JP3232632B2 - Inkjet print 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 print head used in an ink jet printer.

[0002]

2. Description of the Related Art A conventional ink jet print head is:
As shown in FIG. 5, a plurality of nozzle openings are formed on a wall surface of a container constituting the ink tank, and a piezoelectric body is arranged so as to correspond to each nozzle opening so that the direction of expansion and contraction is matched. . In this print head, a drive signal is applied to a piezoelectric element to expand and contract a piezoelectric body, and ink droplets are ejected from nozzle openings by dynamic pressure of ink generated at this time to form dots on printing paper. Such a head has a plurality of ink reservoirs (ink cavities) formed between a glass (plastic) substrate and an elastic vibration plate such as a thin glass (plastic) plate, and a piezoelectric plate having electrodes formed on both surfaces. Is cut to about the area of an ink cavity, and then bonded to each ink cavity with an elastic vibration plate interposed therebetween.

Further, a pressure generating member having a beam-like member composed of a piezoelectric material such as PZT, a metal plate, and a laminated material of ceramic, both ends of which are supported in the longitudinal direction, an ink as a flying medium, and the ink Japanese Patent Publication No. 60-8953 discloses an on-demand type ink jet head which has a nozzle serving as a discharge port, generates pressure from a pressure generator by an applied voltage, and discharges ink from the nozzle. In this head, since the pressure generating member is displaced substantially at right angles to the nozzle forming substrate and the ink flow path of the nozzle meniscus is short, the ink ejection efficiency and ejection stability are high, and air bubbles and dust in the ink are high. This has the advantage that normal operation is possible without being affected by such foreign substances.

In Japanese Patent Publication No. 61-2024, a continuous piezoelectric body is adhered on a continuous elastic vibration plate, and electrodes are selectively formed corresponding to nozzle openings, thereby selectively applying pressure. A structure for driving the generating member is disclosed. This structure has an advantage that even if the number of nozzles increases, the number of steps for bonding the piezoelectric body by the number of nozzles can be reduced.

[0005] Japanese Patent Publication No. 62-134267 discloses a structure in which a piezoelectric body is diffusion-bonded to a head body by using metallized ceramics. This structure has an advantage that pressure loss and variation due to the adhesive can be reduced.

[0006]

However, the conventional ink jet head uses a lead zirconate titanate-based composite perovskite ceramics, which is a material having the best piezoelectric effect, as the piezoelectric body 430. Since it was a cut product, only a thick product of about 100 μm could be used. Therefore, it is necessary to increase the driving voltage to 100 V or more.
Since the rigidity of the mechanical displacement generating means consisting of the glass plate 30 and the thin glass plate 411 is high, in order to obtain a predetermined displacement amount, the piezoelectric body 430 is required.
And it is necessary to increase the area of the glass thin plate 411,
There has been a problem that the entire head becomes large, resulting in an increase in cost.

Further, the width of the ink cavity 420 is about several hundred μm on one side, and a plate of the piezoelectric body 430 having the same size as these can be bonded to each ink cavity 420 as mechanical displacement generating means. Was needed. 4
Reference numeral 40 denotes an ink reservoir for temporarily storing the ink guided to the ink cavity 420; 422, an ink supply path for guiding the ink to the ink cavity 420; and 421, a nozzle from which the ink projects. However, in the head having such a structure, the positioning accuracy between the piezoelectric body 430 and the ink cavity 420 cannot be increased, the workability at the time of bonding the piezoelectric body 430 is poor, the characteristic variation due to the non-uniformity of the bonding is large, There are problems such as easy peeling and large variation in characteristics due to internal strain during cutting.

[0008] In the head structure disclosed in Japanese Patent Publication No. 62-134267, it is necessary to process metallized ceramics with high precision and high density, leading to a dramatic increase in cost.

[0009] These problems are problems that have been highlighted as the number of nozzles is increased or the nozzle density is increased in order to improve the performance of the printer.

An object of the present invention is to solve these problems, and an object of the present invention is to provide a highly reliable ink jet head having high density and uniform characteristics even with a high number of nozzles at a very low cost. It is to be.

[0011]

According to the present invention, there is provided an ink jet print head which discharges ink from a nozzle opening by applying a drive signal to a pressure generating member arranged corresponding to the nozzle opening. In the print head, the pressure generating member is a continuous piezoelectric body,
An elastic vibration plate is provided on one surface of the piezoelectric body corresponding to each of the nozzle openings, and the elastic vibration plate and the piezoelectric body are integrally formed by simultaneous firing. I do. Further, in the above configuration, an intermediate body is provided between the other surface of the piezoelectric body and a nozzle plate that ejects ink droplets, and the intermediate body, the piezoelectric body, and the elastic vibration plate are simultaneously fired. It is characterized by being formed integrally.

[0012]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a structural view of the present embodiment. FIG.
(A) is a top view, (b) is an MM cross-sectional view, and (c) is a bottom view.

The piezoelectric body 10 is made of a piezoelectric material such as a lead zirconate titanate-based composite perovskite ceramic.
On both sides of the piezoelectric body 10, an elastic body 21 and a wiring portion 22 are formed on one surface, and an intermediate body 31 for forming an ink flow path, an ink cavity and the like is formed on the other surface.
A common electrode 23 is formed. Piezoelectric body 10, elastic body 2
1 and the common electrode 23 form the pressure generating member 20. The thickness of the piezoelectric body 10 is 25 μm, the thickness of the elastic body vibrating section is 20 μm, and the thickness of the common electrode 23 is 1 μm or less. The thickness of the intermediate body 31 is 60 μm. A nozzle plate 40 in which a nozzle 41 serving as a discharge port of the ink 60 is formed is joined to the intermediate body 31 with the common electrode 23 interposed therebetween. In the prototype, the nozzle plate 40 is N
i is manufactured by the electroforming method, the thickness is 100 μm, and the diameter of the nozzle 41 is 50 μm. The nozzles 41 are shown in FIG. 1 (c), eight rows vertically and horizontally, 1355 μ in the horizontal direction.
They are arranged at m pitches and vertically at 677 μm pitches. Further, the nozzle rows adjacent in the left-right direction are arranged shifted by Δp. Here, Δp is 85 μm. A cavity 50, an ink supply path 51, and an ink common path 52 are formed by the intermediate body 31, the nozzle plate 40, and the piezoelectric body 10, and these are filled with the ink 60. The size of the cavity 50 is 600 μm × 6
00 μm. The ink supply path 51 is a path that guides the ink 60 from the common ink path 52 to the cavity 50, and is provided at four corners of the cavity 50. Ink supply path 5
1 has a width of 60 μm and a length of 150 μm. The ink common path 52 communicates with an ink tank (not shown). The width of the ink common path 52 is 300 μm. The common electrode 23 is connected to the ground, and the wiring section 22 is connected to a drive circuit (not shown).

Next, a manufacturing method in which a piezoelectric body, an elastic body, and an intermediate body are formed in this embodiment will be described with reference to FIGS.

FIG. 2A shows a process of forming a thin paste-like intermediate material 130 by mixing a binder and a high melting point material such as Cr, Mo, or Pt on the surface plate 70. FIG. 2 (b)
Is a process in which PbO, TiO2, ZrO2, and additives are mixed and mixed, then calcined at 800 to 1000 ° C., pulverized, and a binder is added to form a paste, and the piezoelectric material 110 is thinly formed. FIG. 2C shows a step of further mixing a binder and a high melting point conductive material such as Cr, Mo, and Pt thereon to form a thin elastic material 120 in a paste form. The paste-like laminate thus formed is baked at 1000 to 1200 ° C. while applying pressure.
As a result, the binder flies off, and a three-layered laminate including the piezoelectric body 10, the elastic layer 20, and the intermediate layer 30 is formed as shown in FIG.

Next, the elastic layer 20 and the intermediate layer 30 are processed by using the photolithography technique, so that the elastic body 21, the wiring portion 22, and the intermediate body 31 are formed as shown in FIG. Thereafter, the common electrode 23 is provided on the intermediate body 31 side of the piezoelectric body 10.
A conductive thin film of Ni or the like is formed by plating or sputtering.

Next, the nozzle plate 40 is joined to the nozzle plate 40 with an adhesive such as polyimide to obtain the ink jet head of this embodiment shown in FIG.

Here, as a method of manufacturing the nozzle plate 40, a resist is formed in a desired shape by printing or a photolithography process on the substrate employed in this embodiment, and Ni or the like is grown by electroless plating or electrolytic plating. In addition to the electroforming method, 1, plastic molding method 2, SUS, Ni
Etching method 3 in which a resist is formed in a desired shape by printing or a photolithography process on a metal plate such as a metal plate, and a portion where no resist remains is removed by etching, SUS, N
A pressing method or the like in which a metal plate such as i is punched out by a press is conceivable.

According to the present invention, the piezoelectric body 10, the elastic plate 20
Are bonded by diffusion bonding, so that the reliability of the bonding portion is high. Therefore, even if processing using photolithography technology is performed, the inkjet head with high density and stable ejection characteristics is maintained without deteriorating the reliability of the bonding portion. Can be provided. Further, since the pressure generating member 2 is manufactured by the thick film process,
0 can be made thinner, so that the cavity 50
And the size of the entire head can be reduced. In addition, since ink supply paths are provided at the four corners of the cavity, the air bubbles are easily discharged and the reliability is greatly improved.

[0021]

According to the present invention, since the piezoelectric body and the elastic body are co-fired, the reliability of the joint is high.
Even if processing using the photolithography technique is performed, it is possible to provide an ink jet print head having high density and stable ejection characteristics without impairing the reliability of the joint.

[Brief description of the drawings]

FIG. 1A is a top view illustrating the structure of an embodiment of an ink jet print head according to the present invention. (B) A sectional view taken along the line MM ′ showing the structure of one embodiment of the ink jet print head of the present invention. (C) A bottom view showing the structure of one embodiment of the ink jet print head of the present invention.

FIGS. 2A to 2C are views showing a method of manufacturing an ink jet print head according to one embodiment of the present invention.

FIG. 3 is a diagram showing a method of manufacturing an ink jet print head according to one embodiment of the present invention.

FIG. 4A is a top view in one step of a method for manufacturing an ink jet print head according to one embodiment of the present invention. (B) nn 'sectional drawing in one process of the manufacturing method of the inkjet print head of one Example of this invention. (C) A bottom view in one step of the method for manufacturing an ink jet print head according to one embodiment of the present invention.

FIG. 5 is a diagram showing a conventional example.

[Explanation of symbols]

 10 ··· Piezoelectric body 20 ··· Pressure generating member 21 ··· Elastic body 23 ··· Common electrode 31 ··· Intermediate body 40 ··· Nozzle plate 41 ··· Nozzle 50 ··· Cavity 60 ··· Ink 110 ··· Piezoelectric material 120 ··· Elastic material 130 ··· Intermediate material 420 ··· Ink cavity 430 ··· Piezoelectric material

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B41J 2/045 B41J 2/055

Claims (3)

(57) [Claims] 1. An ink jet print head that ejects ink from a nozzle opening by applying a drive signal to a pressure generating member disposed corresponding to a nozzle opening, wherein the pressure generating member is a continuous piezoelectric element. And a resilient diaphragm disposed on one surface of the piezoelectric body corresponding to the nozzle opening, wherein the resilient diaphragm and the piezoelectric body are integrally formed by simultaneous firing. An ink jet print head characterized by the following. 2. An intermediate body that forms a cavity is provided between the other surface of the piezoelectric body and a nozzle plate that ejects ink droplets, and the intermediate body, the piezoelectric body, and the elastic vibration plate are provided. 2. The ink jet print head according to claim 1, wherein the ink jet print head is formed integrally by simultaneous firing. 3. The ink jet print head according to claim 1, wherein an electrode is formed on the other surface of said piezoelectric body in a region facing said elastic vibration plate.