JP3183107B2 - Method of manufacturing inkjet head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an ink jet head, and more particularly, to a method of manufacturing an ink jet head having a manufacturing step of forming a groove in a piezoelectric body and forming an electrode on the surface of the piezoelectric body. It is about.

[0002]

2. Description of the Related Art In recent years, among the non-impact type recording apparatuses which have been replacing the conventional impact type recording apparatuses and have been greatly expanding the market, the principle is the simplest, and the multi-gradation and colorization are realized. Is easy,
An ink-jet type recording device is exemplified. 2. Description of the Related Art Inkjet printers have attracted attention because of their advantages such as high-speed printing, low noise, high printing quality, and a relatively simple configuration that can reduce manufacturing costs.

[0003] A plurality of types of ink jet heads have been proposed for use in ink jet printers. Among them, a drop head that ejects only ink droplets used for recording is proposed.
The on-demand type is rapidly spreading due to its good injection efficiency and low running cost.

As one example, a piezoelectric ink jet head has been proposed. This is because a plurality of ink chamber grooves are formed in the piezoelectric body, and the volume of the ink chamber can be changed by dimensional displacement of the piezoelectric body when a voltage pulse is applied to the piezoelectric body. Thus, when the volume is reduced, the ink in the ink chamber is ejected from a nozzle connected to the ink chamber, and when the volume is increased, the ink is introduced into the ink chamber. By ejecting ink from the ink chamber at a predetermined position, a desired character or image can be formed.

An example of such a piezoelectric ink jet head will be described with reference to FIGS. The head described here is of a shear mode type.

In the ink-jet head, grooves are formed in parallel with each other by dicing or the like on a piezoelectric ceramic substrate 51 which is a piezoelectric body, and a large number of ink chambers 52 are formed. A nozzle plate 53 is connected to one end of the ink chamber 52. As shown in FIG. 7A, the piezoelectric side wall 57 forming the ink chamber 52 is formed by two piezoelectric side walls having different polarization directions 58.
An electrode 59 is formed on the surface of the piezoelectric side wall 57. A nozzle plate 53 is provided at one end of the ink chamber 52.
The nozzle plate 53 has a nozzle 54 formed therein. Further, the upper portion of the piezoelectric ceramic substrate 51 in which the ink chamber 52 is formed is covered by an upper cover 56 having an ink supply port 55. Ink chamber 52
Are connected to an ink storage tank (not shown) via an ink supply port 55. With such a configuration, the cross-sectional shape of the ink chamber 52 has a rectangular shape surrounded by the piezoelectric side wall 57 and the upper lid 56.

In the conventional ink jet head having such a structure, when a voltage pulse is applied to the electrode 59, the piezoelectric side wall 57 is sheared inward as shown in FIG. Is positive pressure, ink droplets are ejected from a nozzle 54 on a nozzle plate 53 connected to one end of the ink chamber 52.

When the application of the voltage pulse to the electrode 59 is stopped, the piezoelectric side wall 57 returns to the state shown in FIG.
At this time, ink is supplied to the ink chamber 52 from the ink supply port 55 by the negative pressure.

In the ink-jet head having such a configuration, it is necessary to have a large number of ink chambers 52 and selectively eject ink droplets from the nozzles 54 at the tip of each ink chamber. Therefore, the electrodes 59 formed on the surface of the piezoelectric side wall 57 of each ink chamber 52 need to be electrically independent of each other.

As a method for forming the electrode 59,
Generally, a metal thin film forming means such as vacuum deposition, sputtering, or plating is used. However, it is difficult to efficiently and stably form electrically independent electrodes by the above-described means. Therefore, an electrode is once formed on the entire surface of the piezoelectric body by the above-described means, and then a portion of the electrode is selectively removed, whereby an electrically discontinuous portion is arbitrarily formed. A way is being considered.

Here, as a conventional method of manufacturing an ink jet head including such steps, Japanese Patent Laid-Open No. 6-84 is disclosed.
A method disclosed in Japanese Patent Publication No. 50 is known.

According to this manufacturing method, first, the upper lid 56
Is removed by a chemical removal method such as a lift-off method disclosed in JP-A-6-64177, mechanical grinding or polishing, or the like. Next, as shown in FIG. 8, the electrode 59 formed on the bottom surface of the groove which is the ink chamber 52 is removed by a cutting means such as dicing as shown in FIG. That is, a diamond blade 60 having a thickness equal to or less than the width of the groove serving as the ink chamber 52 is inserted into the groove to form a cut having a depth equal to or greater than the thickness of the electrode 59, thereby forming the electrically discontinuous insulating portion 61. It is formed arbitrarily.

[0013]

SUMMARY OF THE INVENTION The present invention provides a low-cost, high-quality inkjet head manufacturing method by facilitating the formation of an independent electrode lead-out portion for controlling the ejection of each ink chamber. The purpose is to:

[0014]

In order to achieve this object, a method of manufacturing an ink jet head according to the present invention comprises a plurality of ejection channels for ejecting ink, the ejection channels constituting the ejection channels, and at least a part of which is polarized. Partition wall made of a piezoelectric material, and an actuator member provided on a side surface of each partition wall and having an electrode for generating a driving electric field in the piezoelectric material, and applying a voltage to the piezoelectric material. A method of manufacturing an ink jet head for ejecting ink droplets from said ejection channel by deforming said partition, comprising: forming a plurality of grooves on one surface of a piezoelectric plate at least partially made of a polarized piezoelectric material. A second step of forming a conductive layer on at least the groove forming surface and a surface different from the groove forming surface of the piezoelectric plate; DOO of the removed portion of the groove forming surface formed conductive layer, different from the third step of dividing the conductive layer into a plurality of electrodes independent for each of the groove, the groove forming surface of the piezoelectric plate and A fourth step of removing a part of the conductive layer formed on the surface and dividing the conductive layer into a plurality of electrode lead portions each of which is electrically connected to the electrode, and applying an electric power to the electrode lead portions divided and formed in the fourth step. And a fifth step of connecting wiring.

In the second step, a conductive layer is formed on at least the groove forming surface of the piezoelectric plate, a surface at which one end in the longitudinal direction of the groove opens, and a surface opposite to the groove forming surface. In the fourth step, a part of the conductive layer may be removed from a surface of the piezoelectric plate where one end in the longitudinal direction of the groove opens to a surface opposite to the groove forming surface to form the electrode lead portion. it can.

[0016]

According to the method of manufacturing an ink jet head according to the first aspect of the present invention having the above-described structure, a conductive layer having a simple pattern is formed, and then the conductive layer is divided, so that an independent groove is formed for each groove. An electrode and an electrode lead-out portion connected to the electrode are easily formed with a small number of steps.

According to the method for manufacturing an ink jet head according to the second aspect, the electrode lead portion extends to the side opposite to the groove forming surface via one end surface in the longitudinal direction of the groove. Therefore, it is possible to connect the electric wire from the driver or the like to the electrode lead portion without interfering with the members such as the nozzle plate and the ink supply port constituting the head.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings.

First, with reference to FIG. 1 and FIG. 2, an example of a configuration and a manufacturing method of an ink jet head of the present invention will be described.

As shown in FIG. 2, the piezoelectric ceramic substrate 1 which is a piezoelectric body is provided with a plurality of grooves which become ink chambers 2 which are parallel to each other, and is a side wall of the groove, and a piezoelectric side wall 7 separating each groove. Are formed. Piezoelectric ceramic substrate 1
A lid 6 having an ink supply port 5 is adhered to the surface on the groove processing side (the upper surface in FIG. 3), and the groove becomes the ink chamber 2.
The nozzle plate 3 is bonded to one end surface of the piezoelectric ceramic substrate 1 and the lid 6 so that the nozzle 4 corresponds to one end of the ink chamber 2. The ink chamber 2 is connected to an ink storage tank (not shown) via an ink supply port 5.

With such a configuration, the cross-sectional shape of the ink chamber 2 has a rectangular shape surrounded by the piezoelectric side wall 7 and the upper lid 6. The piezoelectric side wall 7 is composed of two piezoelectric portions whose polarization directions 8 are opposite to each other.
An electrode 9 is formed on the surface of the piezoelectric side wall 7. Electrode 9
Are provided independently for each side surface of the piezoelectric side wall 7, and as shown in FIG.
And an electrode lead portion 91 provided over the surface 13.
It is electrically conducting one to one. The electrode lead portion 91 is formed such that the end portion radially spreads on the surface 13.
Electrical wirings 15 from a driver that sends a drive control signal for the head are respectively connected to the electrical connection terminals 16 which are the ends.

The above structure is formed by the following manufacturing method.

First, a large number of grooves that become ink chambers 2 that are parallel to each other are formed on a piezoelectric ceramic substrate 1 to which piezoelectric layers whose polarization directions are opposite to each other are bonded. As a means for forming the grooves, dicing is performed using a diamond blade having a thickness capable of forming a desired ink chamber groove width. Here, the distance between the center of the groove of the ink chamber 2 is W1.

Next, the surface of the piezoelectric ceramic substrate 1 on which the grooves are formed (including the inner surfaces of the grooves) and the surface 11 corresponding to one end surface of the ink chamber 2 are formed by a metal thin film forming means such as vacuum evaporation, sputtering, or plating. A conductive layer of a thin metal film is formed on a surface 13 opposite to the surface on which the groove is formed. Of these, a resist film is formed before forming a metal thin film on a portion where an electrode is not required to be formed (for example, on an upper portion of the piezoelectric side wall 7 to which the upper lid 6 is connected or on a side surface of the piezoelectric ceramic substrate 1). Then, a conductive layer is formed by the above-described means, and thereafter, unnecessary portions of the conductive layer are chemically removed by a lift-off method.

Next, the conductive layer formed on the bottom of the groove as the ink chamber 2 is removed by a cutting means such as dicing as in the conventional example. That is, a diamond blade having a thickness equal to or less than the width of the groove as the ink chamber 2 is inserted into the groove to form a cut having a depth equal to or greater than the thickness of the conductive layer, thereby forming an electrically discontinuous insulating portion 10. Is what you do. This insulating part 1
Due to 0, a part of the conductive layer is divided for each side surface of the piezoelectric side wall 7 to become the electrode 9.

Next, the upper surface of the piezoelectric side wall 7 to which the upper cover 6 is connected is formed on the surface 11 of the piezoelectric ceramic substrate 1 which is continuous with the surface of the ink chamber 2 on which the groove is formed, by dicing or the like as described above. Or an insulating portion 12 continuous with the insulating portion 10 is formed.

Further, laser processing is performed on the surface 13 which is continuous with the surface 11 described above. As a result, an insulating portion 14 continuous with the insulating portion 12 is formed on the front surface 13. The insulating portion 14 is formed so as to radially spread from a portion continuous with the insulating portion 12. As a result, an electrode lead portion 91 provided over the surface 11 and the surface 13 of the piezoelectric actuator and electrically connected to the electrode 9 is formed.

Hereinafter, an example of the electrode removal by the laser processing will be described in detail with reference to FIG. Laser processing has very few restrictions on the processing angle and processing shape as compared with the dicing processing and the like, and can process fine and complicated shapes and patterns at high speed. In this regard, it is preferable to perform radial patterning of the surface 13.

The wavelength of the light emitted from the YAG (yttrium aluminum garnet) laser oscillator 17 is 1.
06 μm (micrometer) YAG laser beam 18
Is incident on two sets of scanning mirrors 19 and 20 arranged on the optical path, is changed in direction, and is incident on an f · θ lens 21 arranged below the scanning mirror 20. The YAG laser light 18 is condensed by the f · θ lens 21 and forms a focal point 22 at a position at a predetermined focal length from the f · θ lens 21.

A galvanometer 23 and a control device 24 thereof are connected to one end of the scanning mirrors 19 and 20. With these configurations, the two sets of scanning mirrors 19 and 20 can swing at high speed independently of each other. .

Piezoelectric ceramic substrate 1 to be processed
Is disposed below the f · θ lens 21. Here, the piezoelectric ceramic substrate 1 is arranged such that the focal point 22 of the YAG laser beam 18 is formed in the vicinity of the surface 13 of the piezoelectric ceramic substrate 1 which is a processing portion.
At the focal point 22 of the YAG laser beam 18 of this embodiment,
Generally, the spot diameter of the laser light is 0.1 mm or less,
High power density can be obtained. The electrode 9 irradiated with the high power density YAG laser beam 18 is heated in a very short time, and evaporates. As a result, the surface 13
The conductive layer is locally removed from, forming an insulating portion.

The metal thin film component of the conductive film that evaporates flies upward due to the vapor pressure at the time of evaporation. This metal thin film component is connected to a dust collector (not shown), and is sucked by a dust collecting nozzle 23 arranged near the processing section.

The above processing is performed by using the scanning mirror 19,
While scanning at high speed in the longitudinal direction by the swing of 20,
By irradiating the YAG laser beam 10, the conductive layer removing process for forming one insulating portion 14 is completed. After that, the relative position between the YAG laser beam 10 and the piezoelectric ceramic substrate 1 is changed, and the process proceeds to the next processing of the insulating portion 14, and the laser processing is continued.

By the above processing, the conductive layer is removed from the surface 13 of the piezoelectric ceramic substrate 1, and the insulating portion 14 which is an electrically discontinuous portion on the surface 13 of the piezoelectric ceramic substrate 1 can be formed. In the laser processing apparatus, it is possible to easily obtain a desired removal pattern by setting a predetermined setting in the control device 24 for controlling the swinging of the two sets of scanning mirrors 19 and 20 in advance. The work is not particularly complicated.

Next, a plurality of electrical wirings 15 such as FPCs are independently connected to the electrode lead-out portions 91 electrically independent by the insulating portions 14 by soldering or the like.
Center distance W of electrode lead-out part 91 in electric connection part 16
2 is formed radially as described above, and is wider than the side wall interval W1 of the ink chamber 2 (W1 <W2). Therefore, the pitch of the electric wiring of the FPC to be connected can be made wide according to W2. That is, there is a margin in the accuracy of the FPC to be joined and the joining accuracy, and reliable electric connection can be performed even by using an inexpensive FPC or a joining device. In addition, this FPC
Independent voltage pulses can be applied to the electrodes 9 formed in the respective ink chambers 2 via the electric wiring 15 of
Desired ink ejection control can be performed.

Next, the operation of the inkjet head for ejecting ink will be described with reference to the sectional view of the piezoelectric inkjet head shown in FIG.

In the ink jet head, for example, when the ink chamber 2b is selected according to the given print data, a positive drive voltage is applied to the metal electrodes 9a, 9d,
The metal electrodes 9b and 9c and other metal electrodes corresponding to the ink chambers are grounded. As a result, a driving electric field directed to the right in the drawing is generated on the piezoelectric side wall 7a, and a driving electric field directed to the left in the drawing is generated on the side wall 7b. At this time, since the direction of each drive electric field is orthogonal to the polarization direction 8 of the piezoelectric ceramic plate, the side walls 7a and 7b are bent inside the ink chamber 2b by the piezoelectric thickness-shear effect so as to bend at the joint of the piezoelectric ceramic plates. Rapidly deforms in the direction (Fig. 4
(B)).

Due to these deformations, the volume of the ink chamber 2b decreases, the ink pressure in the ink chamber 2b rapidly increases, a pressure wave is generated, and ink droplets are discharged from a nozzle (not shown) communicating with the ink chamber 2b. Is injected.

When the application of the driving voltage is stopped, the side walls 7a and 7b return to the positions before deformation (see FIG. 4A), so that the ink pressure in the ink chamber 2b decreases and the ink supply port 5 Ink is supplied into the ink chamber 2b through the manifold.

However, the above operation is only a basic operation, and when embodied as a product, a driving voltage is first applied in a direction of increasing the volume, and after the ink is first supplied to the ink chamber 2b, The application of the driving voltage is stopped, and the side walls 7a, 7
b may be returned to the position before the deformation (see FIG. 4A) to eject the ink droplets. Further, in order to attenuate the pressure wave in the ink chamber after the ejection of the ink droplet, a drive voltage pattern called a cancel pulse may be added after an appropriate time.

In the ink jet head having such a configuration, ink droplets cannot be simultaneously ejected from two nozzles communicating with two adjacent ink chambers 2.
For example, after ejecting ink droplets from nozzles communicating with odd-numbered ink chambers 2a and 2c from the left end, ink droplets are ejected from nozzles communicating with even-numbered ink chambers 2b.
Next, the ink chamber 2 and the nozzles are divided into two groups so that the ink droplets are ejected from the odd-numbered nozzles again. Further, the ink chamber 2 and the nozzles may be divided into three or more groups to eject ink droplets.

As described above, in the piezoelectric ink jet printer of this embodiment and the method of manufacturing the same, the electrode lead portion 91 is formed on the electrode 9 and the electric wiring 1 from the driver is provided.
5 and the electrode can be easily connected. In particular, since the electrode lead portions 91 are radially spread at the electrical connection portions 16, the pitch is widened, and reliable and easy electrical connection is made.
Further, it is useful for electrical connection of the electrodes 9 in a high-quality inkjet head in which the ink chambers 2 are highly integrated.

As a result, industrially remarkable effects such as the production of an inexpensive and high-quality ink jet head can be obtained.

The present invention is not limited to the above-described embodiment, and various changes can be made without departing from the gist of the present invention.

For example, as shown in FIG. 5, the shape of the insulating portion 14 may not be radial. Such a shape can be easily obtained by setting the control of a scanning mirror or the like in advance in laser processing.

The electrode 9 in the ink chamber 2 is connected to the insulating portion 10.
Is divided for each side surface of the piezoelectric side wall 7, but if the driving method is selected, the division is not necessarily required. In that case,
Of course, it is not necessary to form the insulating portions 12 and 14 that are continuous with the insulating portion 10.

Further, the above-described shape of the insulating portion can be obtained without laser processing. Even in the conventional dicing process, the above-described radial insulating portion is formed by disposing the piezoelectric ceramic substrate on a rotatable table, forming one insulating portion 14 and then performing predetermined rotation. Is possible. In this case, there is an advantage that the same processing machine can be used as that for forming the insulating part in other parts.

On the contrary, the insulating portion 10 in the groove serving as the ink chamber 2
, The insulating portion 12 on the surface 11, and the removal of the conductive layer on the piezoelectric side wall 7 to which the upper lid 6 is connected may be performed by laser processing.

In laser processing, the type of a high energy beam such as a laser beam, the beam focusing condition of an optical system, and the like may be appropriately selected according to the size of a portion to be removed. For example, a laser beam having a wavelength of 1.06 μm (micrometer), which is a standard wave of a YAG laser, is used to perform single mode (Gaussian mode).
When an f · θ lens with a focal length of 150 mm is used, the minimum spot diameter is about 60 to 80 μm. If a f.theta. Lens having a shorter focal length is used, the minimum spot diameter can be further reduced. When a YAG laser beam having a wavelength of 532 nm (nanometer), which is the second harmonic of the YAG laser, is used, the minimum spot diameter is 40 μm.
It can be: Therefore, it goes without saying that it is possible to cope with high integration of future components.

In the ink jet head of this embodiment, the ink chambers 2 are adjacent to each other with the piezoelectric side wall 7 interposed therebetween.
A non-ejection area to which ink is not supplied may be provided on both sides of each ink chamber 2. For example, the electrodes formed on the inner surface of the ink chamber 2 are not separated on both sides but are electrically connected, and only the electrodes formed on the inner surface of the non-ejection area are separated for each side. It may be something. In this case, the electrode in the ink chamber 2 is always grounded, and a drive pulse is applied to the electrode corresponding to the piezoelectric side wall 7 constituting the ink chamber 2 to be driven for ejection in the non-ejection area.

In the present embodiment, the piezoelectric side wall 7 is composed of two piezoelectric layers whose polarization directions are opposite to each other. However, the piezoelectric side wall 7 is composed of a non-piezoelectric layer and a piezoelectric layer. Is also good. Further, as shown in FIG. 9, the insulating portions 65 may be formed in parallel. For example, a conductive layer conducting to the electrode 59 in the groove is formed on another surface 63 and 64 of the piezoelectric ceramic substrate 51, and thereafter, the insulating portion 61 of the grooved surface 62 of the ink chamber 52 and the upper end of the piezoelectric side wall 57. Then, an insulating portion 65 continuous with the surfaces 63 and 64 is formed. As a method of forming the insulating portion 65 on the surface 63 and the surface 64, the electrode 5 is formed by a cutting mechanism such as the dicing process described above.
9 is removed. As a result, electrode extraction portions 591 that are electrically independent and that are respectively connected to the electrodes 59 in the grooves are separately formed. Thereafter, a plurality of electric wires 66 from a driver are independently connected to an electrode lead-out portion 591 formed on the surface 64 of the piezoelectric ceramic substrate 51 by soldering or the like.

[0052]

As is apparent from the above description, according to the method of manufacturing an ink jet head of the present invention, an electrode lead portion for applying an independent voltage pulse to each electrode formed in each ink chamber is provided. The formation is significantly easier. This is because, after a conductive layer having a simple pattern is formed, the conductive layer is divided, so that an independent electrode for each groove and an electrode lead portion connected to the electrode are formed in a reduced number of steps. Thereby, productivity and reliability are greatly improved.

As a result, an industrially remarkable effect such as the production of an inexpensive and high-quality ink jet head can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic view illustrating a method for manufacturing an ink jet head according to an embodiment of the present invention.

FIG. 2 is a perspective view showing an inkjet head according to an embodiment of the present invention.

FIG. 3 is a perspective view of the ink jet head of the embodiment.

FIG. 4 is a sectional view showing the operation of the ink jet head of the embodiment.

FIG. 5 is a schematic view showing another example of the method for manufacturing an ink jet head of the present invention.

FIG. 6 is a perspective view showing a conventional inkjet head.

FIG. 7 is a cross-sectional view illustrating an operation of a conventional inkjet head.

FIG. 8 is a cross-sectional view illustrating a method for manufacturing a conventional inkjet head.

FIG. 9 is a schematic view showing still another example of the method for manufacturing an ink jet head according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Piezoelectric ceramic substrate 2 Ink chamber 3 Nozzle plate 7 Piezoelectric side wall 9 Electrode 14 Insulating part 15 Electric wiring 18 YAG laser beam

Claims (2)

(57) [Claims] 1. A plurality of ejection channels for ejecting ink, partitions constituting the ejection channels and made of a piezoelectric material at least partially polarized, provided on a side surface of each of the partitions, and the piezoelectric Having an actuator member with an electrode for generating a driving electric field in the material,
A method for manufacturing an ink jet head for applying a voltage to the piezoelectric material to deform the partition wall to eject ink droplets from the ejection channel, wherein at least a part of the piezoelectric plate is made of a polarized piezoelectric material, A first step of forming a plurality of grooves; a second step of forming a conductive layer on at least the groove forming surface of the piezoelectric plate and a surface different from the groove forming surface; and forming a conductive layer on the groove forming surface of the piezoelectric plate. Removing a part of the conductive layer, and dividing the conductive layer into a plurality of independent electrodes for each of the grooves; and a step of separating the conductive layer formed on a surface different from the groove-forming surface of the piezoelectric plate. Removing a portion and dividing into a plurality of electrode lead-out portions each electrically connected to the electrode; and a fourth step of connecting an electric wiring to the electrode lead-out portion divided and formed in the fourth step. A method of manufacturing an ink jet head, characterized by a step. 2. The second step includes forming a conductive layer on at least the groove forming surface of the piezoelectric plate, a surface at which one end in the longitudinal direction of the groove opens, and a surface opposite to the groove forming surface. The fourth step is to form a part of the electrode layer by removing a part of the conductive layer from a surface of the piezoelectric plate where one end in the longitudinal direction of the groove is opened to a surface opposite to the groove forming surface. The method for manufacturing an ink jet head according to claim 1, wherein: