JPH11254683A - Ink jet recording head and method for manufacturing piezoelectric vibrator unit used for the same - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To prevent short-circuit and conduction between internal electrodes due to loss of an edge portion or the like. SOLUTION: A distance L1 between an unexposed end of an internal electrode 2 ′ located on the tip side of a piezoelectric vibrator 5 and a side face facing the piezoelectric vibrator 5 is set to other internal electrodes 2, 2, 2,. 3, 3, ...
Is formed to be larger than the distance L2 between the non-exposed end and the opposing side surface of the piezoelectric vibrator, and the distance between the tip 2a 'of the internal electrode 2' at the tip and the external electrode 10 is long even if the tip is chipped,
It prevents the different external electrodes 9 and 10 from conducting.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording head using, as a pressure generating means, a longitudinal vibration mode piezoelectric vibrator in which a plurality of internal electrodes are alternately laminated with a piezoelectric material interposed therebetween.

[0002]

2. Description of the Related Art As shown in FIG. 10A, an ink jet recording head using a piezoelectric vibrator in a longitudinal vibration mode has a flow path forming substrate D having a pressure generating chamber A, an ink supply port B, and a reservoir C. A channel unit H in which an elastic plate E sealing one surface of the channel forming substrate D and a nozzle plate G having a nozzle opening F communicating with the pressure generating chamber A are stacked.
And a piezoelectric vibrator unit J. Each of the piezoelectric vibrators K constituting the piezoelectric vibrator unit J expands and contracts the pressure generating chamber A to discharge ink droplets from the nozzle openings F. It is to let.

A piezoelectric vibrator K is laminated such that internal electrodes L and M of two poles are wrapped through a piezoelectric material N in a vibrating region, and two opposing electrodes are connected at one end of each internal pole. External electrodes P and Q are formed on the side surface.

In such a piezoelectric vibrator K, a plurality of large-sized piezoelectric vibrating plates are prepared, which are cut into small plates corresponding to the size of the vibrator unit, and external electrodes P and Q are applied to each small plate. The piezoelectric vibrating plate of each small plate is formed with a slit at a constant pitch by a wire saw or the like so that a continuous portion is left at one end.

However, at the stage of manufacturing a large-sized piezoelectric vibrating plate, chipping or the like occurs at the corners in the step of laminating or firing the piezoelectric material. In this state, the external electrodes P and Q are formed by vapor deposition or sputtering. Then, as shown in FIG. 10B, a conductive material layer is also formed on the defective portion R, and the internal electrodes L and M conduct between the different poles, causing a problem of malfunction.

Although a piezoelectric vibrator unit having such a malfunction is not necessarily incorporated as a component of a recording head due to a strict inspection, it is necessary to improve the recording density of the recording head. As the size becomes smaller, there is a problem that the production yield is rapidly reduced.

The present invention has been made in view of such a problem, and aims to improve the yield by minimizing the operation failure of the piezoelectric vibrator due to the defect in the edge region of the piezoelectric vibrator. The object of the present invention is to provide an ink jet recording head capable of performing the following.

Another object of the present invention is to propose a method of manufacturing a piezoelectric vibrator unit for use in an ink jet recording head.

[0009]

According to the present invention, in order to solve such a problem, the first internal electrode and the second internal electrode having different poles are arranged on one side only in parallel in the axial direction. A flow having a piezoelectric vibrator laminated with a piezoelectric material interposed therebetween so as to be exposed and wrapped in the center region, and an elastic plate which abuts on the tip of the piezoelectric vibrator to expand and reduce the volume of the pressure generating chamber. Path unit, the distance between the non-exposed end of the internal electrode located on the tip end side of the piezoelectric vibrator and the opposite side surface of the piezoelectric vibrator is the non-exposed end of another internal electrode. And the distance between the piezoelectric vibrator and the opposing side surface of the piezoelectric vibrator.

[0010]

Since the distance between the non-exposed end of the internal electrode at the leading end where the chipping is likely to occur and the external electrode for connection with the internal electrode of the other electrode is long, a conductive layer of the external electrode is formed at the defective portion at the leading end. However, since the piezoelectric material is interposed, conduction of different external electrodes via the internal electrodes is prevented.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention. FIG. 1 shows an embodiment of the present invention. In a piezoelectric vibrator unit 1 according to the present invention, internal electrodes 2 and 3 having different poles are respectively arranged on one side surface so as to be orthogonal to the axial direction. The piezoelectric vibrators 5 that are exposed and laminated with the piezoelectric material 4 interposed therebetween so as to wrap in the central region are arranged at a fixed pitch on the fixed substrate 6 as shown in FIG. In addition, the code | symbol 7 in a figure,
Reference numeral 7 denotes a dummy piezoelectric vibrator for positioning the piezoelectric vibrator unit provided at an end of the piezoelectric vibrator in the row direction.

A connection portion with a flexible cable 8 for supplying a drive signal is formed from the exposed surfaces of the internal electrodes 2 and 3 on one side and the other side of each piezoelectric vibrator 5 to the front side of the fixed substrate 6. The external electrodes 9 and 10 are formed by vapor deposition or sputtering.

The inner electrode 2 'located at the foremost side of the piezoelectric vibrator 5 is formed shorter than the other electrodes 2, 2,..., 3, 3, 3,. The distance L1 to the side surface of the vibrator is different from the other internal electrodes 2, 2,.
3, 3,... Are formed so as to be longer than the distance L2 between the tip of the side buried in the piezoelectric material and the side surface of the piezoelectric vibrator 5.

The channel forming unit 11 includes a reservoir 12,
A flow path forming substrate 15 that partitions and forms the ink supply port 13 and the pressure generating chamber 14, and an elastic plate 16 that abuts against the tip of the piezoelectric vibrator 5 to expand and reduce the volume of the pressure generating chamber 14.
And a nozzle opening 1 for sealing the other surface of the flow path forming substrate 15 and discharging the ink in the pressure generating chamber 14 as ink droplets.
And a nozzle plate 18 provided with the nozzle 7.

The flow path forming unit 11 includes the head holder 1
The piezoelectric vibrator unit 1 is fixed to the opening surface 19a of the piezoelectric vibrator 9 and the elastic plate 1
6, the fixed substrate 6 and the head holder 19 are fixed by an adhesive to form an ink jet recording head.

In this embodiment, when a drive signal is applied to the piezoelectric vibrator 5 facing the pressure generating chamber 14 communicating with the nozzle opening 17 from which ink droplets are to be ejected, the piezoelectric vibrator 5 expands and contracts, and the pressure increases. The generation chamber 14 is contracted and expanded. As a result, the ink in the pressure generating chamber 14 is pressurized and ejected as ink droplets from the nozzle opening 17, and the ink in the reservoir 12 is supplied to the pressure generating chamber 1 through the ink supply port 13.
Flow into 4.

By the way, in the process of manufacturing a large-sized piezoelectric diaphragm, chipping or the like may occur at an edge portion. When the external electrode 10 is formed by vapor deposition or sputtering of a conductive material in a state where the chipping is present, the conductive layer 10 'is also formed at the defective portion R as shown in FIG. Is located at the tip 2a 'thereof.
Is located inside the deficient portion R and is still buried in the piezoelectric material 4.
It is not possible to reach the internal electrode 2 ′, so that it is possible to prevent a situation in which the external electrodes 9 and 10 of different poles are conducted by the internal electrode 2 ′.

FIGS. 4 to 6 show such a piezoelectric vibrator 5.
In this embodiment, a green sheet 21 of a piezoelectric material having a size corresponding to a plurality of sheets and having a predetermined thickness is placed on a surface plate 20 having a flat surface (FIG. 4).
(I)).

The pattern of the internal electrode exposed on one side surface of one of the internal electrodes 2 is formed on the surface of the conductive material by using a mask at a constant pitch with a non-formed area at least equal to the cutting margin. A layer 22 is formed (FIG. 4 (II)), and a green sheet 21 of a piezoelectric material having a thickness of about the gap between the electrodes is overlaid (FIG. 5 (III)).

Using a mask provided with a pattern for forming the internal electrode 3 serving as the other pole, a non-forming region is provided on the other side surface of the piezoelectric vibrator, and the pattern 22 of the one internal electrode 2 is The conductive material layers 23 are formed at the same pitch (FIG. 4 (VI)).

Hereinafter, such a process is repeated a plurality of times.
At the stage of forming the innermost electrode 2 ′ located at the forefront, a conductive pattern 24 having a width w2 smaller than the width w1 of the normal conductive pattern 22 (FIG. 4I) is formed at the same pitch as the conductive pattern 22. (FIG. 5 (I)), and a green sheet 25 of a piezoelectric material is superposed on the surface thereof (FIG. 5 (II)).

At the stage where the lamination is completed in this manner, the green sheet is dried and then fired, and the blocks 27, 27, 27,. (Fig. 5 (II
I)).

External electrodes 27 and 28 serving as electrodes for connection to the flexible cable 8 (FIG. 1) are formed on the surface by sputtering or vapor deposition, and a high voltage is applied to these electrodes 27 and 28 to perform predetermined polarization processing. After performing (Fig. 6
(I)), the non-electrode forming side is fixed to the fixed substrate 29 with an adhesive (FIG. 6 (II)).

Then, a slit 30 is formed from the front end by a cutting means such as a wire saw so that the internal electrode located on the rear end side, that is, on the side 29 of the base, can be separated. Note that the slit 30 is formed so that its end is oblique or perpendicular to the arrangement surface of the piezoelectric vibrators.

By forming the slit 30 so that the external electrode layer 27 on the front side is separated and the external electrode 28 extending from the back side to the front side via the rear end side is formed in a continuous state, the external electrode layer 27 is formed. The electrode 27 can be formed as a select electrode, and the external electrode 28 can be formed as a common electrode having a small electric resistance.

In the above-described embodiment, the front end 2a 'of the innermost electrode 2' is set back from the side surface. However, as shown in FIG. The tip 3a 'of the located internal electrode 3' may be similarly receded from the side surface.

Further, as shown in FIG. 7 (b), the closer the inner electrode is located to the tip, the more the tip is formed by the virtual lines CC, C'-.
External electrodes 8, 9 formed so as to extend to C '
May be formed so as to gradually increase the distance.

Further, as shown in FIG. 7 (c), the distance L3 of the tip 2a 'of the inner electrode 2' located at the forefront is
While the other internal electrodes 2, 2, 2,..., 3, 3, 3,... Are formed in the same manner, even if the layer thickness D1 of the piezoelectric material 4 ′ at the tip is larger than the layer thickness D2 in other regions. Good.

In the above-described embodiment, the entirety in the axial direction is made of a piezoelectric material. However, as shown in FIGS. A similar effect can be obtained by butt-joining a member 33 made of a highly rigid material having at least a surface having electrical insulation properties, for example, ceramic, and fixing the member 33 to the fixed substrate 6.

In the above-described embodiment, the inactive region of the piezoelectric vibrator is fixed to the fixed substrate. However, as shown in FIG. It is clear that the same effect is obtained even if the fixing is performed.

[0031]

As described above, in the present invention,
A piezoelectric vibrator in which a first internal electrode and a second internal electrode of different poles are exposed in parallel only in one axial direction, and are laminated with a piezoelectric material interposed therebetween so as to be wrapped in a central region. And a flow path unit having an elastic plate that abuts on the tip of the piezoelectric vibrator to expand and reduce the volume of the pressure generating chamber. The distance between the exposed end and the opposing side surface of the piezoelectric vibrator was formed larger than the distance between the non-exposed end of the other internal electrode and the opposing side surface of the piezoelectric vibrator. The distance between the non-exposed end of the internal electrode and the external electrode for connection with the internal electrode of the other electrode facing the electrode is long, so that even if a conductive layer of the external electrode is formed at the defective portion at the tip, the piezoelectric material is an insulating layer. Becomes different through the internal electrode. External electrodes can be prevented from conducting that. Is done.

[Brief description of the drawings]

FIGS. 1A and 1B are a cross-sectional view showing an embodiment of an ink jet recording head according to the present invention, and an enlarged view showing a tip of a piezoelectric vibrator.

FIG. 2 is a perspective view showing one embodiment of a piezoelectric vibrator unit used for the recording head.

FIG. 3 is an enlarged view showing a tip of a piezoelectric vibrator of the piezoelectric vibrator unit.

4 (I) to (IV) are diagrams showing the first half of a method of manufacturing a piezoelectric vibrating plate in the method of manufacturing a piezoelectric vibrator unit according to the first embodiment.

FIGS. 5 (I) to (III) are diagrams showing the latter half of the method of manufacturing the piezoelectric vibrating plate in the method of manufacturing the piezoelectric vibrator unit.

FIGS. 6 (I) to (III) are views showing a step of forming a piezoelectric vibrator using a piezoelectric vibrating plate in the method for manufacturing a piezoelectric vibrator unit of the above.

FIGS. 7A to 7C are views showing another embodiment of the ink jet recording head of the present invention in the form of a piezoelectric vibrator.

FIGS. 8A to 8C are views showing another embodiment of the ink jet recording head of the present invention in the form of a piezoelectric vibrator.

FIG. 9 is a perspective view showing another embodiment of the present invention.

FIGS. 10A and 10B are enlarged views of a conventional ink jet recording head and a tip of a piezoelectric vibrator thereof, respectively.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Piezoelectric vibrator unit 2, 2 'Internal electrode of one pole 3 Internal electrode of the other pole 4 Piezoelectric material 5 Piezoelectric vibrator 6 Fixed substrate 11 Flow path forming unit 12 Reservoir 13 Ink supply port 14 Pressure generation chamber 17 Nozzle opening R missing part

Claims (18)

[Claims] A first internal electrode and a second internal electrode having different polarities are respectively exposed only on one side surface in parallel with an axial direction, and a piezoelectric material is interposed so as to wrap in a central region. An ink jet recording head comprising: a stacked piezoelectric vibrator; and a flow path unit having an elastic plate that abuts on the front end of the piezoelectric vibrator to expand and reduce the volume of the pressure generating chamber. The distance between the non-exposed end of the internal electrode located on the side and the opposing side surface of the piezoelectric vibrator is formed larger than the distance between the non-exposed end of another internal electrode and the opposing side surface of the piezoelectric vibrator. Inkjet recording head. 2. A flow path unit, wherein a flow path unit partitions and forms a reservoir, an ink supply port, and a pressure generation chamber, and a volume of the pressure generation chamber is expanded by contacting a tip of the piezoelectric vibrator. 2. A liquid-tight stack comprising: an elastic plate to be contracted; and a nozzle plate having a nozzle opening for discharging an ink droplet by sealing the other surface of the flow path forming substrate. Inkjet recording head. 3. A distance between a non-exposed end of an internal electrode located on a rear end side of the piezoelectric vibrator and a side face of the piezoelectric vibrator opposite to a non-exposed end of another internal electrode and the piezoelectric vibrator. 2. The semiconductor device according to claim 1, wherein the distance is greater than a distance from an opposite side surface.
3. The ink jet recording head according to item 1. 4. The inkjet according to claim 1, wherein a distance between a non-exposed end of the internal electrode and a side surface of the piezoelectric vibrator facing the piezoelectric vibrator is set to be longer toward a tip end of the piezoelectric vibrator. Type recording head. 5. A piezoelectric material is interposed in such a manner that a first internal electrode and a second internal electrode of different poles are respectively exposed only on one side surface in parallel to the axial direction, and are wrapped in a central region. A laminated piezoelectric vibrator, a flow path unit having an elastic plate that abuts against the distal end of the piezoelectric vibrator to expand and reduce the volume of the pressure generating chamber, and the piezoelectric material on the distal end side of the internal electrode positioned at the forefront Ink jet recording head in which the layer of (1) is formed thicker than between the internal electrodes in other regions. 6. The ink jet recording according to claim 1, further comprising an external electrode for connecting the first and second internal electrodes of each piezoelectric vibrator in parallel on each side surface of the piezoelectric vibrator. head. 7. The flexible cable according to claim 1, wherein an external electrode connected to one internal electrode is connected as a common electrode, and an external electrode connected to the other internal electrode is connected to a flexible cable as a select electrode. Inkjet recording head. 8. An external electrode connected to one internal electrode,
6. The ink jet recording head according to claim 1, wherein one of the piezoelectric vibrators constituting the piezoelectric vibrator unit is connected in parallel with one internal electrode. 9. The ink jet recording head according to claim 1, wherein the piezoelectric vibrator has a non-vibration area fixed to a fixed substrate to constitute a piezoelectric vibrator unit. 10. The ink jet recording head according to claim 1, wherein the piezoelectric vibrator has a side surface of the non-vibration region fixed to the fixed substrate. 11. The ink jet recording head according to claim 1, wherein the piezoelectric vibrator has an end surface of the non-vibration region fixed to the fixed substrate. 12. The piezoelectric vibrator exposes internal electrodes of different poles perpendicular to the direction of expansion and contraction on one side, respectively.
6. The ink jet recording head according to claim 1, wherein a slit is formed in a piezoelectric vibrating plate having a piezoelectric constant d33 laminated with a piezoelectric material interposed therebetween so as to wrap in a vibration region. . 13. The ink jet recording head according to claim 12, wherein the slit is formed in a vibration area. 14. The ink jet recording head according to claim 13, wherein an end face of the slit is inclined with respect to an arrangement surface of the piezoelectric vibrators. 15. The ink jet recording head according to claim 13, wherein an end face of the slit is perpendicular to an arrangement surface of the piezoelectric vibrators. 16. The ink jet recording head according to claim 1, wherein the piezoelectric vibrator is displaced in a direction of a piezoelectric constant d33. 17. A conductive material that is exposed on one side surface of a piezoelectric material layer while leaving a piezoelectric material having a predetermined size and thickness interposed therebetween, leaving a fixed distance from the other side surface, and wrapping at a central portion. A step of forming a layer; a step of baking when the lamination is completed to a predetermined thickness so that the surface becomes a piezoelectric material layer; a step of forming an external electrode for connection on the surface; Forming a slit so as to leave a continuous portion on the non-vibration region side while cutting the teeth to form a slit, and a method of manufacturing a piezoelectric vibrator unit for an ink jet recording head. 18. The method according to claim 17, wherein the slit is formed so as to leave a continuous portion in a non-vibration area.