JP4363038B2 - 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 in parallel, and the front and rear surfaces of the channel portion are arranged so as to be opposed to each other by a so-called harmonica type head chip. Inkjet heads with a large number of wafers taken from one wafer and extremely improved productivity are known (Patent Documents 1 to 3).
[0003]
Since the channel portion of such an ink jet head is a straight type whose size and shape are almost the same in the length direction from the entrance to the exit, wiring for applying a voltage to the drive electrodes formed on each drive wall is provided. It is difficult to form.
[0004]
For example, in the techniques described in Patent Documents 1 to 3, a through hole is formed in the upper or lower substrate facing the drive wall from above and below, and each drive electrode is electrically connected to the through hole. The wiring connected to the head chip is drawn out to the outer surface of the head chip, but the operation of forming such a through hole for each channel portion is complicated, and the drive circuit is further added to the wiring formed in the through hole. Since a work for connecting the wiring from the drive circuit is required, a structure that can more easily make electrical connection with the wiring from the drive circuit is desired.
[0005]
In addition, an ink manifold constituting an ink supply chamber for supplying ink from the inlet side (opposite side of the nozzle plate) to each channel portion is fixed to the rear surface of the head chip using an adhesive. In the prior art, it is necessary to fix the rear surface of the head chip and the ink manifold by applying an adhesive using the surrounding space so that the fixing surface does not cover each channel portion. However, the thickness of the head chip is only about a few millimeters, and the paste margin that can be applied to such an extent that the adhesive does not protrude from the rear surface of such a head chip has a space of about 0.5 mm at most. Therefore, when the ink manifold is fixed to the rear surface of the head chip using an adhesive, it is necessary to carefully apply the adhesive so as not to protrude into a minute space, which leaves a problem in productivity. . In this case, it may be possible to secure a wide space for applying the adhesive by forming large (thick) substrates on the upper and lower sides of the channel portion, but this will unnecessarily increase the size of the head. For this reason, there is a demand for an inkjet head structure capable of further improving productivity without unnecessarily increasing the size of the head chip.
[0006]
[Patent Document 1]
JP 2002-103612 A
[Patent Document 2]
JP 2002-103614 A
[Patent Document 3]
JP 2002-210955 A
[0007]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to easily perform electrical connection between the drive electrode in each channel portion and the wiring from the drive circuit, and to easily form an ink supply chamber for supplying ink into each channel portion. It is an object of the present invention to provide a highly productive ink jet head that can be performed in a simple manner.
[0008]
[Means for Solving the Problems]
The above problems are solved by the following inventions.
[0009]
  The invention described in claim 1Each of the same lengthUpper boardas well asLower boardWhenThe upper substrateWhenThe lower substrateBetween themAnd a drive wall made of piezoelectric elements of the same lengthThe drive wall andAlternatingly arranged side by side and front and backOutThe mouth and the entrance are arranged opposite to each otherAnd a drive electrode formed on the drive wall facing the channel portion.A head chip having six surfaces including a front surface, a rear surface, an upper surface, a lower surface, and both side surfaces.When,
  Upper surface or lower surface of the head chipAnd a wiring board formed on the surface having a driving wiring for applying a voltage to each of the driving electrodes and longer than the length of the channel portion,
  On the surface opposite to the fixing surface of the head chip with the wiring boardFixedThe flow path substrate is longer than the length of the channel portion.When,
  The rear surface of the head chip is surrounded between the flow path substrate and the wiring substrate.An enclosure wall provided in
  Due to the space surrounded by the flow path substrate, the wiring substrate and the surrounding wall, on the rear surface side of the head chip.Formed,Ink supply chamber for supplying ink to each channel sectionAnd having,
  The head chip has a first connection wiring corresponding to a drive electrode in each channel portion formed on at least one of an upper surface of the upper substrate and a lower surface of the lower substrate, and the head chip A second connection wiring for electrically connecting each drive electrode and each first connection wiring is formed on at least one of the front surface and the rear surface.,
  The wiring board is fixed to the head chip with the driving wiring formation surface facing the first connection wiring, whereby the driving wiring and the first connection wiring corresponding to the driving wiring are fixed to the fixing surface. Is electrically connected inThis is an inkjet head.
[0010]
  The invention according to claim 2Each of the same lengthUpper boardas well asLower boardWhenThe upper substrateWhenThe lower substrateBetween themAnd a drive wall made of piezoelectric elements of the same lengthThe drive wall andAlternatingly arranged side by side and front and backOutThe mouth and the entrance are arranged opposite to each otherAnd a drive electrode formed on the drive wall facing the channel portion.A head chip having six surfaces including a front surface, a rear surface, an upper surface, a lower surface, and both side surfaces.The two of these were superimposedHead chipWhen,
  Two wiring boards fixed to the upper surface and the lower surface of the superimposed head chips, respectively, having driving wirings for applying a voltage to the driving electrodes on the surface and formed longer than the length of the channel portion;,
  An enclosing wall provided so as to surround a rear surface of the superimposed head chip between the two wiring boards;
  An ink supply chamber is formed on the rear surface side of the superimposed head chip between the two wiring boards and the space surrounded by the surrounding wall portion, and supplies ink to each channel portion.,
  Each of the overlapped head chips has a first connection wiring corresponding to a drive electrode in each channel portion formed on one of the upper surface of the upper substrate and the lower surface of the lower substrate, and Second connection wirings for electrically connecting the respective drive electrodes and the respective first connection wirings are formed on at least one of the front surface and the rear surface of each of the superimposed head chips, and The surface on which the first connection wiring is formed and the opposite surface are overlapped and fixed,
Each of the two wiring boards corresponds to the driving wiring by being fixed to the upper surface and the lower surface of the overlapped head chip with the driving wiring forming surface facing the first connection wiring, respectively. The first connection wiring is electrically connected to the fixing surfaceThis is an inkjet head.
[0013]
  Claim3The invention described in claim 1 is the ink jet head according to claim 1 or 2, wherein an electrode protective film is formed on the surface of the drive electrode, the second connection electrode and the drive wiring.
[0014]
  Claim4The invention described in claim 1 is characterized in that a flexible board on which a driving IC is mounted is electrically connected to the wiring board.2 or 3It is an inkjet head of description.
[0015]
  Claim5The invention described in claim 1 is characterized in that a driving IC is mounted on the wiring board.4Any one of the inkjet heads.
[0016]
  Claim6In the described invention, at least one of the substrate other than the drive wall in the head chip, the wiring substrate, and the flow path substrate 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.5Any one of the inkjet heads.
[0017]
  The invention according to claim 7 is that the thermal expansion coefficient of at least one of the substrate other than the drive wall, the wiring substrate, and the flow path substrate in the head chip is ± 2 ppm / ° C. of the thermal expansion coefficient of the piezoelectric element. The inkjet head according to claim 1, wherein the inkjet head is provided.
  The invention according to claim 8 is the ink jet head according to any one of claims 1 to 7, wherein the head chip and the wiring substrate are fixed by an adhesive or an anisotropic conductive film. is there.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0019]
FIG. 1 is an overall perspective view showing a first embodiment of an inkjet head according to the present invention, and FIG. 2 is a longitudinal sectional view thereof.
[0020]
In the figure, A is an inkjet head, 1 is a head chip, 2 is a nozzle plate attached to the front surface of the head chip, 3 is a wiring substrate attached to the lower surface of the head chip 1, and 4 is attached to the upper surface of the head chip. The attached flow path substrate 5 is an enclosure wall portion provided between the wiring substrate 3 and the flow path substrate 4.
[0021]
In this specification, the surface on the side where ink is ejected from the head chip 1 is referred to as “front surface”, and the opposite surface is referred to as “rear surface”. In addition, the outer surfaces positioned above and below the channel portions arranged in parallel in the head chip 1 are referred to as “upper surface” and “lower surface”, respectively.
[0022]
In the head chip 1, drive walls 14 and channel portions 15 made of piezoelectric elements 12 are alternately arranged in parallel between an upper substrate 13 and a lower substrate 11. In the illustrated example, an example in which four channel portions 15 and five drive walls 14 are formed is illustrated. The shape of the channel portion 15 is such that both side walls face the vertical 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.
[0023]
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.
[0024]
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.
[0025]
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.
[0026]
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.
[0027]
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.
[0028]
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 joining using an adhesive, the thickness of the adhesive layer after curing is preferably in the range of 1 to 10 μm.
[0029]
Although not shown, the piezoelectric material substrate 12b is thick instead of the lower substrate 11, and a plurality of parallel grooves extending from the upper piezoelectric material substrate 12a side to the middle portion of the piezoelectric material substrate 12b are formed. The drive wall 14 similar to the above may be formed by forming.
[0030]
A drive electrode 16 is formed on each drive wall 14 so as to face the channel portion 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.
[0031]
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. By electroless plating, a uniform and pinhole-free metal coating can be formed.
[0032]
In electrode formation by electroless plating, Ni-P plating or Ni-B 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—P 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.
[0033]
On at least one of the upper surface and the lower surface of the head chip 1, the same number of first connection wires 17 are formed in parallel with each channel portion 15 at the same pitch as each channel portion 15. It extends from the front surface to the rear surface (see FIGS. 9 and 10). Here, it is formed only on the lower surface of the head chip 1, but it may be formed on the upper surface or on both upper and lower surfaces. As will be described in detail later, the first connection wiring 17 is electrically connected to the drive wiring 31 of the wiring substrate 3 for applying a voltage from the drive circuit to each drive electrode 16, and therefore the first connection wiring 17 of the head chip 1. If formed on both the upper and lower surfaces, the connection to the drive wiring 31 can be obtained from either the upper or lower surfaces of the head chip 1. That is, since the wiring board 3 can be fixed to either the upper or lower surface of the head chip 1, it is advantageous in producing the ink jet head regardless of the direction of the head chip 1.
[0034]
Further, at least one of the front surface and the rear surface of the head chip 1 is provided with a second connection wiring 18 having one end electrically connected to the drive electrode 16 formed on the drive wall 14 in each channel portion 15. The other end is electrically connected to the corresponding first connection wiring 17. Accordingly, the wiring to each driving electrode 16 formed on the driving wall 14 in each channel portion 15 is drawn from the rear surface of the head chip 1 to the lower surface of the head chip 1 via the second connection wiring 18. Yes. In the illustrated example, it is formed only on the rear surface of the head chip 1, but it may be formed only on the front surface, or may be formed on both front and rear surfaces.
[0035]
The wiring substrate 3 is 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 is longer than the length of the head chip 1 (the length from the front surface to the rear surface of the head chip 1). A drive electrode 16 formed of a sufficiently long substrate and having a voltage supplied from a drive circuit (not shown) formed on the drive wall 14 of each channel portion 15 on the surface thereof at the same pitch as the channel portion 15 of the head chip 1. The drive wiring 31 for applying to is formed.
[0036]
The wiring substrate 3 has a front end surface that is flush with the front surface of the head chip 1, and the surface on which the drive wiring 31 is formed faces the first connection wiring 17 of the head chip 1. One connection wiring 17 and each drive wiring 31 are fixed to the head chip 1, here the lower surface of the head chip 1, so as to be electrically connected.
[0037]
The flow path substrate 4 is substantially the same width as the head chip 1 and is slightly shorter than the wiring substrate 3, but is formed of a substrate that is sufficiently longer than the length of the head chip 1. The front end surface of the head chip 1 is fixed to the surface opposite to the bonding surface of the wiring substrate 3, that is, the upper surface of the upper substrate 13, so that the front end surface is flush with the front surface of the head chip 1. Thereby, the rear surface of the head chip 1 is covered with the wiring substrate 3 and the flow path substrate 4 protruding from the rear surface side of the head chip 1.
[0038]
The surrounding wall portion 5 is a side wall forming member having a substantially U shape in a plan view provided so as to surround the rear surface of the head chip 1 between the wiring substrate 3 and the flow path substrate 4, polyimide, It is made of high-performance resin called engineering plastic such as polycarbonate. As a result, a space is formed on the rear surface side of the head chip 1 so that the upper and lower sides are covered by the flow path substrate 4 and the wiring substrate 3 and the side surfaces are enclosed by the wall portion 5. An ink supply chamber 51 for supplying the ink is configured. Reference numeral 52 denotes an inflow port 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.
[0039]
The nozzle plate 2 has a size over the front end surfaces of the flow path substrate 4 and the wiring board 3 on the front side of the head chip 1 with the flow path substrate 4 and the wiring board 3 fixed to the upper surface and the lower surface, respectively. It is fixed. Nozzle holes 21 corresponding to the respective channel portions 15 are formed in the nozzle plate 2.
[0040]
In the inkjet head A, the flexible substrate 6 on which the driving IC 61 is mounted is joined by the anisotropic conductive film 7 so that each wiring is electrically connected to the driving wiring 31 on the surface of the wiring substrate 3. . Reference numeral 62 denotes a connector for electrical connection with external wiring. A drive voltage from a drive circuit (not shown) is input to the drive IC 61 via the connector 62, and each drive electrode 16 is supplied from the drive IC 61 via the drive wiring 31, the first connection wiring 17, and the second connection wiring 18. To be applied.
[0041]
In such an ink jet head A, a wiring for applying a voltage to each drive electrode 16 is drawn out to the outer surface of the head chip 1 by the first connection wiring 17 and the second connection wiring 18 and formed on the wiring substrate 3. It is possible to make electrical connection with the wiring from the driving circuit very simply by simply joining to the driving wiring 31 formed, and through holes are formed corresponding to the respective channel portions 15 as in the prior art. Such complicated wiring formation becomes unnecessary.
[0042]
The ink supply chamber 51 for supplying ink to each channel portion 15 is formed by the surrounding wall portion 5 fixed so as to surround the rear surface of the head chip 1 between the flow path substrate 4 and the wiring substrate 3. Therefore, the fixing part with the head chip 1 may be only a very small area of the rear surface side of the wall portion located at both end portions of the head chip 1 and the upper substrate 13 and the lower substrate 11 adjacent thereto. . Accordingly, it is not necessary to fix the ink manifold to the entire area of the upper substrate 13 and the lower substrate 11 so as to surround the channel portion 15 as in the prior art, so the ink manifold is fixed to the entire area of the upper substrate 13 and the lower substrate 11. Therefore, it is not necessary to secure a margin for the adhesive, and it is not necessary to apply an adhesive to the entire area of the upper substrate 13 and the lower substrate 11. For this reason, it is not necessary to form the head chip 1 unnecessarily large in order to form the ink supply chamber 51 as in the prior art, and it is not necessary to apply the adhesive to the minute space, so that productivity can be improved. It is.
[0043]
In the present invention, at least one of the substrate other than the drive wall 14 in the head chip 1, that is, in the present embodiment, both the upper substrate 13 and the lower substrate 11, the wiring substrate 3 and the flow path substrate 4 is composed of aluminum nitride. It is preferably made of any material selected from ceramics, piezoelectric materials, and liquid crystal polymers. 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.
[0044]
Further, the thermal expansion coefficient of at least one of the substrate other than the drive wall 14 in the head chip 1, the wiring substrate 3 and the flow path substrate 4 is ± 2 ppm / of the thermal expansion coefficient of the piezoelectric element 12 constituting the drive wall 14. It is still more preferable that it is ° C. By setting the thermal expansion coefficient within this range, separation or the like due to the difference in thermal expansion coefficient does not occur between the substrates.
[0045]
In the inkjet head A shown in the first embodiment, since the second connection wiring 18 and a part of the driving wiring 31 face the ink supply chamber 51, these are similar to the ink and the driving electrode 16 in each channel portion 15. Contact directly. Therefore, when water-based ink is used as the ink, an electrode protective film is formed on the surfaces of the drive electrode 16, the second connection wiring 18, and the drive wiring 31 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.
[0046]
Next, an example of a method for manufacturing the inkjet head A will be described with reference to FIGS. In addition, the numerical value described below is an example and this invention is not limited to the following numerical values.
[0047]
First, as shown in FIG. 3, a piezoelectric element 12 in which two piezoelectric material substrates (PZT) 12a and 12b each having a thickness of 0.1 mm with polarization directions (indicated by arrows) directed in opposite directions are stacked. A laminated body adhered to a lower substrate 11 (50 mm square) made of a ceramic substrate having a thickness of 0.6 mm is prepared. Note that the lower substrate 11 and the piezoelectric material substrate 12b may be the same. In this case, a laminate is constituted by two piezoelectric material substrates having different polarization directions.
[0048]
Next, as shown in FIG. 4, positive resists 100 and 101 (the portions irradiated with light are dissolved by development) are coated on the upper and lower surfaces of the laminate by spin coating, and then the piezoelectric elements 12 and By exposing and developing the positive resist 101 on the lower surface of the lower substrate 11 on the opposite side using a stripe-shaped mask (mask width 0.07 mm, pitch 0.141 mm), a stripe having a width of 0.71 mm is formed on the lower surface. Get a pattern.
[0049]
Next, as shown in FIG. 5, grooves 151, 151,... 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. To do. The groove 151 is a straight groove having a substantially uniform depth (0.20 mm) in the length direction, and the cross-sectional shape of the groove 151 is not substantially changed in the length direction. When the number of grooves 151 to be processed is 258, for example, 257 driving walls 14 and 256 channel grooves 151 and one extra groove 151 on each side are formed.
[0050]
Thereafter, a metal layer is formed by electroless plating so as to have a film thickness of 0.5 to 5 μm in each groove 151 and on the lower surface of the lower substrate 11 on which the stripe pattern is formed. 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.
[0051]
Next, by removing and removing the resist with a remover, a plating layer is formed on the inner surface of each groove 151 to form a drive electrode 16, and no electrode is formed on each drive wall 14. In the state of FIG. 6, the plating layer is formed between the stripe patterns on the lower surface of 11 and the first connection wiring 17 is formed.
[0052]
Although an example in which the selective plating method using a resist is used as a method for forming the drive electrode 16 and the first connection wiring 17 by the above plating method is shown, the present invention is not limited to this, Instead, a dry film resist is used, and aluminum is formed on the entire surface by vacuum vapor deposition. Then, the drive electrode 16 and the first connection wiring 17 are the same in the lift-off method in which the aluminum on the dry film resist is removed together with the dry film resist with a solvent. Can be patterned. At this time, it is desirable to deposit gold continuously on aluminum.
[0053]
After the drive electrode 16 and the first connection wiring 17 are formed, a separately prepared upper substrate 13 is fixed to the upper surface of the drive wall 14 made of the piezoelectric element 12 using an epoxy adhesive. FIG. 7 shows a state after the upper substrate 13 is fixed. As a result, a head substrate a in which the drive walls 14 and the channel portions 15 formed by the grooves 151 are alternately arranged between the upper substrate 13 and the lower substrate 11 is formed.
[0054]
Next, as shown in FIG. 7, the head substrate a is cut along cut lines C1, C2, C3,... Substantially orthogonal to the length direction of the channel portion 15, and from one head substrate a. A plurality of head chips 1, 1, 1,.
[0055]
As shown in FIG. 8, the cut surface of the produced head chip 1 is patterned with a dry film 200 having openings 201 for forming second connection wirings corresponding to the respective channel portions 15, and then aluminum is deposited. Thus, the second connection wiring 18 is formed. Vapor deposition was performed twice in different directions in order to ensure electrical connection between the drive electrode 16 and the first connection wiring 17. In addition, the method for forming the second connection wiring 18 is not limited to vapor deposition, and may be a sputtering method. Thereafter, when the dry film and the aluminum formed thereon are removed with a solvent, each drive electrode 16 and each first connection wiring 17 are electrically connected by the second connection wiring 18 as shown in FIG. Become.
[0056]
Here, aluminum is vapor-deposited on one cut surface of the head chip 1 (the surface that will later become the rear surface of the head chip 1), but the opposite surface may be used, and both the front and rear surfaces may be used. There may be.
[0057]
Separately, a wiring substrate 3 having a driving wiring 31 formed on the surface at the same pitch as the channel portion 15 of the head chip 1 is prepared. As a method for forming the wiring substrate 3, Cu, Ni, and Au were formed in this order by plating on a 0.6 mm thick substrate (about 50 mm square) as wiring materials. As the wiring substrate 3, a substrate of about 50 mm square was cut in half to have a width of 25 mm and a length of 50 mm.
[0058]
Next, as shown in FIGS. 10A and 10B, the head chip 1 and the wiring substrate 3 were bonded and fixed with an epoxy adhesive with the first connection wiring 17 and the drive wiring 31 facing each other. The first connection wiring 17 of the head chip 1 and the drive wiring 31 of the wiring substrate 3 are attracted by the tensile stress of the adhesive, and a good electrical connection can be achieved. In addition, as a bonding method of the wiring substrate 3, a method using an anisotropic conductive film, a method using a solder, a method using a conductive adhesive, and the like can be applied in addition to an adhesive.
[0059]
Thereafter, the flow path substrate 4 is fixed to the opposite surface of the wiring substrate 3 of the head chip 1. When water-based ink is used as the ink, a parylene film having a film thickness of 5 μm, for example, is formed by CVD, for example, as an electrode protection film with the wiring substrate 3 and the flow path substrate 4 fixed to the head chip 1 as described above. Form.
[0060]
Next, the nozzle plate 2 in which the nozzle holes 21 are formed at the positions corresponding to the respective channel portions 15 is joined over the front surface of the head chip 1 and the front end surfaces of the wiring substrate 3 and the flow path substrate 4. On the rear surface, an enclosing wall portion 5 is provided between the wiring substrate 3 and the flow path substrate 4 so as to surround the rear surface of the head chip 1 to form an ink supply chamber 51. Thereafter, the flexible substrate 6 on which the driving IC 61 is mounted is bonded to the wiring substrate 3 by the anisotropic conductive film 7 (see FIGS. 1 and 2).
[0061]
In the above description, a mode in which the flexible substrate 6 on which the drive IC 61 is mounted is bonded to the wiring board 3 is illustrated. However, as another mode of the first embodiment, as shown in FIG. Alternatively, the driving IC 32 may be mounted. Reference numeral 33 denotes a connector for connecting to an external device, and 34 denotes wiring for electrically connecting the connector 33 and the drive IC 32. As a mounting method of the driving IC 32, a method used in a normal mounting process such as wire bonding and flip chip mounting using a bump can be applied.
[0062]
In this case, as described above, it is possible to save the trouble of separately joining the substrate on which the driving IC is mounted, and the configuration can be simplified and an extremely compact ink jet head can be configured. Further, depending on the type of ink to be ejected, it is necessary to heat the ink. For this purpose, it is necessary to provide a heater on the wiring board 3 or adjacent to the wiring board 3. However, if the driving IC 32 is mounted on the wiring board 3 in this way, the generated driving IC 32 can be used as an ink heating means.
[0063]
Next, a second embodiment of the ink jet head according to the present invention will be described. FIG. 12 is a longitudinal sectional view showing an inkjet head B according to the second embodiment. The same reference numerals as those in the first embodiment denote the same components, and detailed description thereof is omitted unless there is a particular difference.
[0064]
In the inkjet head B according to the second embodiment, two head chips 1 having the same configuration as that described in the first embodiment are overlapped. However, here, the first connection wiring 17 corresponding to the drive electrode 16 in each channel portion 15 is connected to either the upper surface or the lower surface of each head chip 1, here the lower substrate 11 side of each head chip 1. Is formed. The second connection wiring 18 that is electrically connected to the first connection wiring 17 may be formed on at least one of the front and rear surfaces of the head chips 1 and 1.
[0065]
Each of the head chips 1 and 1 has a wiring substrate 3 having a driving wiring 31 for applying a voltage to each driving electrode 16 of the head chip 1 on the surface on which the first connection wiring 17 is formed. The drive wiring 31 is fixed so as to be electrically connected to each of the first connection wirings 17, and the two head chips 1, 1 to which the wiring substrates 3, 3 are fixed are respectively connected to the head chips. The surfaces opposite to the fixing surface with the wiring substrate 3 in 1 and 1, here, the upper substrates 13 are overlapped and fixed. In this inkjet head B, the wiring substrates 3 and 3 are disposed on the upper and lower surfaces of the head chips 1 and 1 that are overlapped, so that the flow path substrate 4 is not necessary.
[0066]
Further, by providing a surrounding wall portion 5 so as to surround the rear surfaces of the two head chips 1 and 1 between the two wiring boards 3 and 3, each channel of the two head chips 1 and 1 is provided. An ink supply chamber 51 for supplying ink to the portion 15 is formed.
[0067]
The nozzle plate 2 has a size extending over the front surfaces of the two head chips 1 and 1 and the front end surfaces of the two wiring boards 3 and 3, and corresponds to the channel portions 15 of the two head chips 1 and 1. The nozzle holes 21 are formed in two upper and lower rows.
[0068]
Here, the driving ICs 32 and 32 are respectively mounted on the surface of the wiring board 3 on the side where the driving wiring 31 is formed, and these are electrically connected to one connector 33 by the wirings 34 and 34, respectively. However, it is good also as an aspect separately joined with the flexible substrate 6 which mounted drive IC61 similarly to FIG. 1, FIG.
[0069]
According to the ink jet head B according to the second embodiment, it is possible to easily form a laminated structure by simply stacking the head chips 1 and 1 to which the wiring board 3 is fixed, and the number of nozzles is doubled. An ink jet head can be configured easily. Moreover, the electrical connection between the drive electrodes 16 and the drive wirings 31 of the head chips 1 and 1 can be made very simply as in the case of the first embodiment.
[0070]
In this inkjet head B, the upper and lower head chips 1, 1 can be shared by using a single substrate (here, the upper substrates 13, 13) located on the overlapping surface of the superimposed head chips 1, 1. It is also possible to reduce the number of parts.
[0071]
Also, after the two head substrates a and a are bonded together, as shown in FIG. 7, they are cut in C1, C2 and C3, and are prepared in the order in which the wiring substrates 3 and 3 are fixed to the head chip. May be.
[0072]
Next, a third embodiment of the ink jet head according to the present invention will be described. FIG. 13 is a longitudinal sectional view showing an inkjet head C according to the third embodiment. The same reference numerals as those in the first embodiment denote the same components, and detailed description thereof is omitted unless there is a particular difference.
[0073]
In the inkjet head C according to the third embodiment, the first connection wiring 17 and the second connection wiring 18 in the inkjet head A according to the first embodiment are not formed. In the head chip 1, the wiring substrate 3 on the surface of which the driving wiring 31 for applying a voltage to each driving electrode 16 of the head chip 1 is formed so that the driving wiring 31 is on the surface opposite to the head chip 1. A front wiring 19 that electrically connects each driving electrode 16 and the driving electrode 31 on the surface of the wiring substrate 3 is formed across the front surface of the head chip 1 and the front end surface of the wiring substrate 3. It is configured.
[0074]
In this inkjet head C, after the head chip 1 and the wiring substrate 3 are fixed, for example, as shown in FIG. 8, the front surface of the head chip 1 and the surface of the wiring substrate 3 (the side opposite to the fixing surface of the head chip 1). By patterning using a dry film and then depositing aluminum, the front wiring 19 electrically connected to the drive wiring 31 can be formed at a time. For this reason, a manufacturing process can be simplified and cost reduction can be aimed at. In addition, since there is no wiring other than the drive electrode 16 in the channel portion 15 in the ink supply chamber 51, when water-based ink is used, an electrode protective film is formed only on the drive electrode 16 that is in direct contact with the ink. That's fine. Therefore, the probability that the electrode is corroded and disconnected due to a defect in the electrode protective film is reduced, and the reliability can be further improved.
[0075]
Although not shown in FIG. 13, the flexible substrate 6 on which the driving IC 61 is mounted may be joined to the wiring substrate 3 as in FIGS. 1 and 2, or the driving may be performed as in FIG. The IC 32 may be mounted directly and the connector 33 may be electrically connected to an external device.
[0076]
Next, a fourth embodiment of the ink jet head according to the present invention will be described. FIG. 14 is a longitudinal sectional view showing an inkjet head D according to the fourth embodiment. The same reference numerals as those in the first, second, and third embodiments indicate the same configuration, and detailed description is omitted unless there is a particular difference.
[0077]
The inkjet head D according to the fourth embodiment is superposed using two head chips 1 and wiring boards 3 having the same configuration as that described in the third embodiment.
[0078]
That is, each head chip 1, 1 has a wiring substrate 3, 3 on the surface of which a drive wiring 31 for applying a voltage to each drive electrode 16 of the head chip 1 is formed. The driving electrodes 16 and the surfaces of the wiring substrates 3 and 3 are driven across the front surfaces of the head chips 1 and 1 and the front end surfaces of the wiring substrates 3 and 3, respectively. The front wiring 19 that electrically connects the electrode 31 is formed.
[0079]
Further, by providing an enclosure wall portion 5 that surrounds the rear surfaces of the two head chips 1 and 1 in common between the two wiring substrates 3 and 3, each channel portion 15 of the two head chips 1 and 1. An ink supply chamber 51 for supplying ink is formed.
[0080]
The nozzle plate 2 has a size extending over the front surfaces of the two head chips 1 and 1 and the front end surfaces of the two wiring boards 3 and 3, and corresponds to the channel portions 15 of the two head chips 1 and 1. The nozzle holes 21 are formed in two upper and lower rows.
[0081]
According to the inkjet head D according to the fourth embodiment, the head chips 1 and 1 each having the wiring substrate 3 fixed thereto are overlapped to form the front wiring 19. An ink jet head having a laminated structure in which the electrical connection between the electrode 16 and the drive wiring 31 can be performed very easily can be configured. In addition, since the wiring boards 3 and 3 are arranged on the upper and lower surfaces of the head chips 1 and 1 that are overlapped, the flow path board 4 is not necessary, and the number of components can be reduced. In addition, the substrate (here, the upper substrates 13 and 13) located on the overlapping surface of the superimposed head chips 1 and 1 can be shared by the upper and lower head chips 1 and 1, and the number of parts can be further reduced. It is also possible to make it easier.
[0082]
Further, as in the third embodiment, no wiring is formed in the ink supply chamber 51. Therefore, when water-based ink is used, an electrode protective film is formed only on the drive electrode 16 that is in direct contact with the ink. Well, the probability that the electrode is corroded and disconnected due to a defect in the electrode protective film is reduced, and the reliability can be further improved.
[0083]
In this embodiment, the driving ICs 32 and 32 are mounted on the surface of the wiring board 3 on the side where the driving wiring 31 is formed, and are electrically connected to the connectors 33 and 33 by the wirings 34 and 34, respectively. Show. In this aspect, since the driving ICs 32 and 32 are directed to the opposite sides, the heat generated by the driving ICs 32 and 32 can be effectively released to the outside. Of course, as in FIGS. 1 and 2, the flexible substrate 6 on which the driving IC 61 is mounted may be bonded to each of the wiring substrates 3 and 3.
[0084]
【The invention's effect】
As described above, according to the present invention, the electrical connection between the drive electrode in each channel portion and the wiring from the drive circuit can be easily performed, and the ink supply chamber for supplying ink into each channel portion can be easily formed. Therefore, it is possible to provide an ink jet head with high productivity.
[Brief description of the drawings]
FIG. 1 is an overall perspective view showing a first embodiment of an inkjet head.
FIG. 2 is a longitudinal sectional view of the ink jet head shown in FIG.
FIG. 3 is a diagram showing one step of a method for manufacturing an inkjet head.
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.
FIG. 11 is an overall perspective view showing another aspect of the inkjet head according to the first embodiment.
FIG. 12 is an overall perspective view showing a second embodiment of the inkjet head.
FIG. 13 is an overall perspective view showing a third embodiment of the inkjet head.
FIG. 14 is an overall perspective view showing a fourth embodiment of an inkjet head.
[Explanation of symbols]
A, B, C, D: Inkjet head
1: Head chip
11: Lower substrate
12: Piezoelectric element
13: Upper substrate
14: Drive wall
15: Channel section
16: Drive electrode
17: First connection wiring
18: Second connection wiring
19: Front wiring
2: Nozzle plate
21: Nozzle hole
3: Wiring board
31: Drive wiring
32: Drive IC
33: Connector
34: Wiring
4: Channel substrate
5: Enclosure wall
51: Ink supply chamber
52: Inlet
6: Flexible substrate
61: Drive IC
62: Connector

Claims (8)

An upper substrate and a lower substrate having the same length, a driving wall made of a piezoelectric element having the same length between the upper substrate and the lower substrate , a driving wall alternately arranged with the driving wall, and a front surface and rear to their respective exit and the inlet and the channel portion arranged opposite shape, by Rukoto and a drive electrode formed on the drive walls facing into the channel portion, the front, rear, top, bottom and A head chip having six sides on both sides ;
A wiring board that is fixed to the upper surface or the lower surface of the head chip, has a driving wiring for applying a voltage to each driving electrode on the surface, and is formed to be longer than the length of the channel portion;
A flow path substrate that is fixed to a surface opposite to the fixing surface of the head chip with the wiring substrate, and is longer than the length of the channel portion;
An enclosing wall portion provided so as to surround a rear surface of the head chip between the flow path substrate and the wiring substrate ;
The flow channel substrate, the space surrounded by the wiring board and the surrounding wall portion, the formed on the rear surface of the head chip, ink will have an ink supply chamber for supplying to each channel unit,
The head chip has a first connection wiring corresponding to a drive electrode in each channel portion formed on at least one of an upper surface of the upper substrate and a lower surface of the lower substrate, and the head chip A second connection wiring that electrically connects each drive electrode and each first connection wiring is formed on at least one of the front surface and the rear surface ;
The wiring board is fixed to the head chip with the driving wiring formation surface facing the first connection wiring, whereby the driving wiring and the first connection wiring corresponding to the driving wiring are fixed to the fixing surface. An ink jet head, wherein the ink jet head is electrically connected . An upper substrate and a lower substrate having the same length, a driving wall made of a piezoelectric element having the same length between the upper substrate and the lower substrate , a driving wall alternately arranged with the driving wall, and a front surface and rear to their respective exit and the inlet and the channel portion arranged opposite shape, by Rukoto and a drive electrode formed on the drive walls facing into the channel portion, the front, rear, top, bottom and A head chip in which two of the six head chips on both sides are superimposed ;
Two wiring boards fixed to the upper surface and the lower surface of the superimposed head chips, each having a driving wiring for applying a voltage to each driving electrode on the surface, and formed longer than the length of the channel portion; ,
An enclosing wall provided so as to surround a rear surface of the superimposed head chip between the two wiring boards;
An ink supply chamber for supplying ink to each channel portion, formed on the rear surface side of the superimposed head chip between the two wiring boards and the space surrounded by the surrounding wall portion ;
Each of the overlapped head chips has a first connection wiring corresponding to a drive electrode in each channel portion formed on one of the upper surface of the upper substrate and the lower surface of the lower substrate, and Second connection wirings for electrically connecting the respective drive electrodes and the respective first connection wirings are formed on at least one of the front surface and the rear surface of each of the superimposed head chips, and The surface on which the first connection wiring is formed and the opposite surface are overlapped and fixed,
Each of the two wiring boards corresponds to the driving wiring by being fixed to the upper surface and the lower surface of the overlapped head chip with the driving wiring forming surface facing the first connection wiring, respectively. An ink jet head, wherein the first connection wiring is electrically connected to a fixing surface .   3. The ink jet head according to claim 1, wherein an electrode protective film is formed on surfaces of the drive electrode, the second connection electrode, and the drive wiring.   4. The ink jet head according to claim 1, wherein a flexible board on which a driving IC is mounted is electrically connected to the wiring board.   The inkjet head according to claim 1, wherein a driving IC is mounted on the wiring board.   At least one of the substrate other than the drive wall, the wiring substrate, and the flow path substrate in the head chip 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 any one of claims 1 to 5.   The thermal expansion coefficient of at least one of the substrate other than the drive wall, the wiring substrate, and the flow path substrate in the head chip is ± 2 ppm / ° C. of the thermal expansion coefficient of the piezoelectric element. The inkjet head in any one of 1-6. The inkjet head according to claim 1, wherein the head chip and the wiring substrate are fixed by an adhesive or an anisotropic conductive film.

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