JP6708523B2 - Piezoelectric substrate, liquid ejection head using the same, and recording device - Google Patents

Description

The present disclosure relates to a piezoelectric substrate, a liquid ejection head using the same, and a recording device.

As a liquid ejection head that ejects a liquid, there is known a liquid ejection head configured by laminating a piezoelectric actuator substrate and a flow path member having a discharge chamber and a pressure chamber connected to the discharge hole (for example, Patent Document 1). See 1.). The piezoelectric actuator substrate described in Patent Document 1 is provided with an individual electrode that drives a piezoelectric element that pressurizes the liquid in the pressurizing chamber. The individual electrode is composed of an individual electrode body that overlaps with the pressurizing chamber and an extraction electrode that is extracted from the individual electrode body, and the extraction electrode is extracted in the same direction with respect to the individual electrode body. ..

JP, 2003-311953, A

The piezoelectric substrate of the present disclosure has a plurality of piezoelectric elements and a first surface, and a plurality of individual electrodes forming a part of each of the plurality of piezoelectric elements are arranged on the first surface. On the first surface, a plurality of individual electrode rows in which the individual electrodes are arranged at predetermined intervals in the third direction are arranged in a first direction that is a direction intersecting with the third direction. The individual electrode includes an individual electrode main body and an extraction electrode drawn from the individual electrode main body, and the extraction electrode is provided in the individual electrode from the individual electrode main body in the first direction side. There is a first individual electrode that is drawn out and a second individual electrode that is drawn out from the individual electrode body toward the second direction side that is the opposite direction of the first direction, and at least one In the individual electrode row, two first individual electrodes and one second individual electrode are alternately arranged.

In addition, the liquid discharge head of the present disclosure includes a piezoelectric substrate, a plurality of discharge holes that are bonded to the piezoelectric substrate on a surface opposite to the first surface, and that correspond to the plurality of piezoelectric elements. And a flow path member having.

Further, the recording apparatus of the present disclosure is characterized by including a liquid ejection head, a conveyance section that conveys a recording medium to the liquid ejection head, and a control section that controls the piezoelectric substrate.

(A) is a side view of a recording apparatus including a liquid ejection head according to an embodiment of the present disclosure, and (b) is a plan view. FIG. 1A is a plan view of a head body that constitutes the liquid ejection head of FIG. 1, and FIG. 1B is a plan view of a wiring board attached to the head body of FIG. FIG. 3 is an enlarged view of a region surrounded by a one-dot chain line in FIG. 2A, and is a plan view in which some flow paths are omitted for explanation. FIG. 3 is an enlarged view of a region surrounded by a dashed line in FIG. FIG. 5 is a vertical sectional view taken along the line VV of FIG. 3. 3A is a further enlarged part of the head main body of FIG. 3, and FIG. 3B is a plan view of a portion of the wiring board corresponding to the portion indicated by the alternate long and short dash line in FIG. 6A is another embodiment of a part of the structure of FIG. 6A, and FIG. 6B is a plan view of a wiring board corresponding to FIG. (A) is a top view of the individual electrode of a reference example. (B) is a plan view of a wiring board of a reference example of a portion corresponding to (a).

FIG. 1A is a schematic side view of a color inkjet printer 1 (hereinafter may be simply referred to as a printer) that is a recording apparatus including a liquid ejection head 2 according to an embodiment of the present disclosure. (B) is a schematic plan view. The printer 1 moves the printing paper P relative to the liquid ejection head 2 by carrying the printing paper P, which is a recording medium, from the guide roller 82A to the carrying roller 82B. The control unit 88 controls the liquid ejection head 2 based on the image or character data to eject the liquid toward the printing paper P, land the droplets on the printing paper P, and print on the printing paper P. Etc. are recorded.

In this embodiment, the liquid ejection head 2 is fixed to the printer 1, and the printer 1 is a so-called line printer. As another embodiment of the recording apparatus of the present disclosure, an operation of moving the liquid ejection head 2 by reciprocating in a direction intersecting the conveyance direction of the printing paper P, for example, a direction substantially orthogonal thereto, and the printing paper P. There is a so-called serial printer that alternately carries the above-mentioned conveyance.

A flat plate-shaped head mounting frame 70 (hereinafter sometimes simply referred to as a frame) is fixed to the printer 1 so as to be substantially parallel to the printing paper P. The frame 70 is provided with 20 holes (not shown), 20 liquid ejection heads 2 are mounted in the respective holes, and the portion of the liquid ejection head 2 that ejects liquid is the printing paper P. To face. The distance between the liquid ejection head 2 and the printing paper P is, for example, about 0.5 to 20 mm. The five liquid ejection heads 2 form one head group 72, and the printer 1 has four head groups 72.

The liquid ejection head 2 has a long and slender shape in the direction from the front to the back in FIG. 1A, and the vertical direction in FIG. This long direction may be called the longitudinal direction. In one head group 72, the three liquid ejection heads 2 are arranged along a direction intersecting the conveyance direction of the printing paper P, for example, a direction substantially orthogonal to each other, and the other two liquid ejection heads 2 are conveyed. One is arranged between each of the three liquid ejection heads 2 at positions displaced along the direction. The liquid discharge heads 2 are arranged such that the printable range of each liquid discharge head 2 is connected in the width direction of the print paper P (in the direction intersecting the transport direction of the print paper P) or the ends overlap. Therefore, it is possible to perform printing without a gap in the width direction of the printing paper P.

The four head groups 72 are arranged along the conveyance direction of the printing paper P. A liquid, for example, ink, is supplied to each liquid ejection head 2 from a liquid tank (not shown). Ink of the same color is supplied to the liquid ejection heads 2 belonging to one head group 72, and four head groups 72 can print four colors of ink. The colors of ink ejected from each head group 72 are, for example, magenta (M), yellow (Y), cyan (C), and black (K). A color image can be printed by controlling and printing such ink with the control unit 88.

The number of the liquid ejection heads 2 mounted on the printer 1 may be one as long as it is monochrome and prints within a printable range with one liquid ejection head 2. The number of liquid ejection heads 2 included in the head group 72 and the number of head groups 72 can be appropriately changed depending on the printing target and printing conditions. For example, the number of head groups 72 may be increased in order to perform printing in more colors. If a plurality of head groups 72 that print in the same color are arranged and printed alternately in the transport direction, the transport speed can be increased even if the liquid ejection heads 2 having the same performance are used. As a result, the printing area per unit time can be increased. Further, a plurality of head groups 72 for printing with the same color may be prepared and arranged in a staggered manner in the direction intersecting the transport direction to increase the resolution in the width direction of the printing paper P.

Further, in addition to printing colored ink, a liquid such as a coating agent may be printed in order to surface-treat the printing paper P.

The printer 1 prints on a printing paper P which is a recording medium. The printing paper P is wound around the paper feed roller 80A, passes between the two guide rollers 82A, then passes under the liquid ejection head 2 mounted on the frame 70, and then It passes between the two conveying rollers 82B and is finally collected by the collecting roller 80B. At the time of printing, by rotating the carry roller 82B, the print paper P is carried at a constant speed and printed by the liquid ejection head 2. The collecting roller 80B winds the printing paper P sent out from the carrying roller 82B. The transport speed is, for example, 75 m/min. Each roller may be controlled by the controller 88 or may be manually operated by a person.

The recording medium may be a roll-shaped cloth or the like other than the printing paper P. Further, the printer 1 may directly convey the conveyance belt and place the recording medium on the conveyance belt instead of directly conveying the printing paper P. By doing so, a sheet, cut cloth, wood, tile or the like can be used as the recording medium. Further, the wiring pattern of the electronic device may be printed by ejecting the liquid containing the conductive particles from the liquid ejection head 2. Furthermore, a chemical agent may be produced by ejecting a predetermined amount of a liquid chemical agent or a liquid containing the chemical agent from the liquid ejection head 2 toward a reaction container or the like to cause a reaction.

Further, a position sensor, a speed sensor, a temperature sensor, or the like may be attached to the printer 1, and the control unit 88 may control each unit of the printer 1 according to the state of each unit of the printer 1 which is known from the information from each sensor. .. For example, the temperature of the liquid ejection head 2, the temperature of the liquid in the liquid tank, the pressure applied by the liquid in the liquid tank to the liquid ejection head 2, and the like affect the ejection characteristics such as the ejection amount and ejection speed of the ejected liquid. When the liquid is being supplied, the drive signal for ejecting the liquid may be changed according to the information.

Next, the liquid ejection head 2 according to an embodiment of the present disclosure will be described. FIG. 2A is a plan view showing the head body 13 which is a main part of the liquid ejection head 2 shown in FIG. FIG. 2B is a plan view of the wiring substrate 60 of the head body 13 that is electrically bonded to the piezoelectric actuator substrate 21. FIG. 3 is an enlarged plan view of the area surrounded by the alternate long and short dash line in FIG. 2A, showing a part of the head body 13. FIG. 4 is an enlarged plan view of the same position as in FIG. In FIGS. 3 and 4, some of the flow paths are omitted for clarity. Further, in FIGS. 3 and 4, the pressurizing chamber 10, the squeeze 12, the discharge hole 8 and the like, which are located below the piezoelectric actuator substrate 21 and should be drawn by broken lines, are drawn by solid lines in order to make the drawings easy to understand. FIG. 5 is a vertical cross-sectional view taken along the line VV of FIG. FIG. 6A is a further enlarged part of the head main body 13 of FIG. 3, and FIG. 6B is a plan view of the wiring board 60 corresponding to FIG. 6A.

The head main body 13 has a flat plate-shaped flow path member 4 and a piezoelectric actuator substrate 21 which is a piezoelectric substrate on the flow path member 4. The flow path member 4 is formed by stacking a nozzle plate 31 having the discharge holes 8 and a flow path member body in which the plates 22 to 30 are stacked. The head body 13 may further include a wiring board 60 that transmits a drive signal that drives the piezoelectric actuator board 21.

The piezoelectric actuator substrate 21 has a trapezoidal shape, and is arranged on the upper surface of the flow path member 4 so that a pair of parallel opposing sides of the trapezoid are parallel to the longitudinal direction of the flow path member 4. Further, two piezoelectric actuator substrates 21 are arranged along each of two virtual straight lines parallel to the longitudinal direction of the flow path member 4, that is, a total of four piezoelectric actuator substrates 21 are arranged on the flow path member 4 in a zigzag manner. There is. The oblique sides of the adjacent piezoelectric actuator substrates 21 on the flow path member 4 partially overlap each other in the lateral direction of the flow path member 4. In the area printed by driving the overlapping piezoelectric actuator substrates 21, the droplets ejected by the two piezoelectric actuator substrates 21 are mixed and landed.

One wiring board 60 is attached to each piezoelectric actuator board 21. The wiring substrate 60 has a trapezoidal portion having substantially the same shape as the piezoelectric actuator substrate 21, and a long side bottom of the trapezoidal portion (hereinafter, the long side bottom is referred to as a long side, and the short side bottom is referred to as a short side. And a rectangular portion extending from the same). The wiring board 60 will be described in detail later.

Inside the flow path member 4, a manifold 5 that is a part of the liquid flow path is arranged. The manifold 5 extends in the longitudinal direction of the flow path member 4 and has an elongated shape, and the opening 5 b of the manifold 5 is formed on the upper surface of the flow path member 4. There are ten openings 5b, and five openings 5b are arranged on each of two straight lines parallel to the longitudinal direction of the flow path member 4. The opening 5b is arranged at a position avoiding the region where the four piezoelectric actuator substrates 21 are arranged. Liquid is supplied to the manifold 5 from a liquid tank (not shown) through the opening 5b.

The manifold 5 formed in the flow path member 4 is branched into a plurality of manifolds (the manifold 5 at the branched portion may be referred to as a sub-manifold 5a). The manifold 5 connected to the opening 5b extends along the oblique side of the piezoelectric actuator substrate 21 and is arranged so as to intersect the longitudinal direction of the flow path member 4. In the region sandwiched between the two piezoelectric actuator substrates 21, one manifold 5 is shared by the adjacent piezoelectric actuator substrates 21, and the sub-manifold 5 a branches from both sides of the manifold 5. The sub-manifolds 5a are arranged adjacent to each other in a region facing the respective piezoelectric actuator substrates 21 inside the flow path member 4, and extend in the longitudinal direction of the head body 13.

The flow path member 4 has four pressurizing chamber groups 9 in which a plurality of pressurizing chambers 10 are formed in a matrix (that is, two-dimensionally and regularly). The pressurizing chamber 10 is a hollow region having a substantially rhombic plan shape with rounded corners. The pressurizing chamber 10 is formed so as to open on the upper surface of the flow path member 4. These pressurizing chambers 10 are arranged over almost the entire area of the upper surface of the flow path member 4 facing the piezoelectric actuator substrate 21. Therefore, each pressurizing chamber group 9 formed by these pressurizing chambers 10 occupies an area having substantially the same size and shape as the piezoelectric actuator substrate 21. The opening of each pressurizing chamber 10 is closed by bonding the piezoelectric actuator substrate 21 to the upper surface of the flow path member 4.

In the present embodiment, as shown in FIG. 3, the manifold 5 is branched into four rows of sub-manifolds 5a arranged in parallel with each other in the lateral direction of the flow path member 4. The pressurizing chambers 10 connected to one sub-manifold 5a constitute two pressurizing chamber rows 11 on one side of the sub-manifold 5a and four pressurizing chamber rows 11 on both sides. Since there are 4 sub-manifolds 5a, 16 pressurizing chamber rows 11 exist. In FIG. 3, the pressurizing chamber rows 11 arranged on the longest side are the pressurizing chamber rows 11-1, the pressurizing chamber rows 11-1 in order from the short side to the pressurizing chamber rows 11-2 to 11. It is shown that -16 is arranged. The number of pressurizing chambers 10 included in each pressurizing chamber row 11 is arranged so as to gradually decrease from the long side to the short side, corresponding to the outer shape of the piezoelectric actuator substrate 32.

In each pressurizing chamber row 11, the pressurizing chambers 10 are arranged at equal intervals along the third direction D3.

In the following description, a direction that intersects the third direction D3 will be described as a first direction D1 and a direction opposite to the first direction D1 will be described as a second direction D2. More specifically, the first direction D1 is a direction in which the wiring 60b provided on the wiring substrate 60 extends toward the external control unit 88 with respect to the individual electrode body 35a described later.

The ejection holes 8 are arranged in the longitudinal direction, which is the resolution direction of the head body 13, at approximately equal intervals of about 42 μm (2600 mm/150=42 μm interval for 600 dpi). As a result, the head main body 13 can form an image with a resolution of 600 dpi in the longitudinal direction. In the portion where the trapezoidal piezoelectric actuator substrates 21 overlap, the ejection holes 8 below the two piezoelectric actuator substrates 21 are arranged so as to complement each other. They are arranged in the longitudinal direction of the main body 13 at intervals corresponding to 600 dpi.

Further, the individual flow passages 32 are connected to each sub-manifold 5a at intervals corresponding to 150 dpi on average. This is because when the discharge holes 8 for 600 dpi are divided into four rows of sub-manifolds 5a and connected to each other, the individual flow passages 32 connected to the sub-manifolds 5a are not always connected at equal intervals. That is, the individual channels 32 are formed at intervals of 170 μm on average (25.4 mm/150=169 μm interval for 150 dpi) in the extending direction, that is, the main scanning direction.

Individual electrodes 35, which will be described later, are formed on the upper surface of the piezoelectric actuator substrate 21 at positions facing the pressurizing chambers 10. The individual electrode 35 is slightly smaller than the pressure chamber 10 and has a shape similar to that of the pressure chamber 10. And an extraction electrode 35b that can be extracted from the individual electrode body 35a to the outside of the pressure chamber 10.

The discharge hole surface 31-2, which is the lower surface of the flow path member 4, has a large number of discharge holes 8 that are openings below the discharge holes 8. The discharge hole 8 is arranged at a position avoiding a region facing the sub-manifold 5a arranged on the lower surface side of the flow path member 4. Further, the ejection holes 8 are arranged in a region facing the piezoelectric actuator substrate 21 on the lower surface side of the flow path member 4. The ejection hole group, which is a collection of the ejection holes 8, occupies a region having substantially the same size and shape as the piezoelectric actuator substrate 21, and by displacing the piezoelectric element of the corresponding piezoelectric actuator substrate 21, that is, the displacement element 50. Droplets can be discharged from the discharge holes 8. The ejection holes 8 in each ejection hole group are arranged at equal intervals along a plurality of straight lines parallel to the longitudinal direction of the flow path member 4.

The flow path member 4 included in the head body 13 has a laminated structure in which a plurality of plates are laminated. These plates are the cavity plate 22, the base plate 23, the aperture plate 24, the supply plates 25 and 26, the manifold plates 27, 28 and 29, the cover plate 30 and the nozzle plate 31 in order from the upper surface of the flow path member 4. is there. Many holes are formed in these plates. The plates are aligned and stacked so that these holes communicate with each other to form the individual flow passage 32 and the sub-manifold 5a. As shown in FIG. 5, in the head main body 13, the pressurizing chamber 10 is on the upper surface of the flow path member 4, the sub-manifold 5a is on the lower surface side inside, and the discharge hole 8 is on the lower surface. The respective parts constituting the above are arranged close to each other at different positions, and the sub-manifold 5a and the discharge hole 8 are connected via the pressurizing chamber 10.

The holes formed in each plate will be described. These holes include the following: First is the pressurizing chamber 10 formed in the cavity plate 22. Secondly, there are communication holes that form a flow path that connects one end of the pressurizing chamber 10 to the sub-manifold 5a. This communication hole is formed in each plate from the base plate 23 (specifically, the inlet of the pressurizing chamber 10) to the supply plate 25 (specifically, the outlet of the sub-manifold 5a). The communication hole includes the aperture 12 formed in the aperture plate 24 and the individual supply passage 6 formed in the supply plates 25 and 26.

Thirdly, it is a communication hole that constitutes a flow path that communicates from the other end of the pressurizing chamber 10 to the discharge hole 8. This communication hole is referred to as a descender (partial flow path) in the following description. The descenders are formed on each plate from the base plate 23 (specifically, the outlet of the pressurizing chamber 10) to the nozzle plate 31 (specifically, the discharge hole 8). The discharge hole 8 side of the descender is a nozzle formed in the nozzle plate 31 having a particularly small cross-sectional area.

Fourthly, there is a communication hole that constitutes the sub-manifold 5a. The communication holes are formed in the manifold plates 27-30.

Such communication holes are connected to each other to form an individual flow passage 32 from the liquid inlet from the sub-manifold 5a (the outlet of the sub-manifold 5a) to the discharge hole 8. The liquid supplied to the sub-manifold 5a is discharged from the discharge holes 8 through the following paths. First, from the sub-manifold 5 a, the individual supply flow paths 6 are passed upward to reach one end of the squeeze 12. Next, it advances horizontally along the extending direction of the squeeze 12 and reaches the other end of the squeeze 12. From there, it reaches one end of the pressurizing chamber 10 in the upward direction. Furthermore, it advances horizontally along the extending direction of the pressurizing chamber 10 and reaches the other end of the pressurizing chamber 10. While moving little by little in the horizontal direction from there, it proceeds mainly downward and advances to the discharge hole 8 opened on the lower surface.

As shown in FIG. 5, the piezoelectric actuator substrate 21 has a laminated structure including two piezoelectric ceramic layers 21a and 21b. Each of these piezoelectric ceramic layers 21a and 21b has a thickness of about 20 μm. The thickness of the displacement element 50, which is the displaced portion of the piezoelectric actuator substrate 21, is about 40 μm, and the displacement amount can be increased by being 100 μm or less. Each of the piezoelectric ceramic layers 21a and 21b extends so as to straddle the plurality of pressurizing chambers 10 (see FIG. 3). These piezoelectric ceramic layers 21a and 21b are made of a lead zirconate titanate (PZT)-based ceramic material having ferroelectricity.

The piezoelectric actuator substrate 21 has a common electrode 34 made of a metal material such as Ag—Pd system and an individual electrode 35 made of a metal material such as Au system. The individual electrode 35 is arranged at a position facing the pressurizing chamber 10 on the upper surface of the piezoelectric actuator substrate 21 as described above. The individual electrode 35 includes an individual electrode body 35a facing the pressure chamber 10 and an extraction electrode 35b that is drawn out of a region facing the pressure chamber 10. The lead-out electrode 35b is provided with a convex-shaped connecting conductor 36 that electrically connects the lead-out electrode 35b and the wiring 60b of the wiring board 60. The connection conductor 36 has a height of, for example, about 5 to 200 μm and is a resin containing conductive particles.

Since the piezoelectric ceramic layers 21a and 21b and the common electrode 34 have substantially the same shape, the warpage can be reduced when these are manufactured by simultaneous firing. The piezoelectric actuator substrate 21 having a thickness of 100 μm or less is likely to be warped during the firing process, and the amount thereof is large. In addition, when warpage occurs, when the flow path member 4 is laminated, the warpage is deformed and joined, and the deformation at that time affects the characteristic variation of the displacement element 50, and consequently the liquid ejection characteristics. Therefore, the warp is preferably as small as or less than the thickness of the piezoelectric actuator substrate 21. Then, in order to reduce the warp due to the difference in firing shrinkage behavior between the place where the internal electrode is present and the place where the internal electrode is not present, the common electrode 34, which is the internal electrode, is formed as a solid pattern having no pattern inside. In addition, having substantially the same shape here means that the difference in the dimension of the outer circumference is within 1% of the width of the portion. The outer peripheries of the piezoelectric ceramic layers 21a and 21b are basically formed by cutting in a stacked state before firing, so that they are at the same position within the range of processing accuracy. When the common electrode 34 is also formed by solid printing and then cutting it at the same time as the piezoelectric ceramic layers 21a and 21b, warpage is unlikely to occur, but by printing with a slightly smaller pattern similar to the piezoelectric ceramic layers 21a and 21b Since the common electrode 34 is not exposed on the side surface of the piezoelectric actuator 21 substrate, electrical reliability is improved.

Although details will be described later, a drive signal is supplied to the individual electrodes 35 from the control unit 88 through a wiring board 60 such as a flexible wiring board (FPC, Flexible Printed Circuit). The drive signal is supplied in a constant cycle in synchronization with the transport speed of the printing paper P. The common electrode 34 is formed in the area between the piezoelectric ceramic layer 21a and the piezoelectric ceramic layer 21b over substantially the entire surface direction. That is, the common electrode 34 extends so as to cover all the pressure chambers 10 in the region facing the piezoelectric actuator substrate 21. The common electrode 34 has a thickness of about 2 μm. The common electrode 34 is grounded in a region (not shown) and held at the ground potential. In this embodiment, a surface electrode (not shown) different from the individual electrode 35 is formed on the piezoelectric ceramic layer 21b at a position avoiding the electrode group including the individual electrode 35. The surface electrode is electrically connected to the common electrode 34 through a through hole formed inside the piezoelectric ceramic layer 21b, and is electrically connected to the wiring 60b of the wiring substrate 60 like the many individual electrodes 35. Connected.

The wiring board 60 has a wiring 60b made of Cu or the like and a land 60ba arranged on a base material 60a made of a resin film or the like, and the wirings 60b are short-circuited with each other or electrically connected to each other. A cover resin 60c is provided on a part of the side of the base material 60a on which the wiring 60b and the land 60ba are arranged so that it is hard to make contact with each other.

The wiring 60b extends substantially along the first direction D1 from the connection electrode 36 arranged on the extraction electrode 35b of the individual electrode 35 or the connection electrode 36 electrically connected to the common electrode 34. The wiring 60b is electrically connected to another substrate, a cable, etc., and finally to the control unit 88. An end of the wiring 60b connected to the connection electrode 36 is a land 60ba wider than the wiring 60b.

As will be described later, by selectively supplying a predetermined drive signal to the individual electrode 35, pressure is applied to the liquid in the pressurizing chamber 10 corresponding to this individual electrode 35. As a result, droplets are ejected from the corresponding ejection holes 8 through the individual channels 32. That is, the portion of the piezoelectric actuator substrate 21 that faces each pressurizing chamber 10 corresponds to an individual displacement element 50 (actuator) corresponding to each pressurizing chamber 10 and the ejection hole 8. That is, in the laminated body composed of two piezoelectric ceramic layers, the displacement element 50 having the structure as shown in FIG. 5 as a unit structure is provided for each pressurizing chamber 10 immediately above the pressurizing chamber 10. The vibrating plate 21a, the common electrode 34, the piezoelectric ceramic layer 21b, and the individual electrodes 35 are included. The piezoelectric actuator substrate 21 includes a plurality of displacement elements 50 that are piezoelectric elements. In this embodiment, the amount of liquid ejected from the ejection hole 8 by one ejection operation is about 5 to 7 pL (picoliter).

When the piezoelectric actuator substrate 21 is viewed in a plan view, the individual electrode main body 35 a is arranged so as to overlap the pressurizing chamber 10, and the individual electrode 35 and the common electrode 34 are located at the center of the pressurizing chamber 10. The piezoelectric ceramic layer 21b sandwiched between is polarized in the stacking direction of the piezoelectric actuator substrate 21. The direction of polarization may be either up or down, and it can be driven by giving a drive signal corresponding to that direction.

As shown in FIG. 5, the common electrode 34 and the individual electrode 35 are arranged so as to sandwich only the uppermost piezoelectric ceramic layer 21b. A region sandwiched between the individual electrode 35 and the common electrode 34 in the piezoelectric ceramic layer 21b is called an active portion, and the piezoelectric ceramic in that portion is polarized in the thickness direction. In the piezoelectric actuator substrate 21 of the present embodiment, only the uppermost piezoelectric ceramic layer 21b includes an active portion, and the piezoelectric ceramic layer 21a does not include an active portion and functions as a vibration plate. The piezoelectric actuator substrate 21 has a so-called unimorph type structure.

In the actual driving procedure in the present embodiment, the individual electrode 35 is set to a higher potential (hereinafter referred to as a higher potential) than the common electrode 34 in advance, and the individual electrode 35 is once set to the same potential as the common electrode 34 each time an ejection request is made. (Hereinafter referred to as low potential), and then again set to high potential at a predetermined timing. As a result, the piezoelectric ceramic layers 21a and 21b return to their original shapes at the timing when the individual electrodes 35 have a low potential, and the volume of the pressurizing chamber 10 increases as compared with the initial state (the state in which the potentials of both electrodes are different). To do. At this time, a negative pressure is applied to the pressurizing chamber 10, and the liquid is sucked into the pressurizing chamber 10 from the manifold 5 side. After that, at a timing when the individual electrode 35 is again set to a high potential, the piezoelectric ceramic layers 21a and 21b are deformed so as to be convex toward the pressurizing chamber 10, and the pressure in the pressurizing chamber 10 is reduced due to the decrease in the volume of the pressurizing chamber 10. The pressure becomes positive and the pressure on the liquid rises, and droplets are ejected. That is, in order to eject the liquid droplets, a drive signal including a pulse with a high potential as a reference is supplied to the individual electrode 35. Ideally, the pulse width is AL (Acoustic Length), which is the length of time that the pressure wave propagates from the manifold 5 to the discharge hole 8 in the pressurizing chamber 10.
According to this, when the inside of the pressurizing chamber 10 is reversed from the negative pressure state to the positive pressure state, the pressures of the both are combined, and the droplets can be ejected with a stronger pressure.

Next, the direction in which the extraction electrode 35b is extracted from the individual electrode 35 will be described. First, a reference example different from the above-described embodiment will be described with reference to FIGS. FIG. 8A is an arrangement of the individual electrodes 235 in the head body 213 of the reference example, and FIG. 8B is a plan view of the wiring board 260 of the reference example of a portion corresponding to FIG. 8A. The pressure chamber 210 of FIG. 8A is a portion corresponding to the pressure chamber row 11-1 of the head body 13. The pressure chamber 210 and the individual electrode 235 corresponding to the pressure chamber 210 are in the third direction. It is lined up in D3. In each individual electrode 235, the extraction electrode 235b is extracted from the individual electrode body 235a in the first direction D1. The connection electrode 236 is arranged at the end of the extraction electrode 235b opposite to the side connected to the individual electrode body 235a.

Lands 260ba are arranged on the wiring board 260 at positions corresponding to the connection electrodes 236. A wiring 260b extends from each land 260ba in the first direction D1, and the wiring 260b is connected to the outside at the tip of the first direction D1. The second direction D2 is the opposite direction of the first direction D1. In the wiring board 260, lands 260ba are arranged in addition to the portions shown in FIG. 8B, and the wiring 260b connected from the lands 260ba (not shown) also extends within the range of FIG. 8B. Passing through. In the wiring board 260, the density of the wirings 260b in the third direction D3 increases as it goes in the first direction D1.

Consider an imaginary line L3 formed by connecting the lands 260ba corresponding to the pressurizing chamber row 11-1. The wiring 260b for 15 rows of the pressurizing chamber rows 11-2 to 11 to 16 must be arranged so as to pass through the virtual line L3. In the virtual line L3, the width of the land 260ba is wider than that of the wiring 260b, and the distance between the wiring 260b and the land 260ba is larger than the distance between the wirings 260b. Therefore, the virtual line L3 has little room for the wiring 260b. Therefore, although the wiring board 260 is illustrated as a reference example, the density of the wirings 260b becomes too high, so that the pressure chamber rows 11-2 to 11 to 16 of the pressure chamber rows 11-2 to 11-16 are actually passed through the virtual line L3. Wiring 260b for 15 rows cannot be arranged.

The extraction electrodes 35b are arranged as shown in FIG. 6A so that the wirings 60b for 15 rows of the pressure chamber rows 11-2 to 11-16 can be arranged. FIG. 6A shows the pressure chamber rows 11-1 and 11-2. FIG. 6B is a plan view of the wiring board 60 corresponding to the portion indicated by the alternate long and short dash line in FIG. The wiring board 60 is connected to the outside at the tip of the first direction D1. The individual electrode 35 is arranged on the first surface 21-1 which is the upper surface of the piezoelectric actuator substrate 21. The piezoelectric actuator substrate 21 is joined to the flow path member 4 at the second surface 21-2 which is the surface opposite to the first surface 21-1. It should be noted that the wiring 60b for 15 rows of the pressurizing chamber rows 11-2 to 11 to 16 is actually drawn, the drawing becomes complicated and difficult to understand. Therefore, FIG. ing. This is the same in FIG. 8(b) described above and FIG. 7(b) described later.

Here, the individual electrode 35 in which the extraction electrode 35b is extracted in the first direction D1 side is referred to as a first individual electrode 35-1, and the extraction electrode 35b is referred to as a first extraction electrode 35b-1 and its individual electrode body 35a. It is called the first individual electrode body 35a-1. The individual electrode 35 in which the extraction electrode 35b is extracted in the second direction D2 side is referred to as a second individual electrode 35-2, the extraction electrode 35b is the second extraction electrode 35b-2, and the individual electrode body 35a is the second individual electrode. It is called the electrode body 35a-2.

In the pressurizing chamber row 11-1, the individual electrodes 35 are the first individual electrode 35-1, the first individual electrode 35-1, the second individual electrode 35-2, and the first individual electrode along the third direction D3. 35-1, the first individual electrode 35-1, and the second individual electrode 35-2 are arranged. That is, two first individual electrodes 35-1 and one second individual electrode 35-2 are alternately arranged.

As shown in FIG. 6B, the virtual line L1 formed by connecting the lands 60ba corresponding to the pressurizing chamber row 11-1 is the first land 160b-1 corresponding to the first extraction electrode 35b-1. Since the second land 60b-2 corresponding to the second extraction electrode 35b-2 is arranged in the first direction D1, the second land 60b-2 meanders vertically and is longer than the virtual line L3. As a result, the number of wirings 60b passing through the virtual line L1 can be increased.

Three wires 60b pass between the first lands 60ba-1. Five wires 60b pass between the first land 60ba-1 and the second land 60ba-2. Therefore, the number of wirings 60b passing through the virtual line L1 for the four lands 60ba is three between the first lands 60ba-1 and 5 between the first lands 60ba-1 and the second lands 60ba-2. And 13 between the second land 60ba-2 and the first land 60ba-1. On the other hand, in FIG. 8B, since three wirings 260b pass between each land 260ba, the number of wirings 260b passing through the virtual line L3 for four lands 260ba is nine. .. In this way, the number of wirings can be increased by changing the designs of FIGS. 8A and 8B as shown in FIGS. 6A and 6B.

That is, the number of wirings 60b arranged between the first lands 60ba-1 and the second lands 60ba-2 is made larger than the number of wirings 60b arranged between the first lands 60ba-1. As a result, the total number of wirings 60b can be increased.

Since the width of the land 60ba is wider than that of the wiring 60b, it is possible to reduce the possibility that electrical connection with the connection electrode 36 cannot be made even if the position is displaced. Since the distance between the wiring 60b and the land 60ba is larger than the distance between the wirings 60b, even if misalignment occurs, the connection electrode 36 is electrically connected to the wiring 260b that is not electrically connected to the land 60ba. The possibility of being connected can be reduced. Although not shown in FIG. 6B, when the connection electrode 36 is covered with the cover resin and exposed only from the periphery of the land 60ba from the cover resin, the distance between the wiring 60b and the land 60ba is increased. By doing so, the boundary of the opening of the cover resin can be easily formed between the wiring 60b and the land 60ba.

In addition, in the pressurizing chamber row 11-2 of FIG. 6A, the first individual electrodes 35-1 and the second individual electrodes 35-2 are alternately arranged. Also in the pressurizing chamber row 11-2, if two first individual electrodes 35-1 and one second individual electrode 35-2 are alternately arranged, the number of wirings 60b passing through the portions can be increased. ..

In the pressure chamber row 11-1, the first direction is not limited to the direction in which the wiring 60b extends from the land 60ba to the outside in that the wiring 60b passing through that portion is increased. That is, the first direction is defined as the direction opposite to the direction in which the wiring 60b extends toward the outside, and the first individual electrode having the two first extraction electrodes extracted in the first direction and the first individual electrode in the second direction. The individual electrode rows may be formed by alternately arranging the second individual electrodes having the extracted second extraction electrodes.

The pressure chamber row 11-1 is located most in the first direction D1 among the pressure chamber rows 11-1 to 11-16. That is, when the wiring substrate 60 of the individual electrode 35 corresponding to the row 11-1 of the pressure chambers is pulled to the outside, the individual electrode may be disconnected between the wiring substrate 60 and the individual electrode 35. For example, the wiring board 60 may be excessively pulled during the manufacture of the liquid ejection head 2. Further, the printing paper P may collide with the liquid ejection head 2 installed in the printer 1 or the temperature of the liquid ejection head 2 having a difference in thermal expansion between constituent members may change, so that a pulling force can be applied to the wiring board 60. There is a nature.

The individual electrode row corresponding to the pressurizing chamber row 11-1 is provided with two first individual electrodes 35 having the first extraction electrode 35b-1 extracted in the first direction D1 and one second direction D2. The second individual electrodes 35-2 having the extracted second extraction electrodes 35b-2 are arranged alternately. By doing so, the number of the connection electrodes 36 located on the side of the wiring board 60 facing the outside of the wiring 60b, that is, on the first direction D1 side is increased, and disconnection between the individual electrodes 35 and the wiring board 60 is less likely to occur. it can.

The pressure chamber row 11-16 is located most in the second direction D2 among the pressure chamber rows 11-1 to 11-16. The influence when the wiring board 60 is pulled to the outside may be small, but since the individual electrodes 35 corresponding to the pressure chamber rows 11-16 are arranged on the outermost side of the pressure chamber group 9, It is considered that the individual electrodes 35 located inside are more likely to be disconnected from the wiring board 60. Although not shown, the individual electrode rows corresponding to the pressurizing chamber rows 11-16 are provided with two second individual electrodes 35 each having a second extraction electrode 35b-2 extracted in the second direction D2 and one individual electrode row. If the second individual electrodes 35-1 having the first extraction electrodes 35b-1 extracted in the one direction D1 are alternately arranged, the number of the connection electrodes 36 located on the outside increases, The individual electrode can prevent the disconnection between the wiring 35 and the wiring board 60 from occurring easily.

Subsequently, a modified example will be described with reference to FIGS. 7(a) and 7(b). FIG. 7A shows two first individual electrodes 135-1 which are modified examples of the two first individual electrodes 35-1 corresponding to the pressurizing chamber rows 11-1 shown in FIG. 6A. The head main body 113 having the above is shown. FIG. 7B shows a wiring board 160 corresponding to the structure of FIG.

The distance in the third direction D3 between the first individual electrode bodies 135a-1 arranged side by side in the third direction D3, that is, the arrangement interval is W1. More specifically, the distance between the area centroids of the first individual electrode body 135a-1 is W1. Further, when the end of the first extraction electrode 135b-1 connected to the first individual electrode body 135a-1 is the extraction source end portion, the extraction source end portions of the first individual electrode body 135a-1 are in the third direction. The distance, that is, the arrangement interval is also W1. More specifically, the distance between the centers of the widths in the third direction at the draw-out end portion is W1.

The end of the extraction electrode opposite to the side connected to the individual electrode body is defined as the extraction end. The leading end of the first individual electrode 135 is referred to as a first leading end. In the present embodiment, the first connection electrode 136-1 is arranged at the first extraction end portion. The distance in the third direction D3 between the first lead-out ends of the first individual electrodes 135 arranged side by side in the third direction D3, that is, the arrangement interval is W2. More specifically, the distance between the centers of the widths in the third direction at the leading end of the drawer is W2.

W2 is larger than W1. This is because the two first extraction electrodes 135b-1 each have a shape that deviates in the third direction D3 as the distance from the extraction source increases and spreads outward from the extraction source. Moreover, as another embodiment, the position of the lead-out source end may be displaced in the third direction with respect to the first individual electrode body 135a-1. Both the arrangement for obliquely pulling out the first extraction electrode 135b-1 and the arrangement for shifting the extraction source end portion may be performed.

In the wiring board 160, the distance between the first lands 160ba-1 arranged side by side in the third direction D3 in the third direction, that is, the arrangement interval is W3. More specifically, the distance between the area centroids of the first lands 160ba-1 is W3. W3 is larger than W2. Originally, the first connection electrode 136-1 is connected to the inside of the first land 160ba-1 in consideration of the manufacturing accuracy of the piezoelectric actuator, the manufacturing accuracy of the wiring board 160, and the bonding accuracy of the piezoelectric actuator and the wiring board 160. As described above, the first land 160ba-1 is larger than the first connection electrode 136-1. The two first lands 160ba-1 are arranged outside the corresponding first end portions within an allowable range including the influence of the above-described manufacturing accuracy and joining accuracy, so that W3 is larger than W2. Is becoming As a result, the first connection electrode 136-1 is connected while deviating from the area center of gravity of the first land 160ba-1.

W3 is made larger than W1 by performing at least one of the expansion of W2 with respect to W1 and the expansion of W3 with respect to W2. Since W3 is enlarged, the number of wirings 160b between the first lands 60ba-1 is four in FIG. 7B, which is three in FIG. 6B. That is, the number of the wirings 160b passing through the virtual line L2 can be increased.

DESCRIPTION OF SYMBOLS 1... Printer 2... Liquid discharge head 4... Flow path member 5... Manifold 5a... Sub-manifold 5b... Manifold opening 6... Individual supply flow path 8... Discharge Hole 9... Pressurizing chamber group 10... Pressurizing chamber 11-1 to 11-16... Pressurizing chamber row 12... Squeezing 13... Head body 21... Piezoelectric actuator substrate (piezoelectric substrate)
21a...Piezoelectric ceramic layer (ceramic diaphragm)
21b... Piezoelectric ceramic layer 21-1... 1st surface 21-2... 2nd surface 22-31... Plate 31-2... Discharge hole surface 32... Individual flow path 34. ..Common electrode 35...individual electrode 35a...individual electrode body 35b...drawing electrode 35-1...first individual electrode 35-2...second individual electrode 36...connection electrode 50 ...Displacement elements (piezoelectric elements)
60... Wiring board 60a... Base material 60b, 160b... Wiring 80ba, 160ba... Land 60c... Cover resin 65... Piezoelectric assembly 70... Head mounting frame 72... Head Group 80A... Paper feeding roller 80B... Collection roller 82A... Guide roller 82B... Conveying roller 88... Control unit D1... First direction D2... Second direction D3... Third direction P... Printing paper

Claims (9)

A piezoelectric substrate which have a plurality of piezoelectric elements and the first surface,
A plurality of individual electrodes forming a part of each of the plurality of piezoelectric elements are arranged on the first surface,
On the first surface, a plurality of individual electrode rows in which the individual electrodes are arranged in the third direction at predetermined intervals are arranged in a first direction that is a direction intersecting the third direction,
The individual electrode includes an individual electrode main body and an extraction electrode extracted from the individual electrode main body,
In the individual electrode, the extraction electrode is a first individual electrode that is extracted from the individual electrode body toward the first direction side, and the extraction electrode is opposite to the first direction from the individual electrode body. There is a second individual electrode that is drawn out to the second direction side that is the direction,
In the at least one individual electrode row, the two first individual electrodes and one second individual electrode are alternately arranged ,
In the extraction electrode, if the end opposite to the side connected to the individual electrode body is the extraction end,
In the two first individual electrodes arranged adjacent to each other in the third direction, the distance between the lead-out end portions in the third direction is larger than the distance between the individual electrode bodies in the third direction. A piezoelectric substrate characterized by the above. The individual electrode row in which the two first individual electrodes and the one second individual electrode are alternately arranged is arranged closest to the first direction side among the plurality of individual electrode rows. The piezoelectric substrate according to claim 1, wherein the piezoelectric substrate is the individual electrode row. Among the plurality of individual electrode rows, the individual electrode row in which the two second individual electrodes and one of the first individual electrodes are alternately arranged is most present in the second direction side. The piezoelectric substrate according to claim 1 or 2, which is characterized. The wiring board further has a plurality of wirings arranged facing the first surface and electrically connected to the plurality of extraction electrodes, respectively.
The piezoelectric substrate according to any one of claims 1 to 3, characterized in that said plurality of wires extends along said first direction. A piezoelectric substrate having a plurality of piezoelectric elements and a first surface,
A plurality of individual electrodes forming a part of each of the plurality of piezoelectric elements are arranged on the first surface,
On the first surface, a plurality of individual electrode rows in which the individual electrodes are arranged in the third direction at predetermined intervals are arranged in a first direction that is a direction intersecting the third direction,
The individual electrode includes an individual electrode main body and an extraction electrode extracted from the individual electrode main body,
In the individual electrode, the extraction electrode is a first individual electrode that is extracted from the individual electrode body toward the first direction side, and the extraction electrode is opposite to the first direction from the individual electrode body. There is a second individual electrode that is drawn to the second direction side that is the direction,
In the at least one individual electrode row, the two first individual electrodes and one second individual electrode are alternately arranged,
The wiring board further has a plurality of wirings arranged facing the first surface and electrically connected to the plurality of extraction electrodes, respectively.
Lands electrically connected to the plurality of extraction electrodes are provided on the plurality of wirings of the wiring board,
The number of the wirings passing between the two lands electrically connected to the first individual electrode and the second individual electrode arranged adjacent to each other in the third direction is,
The number of the wirings passing between the two lands electrically connected to the two first individual electrodes arranged adjacent to each other in the third direction is larger than the number of the wirings. pressure collecting substrate that. Lands electrically connected to the plurality of extraction electrodes are provided in the plurality of wirings of the wiring board,
Two distances electrically connected to the two first individual electrodes are more than a distance in the third direction between two first individual electrodes arranged adjacent to each other in the third direction. The piezoelectric substrate according to claim 4 or 5 , wherein a distance between the lands in the third direction is long. The piezoelectric substrate according to any one of claims 4-6, wherein the wiring board is a flexible wiring board. A piezoelectric substrate according to any one of claims 1 to 8 , which has a plurality of ejection holes which are joined to the piezoelectric substrate on a surface opposite to the first surface and which respectively correspond to the plurality of piezoelectric elements. A liquid discharge head including a flow path member. A recording apparatus comprising: the liquid ejection head according to claim 8; a conveyance unit that conveys a recording medium to the liquid ejection head; and a control unit that controls the piezoelectric substrate.

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