JP2000094677A - Piezoelectric oscillator unit and ink jet recording head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the dimension of a fixing region as much as possible by decreasing the electrical resistance of a common inner electrode. SOLUTION: A connecting electrode 20 is formed in flush with individual inner electrodes 18 while being insulated from a common inner electrode 17 and the individual inner electrodes 18 and exposed to the rear end face. Electrical resistance of the common inner electrode 17 is lowered by setting conductive relationship with a common electrode 22 thus reducing the dimensions of a fixing region.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric vibrator unit in which internal electrodes are stacked in parallel with the direction of an expansion / contraction axis, and more particularly to the structure of internal electrodes and an ink jet recording head.

[0002]

2. Description of the Related Art An ink jet recording head using a piezoelectric vibrator in a longitudinal vibration mode has a narrow gap behind the nozzle plate having a plurality of nozzles as disclosed in Japanese Patent Application Laid-Open No. 4-1052. An elastic plate is provided, and a piezoelectric vibrator having a piezoelectric constant d31 divided so as to correspond to each pressure generating chamber of the flow path forming substrate is brought into contact with the back surface of the elastic plate. After the ink is guided to a pressure generating chamber via a supply port, the ink is pressurized by a piezoelectric vibrator driven according to a recording signal, and is ejected from a nozzle opening as an ink droplet.

[0003]

In such a piezoelectric vibrator, for example, as disclosed in Japanese Patent Application Laid-Open No. 7-195688, one piezoelectric vibrating plate is adjusted to the width of the piezoelectric vibrator and the dummy piezoelectric vibrator. Since the slits are formed by forming slits, the connection area of the common internal electrode that is connected in common between all the piezoelectric vibrators is shortened, the electric resistance of the common internal electrode is increased, and the driving signal is increased. And the heat of Joule heat is generated. To solve such a problem, it is conceivable to enlarge the non-vibration region. However, new problems such as warpage during firing and an increase in material cost arise. The present invention has been made in view of such a problem, and an object of the present invention is to reduce the electric resistance of a common internal electrode and reduce the size of a fixed region as much as possible to reduce the manufacturing yield. An object of the present invention is to provide a piezoelectric vibrator unit capable of improving and reducing material costs. A second object of the present invention is to
An object of the present invention is to provide an ink jet recording head using the piezoelectric vibrator unit.

[0004]

According to the present invention, a common internal electrode and an individual internal electrode are laminated via a piezoelectric material, and the common internal electrode is disposed behind the fixed end. The individual internal electrodes are exposed on the end face on the free end side, and from the tip face to the surface of the fixed area in the drive piezoelectric vibrator formation area, and from the tip face in the dummy piezoelectric vibrator formation area on the free end side. A non-vibration region is fixed to a fixed substrate, and a rear end side is a continuous region, and the conductive layers are mutually connected in a region where the driving piezoelectric vibrator is to be formed. It is configured by splitting with a separable slit.

[0005]

Since the common electrode connected to the common internal electrode is also connected to the connection electrode in parallel, the resistance of the common internal electrode is reduced.

[0006]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a first embodiment of the present invention. FIG. 1 shows an embodiment of an ink jet recording head according to the present invention, in which a flow path unit 1 includes a nozzle plate 3 having nozzle openings 2 formed at a constant pitch, and a pressure communicating with the nozzle openings 2. A generation chamber 4, a flow path forming substrate 7 provided with a reservoir 6 for supplying ink to the generation chamber 4 through an ink supply port 5, and a front end of each of the piezoelectric vibrators 9 in the longitudinal vibration mode of the piezoelectric vibrator unit 8. An elastic plate 10 for expanding and reducing the volume of the pressure generating chamber 4 is integrally laminated.

The piezoelectric vibrator unit 8 is connected to a flexible cable 11 for transmitting a driving signal from the outside, and is housed and fixed in a housing chamber 13 of a head holder 12.
The flow channel unit 1 is fixed to the opening surface 14 of the holder 12 to form a recording head.

As shown in FIG. 3, the piezoelectric vibrator unit 8 fixes the driving piezoelectric vibrator 9 for ejecting ink droplets to the fixed substrate 15 so as to match the arrangement pitch of the pressure generating chambers 4. Dummy piezoelectric vibrators 16 which are positioned at both ends of the vibrators 9 in the row direction and are slightly wider are fixed to a fixed substrate 15.

The piezoelectric vibrators 9 and 16 are formed by laminating a common internal electrode 17 of the driving piezoelectric vibrator 9 and an individual internal electrode 18 in a sandwich shape via a piezoelectric material 19 and fixing the common internal electrode 17. It is configured such that the individual internal electrodes 18 are exposed at the rear end face on the end side and the front end face on the free end side.

A connection electrode 20 independent of the other internal electrodes 17, 18 is formed across the layer 19 a of the piezoelectric material 19 so as to form the same surface as the internal electrode 18 in the width direction of the piezoelectric vibrators 9, 16. It is formed so as to be continuous. The individual internal electrodes 18 of the piezoelectric vibrator 9 are connected at their leading end surfaces to segment electrodes 21 extending from the leading end surface to the fixed region to form a gap between the leading end surface and the rear end surface. Has been drawn to.

On the other hand, as shown in FIG. 2, the dummy piezoelectric vibrator 16 is connected to the common electrode 22 extending at least from the rear end face to the fixed region, and is conductively drawn to the fixed region.

As shown in FIG. 4, such a piezoelectric vibrator unit has a rear end face where a piezoelectric vibrator 9 is to be formed,
The piezoelectric vibrating plate 24 in which the conductive layer 23 is not formed in a part from the rear end surface to the front surface side, the conductive layer in the region where the piezoelectric vibrator 9 is to be formed can be divided on the front surface side, and the back surface side can be divided Common internal electrode 17 and connecting electrode 20 as much as possible
Of the bottom surface 2 so as not to cut the fixed region with the fixed substrate 15.
A slit 25 having an inclined surface 5a is formed by a wire saw or the like, and is divided so as to have a continuous portion in a region facing the fixed substrate 15.

FIG. 5 shows the above-described flexible cable 11.
In this embodiment, the common electrodes 2 are provided on both sides.
2 and a conductive pattern 27 connected to the segment electrode 21 in the central region are formed on the base material so as to match the arrangement pitch of the dummy piezoelectric vibrators 16 and the driving piezoelectric vibrators 9. It is formed so as to be located on a straight line. Reference numeral 28 in the figure indicates a driving semiconductor integrated circuit.

In the flexible cable 11, the ends of the conductive patterns 26 and 27 are connected to the piezoelectric vibrator unit 8
In the area where the dummy piezoelectric vibrator 16 and the piezoelectric vibrator 9 are fixed to the fixed substrate, and positioned on the tip side with respect to the slit 25, soldering is performed, and a conductive relationship is formed by a conductive adhesive and an anisotropic conductive adhesive film. And fixed.

In this embodiment, when a drive signal is supplied from an external drive circuit via the flexible cable 11, the piezoelectric vibrator 9 separates the common internal electrode 17 via the common electrode 22 and the individual internal electrodes 17 via the segment electrode 21. Upon receiving a drive signal from the electrode 18 and expanding and contracting in the axial direction, the specific pressure generating chamber 4 of the channel unit 1 is contracted and expanded, and an ink droplet is ejected from the nozzle opening 2.

In this embodiment, the common internal electrode 17
Is connected in parallel to the connection electrode 20 extending in the width direction of the piezoelectric vibrator unit 8, so that the resistance of the internal electrode 17 whose continuous area is reduced by forming the slit 25 is reduced. The lowering of the level of the drive signal is prevented.

As a result, the width w of the fixed region of the common internal electrode 17 can be made as small as possible, and the material cost can be reduced and the production yield can be improved.

In the above-described embodiment, the rear end face of the driving piezoelectric vibrator 9 is a region where the common electrode 22 is not formed. However, as shown in FIG.
The common electrode 22b may be formed so as to be continuous with the common electrode 22a formed on the rear end face and be separated from the segment electrode 21 of the piezoelectric vibrator 9 by a fixed gap 29.

According to this embodiment, the connection electrode 2 described above is used.
Since the connection is made in parallel with the common electrode 22b in addition to 0, not only the electric resistance can be further reduced, but also the edge of the rear end face is covered with the electrode 22b, so that the piezoelectric vibrator 9 is deteriorated due to moisture absorption or the like. Also, it is possible to prevent the edge from being chipped at the time of connecting the flexible cable.

In the tip region of the piezoelectric vibrator 9 and the dummy piezoelectric vibrator 16, a region 22c in which the segment electrode 21 and the common electrode 22 wrap around to the back side as shown by the dummy piezoelectric vibrator 16 in FIG. Even if it is formed, a similar effect is exerted. When the common electrode 22 is formed so as to extend from the rear end surfaces of the piezoelectric vibrators 9 and 16 to the back surface, that is, to the fixed substrate side, the electric resistance is further increased by conductively bonding to the fixed substrate 15 having conductivity. Can be reduced.

When the segment electrode 21 is formed so as to extend from the front end side to the back side of the piezoelectric vibrator 9 as described above, it is possible to improve the resistance to an impact at the time of assembly.

In the above-described embodiment, the electrodes 22 are formed so as to be continuous from the front end face to the rear end face with respect to the dummy piezoelectric vibrator 16, but as shown in FIG. Similarly to the segment electrode 21, the electrode 22 'is formed on the surface of the element 16 from the rear end face to a position where a fixed gap 30 is formed, while the electrode 3'
The same operation can be achieved by forming the first and second elements.

[0023]

As described above, in the present invention,
The common internal electrode and the individual internal electrode are laminated via a piezoelectric material, the common internal electrode is exposed on the rear end surface of the fixed end side, and the individual internal electrode is exposed on the front end surface of the free end side. A connection electrode is formed on the same surface, is insulated from each internal electrode and is exposed at the rear end surface, and a driving piezoelectric vibrator is formed from the front end surface to the surface of the fixed region in the region where the driving piezoelectric vibrator is formed. In the vibrator formation area, a piezoelectric vibration plate having a conductive layer extending from the front end face to the rear end face is fixed to a non-vibration area on a fixed substrate, and the rear end side is a continuous area, and a driving piezoelectric vibrator is formed. In the area to be formed, the conductive layer is divided by slits that can be separated from each other, so the common electrode connected to the common internal electrode is also connected in parallel to the connection electrode, and the electrical resistance can be reduced, and the fixed area Dimensions And as small as possible, it can be lowered to increase the material cost of the manufacturing yield.

[Brief description of the drawings]

FIG. 1 is a diagram showing one embodiment of an ink jet recording head of the present invention with a sectional structure in a region of a driving piezoelectric vibrator.

FIG. 2 is a diagram showing one embodiment of a dummy piezoelectric vibrator of the recording head.

FIG. 3 is a diagram showing one embodiment of a piezoelectric vibrator unit of the recording head.

FIG. 4 is a view showing an embodiment of a piezoelectric vibrating plate fixed to a fixed substrate before tooth splitting.

FIG. 5 is a diagram showing one embodiment of a flexible cable used for the recording head.

FIG. 6 is a view showing another embodiment of the piezoelectric vibrator unit of the present invention.

FIG. 7 is a view showing another embodiment of the piezoelectric vibrator unit of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flow path unit 2 Nozzle opening 4 Pressure generating chamber 5 Ink supply port 6 Reservoir 8 Piezoelectric vibrator unit 9 Piezoelectric vibrator 11 Flexible cable 16 Dummy piezoelectric vibrator 17, 18 Internal electrode 19 Piezoelectric material 20 Connecting electrode 21 Segment electrode 22 Common electrode 25 Slit 25a Bottom of slit

Claims (17)

[Claims] 1. A common internal electrode and an individual internal electrode are laminated via a piezoelectric material, a common internal electrode is exposed on a rear end surface on a fixed end side, and an individual internal electrode is exposed on a front end surface on a free end side,
In the area where the driving piezoelectric vibrator is formed, the piezoelectric vibrating plate with the conductive layer extending from the front end face to the rear end face is formed in the dummy piezoelectric vibrator forming area. A piezoelectric vibrator unit fixed to a fixed substrate, wherein the rear end side is a continuous area, and in a region where the driving piezoelectric vibrator is to be formed, the conductive layer is divided by slits that can be separated from each other. 2. The piezoelectric vibrator unit according to claim 1, wherein said slit is formed such that a bottom surface thereof is inclined. 3. The piezoelectric vibrator unit according to claim 2, wherein an end of a rear end surface of the slope is located on the front side. 4. The piezoelectric vibrator unit according to claim 1, wherein a conductive layer extending to a region where the dummy piezoelectric vibrator is formed is formed on a rear end surface of the piezoelectric vibrating plate. 5. A conductive layer is formed on a rear end surface of the piezoelectric vibrating plate so as to extend to a region where the dummy piezoelectric vibrator is formed and to be separated from a conductive layer in a region where the driving piezoelectric vibrator is formed. The piezoelectric vibrator unit according to claim 1. 6. The piezoelectric vibrator unit according to claim 1, wherein the conductive layer is formed so as to extend from a front end surface of the piezoelectric vibrating plate to a part of a rear surface. 7. The conductive layer according to claim 1, wherein a conductive layer is formed on a surface, a front end surface, and a side surface of the dummy piezoelectric vibrator, and a rear end surface of the dummy piezoelectric vibrator and the driving piezoelectric vibrator. Piezoelectric vibrator unit. 8. The piezoelectric vibrator unit according to claim 1, wherein connection electrodes are formed on the same surface as the individual internal electrodes and are insulated from each of the internal electrodes and exposed on a rear end face. 9. The piezoelectric vibrator unit according to claim 1, wherein the dummy vibrators are located at both ends in the direction in which the driving piezoelectric vibrators are arranged. 10. The piezoelectric vibrator unit according to claim 1, wherein all layers of the common internal electrode are continuous without being separated by the slit. 11. The piezoelectric vibrator unit according to claim 1, wherein the conductive layer formed on the dummy vibrator extends from a rear end surface of the piezoelectric vibrating plate to a back surface. 12. The conductive layer formed on the dummy vibrator is formed so as to extend from the rear end surface to the back surface of the piezoelectric vibrating plate, and is conductively connected to a fixed substrate having conductivity. 2. The piezoelectric vibrator unit according to 1. 13. A common internal electrode and an individual internal electrode are laminated via a piezoelectric material, and the common internal electrode is exposed at a rear end face on a fixed end side, and is exposed to the rear end face while being insulated from each of the internal electrodes. In addition to forming the connection electrodes, a piezoelectric layer is formed with a conductive layer extending from the front end surface to the surface of the fixed region in the region where the driving piezoelectric vibrator is formed, and in the region where the dummy piezoelectric vibrator is formed. The vibration plate is configured such that the non-vibration region is fixed to the fixed substrate, the rear end side is a continuous region, and in the region where the driving piezoelectric vibrator is to be formed, the conductive layer is divided by slits that can be separated from each other. A piezoelectric vibrator unit, a flow path unit including a pressure generating chamber that is communicated with a nozzle opening and a reservoir and is pressurized by the piezoelectric vibrator, the driving piezoelectric vibrator, and the dummy piezoelectric vibrator. Table with An ink jet recording head comprising a flexible cable for supplying a drive signal to connect to the conductive layer formed on. 14. The flexible cable according to claim 13, wherein flexible cables are arranged in a straight line on conductive layers formed on surfaces of the driving piezoelectric vibrator and the dummy piezoelectric vibrator. Ink jet recording head. 15. The ink jet recording head according to claim 13, wherein the flexible cable is connected to the conductive layer on the side of the distal end face than the slit. 16. The ink jet recording head according to claim 13, wherein the flexible cable is connected to the conductive layer at the fixed area. 17. The same internal surface as the individual internal electrode,
14. The ink jet recording head according to claim 13, further comprising a connection electrode that is insulated from each of the internal electrodes and is exposed at a rear end face.