JP2001341300A - Actuator unit and ink jet recording head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording head in which the required number of terminal arrays can be decreased. SOLUTION: The actuator unit comprises a pressure chamber forming substrate 7 in which a plurality of pressure chambers 6 communicating with a plurality of nozzle openings are formed in at least two arrays, an elastic film formed on the pressure chamber forming substrate 7 to seal the openings in the upper surface of the plurality of pressure chambers 6, a plurality of actuators 60 formed on the elastic film in correspondence with the plurality of pressure chambers 6, and a plurality of terminal arrays 22 each comprising a plurality of terminals 20, 21 connected with the plurality of actuators 60. The plurality of actuators 60 comprises a lower electrode film formed on the elastic film, a plurality of piezoelectric films formed on the lower electrode film, and a plurality of upper electrode films formed on the plurality of piezoelectric films. The plurality of arrays of actuators 60 are connected entirely with a single terminal array 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an actuator unit and an ink jet recording head provided with the same, and more particularly to an actuator unit that vibrates an elastic film constituting a part of a pressure chamber by displacement of a piezoelectric film. The present invention relates to an actuator unit that ejects ink droplets from nozzle openings by changing the pressure of ink in a pressure chamber, and an ink jet recording head.

[0002]

2. Description of the Related Art In general, an ink jet recording head which pressurizes ink in a pressure chamber by a pressure generating means to discharge ink droplets from nozzle openings of a nozzle plate uses a piezoelectric vibrator of a longitudinal vibration mode which expands and contracts in the axial direction. There are a device that uses the piezoelectric vibrator in the flexural vibration mode as a pressure generating device, and a device that uses the piezoelectric vibrator in the flexural vibration mode.

In the former method, the end face of a piezoelectric vibrator is brought into contact with an elastic plate to change the volume of a pressure chamber by the expansion and contraction of the piezoelectric vibrator, so that a recording head suitable for high-density printing can be manufactured. On the other hand, it is necessary to perform a difficult process of cutting the piezoelectric vibrator into a comb-tooth shape in accordance with the arrangement pitch of the nozzle openings, and a work of positioning and fixing the cut piezoelectric vibrator in the pressure chamber, which requires a manufacturing process. There is a problem of complexity.

On the other hand, in the latter case, a piezoelectric vibrator (piezoelectric film) is formed on an elastic film by a relatively simple process of sticking a green sheet of a piezoelectric material according to the shape of the pressure chamber and firing the green sheet. Can be turned on.

FIGS. 8 and 9 are a plan view and a perspective view, respectively, of an actuator unit of a conventional ink jet recording head having a piezoelectric vibrator (piezoelectric film) in a flexural vibration mode. The actuator unit includes a pair of terminal rows 102 including a plurality of terminals 100 and 101 at a pair of edges facing each other. The terminal 100 is a segment terminal separated from each other, and the terminal 101 is a common terminal. The actuator unit has a communication hole forming substrate 105 (FIG. 10A). The communication hole forming substrate 105 has a plurality of nozzle communication holes 103 communicating with a plurality of nozzle openings. Nozzle communication hole arrays 104 are provided.

FIGS. 10 and 11 are diagrams showing each layer of the actuator unit shown in FIGS. 8 and 9. FIG. FIG. 10A shows the communication hole forming substrate 105, and FIG.
(B) shows the pressure chamber forming substrate 106 laminated on the communication hole forming substrate 105. A plurality of nozzle communication holes 103 communicating with the plurality of nozzle openings are formed on the communication hole forming substrate 105 in two rows, and a plurality of reservoir communication holes 108 communicating with the reservoir are formed in two rows.

A plurality of pressure chambers 109 communicating with the nozzle communication holes 103 and the reservoir communication holes 108 are formed in the pressure chamber forming substrate 106 with the nozzle communication holes 103 and the reservoir communication holes 10.
Two rows are formed corresponding to each of the eight rows. FIG. 10 (c)
As shown in (1), an elastic film 110 is formed on the upper surface of the pressure chamber forming substrate 106, and the upper surface openings of the plurality of pressure chambers 109 are sealed by the elastic film 110. On the upper surface of the elastic film 110, pedestals 111 for forming terminals are formed on both opposing edges of the pressure chamber forming substrate 106 as shown in FIG. 10D.

Further, as shown in FIG. 11A, a pair of lower electrodes are provided on the upper surface of the elastic film 110 and the upper surface of the pedestal portion 111 in a predetermined pattern so as to pass above the plurality of pressure chambers 109. The film 112 is formed by a printing process using a conductive material such as platinum. FIG. 11 (a)
Reference numeral 113 denotes a pedestal portion that supports a part of the plurality of piezoelectric films 114 described below.

As shown in FIG. 11B, a plurality of piezoelectric films 114 are formed on the upper surface of the lower electrode film 112 in correspondence with the plurality of pressure chambers 109 by a printing process. On the upper surfaces of the plurality of piezoelectric films 114, a plurality of upper electrode films 115 are formed as shown in FIG. One pressure chamber 109, one piezoelectric film 114, and a corresponding portion of the lower electrode film 112 constitute one actuator. In a conventional recording head, two actuator rows each including a plurality of actuators are formed for each actuator unit.

As shown in FIG. 11D, each segment terminal 100 is connected to each upper electrode film 115.
Are formed on the base 111. The pedestal 11
1 on the common terminal 10 connected to the lower electrode film 112.
1 are also formed, and the common terminals 101 located at both ends of each row of the pressure chamber 109 are connected by a terminal extension 116. The upper electrode film 115 at a position corresponding to the common terminal 101 is covered with the terminal extension 116, and the pressure chamber 109 at this position is not used.

[0011]

As described above, in a conventional recording head, a plurality of actuators are arranged in two rows per one actuator unit so that ink droplets are ejected from two rows of nozzle openings. It is configured.

However, in the above-described conventional recording head, since two terminal rows 102 are required for each of a plurality of actuators formed in two rows, it is necessary to form two terminal rows 102. Therefore, the process of soldering the terminal array 102 during the mounting process of the recording head is complicated, and it is difficult to reduce the size of the recording head.

The present invention has been made in consideration of the above circumstances, and has as its object to provide an ink jet recording head capable of reducing the required number of terminal rows. And

[0014]

In order to solve the above problems, an ink jet recording head according to the present invention comprises a pressure chamber forming substrate in which a plurality of pressure chambers communicating with a plurality of nozzle openings are formed in at least two rows. An elastic film formed on the pressure chamber forming substrate so as to seal upper openings of the plurality of pressure chambers, and a plurality of actuators formed on the elastic film corresponding to the plurality of pressure chambers And a single terminal row composed of a plurality of terminals connected to the plurality of actuators, wherein the plurality of actuators are formed on the elastic film so as to pass above the plurality of pressure chambers. A lower electrode film, a plurality of piezoelectric films formed on the lower electrode film corresponding to the plurality of pressure chambers, and a plurality of upper electrode films formed on the plurality of piezoelectric films. Having the single The child column, characterized in that all the columns of the actuator of the plurality rows are connected.

Preferably, the single terminal row is formed at one edge of the pressure chamber forming substrate.

Preferably, among the actuators in a plurality of rows connected to the single terminal row, the actuators belonging to a row farther from the single terminal row include the single terminal row, The actuator further includes a connecting lead for connecting the upper electrode, and the connecting lead is formed on the same plane as the lower electrode film and belongs to a row closer to the single terminal row. They extend between each other.

Preferably, the connecting conductor is formed simultaneously with the formation of the lower electrode film.

Preferably, the line width of the connecting conductor is smaller than the width of the partition wall between the pressure chambers.

Preferably, the lower electrode film is formed so as to connect the plurality of actuators.

Preferably, of the plurality of actuators connected to the single terminal row, one of the lower electrode films extending from the actuators belonging to a row closer to the single terminal row. The portion extends between the actuators belonging to a row farther from the single row of terminals.

Preferably, the line width of a part of the lower electrode film is smaller than the width of a partition wall between the pressure chambers.

Preferably, two or more rows of the plurality of actuators are provided, and the single terminal row is arranged between rows of the actuators.

Preferably, a plurality of rows of the actuators connected to the single terminal row are alternately arranged between the rows of the actuators.

An ink jet recording head according to the present invention includes any one of the above-described actuator units and a nozzle plate having the plurality of nozzle openings.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an ink jet recording head according to a first embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is an enlarged longitudinal sectional view showing one actuator and its periphery in the recording head according to the present embodiment. As shown in FIG. 1, this recording head has a nozzle plate having a nozzle opening 1. 2, a flow path forming substrate 3 stacked on the nozzle plate 2, and an actuator unit 5 stacked on the flow path forming substrate 3.

The actuator unit 5 has a pressure chamber forming substrate 7 in which a pressure chamber 6 is formed. On the upper surface of the pressure chamber forming substrate 7, an elastic film 8 is formed. A lower electrode film 9 and a connecting conductor 10 are formed in a predetermined pattern on the upper surface of the elastic film 8, and a piezoelectric film 11 is formed on the upper surface of the lower electrode film 9. A plurality of upper electrode films 12 are formed on the upper surface of the piezoelectric film 11 so as to correspond to the respective pressure chambers 6, and the upper electrode film 12 is connected to one end of the connecting wire 10. One piezoelectric film 11, one upper electrode film 12
One actuator 60 is constituted by the lower electrode film 9 and the portion corresponding thereto. A plurality of nozzle communication holes 13 and a plurality of reservoir communication holes 14 are formed in the communication hole forming substrate 4.

The supply port forming substrate 17 has a nozzle communication hole 1
A second nozzle communication hole 18 that communicates with No. 3 and an ink supply port 19 that communicates with the reservoir communication hole 14 are formed. The connection hole 15 communicating with the nozzle opening 1 and the second nozzle communication hole 18 and the ink supply port 1
9 is formed with a reservoir 16 communicating with the reservoir 9. In the reservoir 16, ink supplied to the plurality of pressure chambers 6 is stored. The nozzle communication hole 13 that communicates with the nozzle opening 1 from the pressure chamber 6 and the reservoir communication hole 14 that communicates with the reservoir 16 may have any one of the two holes.

FIG. 2 and FIG. 3 are a plan view and a perspective view of the actuator unit 5 of the recording head according to the present embodiment. The actuator unit 5 includes a single terminal row 22 including a plurality of terminals 20 and 21 on one edge. The terminal 20 is a segment terminal separated from each other, and the terminal 21 is a common terminal. A plurality of nozzle communication holes 13 communicating with the plurality of nozzle openings 1 are formed in the communication hole forming substrate 4 in a total of two rows.

As can be seen from FIG. 2 and FIG.
The actuators 60 belonging to a row closer to 2 and the actuators 60 belonging to a row farther from the terminal row 22 are arranged alternately.

FIG. 4 and FIG. 5 are views showing each layer of the actuator unit 5. FIG. 4A shows the communication hole forming substrate 4, and FIG. 4B shows the pressure chamber forming substrate 7 laminated on the communication hole forming substrate 4. Two rows of nozzle communication holes 13 are formed in the communication hole forming substrate 4 corresponding to the two rows of nozzle openings 1.
A row of reservoir communication holes 14 is formed.

On the other hand, a plurality of pressure chambers 6 communicating with the nozzle communication holes 13 and the reservoir communication holes 14 are provided in the pressure chamber forming substrate 7 in two rows corresponding to each row of the nozzle communication holes 13 and the reservoir communication holes 14. Is formed. As shown in FIG. 4C, an elastic film (diaphragm) 8 is formed on the upper surface of the pressure chamber forming substrate 7, and the elastic film 8 forms a plurality of pressure chambers 6.
Is sealed at the top surface. On the upper surface of the elastic film 8, as shown in FIG.
A pedestal portion 24 for forming a terminal is formed at one edge.

Further, as shown in FIG. 5 (a), a pair of lower electrodes are provided on the upper surface of the elastic film 8 and the pedestal portion 24 in a predetermined pattern so as to pass above the plurality of pressure chambers 6. The film 9 is formed by a printing process using a conductive material such as platinum. Also, of the plurality of rows of actuators 60 connected to the single terminal row 22, a part 9 of the lower electrode film 9 of the actuator 60 belonging to the row closer to the terminal row 22.
“a” extends between the actuators 60 belonging to a row farther from the terminal row 22. Lower electrode film 9
The line width of a part 9a of the pressure chamber 6 is smaller than the width of the partition wall between the pressure chambers 6. In FIG. 5A, reference numeral 25 denotes a pedestal portion that supports a part of the plurality of piezoelectric films 11.

On the upper surface of the elastic film 8, a lower electrode film 9 is provided.
In addition to the above, a connecting wire 10 is also formed.
The lower electrode film 9 is formed by simultaneous printing using a conductive material such as platinum. The connecting wire 10 extends between the actuators 60 belonging to a row near the pedestal section 24 for the terminal row 22, and one end thereof is connected to the pedestal section 24, and the other end is a row remote from the pedestal section 24. Is located near the actuator 60 belonging to The line width of the connecting wire 10 is
The width between the pressure chambers 6 is smaller than the width of the partition wall. By forming the connecting conductor 10 and the lower electrode film 9 by simultaneous printing, it is possible to avoid a problem of mask alignment that occurs when printing is performed twice.

As shown in FIG. 5B, the lower electrode film 9
A plurality of piezoelectric films 11 corresponding to the plurality of pressure chambers 6 are formed on the upper surface of the substrate by a printing process. A plurality of piezoelectric films 1
A plurality of upper electrode films 12 are formed on the upper surface of 1 as shown in FIG. Here, since the connecting wires 10 are formed before the piezoelectric film 11 and the upper electrode film 12 are formed, a difficult operation such as forming the connecting wires 10 between the piezoelectric films 11 is omitted. Can be avoided.

As shown in FIG. 5D, a plurality of segment terminals 20 are formed on the pedestal 24, and the upper electrode film 12 of the actuator 60 belonging to a row close to the terminal row 22 is formed. The segment terminal 20 is directly connected. On the other hand, the segment terminal 20 is connected to the connection lead 10 to the upper electrode film 12 of the actuator 60 belonging to a row far from the terminal row 22, so that the segment terminal 20 and the upper electrode film 12 are electrically connected. Have been.

The common terminals 21 connected to the lower electrode film 9 are formed on both ends of the pedestal portion 24, and the common terminals 21 are connected to each other by a terminal extension 26. The upper electrode film 12 at a position corresponding to the common terminal 21 is covered with the terminal extension 26, and the pressure chamber 6 at this position is not used.

As can be seen from FIG. 5D, two actuator rows are connected to the single terminal row 22. Therefore, despite the fact that two actuator rows 60 are provided, the terminal row 22 is provided. In one line.

As described above, according to the ink jet recording head of this embodiment, two rows of actuators 60 are connected to a single terminal row 22. One terminal row 2
2, the soldering step to the terminal array 22 during the mounting step of the recording head becomes easy, and the size of the recording head can be reduced.

Further, according to the present embodiment, since the terminal row 22 is arranged at the edge of the actuator unit 5, the tape carrier package (TC
Connections such as P) are easy.

Next, an ink jet recording head according to a second embodiment of the present invention will be described with reference to FIGS.

FIGS. 6 and 7 are a plan view and a perspective view, respectively, of the actuator unit 35 of the recording head according to the present embodiment. This recording head also has a plurality of nozzle openings similar to the first embodiment described above. A total of two rows are provided.

In this embodiment, a single terminal row 42 including a plurality of terminals 40 and 41 is arranged between the rows of the actuators 70. The plurality of actuators 70 are staggered between rows. The terminal 40 is a segment terminal separated from each other, and the terminal 41 is a common terminal. The common terminals 41 are connected to each other by a terminal extension 46.

In FIG. 7, reference numeral 43 denotes a nozzle communication hole, reference numeral 44 denotes a reservoir communication hole, and reference numeral 36 denotes a pressure chamber. As can be seen from FIGS. 6 and 7, in the present embodiment, no wiring is provided in the portion above the partition between the pressure chambers 36, that is, in the portion between the actuators 70 belonging to a common row.

As described above, according to the ink jet recording head according to the present embodiment, the two rows of actuators 70 are connected to the single terminal row 42. One terminal row 4
2, the soldering step to the terminal array 42 during the mounting step of the recording head becomes easy, and the size of the recording head can be reduced.

Further, according to the present embodiment, since no wiring is provided between the actuators 70 belonging to the common column, there is a possibility that short-circuiting between the actuators 70 due to protrusion of the wiring and deformation inhibition of the actuator 70 may occur. Therefore, the wiring work can be facilitated.

[0047]

As described above, according to the present invention, a plurality of rows of actuators are connected to a single row of terminals. The process becomes easy, and the size of the recording head can be reduced.

[Brief description of the drawings]

FIG. 1 is an enlarged longitudinal sectional view showing one actuator and its periphery in an ink jet recording head according to a first embodiment of the present invention.

FIG. 2 is a plan view of an actuator unit of the inkjet recording head according to the first embodiment of the present invention.

FIG. 3 is a perspective view of an actuator unit of the ink jet recording head according to the first embodiment of the present invention.

FIG. 4 is a plan view showing each layer of the actuator unit of the ink jet recording head according to the first embodiment of the present invention.

FIG. 5 is a plan view showing each layer of the actuator unit of the inkjet recording head according to the first embodiment of the present invention.

FIG. 6 is a plan view of an actuator unit of an inkjet recording head according to a second embodiment of the present invention.

FIG. 7 is a perspective view of an actuator unit of an inkjet recording head according to a second embodiment of the present invention.

FIG. 8 is a plan view of an actuator unit of a conventional ink jet recording head.

FIG. 9 is a perspective view of an actuator unit of a conventional ink jet recording head.

FIG. 10 is a plan view showing each layer of an actuator unit of a conventional ink jet recording head.

FIG. 11 is a plan view showing each layer of an actuator unit of a conventional ink jet recording head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Nozzle opening 2 Nozzle plate 3 Flow path forming substrate 4 Communication hole forming substrate 5, 35 Actuator unit 6 Pressure chamber 7 Pressure chamber forming substrate 8 Elastic film 9 Lower electrode film 10 Communication lead 11 Piezoelectric film 12 Upper electrode film 13 Nozzle communication Hole 14 Reservoir communication hole 15 Connection hole 16 Reservoir 17 Supply port forming substrate 18 Second nozzle communication hole 19 Ink supply port 20, 40 terminal (segment terminal) 21, 41 terminal (common terminal) 22, 42 Terminal row 26, 46 Terminal extension 60, 70 Actuator

Claims (11)

[Claims] A pressure chamber forming substrate in which a plurality of pressure chambers communicating with a plurality of nozzle openings are formed in at least two rows; and a pressure chamber forming substrate sealing an upper surface opening of the plurality of pressure chambers. An elastic film formed thereon, a plurality of actuators formed on the elastic film corresponding to the plurality of pressure chambers, and a single terminal row including a plurality of terminals connected to the plurality of actuators. The plurality of actuators are provided on the lower electrode film formed on the elastic film so as to pass above the plurality of pressure chambers, and on the lower electrode film corresponding to the plurality of pressure chambers. And a plurality of upper electrode films formed on the plurality of piezoelectric films, wherein all the rows of the actuators are connected to the single terminal row. Act that is characterized by being done Eta unit. 2. The pressure terminal forming substrate according to claim 1, wherein the single terminal row is formed at one edge of the pressure chamber forming substrate.
The actuator unit as described. 3. An actuator belonging to a row farther from the single terminal row among the plurality of rows of actuators connected to the single terminal row, the actuator including the single terminal row and the upper electrode And a connecting lead for connecting the actuators to each other, the connecting lead being formed on the same plane as the lower electrode film and being connected to a row closer to the single terminal row. 3. The actuator unit according to claim 2, wherein the actuator unit extends through the actuator unit. 4. The actuator unit according to claim 3, wherein said connecting lead is formed simultaneously with forming said lower electrode film. 5. The actuator unit according to claim 3, wherein a width of the connecting conductor is smaller than a width of a partition wall between the pressure chambers. 6. The actuator unit according to claim 2, wherein the lower electrode film is formed so as to connect the plurality of actuators. 7. A part of the lower electrode film extending from the actuators belonging to a row closer to the single terminal row among the plurality of rows of actuators connected to the single terminal row, 7. The actuator unit according to claim 6, wherein the actuator unit extends between the actuators belonging to a row farther from a single terminal row. 8. The actuator unit according to claim 7, wherein a line width of a part of the lower electrode film is smaller than a width of a partition between the pressure chambers. 9. The actuator unit according to claim 1, wherein two rows of the plurality of actuators are provided, and the single terminal row is disposed between the rows of the actuators. 10. The actuator according to claim 1, wherein a plurality of rows of the actuators connected to the single row of terminals are arranged so as to be alternate between the rows of the actuators. An actuator unit according to any one of the preceding claims. 11. An actuator unit according to claim 1, wherein: a nozzle plate having a plurality of nozzle openings;
An ink jet recording head comprising: