WO1995010416A1

WO1995010416A1 - Ink jet head, method for producing the same and method for driving the same

Info

Publication number: WO1995010416A1
Application number: PCT/JP1994/001730
Authority: WO
Inventors: Seiichi Osawa
Original assignee: Citizen Watch Co., Ltd.
Priority date: 1993-10-14
Filing date: 1994-10-14
Publication date: 1995-04-20
Also published as: EP0897803A3; EP0897802A3; EP0723866A1; EP0723866A4; EP0897803B1; EP0897803A2; EP0897802A2; DE69427837D1; DE69427837T2; DE69427926T2; DE69427926D1; EP0897802B1

Abstract

A plurality of layers of a pair of laminated piezoelectric actuators (111) are laid on a substrate (110) so as to form a laminated piezoelectric unit. A diaphragm (115) is bonded to the upper end surface of the laminated piezoelectric actuator unit, and a flow path plate (118) is bonded to the upper surface of the diaphragm (115). Here, a plurality of pressurizing chambers (116) and ink flow paths (117) are formed in the flow path plate (118), and the pressurizing chambers (116) are disposed such that they confront the laminated piezoelectric actuators (111), respectively. Furthermore, a nozzle plate (120) having a nozzle hole (119) is bonded to the upper surface of the flow path plate (118), and ink inside the pressurizing chambers (116) is ejected via the nozzle hole (119) in a direction perpendicular to the base plate (110) by deforming the laminated piezoelectric actuators (111) widthwise by applying voltage.

Description

TECHNICAL FIELD The present invention relates to an ink jet head, a method of manufacturing the same, and a method of driving the same.

The present invention relates to an ink head for selectively adhering an ink droplet onto an image recording medium, a manufacturing method thereof, and a driving method thereof. Background art

Today, among the non-impact printers whose markets are expanding significantly, there is an ink jet printer which is the simplest in principle and suitable for color printing. Among them, the so-called drop-on-demand (D〇D) type ink-jet printer, which ejects ink droplets only at the time of dot formation, has become mainstream.

As typical head methods in a D〇D type ink jet printer, there are, for example, a Kaiser type disclosed in Japanese Patent Publication No. 53-121838 and a special head method. There is a thermal jet type disclosed in Japanese Patent Publication No. 6'1-599914.

Of these, the Kaiser-type ink jet jet described in Japanese Patent Publication No. 53-112138 is difficult to miniaturize, and the Kaiser-type ink jet jet described in Japanese Patent Publication No. 6-59914 is difficult. The thermal jet-type ink jet head had a difficult problem in that high heat was applied to the ink, causing the ink to scorch.

As Inkujietsu Toe' de resolve defects as described above at the same time. One using a piezoelectric element having a piezoelectric strain constant d _{3 3} (hereinafter, also referred to as "d _{3 3} mode type") is.

The d _{3 3} mode type I Nkujietsu Bokue' de uses strips of piezoelectric material (the piezoelectric element), and one surface of the piezoelectric strain element, to form a respective electrode on a surface against countercurrent By polarizing this piezoelectric strain element in the same direction as the direction of the electric field between the electrodes, the piezoelectric strain constant d _{a 3}

Corrected form ¾ 91) It has a schematic structure with. Then, the piezoelectric strain element to generate an electric field between the electrodes, Ri by to stretch the d _{3 3} direction, so as to pressurize the Lee ink pressure chamber.

The Lee Nkuje'Tohe' de of the d _{3 3} mode type, conventionally, Tokuoyake flat 4 - 5 2 2 1 3 No. liquid chamber separation type disclosed in Japanese ones and, Kokoku 4 4 8 6 2 The liquid chamber telescopic type disclosed in Japanese Patent Publication No. 2 has already been known.

Of d _{3 a} mode type I Nkujietsu Bokue' de, the structure of those of the liquid chamber separation type, shown in the first 9 FIG.

That is, a plurality of ink flow paths are formed as grooves on the surface of an upper plate 201 made of polysulfone, and the upper plate 201 formed with these ink flow paths is formed into a diaphragm made of thin polysulfone. A plurality of pressure chambers 202 are formed by being covered with 203. A plurality of electrode patterns 208 are formed on the diaphragm 203.

On the other hand, a plurality of electrodes 206 are provided on the piezoelectric element 204 divided by the slits 207. The piezoelectric element 204 is disposed adjacent to the pressure chamber 202 with the electrodes 206 bonded to the plurality of electrode patterns 208 on the vibration plate 203, respectively. .

An electrode 205 is formed on the surface of the piezoelectric element 204 opposite to the electrode 206. On the surface on which the electrode 205 is formed, a U-shaped rigid member 209 on which the common electrode 210 is formed is laminated. Further, the rigid member 209 is joined to the edge portion of the upper plate 201 where the ink flow path is not formed via the diaphragm 203.

Each electrode pattern 208 formed on the vibration plate 203 is electrically connected to each electrode 206 provided at one end of the piezoelectric element 204, while the common electrode 210 is It is electrically connected to an electrode 205 provided at the other end of the piezoelectric element 204.

When a voltage is applied from the outside so that an electric field is generated between the individual electrode patterns 208 formed on the vibration plate 203 and the common electrode 210 in the same direction as the polarization of the piezoelectric element 204. Divided by slit 207

瞧 Sheet paper (¾¾ | IJ91) The piezoelectric element 204 extends in the direction of the electric field.

Therefore, if the rigid member 209 and the upper plate 201 are firmly connected to each other and the rigid member 209 has rigidity enough to withstand the deformation force of the piezoelectric element 204, the piezoelectric element 2 Numeral 04 deflects the diaphragm 203 and pressurizes the ink filling the pressure chamber 202. As a result, ink can be ejected from the nozzle 211.

The second 0 figure shows another conventional example of d _{3 3} mode one de type b Nkujietsu Toe' de.

In the ink jet head shown in this figure, the piezoelectric element 204 in the ink jet head shown in FIG. 19 is replaced by a plate-shaped piezoelectric material 212 and an internal electrode 21 made of a conductive material. 3 and a laminated piezoelectric actuator 214 which is alternately laminated.

According to this configuration, the deformation of the plate-shaped piezoelectric material 212 is added by the number of layers, so that even if the driving voltage is set low, the thickness direction (d ₃ modification of _a direction) is obtained in the laminated piezoelectric Akuchiyue over motor 2 1 4.

At this time, the laminated piezoelectric actuator 2 14 also deforms in a direction perpendicular to the polarization direction (d ₃₁ direction). However, it is possible to deformation amount is more modifications to d _{3 3} direction are added by lamination number of sheets is to generate a large pressure in the pressure chamber 2 0 2.

The second 1 figure of d _{3 3} mode type b Nkuje'Tohe' de illustrates the structure of those EkishitsuShin condensation type.

A small piece of piezoelectric material such as PZT (lead zirconate titanate) is used as a piezoelectric element 222, which is placed in parallel between the conductive support substrate 222 and the insulating lid 222. It is stuck.

A large number of elongated channels are formed between the piezoelectric elements 222. These channels have an ink channel 225 filled with ink and an ink channel 225 serving as an ink flow path, and a dummy channel 226 forming an air gap are alternately provided. ing.

One end of the ink channel 2 25 has a common ink reservoir.

Corrected form (MJ91) It is connected to 227, and ink is supplied from this ink reservoir 227. The other open end is a print nozzle.

The piezoelectric element 222 is polarized in a direction perpendicular to the support substrate 221 as shown by an arrow 230, and an electrode 222 is provided on the upper surface of the lid 222 side. It is provided corresponding to 25. The electrodes 224 are provided for each set of two piezoelectric elements.

When a voltage is applied between the electrode 2 24 and the conductive support substrate 2 21. The piezoelectric elements 22 placed on both sides of the ink channel 2 25 extend in the thickness direction and in the width direction. Shrink. Due to this deformation, the capacity of the ink channel 225 increases.

When the application of the voltage to the electrodes 224 is stopped, the two piezoelectric elements 222 return to the original shape, so that the passage volume rapidly decreases. As a result, the ink droplet 228 is discharged from the print nozzle formed at the end of the passage.

The present invention, the piezoelectric strain constant d _{3 3} have allowed construction of I Nkuje'Tohe' de polarized strips of piezoelectric material in the direction of the electric field as described above, that is, d _{3 3} mode type b Nkujietsu Bokue' It tries to solve the following problems.

That is, the first problem is that it is difficult to reduce the size by increasing the arrangement density and the degree of integration of print nozzles due to the structure.For example, the liquid chamber separation type shown in FIG. 19 In the ink jet head, since the piezoelectric elements 204 are arranged in a line in the arrangement direction of the slits 207 separating each piezoelectric element 204, the processing limit of the slit 207 is limited. Therefore, the pitch dimension of the print nozzles 211 is determined, and the nozzle pitch cannot be increased in density. The limit of the slit machining is about 150 to 200 per inch according to wire-source electric discharge machining.

Similarly, in the ink jet head of the liquid chamber expansion and contraction type shown in FIG. 21, the arrangement pitch of the piezoelectric elements 222 has an eye field, and the dummy channel 222 which does not discharge ink is formed. Since it is necessary for every other column,

瞧 Traded paper 用紙 Item, 1 1) It is difficult to arrange the nozzles at a higher density.

The second problem is that electrical connection for driving the piezoelectric element is difficult, which requires more man-hours for manufacturing and lower reliability of the electrical connection.

For example, in the liquid chamber separation type shown in FIG. 19, the electrodes 205 and 206 are connected to the surface of the piezoelectric element 204 facing the vibration plate 203 and the rigid member 20. 9 must be manufactured separately on the side opposite to.

Further, when the piezoelectric element 204 is driven only by these electrodes 205 and 206, it is necessary to form a joint without any gap between the piezoelectric element 204 and the electrodes 205 and 206. However, the processing technology for joining without gaps was accompanied by great difficulty.

Furthermore, when another electrode is formed on the piezoelectric element 204, there is a disadvantage that the manufacturing cost is high.

Furthermore, when connecting external signal lines to the electrodes, the position of the electrode pattern 208 on the diaphragm 203 and the position of the common electrode 210 are different, so it is necessary to individually make electrical connections. is there.

Further, it is necessary to form an electrode pattern 208 on the diaphragm 203 in advance, and the material of the diaphragm 203 is limited to a non-conductive material.

In the case of the liquid chamber expansion / contraction type shown in FIG. 21 as well, the electrode 224 and the conductive support substrate 221 serving as a common electrode must be electrically connected separately.

A third problem is that there is a risk of clogging of ink and leakage of ink at a nozzle hole portion for discharging ink droplets. In other words, both the liquid chamber separation type and the liquid chamber expansion / contraction type have nozzles that eject ink at the ends of the piezoelectric elements arranged at high density, so that the meniscus that is the ink liquid level of the nozzle holes It is not possible to secure a space for installing a cap mechanism to prevent evaporation of water and a suction mechanism to be used when the nozzle hole is clogged.

Corrected form (MM91) Even if a relatively large nozzle plate with a nozzle hole formed at the end of the piezoelectric element is used, it can be used between a very thin member such as a substrate, a piezoelectric element, and a diaphragm. Since it is necessary to join the nozzle plate with the nozzle, it is difficult to seal the nozzle plate so that the ink does not leak.

Even when a metallic nozzle plate is used, since the upper plate 201 made of polysulfone and the diaphragm 203 have different linear expansion coefficients, the members are deformed due to a temperature change, resulting in structural destruction. I will.

The fourth problem is that energy loss and interference between the pressure chambers are liable to occur, resulting in insufficient or uneven ink ejection force and poor head performance.

When the piezoelectric element is displaced in the thickness direction (d _{3 a} direction), even displacement occurs in the vertical Direction (d _{3 1} direction).

The piezoelectric element and the diaphragm or the substrate, since it is bonded via the electrode, by d _{3 1} the direction of displacement of a piezoelectric element, Yunimoru full deformation occurs between the diaphragm.

For this reason, in the liquid chamber separation type, the diaphragm 203 bends due to the unimorph deformation. Therefore, a loss is generated in the displacement of the piezoelectric element 204 in the thickness direction, and extra energy is required for the ink ejection.

In the liquid chamber expansion / contraction type, the unimorph deformation causes the supporting substrate 22 1 and the insulating lid 22 3 to bend, causing interference between the ink channels.

The fifth issue is that high assembly accuracy is required and head manufacturing is difficult.

In the ink jet head of the liquid chamber separation type shown in FIG. 19, in order to transmit the minute deformation of the piezoelectric element 204 to the diaphragm 203, the piezoelectric element 204 and the rigid member 204 are required. 9 must be joined to the diaphragm 203 by high-precision positioning without steps.

However, in the conventional configuration in which the electrode 206 is formed at one end of the piezoelectric element 204 and the electrode 206 is brought into contact with the diaphragm 203, the rigid portion is not provided. The joining portion of the material 209 and the piezoelectric element 204 to the diaphragm 203 cannot be exposed by processing such as surface grinding. For this reason, high-precision joining was difficult.

If the joining accuracy is poor, the pressure generated in each of the pressure chambers 202 will vary, which will result in variations in the ink injection characteristics.

The present invention is to solve the problems as described above in d _{3 3} mode type Inkujietsu Toe' de, energy loss is small can be efficiently driven, can be fabricated in by Ri low cost Bok configured simply, moreover An object of the present invention is to provide a small, high-density inkjet head with high reliability, and a method of manufacturing and driving such an inkjet head. Disclosure of the invention

In order to achieve the above object, the inkjet head of the present invention employs the following configuration.

That is, the first i Nkuje'Tohe' de according to the present invention, a substrate and a pair having a piezoelectric strain constant d _{3 3} which are arranged on the substrate so as to face each other to form a collecting electrode on both end surfaces laminated piezoelectric Akuchiyue Ichita A multi-row multilayer piezoelectric actuator unit; a common electrode formed by coupling between the collector electrodes formed on opposing end faces in the center of the substrate of each multilayer piezoelectric actuator; and a multilayer piezoelectric actuator And a driving electrode formed of a collecting electrode formed on the other end surface of the piezoelectric actuator, and the ink in the pressure chamber is ejected by driving each of the laminated piezoelectric actuators.

ADVANTAGE OF THE INVENTION According to the structure of this invention, a mounting density can be provided and a high-density and small ink jet head can be provided.

Further, the above-described first inkjet head according to the present invention includes a multilayer piezoelectric element block disposed on the upper surface of the substrate, a first slit for separating a central portion of the multilayer piezoelectric element block, and This first slit The multilayer piezoelectric element unit can be easily formed by the plurality of second slits, which are notched and cut out the multilayer piezoelectric element block in a direction substantially perpendicular to the slit.

Here, since the laminated piezoelectric actuator is small and has high rigidity, the limit of the slit processing is improved, and as a result, the arrangement pitch can be reduced, and the nozzle pitch can be reduced.

Further, the first inkjet head according to the present invention can be a dummy layer that does not drive the uppermost layer and the lowermost layer of each laminated piezoelectric actuator.

With this configuration, the upper surface of the multilayer piezoelectric actuator can be positioned with high precision by grinding or the like, so that the assembly and manufacturing quality is stable and an inexpensive inkjet head with a small number of steps can be provided. In addition, unnecessary deformation in the direction perpendicular to the thickness direction of the laminated piezoelectric actuator does not need to be propagated to other members, so that energy loss and interference between pressure chambers can be prevented.

Further, in the above-described first inkjet head according to the present invention, a plurality of drive electrodes electrically connected to the drive electrodes of the respective laminated piezoelectric actuators can be formed on the substrate.

By forming the drive electrodes on the substrate in this manner, electrical connection with the outside is facilitated.

Second Inkujietsu Bokue' de of the present invention includes a substrate and, stacked pair having a piezoelectric strain constant d _{3 3} which are arranged on the substrate so as to face each other to form a collecting electrode on both end surfaces piezoelectric Akuchiyue Ichita A stacked piezoelectric actuator unit consisting of a plurality of rows, a common electrode formed by coupling between collector electrodes formed on opposing end faces in the center of the substrate of each stacked piezoelectric actuator, and A drive electrode consisting of a current collector formed on the other end face of the piezoelectric actuator, a diaphragm joined to the upper end face of the multilayer piezoelectric actuator, a plurality of pressure chambers corresponding to the individual piezoelectric actuators, A flow path plate that has an ink supply path and is bonded to the diaphragm, and has a plurality of nozzle holes corresponding to the pressure chambers and is bonded to the upper surface of the flow path plate Nozzle plate.

With this configuration, the size can be easily reduced, the area of the nozzle plate can be increased, the capping mechanism that prevents the meniscus in the nozzle hole from drying, and ink clogging can be recovered. The maintenance mechanism to be used can be easily attached.

Further, the second inkjet head of the present invention is characterized in that the laminated piezoelectric actuators located in the front row and the last row of the laminated piezoelectric actuator unit are inactive bodies that are not driven, and these laminated piezoelectric actuators are not driven. Both ends of the flow path plate can be supported by the upper end surface of the writer.

With this configuration, the multilayer piezoelectric actuator unit and the pressure chamber can be firmly connected. For this reason, it is possible to reliably transmit the displacement of the laminated piezoelectric actuator to the pressure chamber. Therefore, an ink jet head having a high ink ejection force can be provided.

A third inkjet head according to the present invention includes a substrate and a plurality of a pair of laminated piezoelectric actuators having _a piezoelectric strain constant d3a arranged on the substrate so that current collectors are formed on both end surfaces thereof and opposed to each other. A laminated piezoelectric actuator unit consisting of a row, supporting columns provided on the upper surface of the substrate and on both sides of the laminated piezoelectric actuator unit, and a diaphragm bonded to the upper end surface of the laminated piezoelectric actuator unit and the supporting column And a flow path plate having a plurality of pressure chambers and an ink supply path corresponding to each of the laminated piezoelectric actuators and joined to the vibration plate, and a flow path having a plurality of nozzle holes corresponding to the pressure chambers. A nozzle plate joined to the upper surface of the road plate.

ADVANTAGE OF THE INVENTION According to the structure of this invention, a flow path plate can be fixed firmly by a support | pillar. Displacement of a laminated piezoelectric actuator can be transmitted reliably to a pressure chamber, and the ink head with a high ink discharge force is provided. As much as possible, interference between adjacent laminated piezoelectric actuators can be minimized.

The third ink jet head of the present invention is configured such that a common electrode is formed by coupling between the collector electrodes formed on opposing end surfaces in the central portion of the substrate of each multilayer piezoelectric actuator and forming a common electrode. Acti Yueichi The collector electrode formed on the other end face of the electrode can be used as a drive electrode. With this configuration, the number of external electrical contacts can be reduced, and the multilayer piezoelectric actuator can be mounted on the substrate with high density. In the third inkjet head according to the present invention, both ends of the diaphragm may be sandwiched between the support and the flow path plate.

According to this configuration, since the diaphragm is firmly fixed to the column and the flow path plate, the supporting conditions are stabilized, and the discharge performance between the pressure chambers can be made uniform.

Furthermore, in the third inkjet head of the present invention, a second support for supporting the diaphragm may be provided at the center of the upper surface of the substrate.

With this configuration, the support conditions of the diaphragm are further stabilized.

In the third ink head of the present invention, the outer side end faces of the respective laminated piezoelectric actuators may be elastically supported by the columns.

With this configuration, the deformation of the laminated piezoelectric actuator in the direction perpendicular to the thickness direction is not restrained by the pillar, and the laminated piezoelectric actuator does not lose its deformation loss in the thickness direction. Therefore, high ink ejection performance can be maintained.

The fourth ink jet head according to the present invention is composed of a plurality of rows of a pair of laminated piezoelectric actuators having _a piezoelectric strain constant da3 arranged on the substrate so that collector electrodes are formed on both end surfaces thereof and opposed to each other. A multi-layer piezoelectric actuator unit, a diaphragm bonded to the upper end surface of the multi-layer piezoelectric actuator unit, a flow plate having a plurality of pressure chambers and an ink channel corresponding to each drive actuator. A nozzle plate having a plurality of nozzle holes corresponding to each of the pressure chambers, wherein the multi-layer piezoelectric actuator is a drive actuator in every other row, a non-drive actuator that does not drive the other multi-layer piezoelectric actuators, and a non-drive actuator. The diaphragm is sandwiched between the rotor and the flow path plate, and the nozzle plate is joined to the flow path plate.

With such a configuration, the diaphragm can be supported under more stable conditions, and stable ink ejection performance can be maintained. Here, the second, third, and fourth inkjet heads of the present invention are arranged such that each laminated piezoelectric actuator and each pressure chamber are inclined with respect to an axis orthogonal to an axis passing through the nozzle hole, and A nozzle hole may be formed corresponding to the pressure chamber.

With this configuration, it is possible to arrange the nozzles at a pitch of 12 which is the arrangement pitch of the laminated piezoelectric actuators, and it is possible to realize high-density printing performance. .

In the second, third, and fourth inkjet heads of the present invention, it is preferable that at least the laminated piezoelectric actuator, the diaphragm, the flow path plate, and the nozzle plate have substantially the same linear expansion coefficient.

With this configuration, at least the laminated piezoelectric body, the vibration plate, the flow path plate, and the nozzle plate expand and contract evenly due to the temperature change, so that undesired stress does not occur between members.

Next, in the method for driving an inkjet head according to the present invention, in the first step, a voltage is applied in the polarization direction of the multilayer piezoelectric actuator to stretch the multilayer piezoelectric actuator in the thickness direction, and the second step is performed. In step (3), the applied voltage is gradually lowered to fill the pressure chamber with ink, and in step (3), the applied voltage is rapidly increased again to expand the laminated piezoelectric actuator in the thickness direction, thereby increasing the pressure. According to _c the driving method that is so as to inject room Inku, since the laminated piezoelectric Akuchiyue Ichita the electric field in the same direction is applied to constantly polarization direction, to weaken the polarization of the laminated piezoelectric Akuchiyue one data Not only does it cause no reverse polarization, but also the vibration that occurs on the liquid surface (meniscus) of the nozzle hole due to the vibration of the ink liquid that occurs in the pressure chamber is supplied to the loose ink supply in the second operation process. Therefore, the speed and diameter of the ejected ink droplets do not vary even when driven at various frequencies.

According to a first method of manufacturing an inkjet head of the present invention, a first slit is formed in a central portion of a multilayer piezoelectric body in a first step, and both ends of the multilayer piezoelectric body and a first slit are formed in a second step. An electrode is formed on the slit, and in the third step, the electrode is substantially perpendicular to the first slit and shallower than the first slit.

Corrected paper A plurality of second slits are formed at a constant pitch to form a plurality of laminated piezoelectric actuators on a substrate, and the upper surface of the laminated piezoelectric actuator is flattened in a fourth step.

By such a manufacturing method, a small-sized laminated piezoelectric actuator can be manufactured simply and at low cost.

Further, in the first method for manufacturing an inkjet head according to the present invention, the first slit is formed in the center of the multilayer piezoelectric body in the first step, and both ends of the multilayer piezoelectric body and the second slit are formed in the second step. An electrode is formed on the first slit, the upper surface of the laminated piezoelectric body is flattened in the third step, and in the fourth step the direction is almost perpendicular to the first slit and shallower than the first slit. By applying a large number of second slits at a constant pitch, a plurality of laminated piezoelectric actuators are formed on the substrate.

Even with such a manufacturing method, a small-sized laminated piezoelectric actuator can be manufactured easily and at low cost.

A fourth inkjet head according to the present invention includes: a substrate; a plurality of partition walls, a lid, and a sealing member formed by laminating a plurality of plate-shaped piezoelectric materials polarized in the thickness direction via a conductive material; Are arranged on the substrate with a certain gap therebetween, and the upper part of the gap is closed with the lid, and the side of the gap is closed with the sealing member to make the gap a pressure chamber. And a nozzle hole is opened in a part of the pressure chamber.

With such a configuration, it is possible to provide an ink jet head having a small number of parts and excellent ink discharge performance.

The fourth Lee Nkuje'Tohe' de of the present invention, partition walls may be configured as a laminated piezoelectric § Kuchiyueta be transformed into I Li thickness direction to the voltage application has a pressure electrostrictive constant d _{3 3.}

A fifth inkjet head according to the present invention includes a substrate, a plurality of partition walls each formed by laminating a plurality of plate-like piezoelectric materials polarized in a thickness direction via a conductive material, a lid, and a sealing member. Are arranged in a matrix with a certain gap on the substrate, the top of the gap is closed with a lid, and the side of the gap is closed with a sealing member to pressurize the gap. Formed as a room

Corrected paper (Eye, U91) Then, a nozzle hole that opens to the pressure chamber is provided in either the substrate or the lid, and an ink supply port is provided in either the substrate, the sealing member, or the lid, and the thickness of the partition wall is increased by applying a voltage to the conductive material. It deforms in the direction to change the volume of the pressure chamber filled with ink, and ejects ink droplets from the nozzle holes.

Even with such a configuration, it is possible to provide an ink jet head having a small number of components and excellent ink ejection performance.

In the fourth and fifth ink heads of the present invention, the gap formed between the partition walls alternately forms a pressure chamber for supplying ink in the arrangement direction and a dummy space for not supplying ink. You may do so.

This makes it possible to simultaneously discharge ink from adjacent nozzles.

In the fourth and fifth inkjet heads of the present invention, the lids can independently close the individual pressure chambers. Thus, interference between the pressure chambers can be reduced.

In the fourth and fifth inkjet heads of the present invention, the gap forming the dummy space can have a width narrower than the gap forming the pressure chamber. This makes it possible to further increase the arrangement pitch of the nozzle holes. _{C In} the fourth and fifth ink heads of the present invention, an insulating coating film is formed on the surface of the partition wall in contact with the pressure chamber. It may be provided. As a result, it is possible to secure the insulating property of the electrode of the conductive material exposed on the partition wall surface, so that the water-based ink can be used. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a front sectional view showing the structure of an ink jet head according to a first embodiment of the present invention.

FIG. 2 is a side sectional view showing a configuration of the inkjet head according to the first embodiment of the present invention.

FIG. 3 (a) is a perspective view showing a method of manufacturing a multilayer piezoelectric element block constituting an ink jet head according to the first embodiment of the present invention. FIG. 3 (b) is a perspective view, following the previous figure, showing the method of manufacturing the laminated piezoelectric element block constituting the ink jet head in the first embodiment of the present invention.

FIG. 3 (c) is a perspective view showing the method of manufacturing the laminated piezoelectric element block constituting the ink jet head in the first embodiment of the present invention, following the front surface.

FIG. 4 is a perspective view showing a method for manufacturing a laminated piezoelectric actuator constituting an ink jet head according to the first embodiment of the present invention. FIG. 5 is an ink jet printer according to the second embodiment of the present invention. FIG. 3 is an exploded perspective view showing the configuration of the head.

FIG. 6 is a front sectional view showing a configuration of an inkjet head according to a second embodiment of the present invention.

FIG. 7 is a perspective view showing a method of manufacturing a laminated piezoelectric actuator constituting an ink jet head according to the second embodiment of the present invention. FIG. 8 is a plan view of a part of an ink jet head according to a third embodiment of the present invention, which is cut away.

FIG. 9 is a front sectional view showing a configuration of an inkjet head according to a fourth embodiment of the present invention.

FIG. 10 is an enlarged front sectional view showing the structure of an ink jet head according to a fifth embodiment of the present invention.

FIG. 11 is a perspective view showing a configuration of an ink jet head according to a sixth embodiment of the present invention.

FIG. 12 is a front sectional view showing a structure of an ink head according to a sixth embodiment of the present invention.

FIG. 13 (a) is a perspective view showing a manufacturing method for forming a piezoelectric element block of an ink head according to the sixth embodiment of the present invention.

FIG. 13 (b) is a drawing of the sixth embodiment of the present invention following the previous drawing. FIG. 4 is a perspective view showing a manufacturing method for forming a piezoelectric element block of an ink jet head.

FIG. 13 (c) is a perspective view, following the previous figure, showing a manufacturing method for forming a piezoelectric element block of an injector head in the sixth embodiment of the present invention.

FIG. 14 is a perspective view showing a manufacturing method for forming a piezoelectric element block of an ink head according to the sixth embodiment of the present invention, following the previous figure.

FIG. 15 is a perspective view showing a manufacturing method for forming a multilayer piezoelectric actuator of an ink head according to a sixth embodiment of the present invention.

FIG. 16 is a perspective view showing a configuration of an injector head according to a seventh embodiment of the present invention.

FIG. 17 is a side sectional view showing the configuration of an inkjet head according to the seventh embodiment of the present invention.

FIG. 18 is a sectional view showing a modification of the sixth and seventh embodiments of the present invention.

FIG. 19 is a perspective view showing the structure of a conventional ink jet head.

FIG. 20 is a cross-sectional view showing the structure of another conventional ink jet head.

FIG. 21 is a perspective view showing the configuration of another conventional ink jet head. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the configuration of the ink jet head in the embodiment of the present invention will be described with reference to the drawings.

1 and 2 show an ink jet head according to a first embodiment of the present invention. FIG. 1 is a front sectional view, and FIG. 2 is a side sectional view. As shown in FIG. 1, the ink jet head of this embodiment includes a pair of laminated piezoelectric actuators 11 1 and 11 1. The pair of laminated piezoelectric actuators 111 and 111 are composed of a plate-shaped piezoelectric material 130 made of a piezoelectric ceramic composed of a mixture of lead-based zirconium and lead-based titanium, and silver-palladium. And conductive materials 13 1 are alternately laminated so that the conductive materials 13 1 are exposed from the end faces.

A pair of laminated piezoelectric actuators 11 1 and 11 1 are arranged in series on a substrate 11 such as a ceramic or the like, and a plurality of such rows are arranged in a direction perpendicular to the paper surface (see FIG. 2). Thus, a matrix-shaped laminated piezoelectric actuator unit 112 is formed.

In the multilayer piezoelectric actuator 111, the exposed outer end surface of the conductive material 131 is formed as an electrode film to form a drive collector 113a to which a voltage can be externally input.

On the other hand, since the end faces on the central portion side of the pair of laminated piezoelectric actuators 11 are opposed to each other, by forming a continuous electrode film between these end faces, the conductive material 13 exposed on the end faces is formed. A common collector electrode 1 1 3b, which is the common electrode of No. 1, is formed. As described above, the common collector 113 b serving as the common electrode is a common electric wire of the pair of laminated piezoelectric actuators 111 (see FIG. 1).

When configured as described above, each laminated piezoelectric actuator 1 11 1 applies a voltage between each drive electrode 113 a and the common electrode 113 b which is a common electrode. Can be driven.

As shown in FIG. 1, the electrode films of the driving collector 113a and the common collector 113b also extend to the substrate 110 side, so that electrical The connection is made easy.

In this way, by using the common electrode at the end faces of the pair of laminated piezoelectric actuators 111 facing each other at the central portion, the dimension between the pair of laminated piezoelectric actuators 111 can be reduced, and the laminated piezoelectric actuator 111 can be reduced. 1 1 1 can be mounted at high density. In addition, electrical

Corrected paper (HIJ91) There is also an advantage that the number of contacts for connection can be reduced.

On the upper surface of the laminated piezoelectric actuator 111, a metal diaphragm 115 is adhered. A plurality of pressure chambers 1 16 and a metal flow path plate 1 18 forming a common ink passage 1 17 communicating with an external ink tank (not shown) are joined to the upper surface of the vibration plate 1 15. I have.

Here, the pressure chambers 116 filled with the ink are formed at positions adjacent to the respective laminated piezoelectric actuators 111 via the vibration plate 115.

Note that the flow path plate 118 and the vibration plate 115 may not be formed as separate members but may be manufactured as an integral member.

A metal nozzle plate 120 having a plurality of nozzle holes 1 19 is adhered to the upper surface of the flow path plate 118. Each nozzle hole 1 19 is arranged at a position communicating with each pressure chamber 1 16.

As shown in FIG. 2, among the plurality of laminated piezoelectric actuators 111 arranged on the substrate 110, the laminated piezoelectric actuators 126, 126 located in the front row and the last row are driven. There is no inactive substance. These non-driven multilayer piezoelectric actuators 126 and 126 have a sufficiently large width dimension and high rigidity as compared with the driven multilayer piezoelectric actuator 111.

The substrate 110 and the flow path plate 118 in which the pressure chambers 116 are formed are firmly joined via laminated piezoelectric actuators 126 and 126 which are not driven.

Here, the diaphragm 115 is not interposed between the inactive multilayer piezoelectric actuator 126 that is not driven and the flow path plate 118, and therefore, the multilayer piezoelectric actuator 126 is not interposed. And is not glued.

Now, when the laminated piezoelectric actuator 111 is driven and the diaphragm 115 is pushed into the pressure chamber 116 due to the deformation of the actuator 111, the deformed diaphragm 115 is formed into a flow path. It is supported by the partition wall 118a of the plate 118. If the material of the partition wall 1 18a is hard and is joined to the diaphragm 1 15 with sufficient width, the support of the diaphragm 1 15 The holding condition can be regarded as a fixed beam at both ends, and a firm support is provided.

However, due to high-density mounting, the partition wall 118a of the flow path plate 118 can only secure a width of several 10 μm, and cannot have sufficient rigidity. Therefore, it is inevitable that the diaphragm 1 15 is supported somewhat elastically. In particular, when the flow path plate 118 is formed of a material having low rigidity such as plastic, the support of the vibration plate 115 becomes more elastic.

Therefore, the diaphragm 1 15 is extended to the undriven piezoelectric actuators 126, 126 with sufficient width and high rigidity, and the actuators 1, 26, 1 26 When the diaphragm 1 15 is sandwiched and supported between the diaphragm and the flow path plate 1 18, the support condition of the diaphragm 1 15 becomes strong at both ends even though it is elastic in the middle. However, the transmission state of the vibration changes depending on the location.

As a result, the state of pressurization of the pressure chambers 116 also varies depending on the location, and a phenomenon occurs in which the ejection characteristics of the ink droplets become uneven throughout the ink jet head.

In fact, in such a structure, even if the flow path plate 118 is made of a highly rigid metal material, the nozzle hole 119 in the center and the non-driven laminated piezoelectric actuators 126, 126 The ejection speed of the ink droplet was different by 10% or more from the nozzle hole 1 19 of FIG. Furthermore, when the flow path plate 118 was formed of plastic such as PSF having low rigidity, the ejection speed of the ink droplet was different by about 30%.

If the ejection speed of the ink droplets varies in this way, in the case of a so-called serial printer that scans the print head to form characters and images, the ink droplets reach the recording medium paper. Time shifts. As a result, the positions of the pixels formed by the ink droplets adhering to the paper are displaced, resulting in deterioration of print quality.

In contrast, the non-driven multilayer piezoelectric actuator 1 26 and the diaphragm If the structure is not joined, the support condition between the diaphragm 1 15 and the flow path plate 1 18 will be the same everywhere, so the multilayer piezoelectric actuator 1 1 1 is driven and the pressure is increased. When ink is ejected from the chamber 1 16, a uniform ink droplet ejection speed can be obtained over the entire ink jet head.

If the pressure chamber 1 16 near the non-driven multilayer piezoelectric actuator 1 26 is used as a dummy and ink is not ejected from it, the unevenness of the ink droplet ejection speed as described above will be almost uniform. Can be resolved. However, providing such dummy pressure chambers 116 is a waste of space, and is not preferable for miniaturization.

Next, a method of manufacturing the laminated piezoelectric actuator unit 112 in the above-described ink jet head will be described.

FIGS. 3 (a), 3 (b), 3 (c), and 4 are perspective views showing a method of manufacturing the laminated piezoelectric actuator unit 112 described above in the order of manufacturing steps. is there.

As shown in FIG. 3 (a), a first conductive material 131 is formed by a printing method on a first green sheet which is formed of piezoelectric ceramic and becomes a plate-like piezoelectric material 130. I do. At this time, the central portion of the plate-shaped piezoelectric material 130 is not covered with the first conductive material 131, but is formed as a first exposed portion 130a.

Next, as shown in FIG. 3 (b), a second green sheet that becomes a plate-like piezoelectric material 140 is stacked on the first conductive material 131, and the plate-like piezoelectric material 140 is further stacked. A second conductive material 141 is formed on the upper surface of the material 140 by a printing method. At this time, both end surfaces of the plate-shaped piezoelectric material 140 are not covered with the second conductive material 141 so as to be the second exposed portions 140a.

After alternately stacking the green sheets forming the plate-like piezoelectric material and the conductive material in this manner, and performing pressure sintering, the piezoelectric element block 150 shown in FIG. 3 (c) is formed. Form.

Next, as shown in FIG. 4, the piezoelectric element block 150 is Then, a first slit 160 reaching the substrate 110 is formed by using a diamond cutter or the like with a cutting tool.

Then, a gold (Au) thin film is formed on the entire surface of the piezoelectric element block 150 and the substrate 110 by thin film forming means such as vacuum evaporation, and the upper surface of the substrate 110 and the piezoelectric element block 150 are formed. An electrode film 161 is formed on the end face and the inner face of the first slit 160.

After that, the upper surface of the piezoelectric element block 150 and the electrode film 161 on other unnecessary surfaces are removed by surface grinding or the like to form a laminated piezoelectric actuator block 162 as shown in FIG. I do.

The second slit 163 shown in FIG. 2 (not shown in FIG. 4) is placed in the laminated piezoelectric actuator block 162 thus formed. It is formed almost perpendicular to 60 with diamond cutter. The second slit 163 reaches the substrate 110 but has a depth smaller than that of the first slit 160. By sequentially forming the second slits 163 at a constant pitch, the laminated piezoelectric actuator 1111 is completed.

The electrode film 161 shown in FIG. 4 is divided into a plurality of patterns by the above-described steps, and each laminated piezoelectric actuator 1111 can be driven individually. The multilayer piezoelectric actuator 11 1 is subjected to polarization processing in the thickness direction by applying a sufficient voltage via the electrode film 16 1.

The present inventor uses the above-described manufacturing method to use 22 plate-like piezoelectric materials 130 with a thickness of 20 μππ and 21 conductive materials 131, and alternately laminate them. Thus, a laminated piezoelectric actuator 111 having a thickness of about 0.5 mm was formed.

The laminated piezoelectric actuator 111 has a small dimension in the thickness direction of 0.5 mm, and the bottom is firmly joined to the substrate 110. The rigidity of the joint is high. There was no concern that the laminated piezoelectric actuators 111 arranged in the area would fall down due to processing or the like. For this reason, the arrangement pitch of the laminated piezoelectric actuators 1 1 1 is 1 I could do more than a book.

In addition, since the electrodes for driving the multilayer piezoelectric actuator 111 are a common electrode at the center and the individual driving electrodes on the outer side, the distance between a pair of opposing multilayer piezoelectric actuators 111 is 0.5. mm or less. In this way, a piezoelectric actuator having a high planar mounting density can be formed by a simple processing method.

Further, in the configuration and manufacturing method of the multilayer piezoelectric actuator unit 112 described above, the upper surface of the uppermost plate-like piezoelectric material 130 of the multilayer piezoelectric actuator 111 and the lowermost plate-like piezoelectric material No conductive material 13 1 is formed on the lower surface of 130. Therefore, the uppermost and lowermost plate-like piezoelectric materials 130 of the multilayer piezoelectric actuator 111 are dummy layers that do not cover the electric field.

Elongation of the thickness of the laminated piezoelectric Akuchiyue polarized in a direction Ichita 1 1 1 applies a voltage to the result the thickness direction (d _{3 a} direction) occurs. Same time, the individual plate-shaped piezoelectric material 1 3 0, shrinkage occurs to perpendicular longitudinal (d _{3 1} direction). However, as described above, by using the uppermost and lowermost plate-like piezoelectric materials 130 as the dummy layers, such deformation does not occur in the plate-like piezoelectric material 130, so that It is not necessary to apply an excessive deformation force to the vibration plate 1 15 and the substrate 1 10 which are connected to the upper and lower surfaces of the piezoelectric material 13.

In other words, by using the uppermost and lowermost plate-like piezoelectric materials 130 of the multilayer piezoelectric actuator 111 as dummy layers, the length of the multilayer piezoelectric actuator 111 can be reduced. The deformation can be absorbed inside the laminated piezoelectric actuator 111, which is a relatively soft member, and the diaphragm 115 and the substrate 110 bonded thereto can be prevented from being deformed.

For this reason, it is possible to prevent the energy gap due to the deformation in the length direction of the diaphragm 115 and the crosstalk between the laminated piezoelectric actuators 111 due to the deformation of the substrate 110.

Further, the configuration of the above-described laminated piezoelectric actuator unit 1 1 2 According to the method and the manufacturing method, the laminated piezoelectric actuator 1 12, the vibration plate 1 15, the flow path plate 1 18, and the nozzle plate 120 are sequentially laminated and bonded, so that simple and high The inkjet head can be manufactured with high accuracy.

A nozzle plate 120 having a large area can be easily formed, and a capping mechanism can be installed to prevent evaporation of water from the meniscus, which is the ink surface of the nozzle hole 119, and the nozzle hole 119 can be easily observed. The space for installing the suction mechanism used when clogging can be secured. In addition, since the nozzle plate 120 and the flow passage plate 118 can be bonded to each other on a relatively large surface, a seal that does not leak ink can be easily formed. Next, the ink jetting operation of the above-described ink jet head will be described.

First, in the first operation, a voltage is applied between the driving collector 113a and the common collector 113b to generate an electric field in the polarization direction of the plate-like piezoelectric material 130, Stretch the laminated piezoelectric actuator 1 1 1 loosely in the thickness direction (da ₃ direction). By this operation, a part of the diaphragm 1 15 is pushed into the pressure chamber 1 16 to reduce the internal volume. At this time, the laminated piezoelectric actuator 11 1 is driven by a sufficiently slow operation so that the ink in the pressure chamber 1 16 does not jump out of the nozzle hole 1 19.

In our embodiment example, the number of laminated piezoelectric Akuchiyueta 1 1 1 of the piezoelectric strain constant d ₃₃ to ^{4 5 0 X 1 0 1 2} m / V, the piezoelectric plate materials 1 3 0 except the dummy layer 2 It was set to 0 sheets. Then, when a voltage of 30 V is applied between the driving collector 113a and the common collector 113b, one plate-like piezoelectric material 130 becomes approximately 0.0 in the thickness direction. It showed an elongation of 14 μππ, and an elongation of 0.2 Ί 11 m, which is the total deformation of the laminated piezoelectric actuator 11 1 plus 20 sheets.

This amount of deformation reduces the internal volume of the pressure chamber 116 by an amount comparable to the amount of ink droplets discharged almost once.

Next, move to the second operation, and slowly weaken the electric field generated in the previous operation.

Corrected form (eyes, | J91) The displacement of the laminated piezoelectric actuator 1 1 1 is reduced. As a result, the volume in the pressure chamber 116 increases from that in the first operation, and ink is supplied into the pressure chamber 116 via the common ink passage 117 shown in FIG. It is.

In a third operation, rapidly generates an electric field in the polarization direction of the plate-shaped piezoelectric material 1 3 0, it extends the laminated piezoelectric Akuchiyueta 1 1 1 in the thickness direction (d _{3 3} direction). At this time, the pressure in the pressure chamber 116 increases rapidly, and the ink filled in the pressure chamber 116 is ejected from the nozzle hole 119. Finally, in a fourth operation, a voltage at the same level as in the first operation is applied to the multilayer piezoelectric actuator 111. The fourth operation may be omitted by setting the applied voltage in the first operation and the applied voltage in the third operation to be the same.

According to such a driving method, since the multilayer piezoelectric actuator 111 is constantly applied with an electric field in the same direction as the polarization direction, the occurrence of reverse polarization that weakens the polarization of the multilayer piezoelectric actuator 111 is generated. Can be prevented. Also, the vibration on the liquid surface (meniscus) of the mezzle hole 1 19 caused by the vibration of the ink liquid generated in the pressure chamber 116 can be reduced by the loose ink supply by the second operation. However, even when driven at various frequencies, the speed and diameter of the ejected ink droplets can be made uniform.

5 and 6 show an ink jet head according to a second embodiment of the present invention. FIG. 5 is an exploded perspective view, and FIG. 6 is a front sectional view. Hereinafter, a second embodiment of the present invention will be described with reference to FIGS. 5 and 6 alternately.

As shown in FIGS. 5 and 6, a pair of laminated piezoelectric actuators 111 are arranged in series on a substrate 110 made of ceramic or the like. A plurality of pairs of the laminated piezoelectric actuators 111 are further arranged in the front-rear direction, thereby forming a laminated piezoelectric actuator unit 112 in the form of a retrix. I have. The laminated piezoelectric actuator 111 is composed of a mixture of lead-based zirconium and lead-based titanium. It is formed by alternately laminating plate-shaped piezoelectric materials made of piezoelectric ceramics and conductive materials made of silver-palladium, and firing them.

As shown in FIG. 6, on the outer end face of the multilayer piezoelectric actuator 111, a driving collector 113a made of a thin film of gold (Au) or the like formed by thin film forming means such as evaporation. Are formed, and the common collector 113 b is formed on the other end surface in the same manner.

As shown in FIGS. 5 and 6, ceramic pillars 114a are provided at both ends of the substrate 110, and the upper surface thereof is flush with the upper surface of the multilayer piezoelectric actuator 111. Adhere so that In addition, between the pair of laminated piezoelectric actuators 111, a ceramic support pillar 114b is formed in the same manner.

A metal diaphragm 1 15 is joined to the upper surface of the laminated piezoelectric actuator 111 and the upper surfaces of the columns 114a and 114b.

Further, a metal flow path plate 1 18 is bonded onto the diaphragm 1 15. A plurality of pressure chambers 116 and a common ink passage 117 communicating with an external ink tank (not shown) are formed in the passage plate 118. Each of the pressure chambers is disposed so as to be vertically adjacent to each of the laminated piezoelectric actuators 111 through the diaphragm 115.

Here, the diaphragm 1 15 is sandwiched between the columns 111 a and 114 b of the laminated piezoelectric actuator unit 112 and the partition wall 118 a of the flow path plate 118. , It is firmly fixed.

Further, a metal nozzle plate 120 having a nozzle hole 119 is adhered to the upper surface of the channel plate 118. Each nozzle hole 1 19 communicates with each pressure chamber 1 16 respectively.

On the circuit board 121, electric wire patterns 123 are formed at the same pitch as the arrangement pitch of the laminated piezoelectric actuators 111. On the other hand, on the substrate 110, an electric wire pattern 122 that is electrically connected to the driving collector 113a and the common collector 113b is formed. These electric wire patterns 123 and 122 are adhered by a conductive adhesive.

Corrected form (HU91) Further, on the circuit board 121, a driving IC 125 for applying a voltage to the multilayer piezoelectric actuator 111 to drive it is mounted. This drive IC 125 is connected to each wire pattern on the circuit board 121.

Conducted with 1 2 3 and electric wire 1 2.

When a signal is externally input to the electrodes 1 2 4, the drive IC 1 2 5 is activated, and the drive electrodes 1 1 3 a of the laminated piezoelectric actuator 1 1 1 via the wire pattern 1 2 3 and the wire pattern 1 2 2 And common collector electrode 1

A voltage is applied between 13b and an electric field is generated in the plate-like piezoelectric material in the actuator 111. This electric field, in advance direction of the electric field to a polarized piezoelectric plate material was Teatsu is deforms in the thickness direction (d _{3 3} direction).

Thus the laminated piezoelectric Akuchiyueta 1 1 1 extends in the thickness direction (d _{3 3} direction). At the same time, the laminated piezoelectric Akuchiyue Ichita 1 1 1, even shrinkage occurs in the thickness direction perpendicular to the direction (d _al direction). Therefore, the laminated piezoelectric actuator 1 11 1 and the support 1 1 4 are separated by a force to leave a slight gap between the laminated piezoelectric actuator 1 1 1 and the adjacent support 1 1 4a, or by an elastic adhesive. It is preferable that a is joined. With such a configuration, the multilayer piezoelectric actuator 111 is not restrained in the direction perpendicular to the thickness, and no loss occurs in the deformation in the thickness direction.

Although not shown in detail in the figure, the laminated piezoelectric actuator 126 located at the outer end in the front-rear direction in FIG. 5 is not used for driving, and the common collector electrode shown in FIG. 1 1 3b is electrically connected to the electric wire pattern 1 2 2 on the substrate 1 1 0.Therefore, a common collector electrode 1 1 2 is provided inside the laminated piezoelectric actuator 1 2 6 An internal electrode that conducts with 3b is formed.

The material forming each member is not limited to the materials described above. In other words, the substrate 110 and the columns 114a and 114b may be insulating members, for example, glass. Further, the diaphragm 115, the channel plate 118, and the nozzle plate 120 may be formed of plastic or the like.

Thus, the substrate 110, the laminated piezoelectric actuator 111, the diaphragm

Corrected paper (^ !! 191) Materials for forming 115, flow path plate 1 18 and nozzle plate 120 can be selected arbitrarily, but if they are made of the above-mentioned materials, their linear expansion coefficients are almost the same, so expansion caused by temperature changes The member deformation due to the difference can be suppressed to a minimum, and the ejection performance of the ink jet head can be kept constant even when the temperature changes.

Further, the substrate 110 and the support columns 114a and 114b may be integrally formed using a part of the piezoelectric material of the laminated piezoelectric actuator.

Furthermore, the strut 1 14 b has a function of firmly fixing the diaphragm 1 15 and the flow path plate 1 18, but if the rigidity of the flow path plate 1 18 is sufficiently high. It may be omitted.

Partition wall existing between adjacent pressure chambers 1 16 in flow path plate 1 18

118 a is joined to the upper surface of diaphragm 115, but the opposite surface (lower surface) of diaphragm 115 is in contact with the groove formed between laminated piezoelectric actuators 111. Therefore, when the diaphragm 115 and the flow path plate 118 are joined by bonding or the like, the vibration plate 115 and the flow path plate 118 are bonded first, and then they are laminated. Piezoelectric actuator 1 1 1 and support 1 1 4 a,

It is good to join by pressing 1 1 4 b. In this way, the vibrating plate 1 15 is supported by a jig or the like from the pressure chamber 1 16 formed through the flow path plate 1 18 and the laminated piezoelectric actuator 1 1 1 Can be pressed.

In addition, when the diaphragm 1 15 is sandwiched between the partition wall 1 18 a of the flow path plate 1 18 and the support 1 1 4 a, a strong fixation can be realized, and the diaphragm 1 15 is stable as an elastic body. Will work. The diaphragm i 15 and the flow path 1

If a stable connection can be realized by firmly joining between

The structure may be such that 14a and the flow path plate 1 18 are directly joined without the interposition of the diaphragm 1 15.

When the nozzle plate 120 is laminated on the flow path plate 118 as described above, the nozzle plate 120 and the flow path plate 118 are joined on a large surface, so that the nozzle hole There is no problem even if the adhesive material protrudes in the vicinity of 119, so there is no need to strictly pursue the bonding quality

Corrected paper Easy to make.

Furthermore, since the nozzle plate 120 can secure a large area, a capping mechanism to ensure the quality of the meniscus, which is the liquid level of the nozzle hole 1 19, sucks the clogged ink in the nozzle hole 1 19 It is easy to attach a mechanism that performs this.

In the embodiment of the present inventor, the laminated piezoelectric actuator 111 has a small length of about 3 mm and a thickness of about 0.5 mm, and the rigidity of the laminated piezoelectric actuator 111 itself is high. A high natural frequency could be provided. As a result, the ink continuous injection performance was improved.

In addition to the high rigidity of the multilayer piezoelectric actuator 111 and its difficulty in breaking, the central part of the multilayer piezoelectric actuator is used as a common electrode and the outer end face is used as a drive electrode, so that electrical connection can be easily made in a minimum space. Accordingly, the planar mounting density of the multilayer piezoelectric actuator 111 can be further increased.

Further, a column 114a is disposed on the end face of the multilayer piezoelectric actuator 111, and the substrate 110 and the flow path plate 118 are connected via the column 114a. Even when each multilayer piezoelectric actuator 111 is driven independently, the substrate is not affected by the reaction force and the pressure generated in the pressure chamber 116.

The pressure between the 110 and the flow path plate 1 18 changes, causing pressure loss in the pressure chamber 1 16 or the deformation of the substrate 110 and the flow path plate 1 18 resulting in the pressure chamber 1 16 There is no interference between them.

In addition, the diaphragm 1 15 is fixed so as to be sandwiched between the columns 1 1 14a and 1 1 4b and the partition 1 1 8a of the flow path plate 1 1 8 so that the diaphragm 1

The vibration system of 115 is stable, and even if the pressure chamber 116 is strongly pushed by the laminated piezoelectric actuator 111, extra vibration is not generated in the diaphragm 115, so that the efficiency is high and the vibration plate is adjacent. Interference between the pressure chambers 1 16 is also small ₍ details are not described in the above configuration, but the multilayer piezoelectric actuator

Assuming that the uppermost plate-like piezoelectric material of 111 is a non-functioning dummy layer, the laminated piezoelectric actuator 111 and pillars 114a and 114b are exposed by plane grinding or the like. Diaphragm with high precision without gaps 1 1 5 can be joined.

Furthermore, 'absorption when a stacked piezoelectric Akuchiyueta 1 1 1 dummy layer that does not function the lowermost plate-shaped piezoelectric material, to the laminated piezoelectric Akuchiyueta 1 1 1 occurs deformation of d _al direction, the deformation in this dummy layer Therefore, stress at the joint surface with the substrate 110 can be reduced. Next, the ink jetting operation of the above-described ink jet head will be described with reference mainly to FIG.

First, in the first operation, an electric field is generated between the driving collector 113a and the common collector 113b to generate an electric field in the polarization direction of the plate-like piezoelectric material, and the lamination is performed. piezoelectric Akuchiyueta 1 1 1 in the thickness direction (d _{3 3} direction) stretching Niyutsuku Li.

By this operation, the diaphragm 1 15 is pushed into the pressure chamber 1 16 to reduce the internal volume. In this case, the multilayer piezoelectric actuator 111 is driven with a sufficiently loose operation so that the ink in the pressure chamber 116 does not jump out of the nozzle hole 119.

Then, the process proceeds to the second operation, before the operation will weaken Ri Yutsuku the electric field generated by, with _t the operation of reducing the displacement of the laminated piezoelectric Akuchiyue Ichita 1 1 1, the pressure chamber 1 1 6 The volume increases as compared to the first operation, and ink is supplied from the common ink passage 1 17 shown in FIG. 5 into the pressure chamber 1 16.

Subsequently, in a third operation, an electric field is rapidly generated in the polarization direction of the plate-shaped piezoelectric material, and the laminated piezoelectric actuator 111 is vigorously stretched in the thickness direction. At this time, the pressure in the pressure chamber 116 increases rapidly, and the ink filled in the pressure chamber 116 is jetted from the nozzle hole 119. Finally, in the fourth operation, the voltage applied to the multilayer piezoelectric actuator 111 is reduced so that the voltage becomes the same level as in the first operation. Note that the fourth operation may be omitted by setting the applied voltage in the first operation and the applied voltage in the third operation to be the same.

According to such a driving method, the multilayer piezoelectric actuator 1 1 1 is constantly applied with an electric field in the same direction as the polarization direction. There is no inversion polarization that weakens the polarization of the piezoelectric actuator 1 1 1. In addition, the vibration on the liquid surface (meniscus) of the nozzle hole 119 caused by the vibration of the ink liquid generated in the pressure chamber 116 is reduced by the loose ink supply in the second operation. Therefore, even if the laminated piezoelectric actuator 111 is driven at various frequencies, the ejection speed and the diameter of the ink droplets can be made uniform.

Next, FIGS. 3 (a), 3 (b), 3 (c), and 7 show a method of manufacturing the laminated piezoelectric actuator unit 112 in the above-mentioned inkjet head. This will be described with reference to FIG.

The manufacture of the piezoelectric element block 150 shown in FIGS. 3 (a) to 3 (c) is substantially the same as the method of manufacturing the multilayer piezoelectric actuator unit 112 in the first embodiment. is there.

That is, as shown in FIG. 3 (a), a first conductive material 1331 is applied to a first green sheet formed of piezoelectric ceramic to become a plate-like piezoelectric material 130 by a printing method. It forms well. At this time, the central portion of the plate-shaped piezoelectric material 130 is not covered with the first conductive material 131, and is made to be the first exposed portion 130a. '

The green sheet and the conductive material forming the plate-like piezoelectric material are alternately stacked in this manner, and then subjected to a pressure sintering process to obtain a piezoelectric element block 150 as shown in FIG. 3 (c). To form

Next, as shown in FIG. 5, the piezoelectric element block 150 is bonded to the substrate 110, and a diamond cutter or the like is used to cut the first slit reaching the substrate 110 using a cutting tool. 16a and 16b are formed.

Then, the entire surface of the piezoelectric element block 150 and the substrate 110 is A gold (Au) thin film is formed by thin film forming means such as vacuum evaporation, and the upper surface of the substrate 110, the end surface of the piezoelectric element block 150, and the first slits 160a and 160b are formed. An electrode film 16 1 is formed on the inner surface.

The second slit 163 shown in FIG. 5 (not shown in FIG. 7) is added to the laminated piezoelectric actuator block 162 thus formed. The first slit 1 It is formed almost perpendicularly to 600a and 160b with a diamond cutter or the like. This second slit 163 reaches the substrate 110 but has a shallower depth than the first slit 160. By forming the second slits 163 sequentially at a constant pitch, the multilayer piezoelectric actuator 111 is completed.

By the above-described steps, the electrode film 161 shown in FIG. 7 is separated into a plurality of patterns, and each laminated piezoelectric actuator 111 can be individually driven.

Next, as shown in Fig. 5, the pillars 114a are bonded to the substrate 110, and the upper surfaces of the multilayer piezoelectric actuator 111 and the pillars 114b, 114a are ground simultaneously. I do.

The order of the surface grinding step and the step of forming the second slit 163 may be reversed.

According to the above-described structure of the ink jet head and the method of manufacturing the multilayer piezoelectric actuator 111, the electrical connection structure for driving the multilayer piezoelectric actuator 111 is formed by thin film forming means and grinding. Easy to form.

Also, due to its structure, the protrusion of the laminated piezoelectric actuator 111 is small, and defects such as chipping are unlikely to occur. Furthermore, since there is no difficult manufacturing process, each component can be formed with high precision, and since each component can be easily assembled by stacking and bonding, the manufacturing cost is low. Next, an ink jet head according to a third embodiment of the present invention will be described. Will be described.

The ink jet head according to the third embodiment differs from the ink jet head shown in the first and second embodiments in the arrangement structure of the nozzle holes 119 and the multilayer piezoelectric actuator 1. This is a configuration in which the arrangement structure of 11 is changed. Therefore, portions other than the above-described arrangement structure are substantially the same as those of the first and second embodiments, and description of the common portions will be omitted as appropriate.

FIG. 8 is a plan view of the nozzle plate 120, the flow channel plate 118, the vibration plate 115, and a part of the multilayer piezoelectric actuator and etaunit 112, which are cut away.

In FIG. 8, the axis X 1 and the axis X 2 are axes passing through the nozzle holes 119 provided in the nozzle plate 120 and indicate the arrangement direction of the nozzle holes 119. The axis Y is an axis orthogonal to the axis XI and the axis X2 on the nozzle plate 120 (in this embodiment, a pair of laminated piezoelectric actuators 111, polarized in the direction perpendicular to the plane of FIG. 8). 1 1 1 are arranged in series on the axis Y and the axis Z inclined at a small angle.

Further, a plurality of pairs of the laminated piezoelectric actuators 111 are arranged along the axis XI and the axis X2 at an arrangement interval of P1. The plurality of pressure chambers 1 16 formed in the flow path plate 1 18 are also formed in parallel with the axis Y and the axis Z inclined at a slight angle, corresponding to the laminated piezoelectric actuators 111 respectively.

And, in each nozzle plate 120, a nozzle hole 119 is formed so as to communicate with each pressure chamber 116.

Here, the nozzle holes 1-9 on the axis XI and the nozzle holes 119 on the axis X2 are both arranged at the pitch of P1 in the coaxial direction. Then, assuming that the distance between the adjacent nozzle holes 1 and 19 on the axis X 1 and the axis X 2 is P 2, and the distance between the axis X 1 and the axis X 2 is S,

P 2 = S X t a η Θ = P 1/2

It is set to be.

用紙 Corrected paper (¾E lj91) When the ink jet head configured as described above is moved relative to the printing medium such as paper in the direction of the axis Y in FIG. 8 to perform a printing operation, the nozzle in the direction of the axis X1 (axis X2) is obtained. Since the arrangement pitch of the holes 1 19 is 12 compared to the first and second embodiments, the number of printed pixels is twice as high and an extremely high quality image can be obtained. it can.

In the embodiment of the present inventor, the laminated piezoelectric body adhered to the substrate 110 is grooved at a pitch of 150 dpi, and the arrangement pitch of the nozzle holes 119 is set to a high density of 300 dpi. Was completed. At this time, since the inclination であ is a very small inclination of about 0.33 radians, the shape of the laminated piezoelectric actuator 111 and the pressure chamber 111 is actually changed to an extreme parallelogram as shown in FIG. It did not take shape.

Next, a fourth embodiment of the present invention will be described mainly with reference to FIG.

The configuration other than the laminated piezoelectric actuator unit 170 described later is the same as that of the above-described second embodiment.

The laminated piezoelectric unit 170 of this embodiment will be described along with the manufacturing process. '

As in the second embodiment, the laminated piezoelectric block 17 1 is formed by alternately laminating a plate-shaped piezoelectric material and a conductive material and subjecting them to a pressure sintering process. The center of the laminated piezoelectric block 17 1 In this case, the first slits 17 2a and 17 2b are formed, and the drive current collectors 17 3a and the first slit 17 A common collector electrode 173b is formed in each of 2a and 172b.

A second slit similar to the second slit 163 (see FIG. 5) in the second embodiment is provided on the laminated piezoelectric block 17 1 thus formed by the first slit. The slits are formed at a constant pitch almost perpendicular to the slits 17a and 17b. As a result, a multilayer piezoelectric actuator unit 170 is completed.

In addition, the drive collector electrode 173a is separated by another slit processing at the same pitch as the second slit, and is separated into each laminated piezoelectric block 1771. Another drive electrode is formed.

After that, as in the second embodiment, the diaphragm 1 15, the flow path plate 1 18, and the nozzle plate 120 are overlapped and joined to complete an ink jet head.

In this embodiment, the base plate 110 and the columns 114a and 114b in the ink jet head of the second embodiment are not formed as separate members but are formed by the laminated piezoelectric actuator itself. It is in the point which did.

In other words, the bottom of the laminated piezoelectric block 171, and the vicinity of the outer end and the center of the block 171, are connected to each other to drive the plate-shaped piezoelectric materials 130, 140 one by one. One of the opposing conductive materials 13 1 and 14 1 does not exist. Therefore, these portions do not deform even when a voltage is applied to the laminated piezoelectric block 17 1. Therefore, the bottom part of the laminated piezoelectric block 171 is used as a substrate, and the outer end and the center of the block 171 are used as pillars, thereby reducing the number of parts.

Therefore, according to the fourth embodiment, the cost of parts can be reduced, the number of manufacturing steps can be reduced, and the manufacturing can be simplified.

Next, a fifth embodiment of the present invention will be described with reference to FIG.

The configuration of the eject head of the present embodiment is the same as that of the above-described first to fourth embodiments, except for the laminated piezoelectric actuator unit 180 described later.

This embodiment is a modification of the bonding structure of the laminated piezoelectric actuator, the diaphragm, and the flow path plate in the above-described first to fourth embodiments. That is, as shown in FIG. A plurality of stacked piezoelectric actuator units 180 arranged in each case are alternately divided into a driving actuator 183 and a non-driving actuator 184 in each row. The non-driving actuators 184 provided in every other row are used as pillars.

Corrected paper Then, the diaphragm 18 1 is joined to the upper end surface of the driving actuator 18 3 and the non-driving actuator 18 4 as a support, and the flow path plate 18 2 is joined to the upper surface of the diaphragm 18 1. I have. Here, diaphragm 18 1 is sandwiched between non-driven actuator 18 and partition wall of flow path plate 18 2.

Further, a nozzle plate 120 is connected to the upper end surface of the flow path plate 18. .

With such a configuration, the supporting condition of the diaphragm 18 1 is constant, so that a variation in the ink discharge performance can be prevented, and interference between adjacent pressure chambers can be prevented.

Next, an ink jet head according to a sixth embodiment of the present invention will be described with reference to FIGS. 11 and 12. FIG.

The ink jet head according to the sixth and subsequent embodiments of the present invention has substantially the same configuration as the ink jet head according to the fifth embodiment described so far, with respect to the laminated piezoelectric actuator unit. However, the configuration of the pressure chamber and the principle of ink ejection are essentially different.

That is, up to the first to fifth embodiments, the structure in which the pressure chamber is pushed by the laminated piezoelectric actuator provided outside the pressure chamber to discharge the ink is used. In the inkjet head, a pressure chamber is formed inside the laminated piezoelectric actuator.

Therefore, drawings (FIGS. 11 to 18) showing the sixth and subsequent embodiments will be described with new reference numerals.

As shown in FIGS. 11 and 12, the first plate-shaped piezoelectric material 1a is bonded to the second plate-shaped piezoelectric material 1b via the first conductive material 2a. . Furthermore, the second plate-shaped piezoelectric material 1b is bonded to the third plate-shaped piezoelectric material 1c via the second conductive material 2b.

Here, the first plate-shaped piezoelectric material 1a is polarized in the thickness direction, and the second plate-shaped piezoelectric material 1b is polarized in the opposite direction to the first plate-shaped piezoelectric material 1a. ing. The third plate-shaped piezoelectric material 1c is polarized in the opposite direction to the second plate-shaped piezoelectric material 1b.

Corrected paper (thin!) 91 The partition 10 is formed by sequentially laminating a necessary number of conductive materials and plate-like piezoelectric materials in the same configuration.

On one end face of the partition wall 10, a first collector electrode 3a made of a gold (Au) thin film or the like formed by a thin film forming means such as a vacuum evaporation method is provided. The first conductive material 2a, the third conductive material 2c, and the like are electrically connected to the first collector electrode 3a.

On the other hand, a second collector electrode 3b is provided on the other end surface of the partition wall 10 by the same method as the first collector electrode 3a, and the second conductive material 2b and the fourth conductive material 2d and the like are electrically connected to the second collector electrode 3b.

With such a configuration, when a voltage is applied between the first collector electrode 3a and the second collector electrode 3, a potential difference is generated between the conductive materials, and an electric field is generated in the thickness direction of the plate-like piezoelectric material. Occurs. For this reason, the partition wall 10 functions as a piezoelectric element block.

A plurality of the partition walls 10 are arranged in a matrix on the substrate 11 where the ink supply port 13 is opened. These partition walls 10 are fixed to the substrate 11 with an adhesive, forming vertical gaps 20 and 21 and a horizontal gap 29 between the partition walls 10.

Further, a sealing member 22 is adhesively fixed on the substrate 11 so as to be in contact with the outer end surface of the partition wall 10 in the longitudinal direction. A lid 14 is provided so as to cover the vertical gaps 20 and 21 and the upper surface of the sealing member 22, and is surrounded by the partition wall 10, the sealing member 22 and the lid 14. A plurality of pressure chambers 15 are formed.

The lid 14 is formed with a plurality of ink jet ports 23 communicating with the respective pressure chambers 15.

On the upper surface of the substrate 11, a wiring pattern 25 electrically connected to the collecting electrodes 3a and 3b of the partition wall 10 is provided. The wiring pattern 25 is connected to the flexible wiring board 26, and an external driving voltage is applied to the collecting electrode of the partition wall 10 via the flexible wiring board 26 and the wiring pattern 25. 3a, 3b I have.

Although not shown in FIGS. 11 and 12, the ink supply port 13 can be supplied with ink from a common ink reservoir of an ink cartridge.

Although the ink supply port 13 is formed on the substrate 11 in this embodiment, it may be formed on the sealing member 22 or the lid 14.

In the above-described inkjet head, in order to realize high-density mounting of the partitions 10, the partitions 10, which are laminated piezoelectric actuators, are arranged in two rows, and the ink ejection ports 23 are opened in the thickness direction. I did it. Note that the partition walls 10 may be arranged in a single row depending on the application.

Next, the operation of the inkjet head according to the above-described embodiment will be described with reference to FIG. 11 and FIG.

When power is supplied to the first collector electrode 3a and the second collector electrode 3b from the flexible wiring board 26 connected via the wiring pattern 25, the first conductive material 2a, A voltage is generated between the conductive materials 2b. Then, an electric field is generated in the thickness direction in the second plate-shaped piezoelectric material 1b.

This second plate-shaped piezoelectric material 1b is polarized in the thickness direction opposite to the electric field. Therefore, the second plate-shaped piezoelectric material 1 b is contracted in the thickness direction (d _{3 3-way} direction).

Here, the thickness t of the plate-shaped piezoelectric material 1 b, deformation amount [delta] t, the applied voltage V, and the piezoelectric constant in the thickness direction when the d _33, the strain is proportional to the field strength, [delta] t / t = d ₃₃ V / t,

That is, 5 t = d ₃₃ V. That is, the above equation means that the amount of deformation is proportional to the voltage and does not depend on the thickness of the piezoelectric material.

Each of the laminated plate-shaped piezoelectric materials undergoes the same deformation as the second plate-shaped piezoelectric material 1b, and the deformation in the entire thickness direction is caused by the lamination of the plate-shaped piezoelectric material having electrodes formed on both sides. In proportion to the number m, m X δ t

Corrected form HIJ91) Therefore, a large amount of deformation can be obtained.

Further, although smaller than the deformation amount in the thickness direction as described above (d _{3 3} direction), the partition 1 0 is a piezoelectric material, occurred elongation in length direction (d _{3 I} direction), by the deformation can also reduce the volume of the pressure chamber 1 5, the force that occurs due to the deformation in the thickness direction of the above-mentioned plate-shaped piezoelectric material (d _{3 3} direction) is large, thereby the cross-sectional area of the pressure chamber 1 5 S Then, the volume of only SX m X δ t contracts. Due to the contraction of the volume, that is, the change in the volume, a pressure is generated in the pressure chamber 15, and the ink droplet 17 can be ejected from the ink ejection port 23.

The amount of change in the volume of the pressure chamber 15 needs a certain amount to form the ink droplet 17. However, in the ink jet head according to the above-described embodiment, a single piezoelectric element block is used. With this configuration, a sufficiently large volume change can be obtained. Therefore, a stable ink droplet 17 can be formed.

Further, in the ink jet head according to the above-described embodiment, since the deformation amount of one piezoelectric element block can be amplified to m times, the cross-sectional area S of the pressure chamber is one step when the piezoelectric element block is constituted by one piezoelectric element block. m, and the pressure chamber can be downsized.

For this reason, the length of the pressure chamber 15 can be reduced. This is advantageous for ink supply, as described below.

In order to generate ink droplets 17 continuously, the same amount of ink as the discharged ink droplets 17 is quickly supplied from the ink supply port 13 into the pressure chamber 15. There must be. In the above-described embodiment, the ink supply port 13 opens to the pressure chamber 15 at the end opposite to the ink injection port 23.

Therefore, in order to continuously form the ink droplet 1 Ί, it is preferable that the duct resistance of the ink flow path formed in the length direction of the pressure chamber 15 is small and short.

According to the inkjet head of this embodiment, the laminated piezoelectric element The thickness direction of the partition wall 10 composed of blocks, that is, the height dimension of the pressure chamber 15 depends on the thickness and the number of laminated piezoelectric materials. By increasing the number of plate-shaped piezoelectric materials, the height of the pressure chamber 15 can be increased, and the volume change can be increased.

Basically, the generated pressure is proportional to the volume change Z pressure chamber volume. For this reason, the increase in the volume of the pressure chamber can be compensated for by the volume change, so that the discharge force does not decrease.

If the height of the partition 10 is increased, the sectional area of the pressure chamber 15 can be increased. For this reason, the pipe resistance of the ink flow path formed in the pressure chamber 15 can be reduced, and the length of the ink flow path can be shortened. Therefore, the ink supply capacity is improved. Thus, a stable ink droplet 17 can be formed continuously. For this reason, the characteristics when ink droplets 17 are continuously ejected are improved.

Even if the same operation is performed with a single-layer partition structure, the volume change of the pressure chamber does not change, but the volume increases by the increase in the thickness of the pressure chamber, and the generated pressure decreases.

In order to increase the generated pressure, the applied voltage may be increased. For example, it is not practical to increase the applied voltage further than 150 V.

Further, in the inkjet head according to the present embodiment, since the piezoelectric element block is configured by laminating a plurality of plate-shaped piezoelectric materials, the amount of deformation of the piezoelectric element block can be amplified in proportion to the number of laminated layers. . Therefore, the applied voltage required to obtain a certain amount of deformation can be made lower than that of a piezoelectric element block formed of a single piezoelectric material, and low-voltage driving of 50 V or less can be performed.

The most characteristic feature of the ink jet head according to the present embodiment is that a plurality of pressure chambers 15 can be arranged in a matrix on the substrate 11. As a result, as shown in FIG. 11, independent pressure chambers 15a and 15b can be formed on the vertical gap 21.

Thus, the independent pressure chambers 15 on the substrate 11 are formed in a matrix.

用紙 Corrected paper (^ | J ₉₁ ) By arranging the ink jets 23 corresponding to the respective pressure chambers 15, a plurality of rows of the ink jets 23 can be formed. Therefore, it is possible to make the inkjet head a multi-nozzle.

This feature is attributed to the fact that the partition wall 10 is composed of the laminated plate-like piezoelectric materials and that a large amount of deformation can be obtained by driving this, that is, a large amount of deformation can be obtained. 5 can be made smaller, and accordingly, a plurality of independent pressure chambers 15 can be arranged in a matrix on the substrate 11.

In the above-described embodiment, the ink is ejected by the contraction of the piezoelectric element block. However, the direction of the electric field to be generated and the polarization direction of the plate-shaped piezoelectric material are set to the same direction, and the thickness of the plate-shaped piezoelectric material is increased. To increase the volume of the pressure chamber 15 and then stop applying voltage to generate pressure when the piezoelectric element block is returned to its original state. Injection is also possible.

The vertical gap 20 shown in FIG. 11 is filled with ink as a pressure chamber 15, and the adjacent vertical gap 21 forms a gap-free space filled with ink. .

By forming the dummy space not filled with the ink, the pressure chambers 15 formed by the adjacent vertical gaps 20 and 20a can be individually driven.

Therefore, it is possible to freely drive in terms of time. For example, it is possible to simultaneously inject the ink in the adjacent pressure chambers 15 or to inject one of them with a delay.

In the case where the vertical gap 21 is not a dummy space that is not filled with ink, the partition wall 10 between the adjacent pressure chambers 15 is shared for driving the pressure chambers 15. Therefore, it is necessary to set conditions so that when one of the pressure chambers 15 is driven, the ink droplets do not fly out of the adjacent pressure chambers.

Specifically, it is necessary not to displace more than a certain amount. Complicated settings such as selecting a drive timing that prevents the ink from popping out according to the liquid level vibration of the meniscus of the injection port are required.

Since the vertical gap 21 serving as the dummy space is formed only for the function of making the partition wall 10 of the adjacent pressure chamber 15 independent, it is sufficient that the width is such that the adjacent partition wall 10 does not contact. .

It is effective to increase the arrangement pitch density of the pressure chambers 15 by reducing the width of the vertical gap 21 forming the dummy space to the width of the processing limit. Therefore, it is possible to obtain a small head having a higher nozzle pitch.

Next, FIGS. 13 (a), 13 (b), 14 (c), 14 and 15 show a method of manufacturing the above-described inkjet head according to the present embodiment. It will be described with reference to FIG.

First, as shown in FIG. 13 (a), the first conductive material 2a is placed on the upper surface of a first green sheet made of piezoelectric ceramic, which is the first plate-like piezoelectric material 1a. Is formed by a printing method. At this time, the surface central part 41a of the first plate-shaped piezoelectric material 1a is exposed without being covered with the first conductive material 2a.

Next, as shown in FIG. 13 (b), a new second green sheet to be the second plate-like piezoelectric material 1b is stacked on the first conductive material 2a, and the A second conductive material 2b is formed on the surface by a printing method. At this time, both edge portions of the second plate-shaped piezoelectric material 1b are exposed without being covered with the second conductive material 2b.

After a predetermined number of green sheets and conductive materials, which are to be plate-like piezoelectric materials, are alternately stacked and subjected to pressure sintering, a piezoelectric element block 6 as shown in FIG. 13 (c) is obtained. 0 can be formed. <Next, as shown in FIG. 14, a piezoelectric element block 60 is bonded to the upper surface of a substrate 11 made of a glass material or the like.

Then, a part of the piezoelectric element block 60 and a part of the substrate 11 are re-cut with a cutting tool such as a diamond cutter to form a lateral gap 29. Further, while the upper surface 61 of the piezoelectric element block 60 is masked, a thin film made of a conductive material such as gold (Au) is applied to the entire surface of the piezoelectric element block 60 and the substrate 11 by a vacuum deposition method or the like. The electrode 70 is formed.

At this time, the first conductive material 2a, the second conductive material 2b, and the like in the piezoelectric element block 60 are applied to the electrodes 70a and 70b formed on the wall surfaces 70a and 70b of the piezoelectric element block 60, respectively. Is electrically connected to the

Subsequently, as shown in FIG. 15, the piezoelectric element block 60 and a part of the substrate 11 are cut by a cutting tool such as a diamond cutter in a direction perpendicular to the lateral gap 29. As a result, a partition 10, a vertical gap 20, and a vertical gap 21 are formed, and the piezoelectric elements 0, 0, and 0 are separated from the electrode 70.

Then, as shown in FIG. 11, a sealing member 22 is adhered to the end of the partition 10, and a lid 14 made of a glass material or the like in which the ink ejection port 23 is formed is adhered to the partition 10. Thus, a plurality of pressure chambers 15 can be formed.

According to the above-described manufacturing method, as shown in FIG. 15, the first current collector 80a and the second current collector each electrically connected to a conductive material for driving the piezoelectric element block. 80 b and the third collector electrode 80 c can be easily formed at both ends of the partition wall 10.

Further, as shown in FIG. 15, a first current collector 80a and a second current collector 80b are provided at both ends of the first row of partition walls 10a, and By arranging the second collector electrode 80b and the third collector electrode 80c at both ends of the second row of partition walls 10b, connection with an external drive line is facilitated. So effective.

Further, according to the above-described manufacturing method, as shown in FIG. 15, a wiring pattern 81 for supplying power to the first collecting electrode 80a can be formed on the substrate 11; The wiring pattern 82 for supplying power to the second collecting electrode 80b and the wiring pattern 83 for supplying power to the third collecting electrode 80c can be formed simultaneously. . According to the configuration in which the wiring patterns 81, 82, and 83 shown in FIG. 15 are formed on the substrate 11, electrical connection with the flexible wiring board 26 shown in FIG. It has an effect.

Here, the second collecting electrode 80b is a common electrode that drives the first row of partitions 1Oa and the second row of partitions 10b. As a result, since all the partition walls 10 use the wiring pattern 82 on the substrate as a common electrode, the number of electrical connection points with the flexible wiring board 26 can be reduced.

The manufacturing method for forming the structure of the ink jet head in the sixth embodiment has been described above, but the present invention is not limited to this structure.

For example, the substrate 11 is not limited to a glass material, but may be formed of a material such as ceramic or plastic.

In addition, as for the lid 14, ceramic, plastic, metal material, etc. can be applied in addition to glass material.

In addition, although a piezoelectric ceramic is used as the plate-like piezoelectric material, an organic high molecular weight piezoelectric film can be used.

No electrode is formed on the bonding surface between the partition wall 10 and the substrate 11 and between the partition wall 10 and the lid 14. However, a plate-like piezoelectric material adjacent to the substrate and the lid can be driven by providing a conductive material on the surface of the substrate and the lid of the piezoelectric element block 60 and forming electrodes. Furthermore, although the vacuum deposition method was used to form the collector electrode, an electrode may be formed on the end face of the piezoelectric element block using a conductive coating. Then, a flexible wiring board may be directly connected from the collector electrode on the piezoelectric element block.

Next, an ink jet head according to a seventh embodiment of the present invention will be described with reference to FIGS. 16 and 17. FIG.

On the substrate 1 1, _t partition wall 1 0 that is bonded by disposing a plurality of partition walls 1 0 in a row has the same structure as the sixth embodiment. That is, the partition 10 is made of the first plate-shaped piezoelectric material 1 a and the first conductive material 2. a, and the second plate-shaped piezoelectric material 1 b is bonded to the second plate-shaped piezoelectric material 1 b via the second conductive material 2 b. Are formed so as to be bonded to each other, thereby forming a laminated piezoelectric actuator.

Here, the first plate-shaped piezoelectric material 1a is polarized in the thickness direction, and the second plate-shaped piezoelectric material 1b is polarized in the opposite direction to the first plate-shaped piezoelectric material 1a. I have. The third plate-shaped piezoelectric material 1c is polarized in the opposite direction to the second plate-shaped piezoelectric material 1b.

On one end face of the partition wall 10, a first collector electrode 3a made of a gold (Au) thin film or the like formed by a thin film forming means such as a vacuum evaporation method is provided. The first conductive material 2a and the like are electrically connected to the first collector electrode 3a.

On the other hand, a second collector electrode 3b is provided on the other end surface of the partition wall 10 by the same method as the first collector electrode 3a, and the second conductive material 2b and the like are provided in the second collector electrode 3b. Is electrically connected to the collector electrode 3b.

With such a configuration, when a voltage is applied between the first collector electrode 3a and the second collector electrode 3b, a potential difference is generated between the conductive materials, and the potential difference occurs in the thickness direction of the plate-like piezoelectric material. An electric field is generated. For this reason, the partition wall 10 functions as a laminated piezoelectric actuator.

The gaps 20 and 21 formed between the partition walls 10 are closed at one end surface in the length direction by the sealing member 22. A nozzle plate 24 having a nozzle hole 23 is provided on the other end surface of the gaps 20 and 21. The nozzle plate 24 also functions as a sealing member for the gaps 20 and 21.

Further, a cover 14 is provided so as to cover the upper portions of the gaps 20 and 21. The lid 14 is bonded and fixed to the upper surface of the partition 10. With the above configuration, the gap 20 forms the pressure chamber 15. The gap 21 adjacent to the gap 20 is a dummy space to which no ink is supplied, as in the sixth embodiment.

The lid 14 has an ink supply port 13 formed therein.

Corrected form (Rule 91) An ink is supplied from the supply port 13 into the pressure chamber 15.

In the ink jet head of the present embodiment, the ink supplied from the ink supply port 13 into the pressure chamber 15 is discharged from the nozzle hole 23 in the length direction. Also in this embodiment, a stable ink droplet 17 can be formed as in the sixth embodiment.

FIG. 18 shows a modification of the sixth and seventh embodiments described above.

That is, in the ink jet head according to the sixth or seventh embodiment, the plurality of vertical gaps 20 filled with ink may be covered with independent lids 30 respectively.

With such a configuration, there is no mechanical effect such as displacement of the partition wall 10 for ejecting ink droplets or vibration transmission due to deformation of the lid 30 on the adjacent pressure chamber 15. . Therefore, interference between the pressure chambers 15 can be completely prevented.

In the inkjet heads according to the sixth and seventh embodiments, it is preferable to form an insulating coating film on the inner surface where the pressure chamber is formed.

For example, a coating film 40 is formed on the inner surface of the partition wall 10 forming the pressure chamber 15 shown in FIG. 18 by chemical vapor deposition using a polyparaxylene resin or the like.

A drive electrode that is electrically connected to the conductive material is exposed on the inner surface of the partition wall 10 that forms the pressure chamber 15. Therefore, there is a disadvantage that the usable ink is limited, for example, a water-based ink cannot be used with the structure as it is. Therefore, by forming the coating film 40 having high electrical insulation on the partition wall 10 in the pressure chamber 15, it is possible to prevent the drive electrode from coming into contact with the ink.

Therefore, the drive electrode does not corrode or generate gas due to the chemical change of the ink, and it is possible to use any of an aqueous ink and an oily (non-aqueous) ink.

In addition, the conductive material is used in advance in the partition 10 that forms the pressure chamber 15 in advance.

Sharpened paper If the piezoelectric element block is formed so as to be embedded in the portion, various inks can be used without forming a coating film. Industrial applicability

INDUSTRIAL APPLICATION This invention can be utilized as a head of various ink jet printers.

ADVANTAGE OF THE INVENTION According to this invention, it can drive efficiently with little energy loss, can be manufactured at low cost by a simple structure, and can provide a small, high-density ink jet head with high reliability. Becomes

Claims

The scope of the claims

1. Substrate and a pair of laminated piezoelectric Akuchiyueta laminated piezoelectric § Chi Yu eta Interview Stevenage comprising a plurality rows of Bok having piezoelectric strain constant d _{3 3} which are arranged on the substrate so as to form opposite each other collectors to both end surfaces A common electrode formed by coupling between collector electrodes formed on opposing end faces in the center of the substrate of each of the laminated piezoelectric actuators; and a collector electrode formed on the other end face of each of the laminated piezoelectric actuators. An ink jet head comprising: a drive electrode comprising: a plurality of piezoelectric actuators;

2. A laminated piezoelectric element block disposed on the upper surface of the substrate, a first slit separating a central portion of the laminated piezoelectric element block, and shallower than the first slit and substantially equal to the slit. The claim 1 characterized in that the multilayer piezoelectric actuator unit is formed by a plurality of second slits which cut out the multilayer piezoelectric element block in a direction perpendicular to the multilayer piezoelectric element block. The described ink jet head.

3. The ink jet head according to claim 1, wherein the uppermost layer and the lowermost layer of each of said laminated piezoelectric actuators are non-driving dummy layers.

4. The inkjet head according to claim 1, wherein a plurality of drive electrodes electrically connected to the drive electrodes of each of the laminated piezoelectric actuators are formed on the substrate. .

5. Board and a pair of laminated piezoelectric Akuchiyueta laminated piezoelectric § Chi Yu eta Interview Stevenage comprising a plurality rows of Bok having piezoelectric strain constant d _{3 3} which are arranged on the substrate so as to form opposite each other collectors to both end surfaces Current collectors formed on opposing end faces in the center of the substrate of each of the laminated piezoelectric actuators. A common electrode formed by coupling the poles, a driving electrode formed of a collector electrode formed on the other end surface of each of the laminated piezoelectric actuators, and a vibration bonded to an upper end surface of the laminated piezoelectric actuator unit A plate, a plurality of pressure chambers corresponding to the respective laminated piezoelectric actuators, a flow path plate having an ink supply path, and joined to the diaphragm, and a plurality of nozzle holes corresponding to the pressure chambers. An ink jet head comprising: a nozzle plate joined to an upper surface of the flow path plate.

6. The laminated piezoelectric actuators located in the front row and the last row of the laminated piezoelectric actuator unit are inactive bodies that are not driven, and both ends of the flow path plate are connected to the upper end surface of these laminated piezoelectric actuator units. 6. The ink jet according to claim 5, wherein the lid is supported.

7. Substrate and, laminated piezoelectric § Chi Yu eta Interview Knitting comprising a plurality rows of the pair of laminated piezoelectric Akuchiyue Ichita having a piezoelectric strain constant d _{3 3} which are arranged on the substrate so as to face each other to form a collecting electrode on both end faces A support provided on an upper surface of the substrate and on both sides of the laminated piezoelectric actuator; and a diaphragm bonded to an upper end surface of the laminated piezoelectric actuator and the support. A flow path plate having a plurality of pressure chambers and an ink supply path corresponding to each laminated piezoelectric actuator and joined to the diaphragm, and a flow path having a plurality of nozzle holes corresponding to the pressure chambers; An ink jet head comprising a nozzle plate bonded to an upper surface of the plate.

8. The collector electrodes formed on the opposite end faces in the center of the substrate of each of the multilayer piezoelectric actuators are connected to each other to form a common electrode. The collector electrodes formed on the other end faces of the multilayer piezoelectric actuators are connected to each other. 8. The ink jet head according to claim 7, wherein the drive electrode is a driving electrode.

9. The ink jet head according to claim 7, wherein both end portions of said diaphragm are sandwiched between said column and said flow path plate.

10. The ink jet head according to claim 9, wherein a second support for supporting the vibration plate is arranged at a central portion of the upper surface of the substrate.

11. The ink jet as set forth in claim 7, 8, 9 or 10, wherein said support column elastically supports an outer side end face of each of said laminated piezoelectric actuators. Good.

12. A multilayered piezoelectric actuator unit consisting of a plurality of rows of a pair of multilayered piezoelectric actuators having _a piezoelectric strain constant da3 arranged on the substrate so that collector electrodes are formed on both end surfaces thereof and opposed to each other. A vibration plate joined to the upper end surface of the laminated piezoelectric actuator unit, a flow path plate having a plurality of pressure chambers and an ink flow path corresponding to each drive actuator, and a pressure plate corresponding to each of the pressure chambers. A nozzle plate having a plurality of nozzle holes, wherein the laminated piezoelectric actuators are arranged as drive actuators in every other row, and the non-driven actuators which do not drive other laminated piezoelectric actuators are provided. An ink jet head characterized in that the diaphragm is sandwiched between a flow path plate and the nozzle plate is bonded on the flow path plate.

13. Each of the laminated piezoelectric actuators and each of the pressure chambers are arranged obliquely with respect to an axis orthogonal to an axis passing through the nozzle holes, and the nozzle holes are formed corresponding to the pressure chambers. The inkjet head according to claim 5, 7 or 12, wherein the inkjet head has been manufactured.

14. At least the laminated piezoelectric actuator, the vibration plate, the flow path plate, and the nozzle plate have substantially the same linear expansion coefficient. An ink jet head according to claim 5, 7, or 12.

1 5. Substrate and, laminated piezoelectric Akuchiyue one Tayuni' Bok pressure chamber comprising a plurality of rows of the pair of laminated piezoelectric Akuchiyueta having a piezoelectric strain constant d _{3 3} which are arranged on the substrate so as to face each other to form a collecting electrode on both end faces This is a method of driving an ink jet head that injects the ink of

In a first step, a voltage is applied in the polarization direction of the multilayer piezoelectric actuator to extend the multilayer piezoelectric actuator in the thickness direction, and in a second step, the applied voltage is gradually reduced to cause an ink to enter the pressure chamber. In the third step, the laminated piezoelectric actuator is stretched in the thickness direction by rapidly increasing the applied voltage again in the third step to eject the ink in the pressure chamber. The method of driving the inkjet head.

1 6. Substrate and both end faces to the laminated piezoelectric § Chi Yu eta Interview Knitting bets composed of a plurality rows of the pair of laminated piezoelectric Akuchiyueta having a piezoelectric strain constant d _{3 3} which are arranged on the substrate so as to face each other to form a collecting electrode A method for manufacturing an ink jet head in which ink in a pressure chamber is jetted, comprising:

In a first step, a first slit is applied to a central portion of the laminated piezoelectric body, and in a second step, electrodes are formed on both ends of the laminated piezoelectric body and the first slit, and a third slit is formed. Forming a plurality of second slits at a constant pitch in a direction substantially perpendicular to the first slits and shallower than the first slits in the step, and forming the plurality of laminated piezoelectric actuators on the substrate; And manufacturing an ink jet head by flattening the upper surface of the multilayer piezoelectric actuator in a fourth step.

1 7. Substrate and a pair having a piezoelectric strain constant d _{3 3} which are arranged on the substrate so as to face each other to form a collecting electrode on both end surfaces laminated piezoelectric Akuchiyueta A method of manufacturing an ink jet head in which an ink in a pressure chamber of a multilayer piezoelectric actuator unit comprising a plurality of rows is jetted.

In a first step, a first slit is formed in the center of the laminated piezoelectric body, and in a second step, electrodes are formed on both ends of the laminated piezoelectric body and the first slit, and a third slit is formed. In a step, the upper surface of the laminated piezoelectric body is flattened, and in a fourth step, a large number of second slits are formed in a direction substantially perpendicular to the first slits and at a constant pitch smaller than the first slits. Forming a plurality of the laminated piezoelectric actuators on the substrate by applying the method.

18. A substrate, comprising a plurality of partitions, a lid, and a sealing member formed by laminating a plurality of plate-like piezoelectric materials polarized in the thickness direction via a conductive material, and the plurality of partitions are provided on the substrate. The gap is formed as a pressure chamber by closing an upper portion of the gap with the lid, and closing a side portion of the gap with the sealing member, and forming the pressure chamber as a pressure chamber. An ink jet head characterized in that a nozzle hole is opened in a part of the ink jet head.

19. The ink jet unit according to claim 18, wherein the partition wall is a laminated piezoelectric actuator having _a piezoelectric strain constant da3 and deforming in a thickness direction by applying a voltage. Good.

20. A substrate, comprising: a plurality of partitions, a lid, and a sealing member formed by laminating a plurality of plate-like piezoelectric materials polarized in the thickness direction via a conductive material; The gap is formed as a pressure chamber by closing the upper part of the gap with the lid and closing the side of the gap with the sealing member. A nozzle hole that opens into the pressure chamber is provided in one of the base plate and the lid, and an ink supply port is provided in one of the substrate, the sealing member, and the lid, and the voltage is applied to the conductive material. Deform the bulkhead in the thickness direction A volume of the pressure chamber filled with ink, and ejecting an ink droplet from the nozzle hole.

21. The gap defined between the partition walls, wherein a pressure chamber for supplying ink and a dummy space for not supplying ink are alternately formed in the arrangement direction. 20. The ink head described in paragraph 20.

22. The inkjet head according to claim 18 or 20, wherein the lid independently closes each pressure chamber.

23. The ink jet head according to claim 21, wherein the gap forming the dummy space has a narrower width dimension than the gap forming the pressure chamber.

24. The ink jet head according to claim 18 or 20, wherein an insulating coating film is provided on a surface of said partition wall in contact with said pressure chamber.