JP4670159B2 - Inkjet printer head - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ink jet printer head, and more particularly to an ink jet printer head capable of grasping the position of an internal electrode in a piezoelectric actuator from the outside and combining a cavity plate and a piezoelectric actuator in accordance with the position of the internal electrode. is there.
[0002]
[Prior art]
A prior art on-demand type piezoelectric ink jet printer head includes a cavity plate having a plurality of nozzles and a pressure chamber for each nozzle, a planar individual electrode formed for each pressure chamber, and a plurality of adjacent electrodes. A plate-type piezoelectric actuator in which a piezoelectric sheet (a green sheet made of a ceramic material) is sandwiched between common electrodes common to the pressure chambers, and this piezoelectric actuator is connected to the cavity plate with each individual electrode in the piezoelectric actuator. Are stacked so as to correspond to each pressure chamber.
[0003]
The piezoelectric actuator in the piezoelectric ink jet printer head configured as described above is configured such that an end portion of each individual electrode extends to the end edge portion of the piezoelectric sheet and is exposed, and at least the individual electrode is disposed on a side surface in the stacking direction. Side electrodes that are electrically connected to the exposed ends are formed by metal vacuum deposition, sputtering, or application of conductive paste, and the individual electrodes are connected to the outside via the side electrodes. It was composed.
[0004]
When the individual electrodes of the piezoelectric actuator are associated with the pressure chambers of the cavity plate, the end portions of the individual electrodes are not visible because they are covered with the side electrodes. When forming the side electrode, slight positional deviation is unavoidable, and it cannot be used as an assembly mark for associating the individual electrode with the pressure chamber. For this reason, a notch is provided between the end portions of the piezoelectric sheet and the end portions of the individual electrodes extending to the end edge portion, and the notches are assembled to the piezoelectric actuator and the cavity plate. It was marked for use.
[0005]
However, since the arrangement interval of the individual electrodes is small, the width of the notch is considerably small, so that recognition is difficult, assembly work accuracy is deteriorated, and so-called product yield is deteriorated.
[0006]
Therefore, the individual electrodes provided on the piezoelectric sheet are arranged as shown in FIG. 9 to secure a space for providing assembly marks. FIG. 9 is a diagram showing an array pattern of individual electrodes in a conventional piezoelectric sheet. Specifically, a notch 53 having a predetermined width is disposed at the center of the longitudinal edge of the piezoelectric sheet 50, and the end 51 a of the individual electrode 51 on at least one side of the notch 53 is notched 53. It was bent to avoid. The reason why the patterns of the two rows of individual electrodes 51 are point-symmetric with respect to the central portion of the piezoelectric sheet 50 is that there are two rows of pressure chambers in the cavity plate, as will be described later in the embodiment.
[0007]
As a result, a space for providing the notch 53 as a positioning mark and assembling mark can be secured. Thus, as shown in FIG. 10, the piezoelectric actuator 56 and the cavity are targeted for the notch 53 formed on the side surface of the piezoelectric actuator 56 formed by laminating the piezoelectric sheets and the mark 58 formed on the surface of the cavity plate 57. By combining the plate 57 and the flexible flat cable 55 on the surface of the piezoelectric actuator 56, an ink jet printer head is configured.
[0008]
[Problems to be solved by the invention]
However, since the individual electrode described above has a bent portion, when the electrode is printed by screen printing, a uniform electrode material cannot be applied to the bent portion, and irregularities are generated on the surface thereof. Due to the unevenness, there is a problem in that the electrostatic capacity of the individual electrode beyond the bent portion is not constant, which causes non-uniform ink ejection or causes ejection failure.
[0009]
In addition, the notch as an assembly mark with the cavity plate exists independently from the individual electrode. Therefore, if the position of the individual electrode changes due to contraction in the sintering process of the piezoelectric actuator, The positional relationship between the electrode and the notch as an assembly mark is unclear, and it is necessary to combine the pressure chamber of the cavity plate and the individual electrode of the piezoelectric actuator in a corresponding manner. There was a problem that could not be reflected in.
[0010]
The present invention has been made to solve the above-described problems, and grasps the position of the internal electrode in the piezoelectric actuator from the outside, and combines the cavity plate and the piezoelectric actuator in accordance with the position of the internal electrode. It is an object of the present invention to provide an ink jet printer head capable of performing the above.
[0011]
[Means for Solving the Problems]
  In order to achieve this object, an ink jet printer head according to claim 1 includes a cavity plate having a plurality of nozzles and pressure chambers formed for each of the plurality of nozzles, and corresponding to each of the pressure chambers. A plurality of internal electrodes and a piezoelectric actuator in which a plurality of piezoelectric sheets are stacked are stacked, and the internal electrode of the piezoelectric sheet includes a through-hole penetrating in the stacking direction of the piezoelectric sheet and the through-hole. And at least one of its internal electrodes extends to the edge of the piezoelectric sheet.The cavity plate has a mark indicating the position of the pressure chamber corresponding to the extension internal electrode.Yes.
[0012]
According to the ink jet printer head of the first aspect, the ink supplied from the ink supply source to the ink jet printer head is distributed to the plurality of pressure chambers provided in the cavity plate. The pressure inside the plurality of pressure chambers to which the ink has been distributed fluctuates due to the piezoelectric sheets that are fluctuated by the plurality of internal electrodes provided corresponding to the respective pressure chambers. Due to the pressure fluctuation, ink is ejected from a plurality of nozzles provided corresponding to the plurality of pressure chambers, and printing is performed.
[0013]
Here, the piezoelectric actuator is formed by laminating a plurality of internal electrodes and a plurality of piezoelectric sheets, and the internal electrode of the piezoelectric sheet includes a through hole penetrating in the lamination direction of the piezoelectric sheet and a conductive material filled in the through hole. They are electrically connected to each other by the material. Then, among the plurality of internal electrodes, the position of the internal electrode is grasped by at least one internal electrode extending to the edge of the piezoelectric sheet, and the piezoelectric actuator and the cavity plate are associated with the pressure chamber of the cavity plate. And an ink jet printer head.
[0014]
  The ink jet printer head according to claim 2 is the ink jet printer head according to claim 1, wherein each piezoelectric sheet of the piezoelectric actuator is provided with each internal electrode at a position corresponding to another piezoelectric sheet. The electrode extends to the edge of the piezoelectric sheet.SaidThe position of the extended internal electrode is the same in each piezoelectric sheet.
[0015]
According to the ink jet printer head of the second aspect, the same action as that of the ink jet printer head according to the first aspect is achieved, and each internal electrode of each piezoelectric sheet of the piezoelectric actuator corresponds to each corresponding internal electrode of another piezoelectric sheet. It is provided at the same position. And the internal electrode of each piezoelectric sheet provided in the same position is extended to the edge part of a piezoelectric sheet.
[0017]
  Claim3An ink jet printer head according to claim 1.Or 2In the ink jet printer head according to the above, the pressure chambers are arranged in two rows, and the internal electrodes correspond to the rows of the pressure chambers in two rows along the edge of the long side of the piezoelectric sheet. And at least one extended internal electrode is provided for each column of the internal electrodes.
[0018]
  This claim3According to the ink jet head printer described in claim 1,Or 2In addition, the pressure chambers are arranged in two rows, and the internal electrodes correspond to each row of the pressure chambers along the long side edge of the piezoelectric sheet. Arranged in columns. At least one of the extended internal electrodes is provided in each row of the internal electrodes.
[0019]
  Claim4Inkjet printer head as claimed in claim3In the ink jet printer head described in (1), the extended internal electrode is provided substantially at the center of each row of the internal electrodes.
[0020]
  Claim5The ink jet printer head according to claim 1.4In the ink jet printer head according to any one of the above, the extending internal electrodes are linearly formed on the piezoelectric sheets.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a perspective view showing an embodiment of a color ink jet printer as an ink jet recording apparatus of the present invention. In FIG. 1, a color ink jet printer 100 includes an ink cartridge 61 filled with, for example, four color inks of cyan, magenta, yellow, and black, and an ink jet printer head 6 (hereinafter referred to as a head) for printing on paper 62. 6), a carriage 64 on which the ink cartridge 61 and the head unit 63 are mounted, a drive unit 65 for reciprocating the carriage 64 in a linear direction, and a head 64 extending in the reciprocating direction of the carriage 64. 6, a platen roller 66 disposed opposite to 6, and a purge device 67.
[0022]
The drive unit 65 includes a carriage shaft 71 disposed at the lower end portion of the carriage 64 and extending in parallel with the platen roller 66, a guide plate 72 disposed at the upper end portion of the carriage 64 and extending in parallel with the carriage shaft 71, and the carriage shaft 71. It consists of two pulleys 73 and 74 disposed between the guide plate 72 and at both ends of the carriage shaft 71, and an endless belt 75 spanned between the pulleys 73 and 74.
[0023]
When one pulley 73 is rotated forward and backward by driving the motor, the carriage 64 joined to the endless belt 75 is moved to the carriage shaft 71 and the guide plate 72 as the pulley 73 rotates forward and backward. And reciprocally moved in a linear direction.
[0024]
The paper 62 is fed from a paper feed cassette (not shown) provided on the side of the inkjet printer 100, introduced between the head 6 and the platen roller 66, and ejected from the head 6. Predetermined printing is performed, and then the paper is discharged. In FIG. 1, the paper feed mechanism and paper discharge mechanism for the paper 62 are not shown.
[0025]
The purge device 67 is provided on the side of the platen roller 66 and is disposed so as to face the head 6 when the head unit 63 is at the reset position. The purge device 67 includes a purge cap 81 that comes into contact with an opening surface of the nozzle 6 so as to cover a plurality of nozzles to be described later of the head 6, a pump 82 and a cam 83, and an ink reservoir 84. When the head unit 63 is at the reset position, the nozzle of the head 6 is covered with the purge cap 81, and the defective ink containing bubbles accumulated inside the head 6 is sucked by the pump 82 by driving the cam 83. The head 6 is recovered. The sucked defective ink is stored in the ink storage unit 84.
[0026]
The cap 85 covers the plurality of nozzles 15 (see FIG. 2) of the head 6 mounted on the carriage 64 that is returned to the reset position when printing is completed in order to prevent ink from drying.
[0027]
FIG. 2 shows a perspective view of the head unit 63 with the nozzle 15 side up. As shown in FIG. 2, the head unit 63 mounted on the carriage 64 that runs along the paper 62 is formed in a substantially box shape with the upper surface open, and four ink cartridges 61 are detachably mounted from above. The ink supply passages 4 a, 4 b, 4 c, and 4 d that can be connected to the ink discharge portions of the ink cartridges 61 communicate with the lower surface of the bottom plate 5 of the head unit 63. ing. The ink supply passages 4a, 4b, 4c, and 4d are provided with a packing 47 made of rubber or the like so as to be in close contact with an ink supply hole 19a described later.
[0028]
On the lower surface side of the bottom plate 5, four support portions 8 for arranging four heads 6 in parallel are formed in a stepped shape. A plurality of cavities 9a and 9b for fixing the head 6 with a UV adhesive material are formed in each support portion 8 so as to penetrate vertically.
[0029]
FIG. 3 is a perspective view of the head 6. As shown in FIG. 3, the head 6 includes a laminated cavity plate 10, a plate-type piezoelectric actuator 20 that is bonded and laminated to the cavity plate 10 via an adhesive or an adhesive sheet, and an upper surface thereof. For electrical connection with an external device, a flexible flat cable 40 is formed by overlapping and bonding with an adhesive, and ink is ejected downward from a nozzle 15 opened on the lower surface side of the cavity plate 10. The piezoelectric actuator 20 will be described in detail with reference to FIG.
[0030]
FIG. 4 is an exploded perspective view of the cavity plate 10. 5 is an exploded enlarged perspective view of the cavity plate 10 (cross section taken along the VV direction in FIG. 3). As shown in FIG. 4, the cavity plate 10 is formed by laminating and bonding five thin metal plates, ie, a nozzle plate 11 and two manifold plates 12X and 12Y, a spacer plate 13 and a base plate 14 with an adhesive. It is a structure. In the present embodiment, each of these plates 11 to 14 is made of 42% nickel alloy steel plate (42 alloy) and has a thickness of about 50 μm to 150 μm. In addition, each of these plates 11-14 is not restricted to metal, For example, you may form with resin.
[0031]
As shown in FIG. 5, a plurality of narrow pressure chambers 16 extending in a direction perpendicular to the longitudinal direction of the base plate 14 are formed in the base plate 14 in two rows in a staggered arrangement. Further, on the spacer plate 13 side of the base plate 14, a throttle portion 16 d connected to each pressure chamber 16 and an ink supply hole 16 b connected to the throttle portion 16 d are recessed. Each ink supply hole 16 b communicates with the common ink chamber 12 a in the manifold plate 12 </ b> X via each ink supply hole 18 formed in the left and right side portions of the spacer plate 13. Here, the cross-sectional area perpendicular to the direction in which the ink flows in each throttle portion 16 d is smaller than the cross-sectional area in each pressure chamber 16. This is because the flow path resistance is increased by reducing the cross-sectional area of the throttle portion 16d.
[0032]
One end portion 16a of each pressure chamber 16 has a small-diameter through hole formed in the staggered arrangement of nozzles 15 in the nozzle plate 11 in the spacer plate 13 and the two manifold plates 12X and 12Y in the same staggered arrangement. 17 to communicate with each other.
[0033]
Further, as shown in FIG. 4, the base plate 14 and the spacer plate 13 have two ink supply holes 19a and 19b for supplying ink from a common ink cartridge to the two common ink chambers 12a in the manifold plate 12, respectively. It has been drilled.
[0034]
The ink supply hole 19a of the base plate 14 is formed close to the end of the row formed by the plurality of pressure chambers 16 in order to reduce the size of the inkjet head. Further, since the ink supplied to the two ink supply holes 19a is supplied from a common ink cartridge, the two ink supply holes 19a are arranged close to each other. Since the two ink supply holes 19a supply ink to the corresponding two common ink chambers 12a via the two ink supply holes 19b formed in the spacer plate 13, the ink supply on the spacer plate 13 is performed. If two holes 19b are formed, the number of ink supply holes 19a on the base plate 14 may be one.
[0035]
As shown in FIG. 4, two common ink chambers 12 a and 12 b are provided on the two manifold plates 12 </ b> X and 12 </ b> Y so as to sandwich a row formed by a plurality of nozzles 15 in the nozzle plate 11. The common ink chambers 12 a and 12 b are located in a plane parallel to the surface formed by the plurality of pressure chambers 16 in the base plate 14, and are closer to the opening surfaces of the plurality of nozzles 15 in the nozzle plate 11 than the plurality of pressure chambers 16. Are arranged.
[0036]
Of the two manifold plates, the manifold plate 12X on the spacer plate 13 side has a common ink chamber 12a formed through the manifold plate 12X, and the manifold plate 12Y on the nozzle plate 11 side has the former manifold plate 12X. It is recessed so as to open only to the side. Then, by stacking the two manifold plates 12X and 12Y and the spacer plate 13, the common ink chambers 12a and 12b that are vertically overlapped each have one common ink chamber on each side of the row of the through holes 17 respectively. Form. Thereby, a sufficient amount of ink to be supplied to the plurality of pressure chambers 16 can be secured. The reason why two rows of common ink chambers are provided on both sides of the row of through holes 17 is to correspond to the pressure chambers 16 arranged in two rows.
[0037]
As shown in FIG. 4, a plurality of ink ejection nozzles 15 having a minute diameter (about 25 μm in the present embodiment) are arranged on the nozzle plate 11 with a minute pitch P along the longitudinal direction of the nozzle plate 11. Drilled in a staggered pattern at intervals.
[0038]
With the configuration of the cavity plate 10 described above, ink that has flowed into the common ink chambers 12a and 12b from the ink supply holes 19a and 19b formed in one end of the base plate 14 and the spacer plate 13 is transferred from the common ink chamber 12a to each ink. The ink is distributed to the pressure chambers 16 through the supply holes 18, the ink supply holes 16b, and the throttle portions 16d. Then, ink flows in the direction of the one end portion 16 a of each pressure chamber 16, passes through each through hole 17, and reaches the nozzle 15 corresponding to each pressure chamber 16.
[0039]
FIG. 6 is an exploded perspective view of the plate-type piezoelectric actuator 20. As shown in FIG. 6, the plate-type piezoelectric actuator 20 includes ten piezoelectric sheets 21, 22, 23, 24, 25, 26, 27, 28. , 29 and 30 are stacked.
[0040]
Among the piezoelectric sheets 21 to 30, narrow individual electrodes 31 are provided on the upper surfaces of the piezoelectric sheets 26, 28, and 30 at positions corresponding to the pressure chambers 16 (see FIG. 5) provided in the cavity plate 10. Each is formed. Further, a discarded pattern electrode 32b, which is a land pattern that does not participate in the deformation of the piezoelectric sheet, is formed at a position corresponding to an end portion 32a of the common electrode 32 described later. A specific pattern of the individual electrode 31 will be described with reference to FIG.
[0041]
On the upper surface of the piezoelectric sheets 25, 27, and 29, a strip-shaped common electrode 32 that is a common electrode for the plurality of pressure chambers 16 is formed. Further, a discarded pattern electrode 31b, which is a land pattern not involved in the deformation of the piezoelectric sheet, is formed at a position corresponding to the end portion 31a of the individual electrode 31. The discarded pattern electrodes 31b and 32b are formed to have the same thickness as the individual electrode 31 and the common electrode 32. When the piezoelectric sheets are laminated as will be described later, the piezoelectric sheet in the portion where the individual electrode 31 and the common electrode 32 are not formed is recessed. It has been corrected. The common electrode 32 and the discard pattern 31b are formed on the upper surfaces of the piezoelectric sheets 22, 23, and 24, but the piezoelectric operation is not performed on these sheets.
[0042]
On the upper surface of the uppermost piezoelectric sheet 21, a surface electrode 33 for each of the individual electrodes 31 and a surface electrode 34 for the common electrode 32 are arranged along side edges extending in parallel with the arrangement direction of the individual electrodes 31. It is provided in two rows.
[0043]
Except for the lowermost piezoelectric sheet 30, all the other piezoelectric sheets 21 to 29 further include the surface electrode 33, the individual electrode 31 and the disposal pattern electrode 31 b at the corresponding position (the same vertical position). Through holes 36 are formed so as to communicate with each other (see FIG. 7). Similarly, a through hole 37 is formed so that the surface electrode 34 and the common electrode 32a and the discard pattern electrode 32b at the corresponding positions communicate with each other.
[0044]
The through holes 36 and 37 are filled with a conductive material, and are configured so that the individual electrodes 31 of each layer and the surface electrode 33 at a position corresponding thereto are electrically connected. 32 and the surface electrode 34 of the position corresponding to 32 are electrically connected.
[0045]
FIG. 7 is a diagram showing an arrangement pattern of the individual electrodes 31 and the discard pattern electrodes 32b provided on the piezoelectric sheets 26, 28, and 30. FIG. As shown in FIG. 7, the pattern of the individual electrodes 31 in the row on one side of the long side end of each piezoelectric sheet 26 or the like is linear and in a direction orthogonal to the end edge of the piezoelectric sheet 26 or the like. The pattern of the individual electrodes 31 in the other row is in a staggered position shifted by half with respect to the individual electrodes 31 in the other row, and the edge of the piezoelectric sheet 26 or the like It is formed to extend in a direction orthogonal to the part.
[0046]
Further, the end portions 31a of the individual electrodes 31 are not exposed from the end edge portions of the piezoelectric sheets 26 and the like. Since the corresponding individual electrodes 31 such as the piezoelectric sheets 26 are electrically connected to each other by the through holes 36 and the conductive material filled in the through holes 36, for example, the end portions 31 a of the individual electrodes 31. This is because, unlike the case where the individual electrodes 31 are electrically connected to each other by the side electrodes, it is not necessary to expose the end portions 31a of the individual electrodes 31 from the end edges of the piezoelectric sheets 22 and the like. .
[0047]
However, if the end portions 31a of all the individual electrodes 31 are not exposed from the piezoelectric sheets 26 and the like, the positions of the individual electrodes 31 cannot be grasped from the outside when the piezoelectric sheets 26 and the like are stacked. Therefore, among the patterns of the individual electrodes 31 in each row formed on each piezoelectric sheet 26 or the like, the end portion 31Xa of the central individual electrode 31X is extended to the end edge portion of each piezoelectric sheet 26 or the like and exposed. The portion 31Xa is used as a mark indicating the position of the internal electrode.
[0048]
The reason why the extended individual electrode 31X is provided at substantially the center of each row of the individual electrodes 31 is that the piezoelectric actuator 20 is manufactured by laminating and sintering the piezoelectric sheets 22 and the like, as will be described later. Shrinkage occurs in the sintering process, and the shrinkage slightly differs for each piezoelectric actuator, and the pitch of the individual electrodes 31 and the pitch of the pressure chambers 16 of the cavity plate do not exactly match. This is because the position error between the internal electrode 31 and the corresponding pressure chamber at both ends can be reduced by assembling with the cavity plate 10 with reference to the end portion 31Xa of the central extending individual electrode 31X.
[0049]
The same applies to the end of the discarded pattern electrode 31b in the piezoelectric sheets 22, 23, 24, 25, 27, and 29 provided at the position corresponding to the position of the extended individual electrode 31X and the end of the surface electrode 33 in the piezoelectric sheet 21. Further, each piezoelectric sheet is exposed.
[0050]
Next, a method for manufacturing the piezoelectric actuator will be described. First, a first material sheet (ceramic green sheet) having a size in which a plurality of piezoelectric sheets 26 (same for 28 and 30) are arranged in a matrix is formed, and each piezoelectric sheet that becomes the piezoelectric sheets 26 and 28 is formed. Through-holes 36 and 37 are drilled in advance along the periphery of the location. Similarly, a second material sheet (ceramic green sheet) having a size in which a plurality of piezoelectric sheets 22 (23, 24, 25, 27, and 29) are arranged in a matrix is formed, and each of the piezoelectric sheets and Through-holes 37 and 36 are drilled in advance along the periphery of the portion. Further, in the same manner as described above, a third material sheet (ceramic green sheet) having a size in which a plurality of uppermost piezoelectric sheets 21 are arranged in a matrix is formed, and the uppermost piezoelectric sheet 21 on the surface thereof is formed. Through-holes 36 and 37 are drilled along the periphery of the portion to be formed.
[0051]
Next, the individual electrode 31 and the discard pattern electrode 32b are provided on the surface of the green sheet for each of the piezoelectric sheets 26, 28, and 30, and the piezoelectric sheets 22, 23, 24, 25, 27, and 29 are provided on the surface of the green sheet. The common electrode 32 and the discarded pattern electrode 31b are formed on the surface of the green sheet, and the surface electrodes 33 and 34 are formed on the surface of the green sheet surface where the uppermost piezoelectric sheet 21 is formed. Form with.
[0052]
Here, since each through-hole 36, 37 penetrates the upper and lower wide surfaces of each green sheet, the conductive paste penetrates into each through-hole 36, 37 and passes through each through-hole 36, 37. Each electrode portion can conduct electricity on the upper and lower surfaces of the piezoelectric sheet. Moreover, since each individual electrode 31 is formed in a straight line shape, the surface can be printed uniformly compared to the case where there is a bend. Therefore, the electrostatic capacity in the individual electrode becomes constant, and stable ink ejection can be realized.
[0053]
  Also, the extension on the surface of each piezoelectric sheet 26, 28, 30IndividualSince all the electrodes 31X are formed at the same position, the electrode arrangement of each piezoelectric sheet 26, 28, 30 can be printed in the same pattern. The same applies to other piezoelectric sheets.
[0054]
Next, each green sheet is laminated. At this time, the individual electrode 31, the discarded pattern electrode 31b and the surface electrode 33 of each sheet correspond to the stacking direction, and the end 32a of the common electrode 32, the discarded pattern electrode 32b and the surface electrode 33 correspond to the stacking direction, And it laminates | stacks so that the surface electrodes 33 and 34 of the sheet | seat 50 may be exposed, degreases, sinters and integrates. Thereby, the individual electrode 31, the discard pattern electrode 31 b, and the surface electrode 33 of each green sheet stacked on the top and bottom are electrically connected via the through hole 36, and the common electrode 32, the discard pattern electrode 32 b and the surface electrode 33 are connected. Are electrically connected through a through hole 37.
[0055]
Thereafter, the laminate is cut for each piezoelectric actuator. At this time, the end of the extended individual electrode 31 and the end of the center of the discarded pattern electrode 33 are exposed on the side surface of each piezoelectric actuator 20 in the stacking direction.
[0056]
As shown in FIG. 8, the cavity plate 10 and the piezoelectric actuator 20 configured as described above are laminated and fixed so that each pressure chamber 16 in the cavity plate 10 and the individual electrode 31 in the piezoelectric actuator 20 correspond to each other. Is done. 8 is a cross-sectional view of the piezoelectric actuator 20 and the cavity plate 10 taken along line VIII-VIII in FIG.
[0057]
A mark 39 indicating the position of the pressure chamber 16X corresponding to the extended individual electrode 31X is provided on the surface of the cavity plate 10 to be overlapped with the piezoelectric actuator 20. By combining the mark 39 and the end portion 31Xa of the extended individual electrode 31X exposed from the piezoelectric actuator 20, the end portion 31Xa of the extended individual electrode 31X can be used as an assembly mark of the piezoelectric actuator 20 and the cavity plate 10. Further, since the extended individual electrode 31X is directly used as an assembly mark, the pressure chamber 16 can be accurately arranged in correspondence with the actual position of the individual electrode 31.
[0058]
In addition, when the flexible flat cable 40 (see FIG. 3) is superimposed and pressed on the upper surface of the piezoelectric actuator 20, various wiring patterns (not shown) in the flexible flat cable 40 are connected to each surface electrode. 33 and 34 are electrically joined.
[0059]
Through the flexible flat cable 40, a higher voltage is applied between all the individual electrodes 31 and the common electrode 32 than during normal ink ejection operation, and between the individual electrode 31 and the common electrode 32. The portions of the sandwiched piezoelectric sheets 25 to 29 are subjected to polarization treatment, and these portions are formed as active layers. This polarization treatment can also be performed before the piezoelectric actuator 20 is joined to the cavity plate 10 or the flexible flat cable 40.
[0060]
In addition, since the piezoelectric sheets 21 to 24 are only sandwiched between the common electrodes 32 and the surface electrodes 33 and 34 and are not polarized, they do not perform a piezoelectric operation. In these sheets, the piezoelectric actuator is warped or waved in the sintering process so that the flatness is not impaired, and the active layer of the piezoelectric sheets 25 to 29 is deformed only in the direction of the pressure chamber 16. It functions as a constraining layer for doing so.
[0061]
Then, by applying a voltage between an arbitrary individual electrode 31 of the individual electrodes 31 of the piezoelectric actuator 20 in the head 6 and the common electrode 32, it corresponds to the individual electrode 31 to which a voltage is applied in the piezoelectric sheet. In the active layer, distortion in the stacking direction due to piezoelectricity occurs. The ink in the pressure chamber 16 is ejected in the form of droplets from the nozzle 15 by the pressure caused by this distortion, and predetermined printing on the paper 62 is performed.
[0062]
As described above, according to the head 6 of the present embodiment, at least one of the individual electrodes 31 such as each piezoelectric sheet 22 extends to the end edge portion of each piezoelectric sheet 22 or the like. Even when 22 or the like are stacked, since the position of at least one individual electrode 31 can be confirmed from the outside, the end of the individual electrode 31 can be used as a mark indicating the position of the internal electrode.
[0063]
Further, by combining the end 31Xa of the extended individual electrode 31X and the mark 39 of the cavity plate 10, the cavity plate 10 and the piezoelectric actuator 20 can be combined according to the actual position of the individual electrode.
[0064]
Although the present invention has been described based on the above embodiment, the present invention is not limited to the above embodiment, and various modifications and changes can be easily made without departing from the gist of the present invention. Can be inferred.
[0065]
For example, in the above embodiment, only the individual electrode 31 at the center of the row formed by the individual electrodes 31 is the extended individual electrode 31X. However, the individual electrode 31X is not limited to the individual electrode 31 at the center, It may be every other individual electrode 31 in the row, or all the individual electrodes 31 may be extended. By exposing many internal electrodes 31, the position of each internal electrode 31 can be grasped more accurately than in the case where some internal electrodes 31 are exposed.
[0066]
In the above embodiment, all the individual electrodes 31, the pattern electrodes 31b, and the surface electrodes 33 corresponding to the piezoelectric actuator in the stacking direction are extended to the end portions of the piezoelectric sheets to be exposed. When using the formed end as an assembly mark with the cavity plate 10, the individual electrode 31 and the like are exposed from at least one piezoelectric sheet on the cavity plate 10 side, and the other sheets are omitted. Also good.
[0067]
Further, although the end of the individual electrode 31 is extended to the edge of the piezoelectric sheet as an internal electrode, the common electrode 32 is provided individually corresponding to each pressure chamber in the same manner as the individual electrode 31, and the end of the common electrode 32 is provided. By extending the portion to the edge of the piezoelectric sheet, the position of the internal electrode composed of the common electrode 32 and the individual electrode 31 can be displayed on the side surface of the actuator.
[0068]
【The invention's effect】
  According to the ink jet printer head of claim 1, the internal electrodes of the piezoelectric sheet are electrically connected to each other by a through hole penetrating in the stacking direction of the piezoelectric sheet and a conductive material filled in the through hole. Since at least one of the internal electrodes extends to the end edge of the piezoelectric sheet, the end of the internal electrode extended to the end edge of the piezoelectric sheet is positioned at the position of the internal electrode. It can be a mark indicating. Therefore, there is no need to provide a separate mark as in the prior art, and there is an effect that the position of the internal electrode can be grasped from the outside and the internal electrode and the pressure chamber can be associated with each other.
  Further, since the cavity plate is provided with a mark indicating the position of the pressure chamber corresponding to the extended internal electrode, the cavity plate can be extended by combining the mark and the end of the extended internal electrode exposed from the piezoelectric actuator. There is an effect that the end of the inner electrode can be used as an assembly mark of the piezoelectric actuator and the cavity plate.
  Furthermore, since the extended internal electrode is directly set as an assembly mark, for example, compared with a case where a notch or the like provided at the edge of the piezoelectric sheet is used as an assembly mark, the piezoelectric actuator is arranged in accordance with the actual position of the internal electrode. There is an effect that the cavity plate and the piezoelectric actuator can be assembled by making the internal electrode correspond to the pressure of the cavity plate.
[0069]
  According to the ink jet printer head of the second aspect, in addition to the effect achieved by the ink jet printer head of the first aspect, each piezoelectric sheet of the piezoelectric actuator has each internal electrode at a position corresponding to the other piezoelectric sheet. It is provided and extends to the edge of the piezoelectric sheet among the internal electrodesSaidSince the position of the extended internal electrode is the same in each piezoelectric sheet, for example, when all of the internal electrodes corresponding to the stacking direction are extended, the end of the extended internal electrode is It is formed in a straight line in the side stacking direction. Thereby, the edge part of the some extended internal electrode formed in a linear form can be caught integrally, and there exists an effect that the position of an internal electrode can be grasped | ascertained clearly from the outside.
[0070]
In addition, the printed patterns of the internal electrodes in each piezoelectric sheet are the same, and there are effects that the types of parts can be reduced and the manufacturing process can be simplified. Furthermore, if the end portions of the internal electrodes formed on the side surfaces of the piezoelectric actuator are not linear, the internal electrodes may not be in electrical communication. There is an effect that can be eliminated.
[0073]
  Claim3According to the inkjet printer head described in claim 1,Or 2In addition to the effects produced by the inkjet printer head described above, the internal electrodes are arranged in two rows along the long side edge of the piezoelectric sheet corresponding to each row of the pressure chambers, and at least for each row of the internal electrodes, Since the one extended internal electrode is provided, at least one end of the extended internal electrode is exposed from the opposite side surface of the piezoelectric actuator. Therefore, when the piezoelectric actuator and the cavity plate are combined, there is an effect that the assembly can be accurately performed by the assembly marks formed on both long sides.
[0074]
  Claim4According to the inkjet printer head described in claim3In addition to the effects exhibited by the inkjet printer head described in 1., the extended internal electrodes are provided at substantially the center of each row of internal electrodes, so that the internal electrodes of the piezoelectric actuator overlap the pressure chambers of the corresponding cavity plates. There is an effect that the position error at the time can be reduced.
[0075]
  Claim5According to the ink jet printer head described in claim 1,4In addition to the effect of the inkjet printer head described in any of the above, since the extended internal electrodes are formed linearly on each piezoelectric sheet, for example, when printing the extended internal electrodes by screen printing, The surface can be printed uniformly. That is, there is an effect that the electrostatic capacity in the extended internal electrode becomes constant and stable ink discharge can be realized.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a color ink jet printer which is an embodiment of an ink jet printer head of the present invention.
FIG. 2 is a perspective view with the nozzle side of the head unit facing up.
FIG. 3 is a perspective view of each component of the inkjet printer head.
FIG. 4 is an exploded perspective view of a cavity plate.
FIG. 5 is an exploded enlarged perspective view of a cavity plate.
FIG. 6 is an exploded perspective view of a piezoelectric actuator.
FIG. 7 is a plan view showing a pattern of individual electrodes in a piezoelectric sheet.
FIG. 8 is an exploded perspective view of a piezoelectric actuator and a cavity plate.
FIG. 9 is a plan view showing a pattern of individual electrodes in a conventional piezoelectric sheet.
FIG. 10 is a perspective view of each component of a conventional inkjet printer head.
[Explanation of symbols]
6 Inkjet printer head
10 Cavity plate
15 nozzles
20 Piezoelectric actuator
21-30 Piezoelectric sheet
31 Individual electrode (internal electrode)
31a End of individual electrode
31X extensionIndividualelectrode(Extended internal electrode)
31Xa extensionIndividualEnd of electrode(End of extended internal electrode)
31b Discard pattern electrode
32 Common electrode
32b Discard pattern electrode
33, 34 Surface electrode
36, 37 Through hole
39 Mark (Cavity plate side assembly mark)

Claims (5)

Piezoelectric actuator comprising a plurality of nozzles and a cavity plate having a pressure chamber formed for each of the plurality of nozzles, and a plurality of internal electrodes and piezoelectric sheets provided corresponding to each of the pressure chambers. In an inkjet printer head configured by overlapping
The internal electrodes of the piezoelectric sheet are electrically connected to each other by a through-hole penetrating in the stacking direction of the piezoelectric sheet and a conductive material filled in the through-hole,
At least one of the internal electrodes is an extended internal electrode that extends to an edge of the piezoelectric sheet ,
The ink jet printer head according to claim 1, wherein the cavity plate includes a mark indicating a position of a pressure chamber corresponding to the extended internal electrode . Each piezoelectric sheet of the piezoelectric actuator is provided with each internal electrode at a position corresponding to the other piezoelectric sheet,
The position of the extending internal electrodes extending to the edge portion of the piezoelectric sheet among the internal electrodes, the ink jet printer head according to claim 1, wherein the the same in each of the piezoelectric sheets. The pressure chambers are arranged in two rows,
The internal electrodes are arranged in two rows along the long side edge of the piezoelectric sheet, corresponding to each row of the pressure chambers,
3. The ink jet printer head according to claim 1, wherein at least one extended internal electrode is provided for each row of the internal electrodes. 4. The ink jet printer head according to claim 3 , wherein the extended internal electrode is provided substantially at the center of each row of the internal electrodes. The extending internal electrodes, the ink jet printer head according to any of claims 1 4, characterized in that it is formed linearly to the each piezoelectric sheet.

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