JP2002036568A - Piezoelectric actuator and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure accurate alignment of a piezoelectric actuator 20, a cavity plate 10 and a flexible flat cable 40 integrated through lamination of a piezoelectric sheet having discrete electrodes and surface electrodes 30. SOLUTION: At the long side edge part and the short side edge part of a piezoelectric actuator 20 having a large number of surface electrodes 30 corresponding to discrete electrodes formed in parallel at the long side edge part, cuts 42', 43' are provided while having a pair of edges of semicircular plan view at the middle point of each side in the thickness direction of the piezoelectric actuator 20. Consequently, a reference position can be recognized clearly and accurately even when the piezoelectric actuator 20 is observed from the thickness direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a plate type piezoelectric actuator used for printing drive by a piezoelectric type ink jet printer head and a method of manufacturing the same. The present invention relates to a configuration and formation of a positioning mark for facilitating an assembling operation and the like.

[0002]

2. Description of the Related Art In the prior art on-demand type piezoelectric ink jet printer head, Japanese Patent Application No.
As described in the specification of Japanese Patent Application No. 72678, a cavity plate having a plurality of nozzles and pressure chambers for each of the nozzles, a planar individual electrode formed for each of the pressure chambers, and an adjacent electrode are provided. And a plate-type piezoelectric actuator laminated with a piezoelectric sheet (a green sheet made of a ceramic material) sandwiched by common electrodes common to a plurality of pressure chambers, and the piezoelectric actuator is attached to the cavity plate by the piezoelectric actuator. A structure in which individual electrodes are stacked so as to correspond to pressure chambers is disclosed. In that case, multiple nozzles
It is parallel to the long side of the cavity plate and is arranged in a row at the center of the short side (width direction). The corresponding pressure chamber is located at the center of the cavity plate in the width direction (short side). On both sides of the line, they were arranged in a staggered arrangement so as to extend in the long side direction parallel to the short side edges of the cavity plate.

In manufacturing the piezoelectric actuator, conventionally, a piezoelectric sheet 100 on which individual electrodes are formed and a piezoelectric sheet 101 on which common electrodes and dummy individual electrodes (not shown) are formed are alternately laminated after drying. After pressing and firing, the side electrodes 10 are arranged on the side surfaces orthogonal to the wide surfaces of the piezoelectric sheets 100 and 101 in the thickness direction of the sheets.
2, electrically connecting the edges of the individual electrodes and dummy individual electrodes having the same vertical positional relationship, electrically connecting the common electrodes in the same manner, and furthermore, a piezoelectric sheet as a top sheet of the piezoelectric actuator. 103 wide surface (upper surface)
The surface electrode 104 and the side electrode 102 are connected to apply an electric signal from an external circuit (see FIG. 12).

When a pattern such as the individual electrodes is formed on a single large material sheet 102 made of a piezoelectric ceramic green sheet by screen mask printing or the like using a conductive paste, each piezoelectric sheet 100, 1
01, a printing mark 105 for positioning is formed at the same time near the long edge or the short edge, and after drying, the piezoelectric sheet 100 is formed such that the positions of the marks 105 are substantially aligned vertically. 101 was laminated and pressed, and then baked into a single piezoelectric actuator, which was cut and separated by a dicing cutter rotating at a high speed to a predetermined piezoelectric sheet size.

Thus, the end of the individual electrode and the end of the positioning mark 105 are exposed from the end face of the piezoelectric actuator. It was used as a reference for positioning for the work of bonding and fixing at a predetermined position on the cavity plate by checking with a magnifying lens.

[0006]

However, the width of the individual electrodes is small and the spacing between the individual electrodes is small, so that the width of the positioning mark 105 is considerably small. Further, the mark 1 exposed from the end face of the piezoelectric actuator is not required.
Since the layer thickness at the end portion 05 is very small, the recognition becomes difficult, the accuracy of the assembling work is deteriorated, and the so-called product yield is deteriorated.

An object of the present invention is to provide a plate type piezoelectric actuator which solves such a problem.

[0008]

According to a first aspect of the present invention, there is provided a piezoelectric actuator, comprising: a cavity plate provided with a plurality of pressure chambers for each of a plurality of nozzles; A piezoelectric actuator is formed by laminating piezoelectric sheets on the surface of which a pattern of drive electrodes to be driven for each pressure chamber is formed, and the piezoelectric actuator is mounted on the cavity plate, and each drive electrode of the piezoelectric actuator is provided with a pressure. A piezoelectric actuator in a piezoelectric ink jet printer head laminated to correspond to the chamber, the piezoelectric sheet in which the rows of individual electrodes are formed among the drive electrodes, and the piezoelectric sheet in which the common electrode is formed, A notch for a positioning mark is provided at a predetermined position in each side direction at the long side edge and the short side edge of each piezoelectric sheet. Each is provided, in which respective cut-out portion is configured to substantially align in the stacking direction.

The invention described in claim 2 is the first invention.
Wherein the notch for the positioning mark is provided at a long side edge and a short side edge of each of the piezoelectric sheets, and at a midpoint in each side direction, respectively. It is.

According to a third aspect of the present invention, in the piezoelectric actuator according to the first or second aspect, the individual electrodes formed on one surface of the one piezoelectric sheet are arranged in the same direction as the arrangement direction of the nozzles. On both sides of the parallel center line, are formed in parallel rows at a constant interval from each other to extend from the position near the center line to the long side edge of the piezoelectric sheet parallel to the center line, On one surface of the other piezoelectric sheet, the common electrode is formed at a central portion sandwiching the center line, and a dummy individual electrode extending to a long side edge portion of the piezoelectric sheet is formed appropriately separated from the common electrode. The piezoelectric sheet is formed by alternately stacking the one piezoelectric sheet and the other piezoelectric sheet.

Further, according to a fourth aspect of the present invention, in the piezoelectric actuator according to any one of the first to third aspects, the pattern of the individual electrodes in the row on one side sandwiching the center line is linear. And formed so as to extend in a direction perpendicular to one of the edge portions of the piezoelectric sheet,
The pattern of the individual electrodes in the row on the other side sandwiching the center line is in a zigzag arrangement at a position close to the center line and shifted from the individual electrodes in the row on one side by half the fixed interval. Extending in a direction orthogonal to the center line, and bending at a longitudinally intermediate portion of each individual electrode, and furthermore, at one end edge side of the piezoelectric sheet in the one side row of individual electrodes. Corresponding to the position, the piezoelectric sheet is formed so as to extend in a direction perpendicular to the other of the edge portions, and at a center position of the center line, a pattern of the individual electrodes in the row on one side, The pattern of the individual electrodes in the other row is formed in a point-symmetrical manner, and the notch formed in the long side edge is located between the patterns of the individual electrodes. It was done.

According to a fifth aspect of the present invention, there is provided a method of manufacturing a piezoelectric actuator, wherein at least one of two opposing sides of the piezoelectric sheet is adjacent to a material sheet constituting the piezoelectric sheet in the piezoelectric actuator. , A plurality of regions of the piezoelectric sheet are arranged side by side, and in each region,
The individual electrodes are arranged in parallel rows at regular intervals so as to extend from the position near the center line to the two sides of the region on both sides of the center line parallel to the two sides between the two sides of the region. Formed and a notch for the positioning mark,
It is characterized in that it is formed at a predetermined position on a line of each side of the region with a through hole having a size that straddles each side, and is divided into the region along with the through hole along the four sides. is there.

[0013] The invention described in claim 6 is the invention according to claim 5.
In the method for manufacturing a piezoelectric actuator according to the above, the through hole is on a line intersecting the center line,
At the intersection of the two sides in the direction intersecting with the two sides at the center position of two sides and the extension of the center line in each of the piezoelectric sheets, the piezoelectric sheet is provided so as to straddle each side. It is characterized by the following.

According to a seventh aspect of the present invention, in the method for manufacturing a piezoelectric actuator according to the fifth or sixth aspect, the area of each of the piezoelectric sheets is formed in a rectangular shape in plan view. .

According to an eighth aspect of the present invention, in the method for manufacturing a piezoelectric actuator according to any one of the fifth to seventh aspects, the pattern of the individual electrodes in one side of the row sandwiching the center line is a straight line. And is formed so as to extend in a direction perpendicular to one side of the region, and the pattern of the individual electrodes in the row on the other side sandwiching the center line is formed on the one side on the side close to the center line. At a staggered position shifted from the individual electrodes in the row by half of the predetermined interval, extends in a direction orthogonal to the center line of the region, and bends at a longitudinal middle part of each individual electrode, After being formed so as to extend in a direction orthogonal to the other side of the region so as to be connected to the end of the individual electrode of the row on one side in the region adjacent on the side, Divide the material sheet It is characterized in creating a conductive sheet.

According to a ninth aspect of the present invention, in the method of manufacturing a piezoelectric actuator according to any one of the fifth to eighth aspects, the one side of the one side is located at a center position of a center line of each region. Patterns of individual electrodes in a row,
The pattern of the individual electrode in the other row is formed in a point-symmetrical manner, and at least one side of an adjacent region is connected without a break.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1, 10 and 11 show a piezoelectric inkjet printer head according to an embodiment of the present invention. In these figures, a flexible flat cable 40 is connected to an upper surface of a plate type piezoelectric actuator 20 laminated with a metal plate cavity plate 10 with an adhesive for connection with an external device, and is joined thereto. It is assumed that ink is ejected downward from a nozzle 15 opened on the lower surface side of the lowermost cavity plate 10.

The cavity plate 10 is configured as shown in FIGS. That is, it has a structure in which five thin metal plates of a nozzle plate 11, two manifold plates 12, a spacer plate 13, and a base plate 14 are laminated. The nozzle plate 11
The nozzles 15 for ejecting ink having a small diameter are provided in a staggered arrangement of two rows along a first direction (long side direction) of the nozzle plate 11. That is, the parallel reference lines 11 on both sides of the center line of the nozzle plate 11 in a second direction (short side direction) orthogonal to the first direction.
A number of nozzles 15 are formed in a zigzag pattern at intervals of a minute pitch (P0) along a and 11b (FIG. 4).
reference).

In the two manifold plates 12, ink passages 12a and 12b are formed so as to extend along both sides of the row of the nozzles 15 and substantially along the long side of the plate 12. However, the ink passage 12b in the manifold plate 12 facing the lower nozzle plate 11 is formed to be concave only to be opened above the manifold plate 12 (see FIG. 4). The ink passages 12a and 12b are provided with the spacer plate 13 with respect to the two manifold plates 12.
The structure is hermetically sealed by lamination.

The base plate 14 has a plurality of narrow pressure chambers 16 extending in a second direction (short side direction) orthogonal to a center line along the long side (the first direction). Are drilled. When the longitudinal reference lines 14a and 14b are set in parallel on both the left and right sides of the center line, the tip 16a of the pressure chamber 16 on the left side of the center line is located on the left longitudinal reference line 14a, Conversely, the tip 16a of the pressure chamber 16 on the right side of the longitudinal center line is located on the right longitudinal reference line 14b.
The six tips 16a are alternately arranged. Therefore, as shown in FIGS. 3 and 4, the pressure chambers 16 on the left and right sides are alternately arranged (in a so-called staggered arrangement) so as to extend in the opposite direction every other one. The pitch dimension between the pressure chambers 16 and 16 in the row is P2, the array pitch dimension of the left pressure chamber 16 and the right pressure chamber 16 is (P2) / 2, and the value of (P2) / 2 is Usually, it is equal to the value of the minute pitch (P0).

The tip 16a of each pressure chamber 16 is connected to the staggered nozzles 15 of the nozzle plate 11.
Are connected to the spacer plate 13 and the both manifold plates 12 through small-diameter through holes 17 also formed in a staggered arrangement. On the other hand, the other end 16 b of each of the pressure chambers 16 is connected to the ink passages 12 in the manifold plates 12 through through holes 18 formed in both right and left portions of the spacer plate 13.
a, 12b. The other end 16b is
As shown in FIG. 4, the recess is formed so as to open only on the lower surface side of the base plate 14. Also,
A filter 29 for removing dust in ink supplied from an ink tank above the supply hole 19a is provided on an upper surface of a supply hole 19a formed at one end of the uppermost base plate.

Thus, the base plate 14
And a supply hole 19 formed at one end of the spacer plate 13.
The ink flowing into the ink passages 12a and 12b from the ink passages 12a and 12b is distributed from the ink passages 12a to the pressure chambers 16 through the through holes 18 and then from the pressure chambers 16 to the ink passages 12a and 12b. The configuration is such that the gas reaches the nozzle 15 corresponding to the pressure chamber 16 through the through hole 17.

On the other hand, as shown in FIG. 5 and FIG.
2. A structure in which the top sheet 23 and the top sheet 23 are stacked, and the upper surface (wide surface) of the lowermost piezoelectric sheet 21 of the piezoelectric sheets.
In each of the pressure chambers 16 in the cavity plate 10, narrow individual electrodes 24a and 24b are formed in a row along a first direction (long side direction). Reference numeral 24b extends along the second direction orthogonal to the first direction to the vicinity of the long side edge of the piezoelectric sheet 21.

On the upper surface (wide surface) of the upper piezoelectric sheet 22, a common electrode 25 common to the plurality of pressure chambers 16 is formed.

The number of layers of the piezoelectric sheet 21 on which the individual electrodes 24a and 24b are formed and the piezoelectric sheet 22 on which the common electrode 25 is formed is related to the magnitude of the ink ejection pressure in each of the corresponding pressure chambers 16. That is, as shown in FIG. 9, eight to ten layers may be used. In the embodiment,
As can be understood from FIG. 5 and FIG.
The widths of the pressure chambers 4a and 24b are set to be slightly smaller than the wide portions of the corresponding pressure chambers 16 in plan view.

On the other hand, since the pressure chambers 16 are arranged in two rows along the first direction (long side) on the center side of the short side of the base plate 14, the common electrodes 25 are formed.
Is formed in a substantially rectangular shape in a plan view extending along the long side of the piezoelectric sheet 22 so as to integrally cover the left and right pressure chambers 16, 16 across the center of the short side of the base plate 14. In the vicinity of a pair of short sides of the piezoelectric sheet 22, the lead portions 25a, 2 extending over substantially the entire length of the short side.
5a are integrally formed.

The same vertical position (corresponding position) as each of the individual electrodes 24a and 24b is located on the surface near the pair of long sides of the piezoelectric sheet 22 where the common electrode 25 is not formed. The individual electrodes 24a, 24
A dummy individual electrode 26 having a width substantially equal to b and a short length is formed. In this case, as shown in FIGS. 5 and 6, each dummy individual electrode 26 is separated from the common electrode 25 by an appropriate gap size.

On the other hand, on the upper surface (wide surface) of the piezoelectric sheet 21, a dummy common electrode 27 is provided at a position (the same vertical position, near the short side of the pair of piezoelectric sheets) corresponding to the lead portions 25 a, 25 a. It forms.

Each of the individual electrodes 24 is placed on the upper surface of the top sheet 23 along the edge of the long side thereof.
A surface electrode 30 for each of a and 24b and a surface electrode 31 for the common electrode 25 are provided.

Then, as shown in FIGS. 2 and 6, the side surfaces (surface electrodes 30, 3) of the laminated body of the piezoelectric actuator 20 are formed.
Long side edge 2 on the side surface orthogonal to the wide surface on which 1 is formed
0a side), side electrodes 32 and 33 are formed, and a surface electrode 30 is formed.
Are the individual electrodes 24a, 24 via the side electrodes 32.
The surface electrode 31 electrically connects the common electrode 25 and the dummy common electrode 27 via another side electrode 33 while electrically connecting the dummy electrode b to the dummy individual electrode 26. In this case, a concave groove exposing at least each of the drive electrodes (common electrode, individual electrode, etc.) is provided on a side surface (the long edge 20a side) of the piezoelectric actuator orthogonal to both front and back surfaces. A side electrode electrically connected to the drive electrode may be formed in the concave groove.

As will be described later, when laminating a plurality of material sheets 34, 38, 41, when cutting each size of piezoelectric sheet after lamination, and after separating each piezoelectric actuator 20, the side electrode 32 , 33, and further, when the piezoelectric actuator 20 is overlaid and fixed at a predetermined position on the cavity plate 10,
In order to use as a reference for positioning when fixing the flexible flat cable 40 on the upper surface of the piezoelectric actuator 20, the long side edge and the short side edge of each piezoelectric actuator 20 have a midpoint in the long side direction and the short side direction. Notches 42 ', 4 for positioning marks having a substantially semicircular shape in plan view at predetermined positions.
3 'is provided in advance (see FIGS. 1, 5 and 6). As will be described later, through holes 42 and 43 are drilled in advance at predetermined positions of the material sheets 34, 38 and 41, and when the piezoelectric actuators 20 are separated and cut, the through holes are also cut at the same time. As shown in FIG. 6, there are cutouts 42 'and 43' for semicircular positioning marks.

The above-structured piezoelectric actuator 20
Is manufactured by the method described below. That is, FIG.
As shown in FIG. 8, a plurality of piezoelectric sheets 21 in which individual electrodes 24a and 24b having a shape and an arrangement relationship as described later are formed on a surface of a first material sheet 34 made of a green sheet made of piezoelectric ceramics. The areas 35 are arranged in a matrix without any gap. In that case, the shape and arrangement of the individual electrodes 24 in one piezoelectric sheet 21 are as follows.

As shown in FIGS. 5 and 7, the individual electrodes 24a and 24b formed on one side of the piezoelectric sheet 21 are formed.
The two edge portions 21a, 2 of the piezoelectric sheet 21 parallel to the center line 36 from a position near the center line 36 on both sides of the center line 36 parallel to the staggered arrangement direction.
1a are formed in parallel rows at a constant interval P2 (the same interval as the arrangement pitch P2 of the pressure chambers 16) and are arranged in a row on one side (left side in FIG. 5) sandwiching the center line 36. The pattern of the individual electrodes 24a is formed so as to be linear and extend in a direction orthogonal to one of the edge portions 21a of the piezoelectric sheet.

The pattern of the individual electrodes 24b in the row on the other side (right side in FIG. 5) sandwiching the center line 36 is such that the individual electrodes 24a in the row on one side are closer to the center line 36.
At a staggered position shifted by a half of the predetermined interval P2, extending in a direction orthogonal to the center line 36, and extending in the longitudinal direction of the individual electrode 24b.
Bend at c. Further, the individual electrodes 24a in the row on one side are orthogonal to the other of the edge portions 21a of the piezoelectric sheet 21 corresponding to the positions on the one edge portion 21a side of the piezoelectric sheet 21. It is formed so as to extend in the direction. The straight portion of the center line 36 near the halfway portion 24c bent in the individual electrode 24 is the pressure chamber 1
It is in the position corresponding to 6.

Then, as shown in FIG. 7 and FIG.
The first material sheet 34 constituting the first material sheet 1 has at least the long sides of the piezoelectric sheet 21 facing each other (in FIG. 7, the side connecting K1 and M1 and the side connecting K2 and M2; in FIG. 8, the side connecting M1 and N1). One of two sides (referred to as a side connecting M2 and N2) is adjacent to each other, and the regions 35 of the plurality of piezoelectric sheets 21 are formed side by side. In FIG. 7, each area 35
Are the four points K1, K2, M2, M1 and K2, K3, M
It is indicated by a rectangular range surrounded by four points of 3 and M2, respectively. In FIG. 8, since the piezoelectric sheets 21 are arranged in a plurality of rows in two stages with respect to the first material sheet 34, the area 35 has four points K1, K2, M2, M1 and K2, K3, M3, M2, M1, M2, N2
It is indicated by a rectangular range surrounded by four points of N1 and four points of M2, M3, N3, and N2.

In the example shown in FIG. 7, the left area 35a and the right area 35b are adjacent to each other at (K2-M2).
In the left region 35a, the individual electrodes 24a and 24b are connected to both sides of the region 35a (for example, K1-M1 and K2-M
2) are formed in parallel rows at a constant interval P2 so as to extend from the position near the center line 36 on both sides of the center line 36 parallel to the both sides to the both sides of the area 35a. . One side (K1-M) sandwiching the center line 36
The pattern of the individual electrodes 24a in the row on the side closer to the side 1 is linear and one side (K1-M1) of the region 35a.
It is formed so as to extend in a direction orthogonal to 1).

The other side of the center line 36 (K2-M
The pattern of the individual electrodes 24b in the row (closer to the side 2) is a zigzag pattern in which the individual electrodes 24a in the row closer to the center line 36 are shifted from the individual electrodes 24a in the one side by half of the fixed interval P2. And extends in a direction orthogonal to the center line 36, and is bent at a longitudinal middle portion 24c of each individual electrode 24b.
M2), the region 35b is connected to the end of the individual electrode 24a in the one side row in the adjacent region 35b.
(For example, K2-M2).

Printing of the individual electrodes 24a, 24b on the first material sheet 34 due to the notches 42 ', 43' for positioning marks provided at predetermined positions in the long side direction and the short side direction of each piezoelectric actuator 20. Before or simultaneously with the formation, through holes 42 and 43 are formed at corresponding positions.

In the embodiment, through holes 42 and 43 are formed at the midpoint of each long side and each short side of each area of the piezoelectric sheet 21. Further, when a plurality of regions are formed on the first material sheet 34 without gaps or when the regions are separated by the long side and the short side, the region extends over the adjacent region and over each side. Through holes 42 and 43 are provided (see FIGS. 7 and 8). These through holes 4
The shapes of 2, 43 may be circular or elliptical in plan view of the piezoelectric sheet, or other shapes.

As described above, the linear individual electrodes 2
4a and the individual electrode 2 having the bending part 24c
4b are formed point-symmetrically, at the midpoint of each long side of each region, the distance between adjacent individual electrodes 24a and 24b is 1.5 times the constant distance P2. Therefore, a through hole 43 having a diameter as large as possible (in the embodiment, a diameter of 50 μm to 150 μm) can be formed, and a notch 43 ′ for a positioning mark having a notch having a large diameter can be formed. As a result, there is an effect that the later image recognition becomes easy.

Further, as shown in FIG.
In the same manner as the piezoelectric sheet 21 described above, the regions of the plurality of piezoelectric sheets 22 are formed side by side on the material sheet 38 constituting.
In FIG. 7, K1, K2, M
2 and M1 and a range surrounded by four points K2, K3, M3, and M2. A common electrode 25 and a dummy individual electrode 26 are formed in each region. Each dummy individual electrode 26 located on both sides of the common electrode 25 includes an individual electrode 24a, 24.
b, that is, a shape corresponding to the upper and lower sides, that is, a straight shape on one side and a bent shape on the other side, extending orthogonal to the long side between adjacent regions, and connecting to the dummy individual electrode 26 in the adjacent region. I have.

Similarly, on the third material sheet 41, a plurality of regions of the top sheet 23 are formed side by side, and the surface electrodes 30 and
31 is formed so as to straddle a long side between adjacent regions. The second and third material sheets 38 and 41 are laminated, and through holes 42 and 43 are formed at the same positions as described above. Thereafter, the material sheets 34, 38 and 41 are laminated and then integrated by pressing in the laminating direction to form one laminated body. Then, it is fired.

After firing, the vertical cutting lines 37a, 37b, 37c and the horizontal cutting lines 39a, 3c are set so that the long side and the short side of each of the piezoelectric sheets are provided for each of the regions 35a, 35b.
9B, each piezoelectric actuator 20 is created by being divided.

In these cases, each of the vertical cutting lines 37a, 37
When the material sheet is cut (divided) by a dicing cutter that rotates at high speed along the cutting lines 7b and 37c and the horizontal cutting lines 39a and 39b, as described above, the linear individual electrodes 2 are cut.
4a and the individual electrode 24b bent at the intermediate portion 24c are formed in a pattern so as to be continuous, the second material sheet 38 on which the common electrode 25 is formed later and the top sheet 2
When the material sheet is cut along each of the vertical cutting lines 37a, 37b, and 37c after being integrated with the third material sheet 41, which becomes the third material sheet 41, the individual electrodes 24a, Since the end of 24b is reliably exposed, electrical connection with the later side electrodes 32 and 33 can be ensured.
Further, since no discarded portion is generated between the adjacent regions 35a and 35b, there is an effect that the efficiency of material removal is greatly improved.

The vertical cutting lines 37a, 37b,
When cut along the cutting line 37c and the horizontal cutting lines 39a and 39b, the positions of the through holes 42 and 43 are in a half-split state.
As shown in FIG. 6, notches 42 'and 43' for semicircular positioning marks are formed.
3 'are substantially aligned in the laminating direction of the piezoelectric sheets (FIG. 6).
reference). For this purpose, the plurality of piezoelectric sheets 21,
At the time of stacking work of 22, 23, the through hole 42,
It is preferable to perform image recognition of 43 and position it.

In the embodiment shown in FIGS. 7 and 8, the individual electrodes 24a and 24b on the left and right sides of the piezoelectric sheet 21 are used.
Is formed point-symmetrically with respect to the center of each of the regions 35a and 35b in plan view. In other words, the linear individual electrode 24a is positioned diagonally on the long side with respect to the intersection of the center line 36 and the line connecting the through holes 43 for the positioning marks at the midpoint of the long side. If a row is formed, a row of individual electrodes 24b having a bent middle portion 24c is formed at the opposite diagonal position.

When a large number of piezoelectric sheets are laminated on the basis of the through hole 43 at the midpoint of the long side as described above, the material sheet is shrunk in the long side direction after firing. And the position error of the individual electrodes 24a and 24b can be further reduced.

In the embodiment shown in FIG. 8, since the piezoelectric sheets 21 formed on the first material sheet are arranged in two rows and a plurality of rows (for example, six rows), 12 pieces are taken. The cutting lines 37a, 37b, 37c} increase and extend, and the horizontal cutting lines also become 39a, 39b, 39c.
It becomes three. Also, if cut off at the horizontal cutting line 39b,
The first and second dummy common electrodes 27, 27 are automatically formed.

The individual electrodes 24a, 24b, the dummy individual electrodes 26, 26, the common electrode 25, and the dummy common electrode 27 are, of course, formed by screen printing of a conductive paste.

The plate-type piezoelectric actuator 20 having the above-described structure is provided with the cavity plate 1.
0, the individual electrodes 24a and 24b of the piezoelectric actuator 20 are
(See FIGS. 1, 9 and 10) so as to correspond to each of the pressure chambers 16 in FIG. In this case, on the upper surface of the base plate 14 of the cavity plate 10, long grooves 45 and 46 are formed.
5 is a side electrode 3 corresponding to the individual electrodes 24a and 24b.
The lower end of the second row faces the common electrode 2 on the concave groove 46.
It is preferable that the lower ends of the side electrodes 33 at the four corners corresponding to 5 face each other so that the side electrodes 32 and 33 do not directly contact the conductive base plate 14.

The flexible flat cable 40 is overlaid and pressed on the upper surface of the piezoelectric actuator 20, so that various wiring patterns (not shown) of the flexible flat cable 40 are applied to the respective surface electrodes. 30 and 31 are electrically connected.

In this configuration, of the individual electrodes 24 in the piezoelectric actuator 20, any individual electrode 2
4 and the common electrode 25, a voltage is applied to the individual electrodes 24a and 24b of the piezoelectric sheet 22, which causes distortion in the stacking direction due to piezoelectricity. When the internal volume of the pressure chamber 16 corresponding to each of the individual electrodes 24 and 24b is reduced, the ink in the pressure chamber 16 is ejected from the nozzle 15 in the form of droplets, and predetermined printing is performed (FIG. 11).

Between the dummy individual electrode 26 and the individual electrode 24,
Since the potential is the same between the dummy common electrode 27 and the common electrode lead portion 25a, the piezoelectric sheet therebetween is not displaced. Dummy individual electrode 26, dummy common electrode 27
Is for correcting unevenness due to the thickness of the individual electrode 24 and the common electrode 25 when the piezoelectric sheets are stacked.

The piezoelectric actuator laminate was immersed in a plating solution.
A metal plating layer may be formed on the surface of each of the surface electrodes 30 and 31 by applying an electric current to the surface electrode 31 through a narrow electrode pattern to perform electroplating. The metal plating layer is, for example, formed by forming a gold plating layer on a nickel plating layer as a base. By forming the metal plating layer, the surface electrodes 30, 31 of each wiring pattern in the flexible flat cable 40 are formed. Can greatly improve the electrical bondability to the substrate.

According to the present invention, a plurality of material sheets 34, 38,
The through-holes 42 and 43 are formed in advance in 41, and the through-holes 42 and 43 are formed even when different types of piezoelectric sheets are stacked or cut or divided for each piezoelectric sheet (each area). It becomes extremely easy to work as a reference for positioning.

Furthermore, if the through holes 42 and 43 are formed so as to straddle a cutting line (area or side of the piezoelectric sheet) for dividing the area, even if the through hole has a relatively small diameter, the adjacent area may not be formed. Notch portions 42 ', 43' for positioning marks can be provided simultaneously in the two regions by one through hole 42 (43), so that the work of creating the positioning marks can be omitted.

Since the pair of edges of the notch portions 42 ', 43' for positioning marks on one side of the piezoelectric actuator 20 are formed longer in the thickness direction of the piezoelectric sheet, the image is formed from the thickness direction of the piezoelectric actuator 20. It becomes easy to recognize.
Therefore, as shown in FIG. 9, when the number of stacked piezoelectric sheets 21 and 22 is large, the average value of the lateral displacement of the pair of notches 43 ′ arranged vertically is calculated and the notch is calculated. Part 4
It is also possible to accurately determine the position (coordinate) of 3 '. Such position determination is performed by using the notches 42 ',
3 ', so that each piezoelectric actuator 2
When the side electrodes 32 and 33 are formed after separation at every 0, and when the piezoelectric actuator 20 is further overlapped and fixed at a predetermined position of the cavity plate 10, the flexible flat cable 40 is fixed to the upper surface of the piezoelectric actuator 20. It is extremely easy to use the reference for positioning at that time, and the fixed position can be determined accurately. In particular, when the number of the individual electrodes 24a, 24b and the dummy individual electrodes 26, 26 arranged along the long side edge of the piezoelectric element is large and the arrangement interval is small (for example, when the width is 1).
When individual electrodes of about 50 μm are arranged at a pitch of 200 μm, etc.), the alignment when aligning the individual electrodes and the dummy individual electrodes in one row in the laminating direction becomes accurate.

The notch portions 42 ', 43' for the positioning marks are provided especially between the arrangement of the individual electrodes 24a, 24b and the dummy individual electrodes 26, 26. Can be eliminated. By providing a total of four notches 43 'and 42' at two long sides and two short sides of the piezoelectric actuator 20, for example, the piezoelectric actuator 20 is arranged at a predetermined position on the upper surface of the cavity plate 10. At the time of fixing, the orientation of the long side and the short side of the piezoelectric actuator 20 and the relative positional relationship to the cavity plate 10 can be easily recognized by an image recognition device (not shown). Further, when the flexible flat cable 40 is put on the upper surface of the piezoelectric actuator 20 and fixed,
4 from above the flexible flat cable 40
When it is not possible to recognize the notches 42 ′ and 43 ′ as marks of all the positions, positioning can be performed by recognizing one to three marks.

In the present invention, the individual electrodes 24 a and 24 a are arranged such that the lowermost piezoelectric sheet having the common electrode 25 faces the base sheet 14 in the cavity sheet 10.
It is needless to say that the present invention can be applied to the case where the stacking order of the layer 24b and the common electrode 25 is changed.

[0060]

As described above, according to the first aspect of the present invention,
The piezoelectric actuator according to the invention described in (1), a cavity plate provided with a plurality of pressure chambers for each of a plurality of nozzles in a row, and a piezoelectric sheet having a surface on which a pattern of a drive electrode to be driven for each of the pressure chambers is formed. And a piezoelectric actuator comprising: a piezoelectric actuator comprising: a piezoelectric actuator; and a drive electrode of the piezoelectric actuator laminated on the cavity plate so as to correspond to each pressure chamber. Among the drive electrodes, the piezoelectric sheet on which the rows of individual electrodes are formed and the piezoelectric sheet on which the common electrode is formed include a long side edge and a short side edge of each piezoelectric sheet. Notches for positioning marks are respectively provided at predetermined positions in the direction, and the respective notches are configured to be substantially aligned in the stacking direction. It is intended.

Accordingly, since the pair of edges of the notch are formed longer in the thickness direction of the piezoelectric sheet, it becomes easier to recognize an image from the thickness direction of the piezoelectric actuator. Further, when the number of stacked piezoelectric sheets is large, the average value of the lateral displacement of the edges of the pair of cutouts arranged vertically is calculated to accurately determine the position (coordinates) of the cutout. Is also possible,
When forming side electrodes after separating each piezoelectric actuator, further, when bonding and fixing the piezoelectric actuator at a predetermined position on the cavity plate, and when fixing a flexible flat cable to an external circuit on the top surface of the piezoelectric actuator This makes it extremely easy to use as a reference for positioning, and the fixing position can be determined accurately.

Further, the invention described in claim 2 is the same as that in claim 1
Wherein the notch for the positioning mark is provided at a long side edge and a short side edge of each of the piezoelectric sheets, and at a midpoint in each side direction, respectively. It is. In this way, even if the piezoelectric sheet shrinks in the side direction due to the firing of the piezoelectric actuator, the positional deviation error of the individual electrodes when the layers are stacked with reference to the cutout portion at the midpoint of the side is reduced, In addition to the effect of the first aspect of the present invention, there is an effect that positioning can be accurately performed in a subsequent step.

According to a third aspect of the present invention, in the piezoelectric actuator according to the first or second aspect, each of the individual electrodes formed on one surface of the one piezoelectric sheet is aligned with the arrangement direction of the nozzle. On both sides of the parallel center line, are formed in parallel rows at a constant interval from each other to extend from the position near the center line to the long side edge of the piezoelectric sheet parallel to the center line, On one surface of the other piezoelectric sheet, the common electrode is formed at a central portion sandwiching the center line, and a dummy individual electrode extending to a long side edge portion of the piezoelectric sheet is formed appropriately separated from the common electrode. The piezoelectric sheet is formed by alternately stacking the one piezoelectric sheet and the other piezoelectric sheet.

As described above, when the piezoelectric sheets having the individual electrodes and the piezoelectric sheets having the dummy individual electrodes are alternately laminated, even if the width dimension and the arrangement interval of these electrodes are small and the number of these electrodes is large, these electrodes are small. This has the effect that the electrodes can be accurately aligned in one row and one straight line along the lamination direction, and the position can be accurately fixed to other components (such as a cavity plate).

According to a fourth aspect of the present invention, in the piezoelectric actuator according to any one of the first to third aspects, the pattern of the individual electrodes in one side of the row sandwiching the center line is linear. And formed so as to extend in a direction perpendicular to one of the edge portions of the piezoelectric sheet,
The pattern of the individual electrodes in the row on the other side sandwiching the center line is in a zigzag arrangement at a position close to the center line and shifted from the individual electrodes in the row on one side by half the fixed interval. Extending in a direction orthogonal to the center line, and bending at a longitudinally intermediate portion of each individual electrode, and furthermore, at one end edge side of the piezoelectric sheet in the one side row of individual electrodes. Corresponding to the position, the piezoelectric sheet is formed so as to extend in a direction perpendicular to the other of the edge portions, and at a center position of the center line, a pattern of the individual electrodes in the row on one side, The pattern of the individual electrodes in the other row is formed in a point-symmetrical manner, and the notch formed in the long side edge is located between the patterns of the individual electrodes. It was done.

Therefore, according to the above configuration, the interval between the individual electrode having the bent portion in the middle and the linear individual electrode is slightly widened. In addition to the effects of the invention described above, there is an effect that a notch can be provided at a location of the wide interval so as not to touch the individual electrode.

On the other hand, a method of manufacturing a piezoelectric actuator according to a fifth aspect of the present invention provides a method of manufacturing a piezoelectric actuator, wherein at least one of two opposing sides of the piezoelectric sheet is adjacent to a material sheet constituting the piezoelectric sheet in the piezoelectric actuator. , A plurality of regions of the piezoelectric sheet are arranged side by side, and in each region,
The individual electrodes are arranged in parallel rows at regular intervals so as to extend from the position near the center line to the two sides of the region on both sides of the center line parallel to the two sides between the two sides of the region. Formed and a notch for the positioning mark,
It is characterized in that it is formed at a predetermined position on a line of each side of the region with a through hole having a size that straddles each side, and is divided into the region along with the through hole along the four sides. is there.

Therefore, when dividing into regions, the portion of the through hole can be divided at the same time, and the divided portion becomes a notch having a long edge in the thickness direction of the piezoelectric sheet.
Even after being integrated as a piezoelectric actuator, the positioning mark becomes clear as a positioning mark, and there is an effect that the positioning operation for fixing the piezoelectric actuator to other parts can be performed accurately and easily in addition to the operation of accumulating the piezoelectric sheets.

The invention according to claim 6 is the same as the invention according to claim 5
In the method for manufacturing a piezoelectric actuator according to the above, the through hole is on a line intersecting the center line,
At the intersection of the two sides in the direction intersecting with the two sides at the center position of two sides and the extension of the center line in each of the piezoelectric sheets, the piezoelectric sheet is provided so as to straddle each side. It is characterized by the following.

By providing the through holes at such positions, notches can be easily formed on the four sides of the piezoelectric sheet, and each notch is located at the midpoint between the long side and the short side of the piezoelectric sheet. Even if there is a contraction in the side direction of the piezoelectric sheet due to the firing of the piezoelectric actuator, the displacement error of the individual electrodes when laminating based on the notch at the midpoint of the side is reduced. In addition to the effects of the described invention, there is an effect that positioning can be accurately performed in a later step.

According to a seventh aspect of the present invention, in the method for manufacturing a piezoelectric actuator according to the fifth or sixth aspect, since the area of each of the piezoelectric sheets is formed in a rectangular shape in plan view, the rectangular material sheet is formed. Thus, the number of piezoelectric sheets to be removed from the substrate can be increased, and the area of the waste portion can be reduced, thereby improving the efficiency of removing the material.

According to an eighth aspect of the present invention, in the method of manufacturing a piezoelectric actuator according to any one of the fifth to seventh aspects, the pattern of the individual electrodes in one side of the row sandwiching the center line is a straight line. And is formed so as to extend in a direction perpendicular to one side of the region, and the pattern of the individual electrodes in the row on the other side sandwiching the center line is formed on the one side on the side close to the center line. At a staggered position shifted from the individual electrodes in the row by half of the predetermined interval, extends in a direction orthogonal to the center line of the region, and bends at a longitudinal middle part of each individual electrode, After being formed so as to extend in a direction orthogonal to the other side of the region so as to be connected to the end of the individual electrode of the row on one side in the region adjacent on the side, Divide the material sheet It is characterized in creating a conductive sheet.

Therefore, the distance between the individual electrode having the bent portion in the middle and the linear individual electrode is slightly widened, so that the effects of the fifth to seventh aspects can be obtained. In addition, there is an effect that through holes can be provided at the above-mentioned wide intervals so as not to touch the individual electrodes.

Further, according to a ninth aspect of the present invention, in the method of manufacturing a piezoelectric actuator according to any one of the fifth to eighth aspects, the one side of the piezoelectric actuator is positioned at a center position of a center line of each of the regions. Patterns of individual electrodes in a row,
The pattern of the individual electrodes in the other row is formed in a point-symmetrical manner, and at least one side of an adjacent region is connected without a break. Either the number of piezoelectric sheets taken from the material sheet is increased, or the size of the original material sheet can be reduced for a given number of piezoelectric sheets, resulting in a significant improvement in material removal efficiency. To play.

Further, since there is no need for a cutting line for forming the discarded portion, the number of cutting steps is reduced, and the production efficiency can be greatly improved.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a piezoelectric inkjet printer head according to an embodiment of the present invention.

FIG. 2 is an enlarged perspective view showing one end of a cavity plate and a piezoelectric actuator.

FIG. 3 is an exploded perspective view of a cavity plate.

FIG. 4 is a partially enlarged perspective view of a cavity plate.

FIG. 5 is an exploded perspective view of the piezoelectric actuator.

FIG. 6 is a perspective view of a piezoelectric actuator.

FIG. 7 is a perspective view showing a pattern of an individual electrode, a common electrode, a surface electrode, a notch and the like on a material sheet of a piezoelectric actuator.

FIG. 8 is a plan view showing patterns of individual electrodes and cutouts in a material sheet, and cutting lines and the like of regions.

FIG. 9 is an enlarged perspective view of a main part showing the arrangement relationship of notches in another embodiment.

FIG. 10 is an enlarged sectional view taken on line XX of FIG. 1;

FIG. 11 is an enlarged sectional view showing a state in which a flexible flat cable, a cavity plate, and a piezoelectric actuator are stacked.

FIG. 12 is an enlarged perspective view of a main part showing a positioning mark in a conventional piezoelectric actuator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Cavity plate 11 Nozzle plate 12 Manifold plate 13 Spacer plate 14 Base plate 15 Nozzle 16 Pressure chamber 20 Piezoelectric actuator 21, 22 Piezoelectric sheet 23 Top sheet 24a, 24b Individual electrode 24c Midway 25 Common electrode 26 Dummy individual electrode 27 Dummy common electrode 30, 31 Surface electrode 32, 33 Side electrode 34 First material sheet 35a, 35b Area 40 Flexible flat cable 37a, 37b, 37c Vertical cutting line 39a, 39b, 39c Vertical cutting line 42, 43 Through hole 42 ', 43' Positioning Notch for mark

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 41/22

Claims (9)

[Claims] 1. A piezoelectric actuator comprising: a cavity plate having a plurality of pressure chambers for each of a plurality of nozzles arranged in a row; and a piezoelectric sheet having a pattern of drive electrodes for driving each of the pressure chambers formed on a surface thereof. And a piezoelectric actuator in a piezoelectric ink jet printer head, wherein the piezoelectric actuator is laminated on the cavity plate so that each drive electrode of the piezoelectric actuator corresponds to each pressure chamber. Of these, the piezoelectric sheet on which the rows of individual electrodes are formed and the piezoelectric sheet on which the common electrode is formed have a predetermined position in the direction of each side at the long side edge and the short side edge of each piezoelectric sheet. A piezoelectric element, wherein notches for positioning marks are provided, and the notches are substantially aligned in the laminating direction. Actuator. 2. The notch for the positioning mark is provided at a long side edge and a short side edge of each of the piezoelectric sheets, and at a midpoint in each side direction. The piezoelectric actuator according to claim 1, wherein 3. Each of the individual electrodes formed on one surface of the one piezoelectric sheet is positioned on both sides of a center line parallel to the direction in which the nozzles are arranged. The piezoelectric sheets are formed in parallel rows at regular intervals so as to extend to the long side edges of the parallel piezoelectric sheets, and the common electrode is formed on one surface of the other piezoelectric sheet at a central portion sandwiching the center line. And a dummy individual electrode extending to the long side edge of the piezoelectric sheet at an appropriate distance from the common electrode, wherein the one piezoelectric sheet and the other piezoelectric sheet are alternately laminated. The piezoelectric actuator according to claim 1 or 2, wherein 4. The pattern of individual electrodes in a row on one side sandwiching the center line is formed so as to be linear and extend in a direction orthogonal to one of the edge portions of the piezoelectric sheet. The pattern of the individual electrodes in the row on the other side sandwiching the line is located in a staggered position shifted from the individual electrodes in the row on one side on the side close to the center line by half of the fixed interval, It extends in a direction orthogonal to the center line, and is bent at a middle part in the longitudinal direction of each individual electrode, and further, a position of the piezoelectric sheet in the one side row of the individual electrodes on the one edge side of the piezoelectric sheet. Corresponding to the edge of the piezoelectric sheet is formed so as to extend in a direction orthogonal to the other, and at the center position of the center line, the pattern of the individual electrodes in the row on one side and the other Of the individual electrodes in the side row The turn and the turn are formed in point symmetry, The notch formed in the said long side edge part is located between the pattern of both said individual electrodes, The Claims 1 thru | or 3 characterized by the above-mentioned. The piezoelectric actuator according to any one of the above. 5. A plurality of piezoelectric sheet regions are formed side by side on a material sheet constituting a piezoelectric sheet in a piezoelectric actuator, with at least one of two opposing sides of the piezoelectric sheet being adjacent to each other. The individual electrodes are parallel to each other at regular intervals so as to extend from the position close to the center line to the two sides of the region on both sides of the center line parallel to the two sides between the two sides of the region. Formed in a row, a notch for a positioning mark is formed at a predetermined position on a line of each side of the region with a through hole sized to straddle each side, and the through-hole is formed along the four sides. A method of manufacturing a piezoelectric actuator, comprising dividing each of the regions together with a hole. 6. The piezoelectric device according to claim 6, wherein the through hole is on a line intersecting the center line, and is located at a center position of two sides of each of the piezoelectric sheets and another direction intersecting the two sides on an extension of the center line. The method for manufacturing a piezoelectric actuator according to claim 5, wherein the piezoelectric actuator is provided so as to have a size that straddles each side at an intersection between the two sides. 7. The method according to claim 5, wherein the area of each of the piezoelectric sheets is formed in a rectangular shape in a plan view. 8. A pattern of individual electrodes in a row on one side sandwiching the center line is formed so as to be linear and extend in a direction orthogonal to one side of the region, and the other electrode sandwiching the center line is provided. The pattern of the individual electrodes in the row on the side of the side is located in a staggered position shifted from the individual electrodes in the row on the one side by half of the fixed interval on the side close to the center line, and the center of the region is A region extending in a direction perpendicular to the line, and bending at a middle portion in a longitudinal direction of each individual electrode, and further connected to an end of the individual electrode of the one side row in a region adjacent on the side. 8. The piezoelectric sheet according to claim 5, wherein the material sheet is formed so as to extend in a direction orthogonal to the other side of the sheet, and then the material sheet is divided for each of the regions. Manufacture of piezoelectric actuator described in Law. 9. A pattern of the individual electrodes in the one side row and a pattern of the individual electrodes in the other side row are formed point-symmetrically at a center position of a center line of each of the regions, and The method for manufacturing a piezoelectric actuator according to any one of claims 5 to 8, wherein at least one side of adjacent regions is connected without a break.