the ink supply chamber forming member 5 is formed. It is pulled out to the top surface. The other third wiring 542 is formed on the lower surface of the ink supply chamber forming member 5 in parallel with the same number and at the same pitch as the second wiring 42, and the protruding portion 53 of the ink supply chamber forming member 5 is formed. It is pulled out to the lower surface. Such third wirings 541 and 542 can be formed by patterning the ink supply chamber forming member 5 and depositing metal using an electroless plating method or the like.
[0048]
As a result, the wirings electrically connected to the drive electrodes 161 to 164 at each stage of the head chip 1 are connected to the upper surface of the upper substrate 3, the lower surface of the lower substrate 4, and the protruding portion 53 of the ink supply chamber forming member 5. Since the upper surface and the lower surface are exposed on the head surface, even the second-stage and third-stage drive electrodes located in the middle in the vertical direction of the head chip 1 are connected to the drive circuit outside the inkjet head A. It can be easily connected electrically.
[0049]
That is, to this ink jet head A, four wiring boards 61 to 64 that are electrically connected to the drive circuits are bonded to the stages a1 to a4 of the head chip 1, respectively. The wiring substrate 61 is made of an anisotropic conductive film so that the wiring 611 formed on the lower surface of the upper substrate 3 and the second wiring 32 drawn out on the upper surface of the upper substrate 3 are electrically connected to each other. Bonded and extends rearward of the inkjet head A. The wiring board 62 has a wiring 621 formed on the lower surface thereof on the upper surface of the protruding portion 53 of the ink supply chamber forming member 5 and a third wiring 541 drawn on the upper surface of the protruding portion 53 of the ink supply chamber forming member 5. Are joined by an anisotropic conductive film so as to be electrically connected, and extend behind the inkjet head A. The wiring substrate 63 is anisotropically conductive on the lower surface of the lower substrate 4 so that the wiring 631 formed on the upper surface of the wiring substrate 63 and the second wiring 41 drawn out on the lower surface of the lower substrate 4 are electrically connected. It is joined by a film and extends behind the inkjet head A. The wiring board 64 includes a wiring 641 formed on the upper surface of the protruding portion 53 of the ink supply chamber forming member 5 and a third wiring 542 drawn to the lower surface of the protruding portion 53 of the ink supply chamber forming member 5. Are joined by an anisotropic conductive film so as to be electrically connected, and extend behind the inkjet head A.
[0050]
As described above, the wiring boards 61 and 63 are fixed using the outer surfaces of the upper substrate 3 and the lower substrate 4, and the wiring boards 62 and 64 use the upper and lower surfaces of the protruding portion of the ink supply chamber forming member 5. Accordingly, the drawing directions of all the wiring boards 61 to 64 can be aligned rearward, and the inkjet head A is electrically connected to the driving circuit by electrical connection with these wiring boards 61 to 64. A voltage can be applied to each of the drive electrodes 161-164.
[0051]
The wiring boards 61 to 64 for electrical connection with the drive circuit are preferably flexible wiring boards (FPC). In addition, although not shown in the drawings, each wiring board 61 to 64 is preferably mounted with a driving IC in order to reduce the number of connection terminals.
[0052]
At least one of the members (the cover substrate 11 in this embodiment), the upper substrate 3 and the lower substrate 4 other than the drive wall 14 in the head chip 1 is made of ceramic, piezoelectric material, or liquid crystal polymer containing aluminum nitride as a component. It is preferably made of any material selected from among them. As a result, there is an effect that an ink jet head having excellent heat dissipation characteristics and stable against temperature changes can be obtained.
[0053]
Further, at least one of the members other than the drive wall 14 (the cover substrate 11 in the present embodiment), the upper substrate 3 and the lower substrate 4 in the head chip 1 has a piezoelectric element constituting the drive wall 14. ± 2 × 10 with a coefficient of thermal expansion of 12^-6More preferably, the temperature is / ° C. By setting the thermal expansion coefficient within this range, separation or the like due to a difference in thermal expansion coefficient does not occur between the members.
[0054]
Further, since the first wiring 17 and a part of the second wirings 31 and 42 face the ink supply chamber 51, they are in direct contact with the ink as in the drive electrode 16 in each channel portion 15. Therefore, in order to make it possible to use water-based ink as the ink, it is preferable to form an electrode protective film on the surface of the drive electrode 16, the first wiring 17, and the second wirings 31 and 42 in each channel portion 15. The electrode protective film has flexibility and is difficult to peel off, can easily follow the shear deformation of the drive wall 14, and can further improve the durability of the drive electrode 16, so that an organic insulating film such as a parylene film can be used. Is preferred.
[0055]
Here, an example of a method for manufacturing the head chip 1 will be described. In addition, the numerical value described below is an example to the last, and this invention is not limited to the following numerical values.
[0056]
First, as shown in FIG. 4, a piezoelectric element 12 in which two piezoelectric material substrates (PZT) 12 a and 12 b having a thickness of 0.1 mm each having polarization directions (indicated by arrows) in opposite directions are laminated. A laminated body attached to a cover substrate 11 (50 mm square) made of a ceramic substrate having a thickness of 0.6 mm is prepared. As described above, the cover substrate 11 and the piezoelectric material substrate 12b may be the same. In this case, the laminate is constituted by two piezoelectric material substrates having different polarization directions.
[0057]
Next, as shown in FIG. 5, positive resists 100 and 101 (the portions irradiated with light are dissolved by development) are coated on the upper and lower surfaces of this laminate by spin coating, and then shown in FIG. As described above, the grooves 150, 150... Parallel to each other at a pitch of 0.141 mm are ground using a disc-shaped grindstone (dicing blade) 0.08 mm thick from the piezoelectric element 12 side. The groove 150 is a straight groove having a substantially uniform depth (0.20 mm) in the length direction, and the cross-sectional shape of the groove 150 is not substantially changed in the length direction. When the number of grooves 150 to be processed is 258, for example, 257 drive walls 14 and 256 channel grooves 150 and one excess groove 150 are formed on both sides.
[0058]
Thereafter, a metal layer is formed in each groove 150 to have a thickness of 0.5 to 5 μm by an electroless plating method. For example, the metal layer has a laminated structure in which the lower layer is a Ni-B plating layer and the upper layer is an Au plating layer. At this time, so-called selective plating in which plating is not deposited on the resist is performed by appropriately performing pretreatment of the electroless plating treatment.
[0059]
Next, the resist is dissolved and removed by a remover to form a plating layer on the inner surface of each groove 150 to form the drive electrode 16, and a plating layer is formed on the upper surface of each drive wall 14 and the lower surface of the cover substrate 11. The state shown in FIG. 7 is not performed.
[0060]
Although the example which performs the selective plating method using a resist was shown as a formation method of the drive electrode 16 by the above plating method, it is not limited to this, As another method, a dry film resist is used instead of a resist. The same drive electrode 16 and first wiring 17 can be patterned by a lift-off method in which aluminum is formed on the entire surface by vacuum deposition and then the aluminum on the dry film resist is removed together with the dry film resist with a solvent. At this time, gold is preferably deposited continuously on the aluminum.
[0061]
In this way, two substrates on which the drive electrodes 16 are formed are prepared, laminated so that each channel portion 15 is shifted by a half pitch, and the cover substrate 11 is further fixed to the upper portion so that the drive wall 14 and the channel portion 15 are formed. After forming the substrates stacked in two upper and lower stages, the two substrates in two stages are stacked to form the upper and lower four stages (a1 to a4) of substrates a as shown in FIG.
[0062]
Next, the cover substrate a is cut along cut lines C1, C2, C3... Substantially orthogonal to the length direction of the channel portion 15, and a plurality of head chips 1, 1,. Create 1 ...
[0063]
As shown in FIG. 9, each of the cut surfaces (the front surface and the rear surface of the head chip 1) of the produced head chip 1 has a first wiring formation opening 201 corresponding to each channel portion 15. By patterning each with the film 200 and then depositing aluminum, a part of the first wiring, that is, the front part and the rear part of the head chip 1 in the first wiring are formed.
[0064]
Also, on the upper and lower surfaces of the head chip 1, as shown in FIG. 10, patterning is performed with a dry film 300 having first wiring formation openings 301 corresponding to the respective channel portions 15, and then aluminum is deposited. As a result, the remaining portions of the first wiring electrically connected to a part of the first wiring formed on the front surface and the rear surface of the head chip 1 are formed. Note that wiring may be formed in advance in the pattern shown in FIG. 10 on the cover substrate 11 corresponding to the upper surface and the lower surface of the head chip 1.
[0065]
These wiring forming methods are not limited to vapor deposition, but may be sputtering.
[0066]
Thereafter, when the dry film and the aluminum formed thereon are removed with a solvent, the first wirings 171 to 174 are drawn from the driving electrodes 161 to 164 to the upper surface and the lower surface through the front surface and the rear surface of the head chip 1. The state shown in FIG.
[0067]
The above-described inkjet head A exemplifies a head chip 1 having a four-stage configuration of a1 to a4. However, the head chip 1 has a plurality of stages in which the drive wall 14 and the channel portion 15 are arranged in parallel in the vertical direction. However, it is not limited to four steps, and may be two or more steps. However, if the number of stages of the head chip is five or more, the pitch between the first wirings becomes narrow and it becomes difficult to join the wiring substrate, so the number of stages of the head chip is two, three, or four. It is preferable to have a stage, and it is most preferable to have a four-stage configuration in consideration of high density of the inkjet head and work efficiency.
[0068]
【The invention's effect】
According to the present invention, it is possible to provide a high-productivity, high-density inkjet head in which electrical connection between the drive electrode in each channel portion and the wiring from the drive circuit can be easily performed.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of an inkjet head according to the present invention.
FIG. 2 is a longitudinal sectional view of the inkjet head taken along line (ii)-(ii) in FIG.
3A is a front view of a head chip, and FIG. 3B is a rear view of the head chip.
FIG. 4 is a diagram showing one step of a method for manufacturing an inkjet head.
FIG. 5 is a diagram showing a step of a method for manufacturing an inkjet head.
FIG. 6 is a diagram showing one step of a method for manufacturing an inkjet head.
FIG. 7 is a diagram showing one process of an ink jet head manufacturing method.
FIG. 8 is a diagram showing a step of a method for manufacturing an inkjet head.
FIG. 9 is a diagram showing one step of a method for manufacturing an inkjet head.
FIG. 10 is a diagram showing a step of a method for manufacturing an inkjet head.
[Explanation of symbols]
A: Inkjet head
1: Head chip
11: Cover substrate
12: Piezoelectric element
14 (141-144): Drive wall
15 (151 to 154): channel portion
16: Drive electrode
171 to 174: first wiring
2: Nozzle plate
21: Nozzle hole
3: Upper substrate
31, 32: second wiring
4: Lower substrate
41, 42: second wiring
5: Ink supply chamber forming member
51: Ink supply chamber
52: Inlet
53: Overhang part
54: Third wiring
61-64: Wiring board

Claims (5)

Drive walls made of piezoelectric elements and channel portions are alternately arranged side by side, and outlets and inlets of the channel portions are arranged oppositely on the front and rear surfaces, respectively, and the drive walls and the channel portions are vertically arranged. An upper substrate and a lower substrate formed longer than the length of the channel portion are fixed to the upper and lower surfaces of the head chip formed in a plurality of stages, respectively, and extend to the rear side of the channel portion,
Over between the two substrates, arranged so that the ink supply chamber forming member formed by enclosing wall portion for forming the ink supply chamber for supplying ink to each channel portion, surrounds the rear surface of the head chip Being
First wirings that are electrically connected to the drive electrodes of the respective channel portions are drawn out from the outer surface of the head chip,
Of each of the first wirings, electrically connected to the drive electrode of each of the two channel portions of each channel portion of the step located on the outermost side of the head chip and each channel portion of the step adjacent to this step The first wiring is distributed to the front surface and the rear surface of the head chip for each stage, and is led out to either the upper surface or the lower surface through the front surface and the rear surface,
The upper substrate or the lower substrate fixed to the upper surface or the lower surface of the head chip from which each of the first wirings is drawn is connected to each of the first wirings. Each wiring is formed,
Of each of the second wirings, one end is electrically connected to the one of the first wirings that is drawn out through either the front surface or the rear surface of the head chip. The other end of the wiring is led out from the surface fixed to the head chip to the outer surface of the upper substrate or the lower substrate on which the second wiring is formed , and one end of the second wirings. The other end of the second wiring that is electrically connected to the one of the first wirings that is led out through the other one of the front surface and the rear surface of the head chip is connected to the head chip. It extends to the rear end in the fixing side,
The ink supply chamber forming member is formed with a third wiring electrically connected to the other end of the second wiring, one end of which extends to the rear end on the fixing surface side to the head chip. And the second wiring has a protruding portion protruding rearward from the upper substrate or the lower substrate formed on both the outer surface and the fixing surface side of the head chip. The other end of the third wiring is exposed on the head surface at the protruding portion . The ink supply chamber forming member is formed by a wall portion provided so as to surround the rear surface of the head chip between the upper substrate and the lower substrate, and is surrounded by both the substrate and the wall portion. the space, the ink-jet head according to claim 1, characterized in that forming said ink supply chamber. 3. The ink jet head according to claim 1, wherein an electrode protective film is formed on surfaces of the drive electrode, the first wiring facing the ink supply chamber, and the second wiring. At least one of the member other than the drive wall in the head chip, the upper substrate, and the lower substrate is made of any material selected from ceramics, piezoelectric materials, and liquid crystal polymers containing aluminum nitride as a component. The inkjet head according to claim 1 , 2 or 3 . The thermal expansion coefficient of at least one of the member other than the drive wall, the upper substrate, and the lower substrate in the head chip is ± 2 × 10 ⁻⁶ / ° C. of the thermal expansion coefficient of the piezoelectric element. The inkjet head according to any one of claims 1 to 4 .

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