JP2855892B2 - Method of manufacturing ink jet recording 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 recording head for reducing the number of steps involved in electrostatic bonding between a silicon substrate as a cavity plate and a glass plate as a diaphragm and improving the yield.

[0002]

2. Description of the Related Art Conventionally, a method of performing recording by ejecting ink from fine nozzle holes and attaching the ink to a recording medium such as paper is known as an ink jet recording method. One of the principles is an on-demand type inkjet recording head. Generally, as shown in FIG. 3 which is a plan view seen from a groove side of a cavity plate and FIG. 4 which is a cross-sectional view, an ink jet recording head of this type is formed by etching or machining a glass or metal plate. After a plurality of ink jet nozzles 2, jet flow paths 3, ink pressurizing chambers 5, ink supply paths 6, and a common ink reservoir 7 are formed, the cavity plate 1 and the vibration plate 9 are laminated and integrated by, for example, A piezoelectric element 10 as an electromechanical conversion element is joined to a position facing the ink pressurizing chamber 5 on the outer surface of the vibration plate 9 via a conductive film 11.

In such a structure, when a voltage as an electric signal is applied to the piezoelectric element 10, the vibration plate 9 is displaced inside the ink pressurizing chamber 5 to rapidly reduce the volume of the ink pressurizing chamber 5, Ink corresponding to the volume is ejected from the nozzles 2 and becomes ink droplets, which are spotted and printed on the opposing recording paper.

[0004] When the cavity plate 1 and the vibration plate 9 are joined, it is conceivable to use an organic adhesive. However, the ink used in the ink jet recording head is often an alkaline ink in consideration of familiarity with plain paper, and therefore, there is a problem in reliability with an organic adhesive. In addition, there is a possibility that the injection flow path 3 or the like that has been finely processed is filled by the dripping of the adhesive. Therefore, when the material is glass, thermocompression bonding is performed, and when the metal is metal, bonding is performed by diffusion bonding or the like.

In FIG. 2, which is a perspective view of an application example of the conventional method, before the electrostatic bonding between the cavity 1 and the diaphragm 9, the conductive film 11 is attached to the portion of the diaphragm 9 where the piezoelectric element 10 is fixed. Is deposited on the region including. The conductive film 11 has a function as a common electrode of the piezoelectric element 10 and is a transparent film of indium tin oxide having a thickness of 1 μm or less formed by electron beam evaporation. As described above, by using the transparent film, the condition of the groove of the cavity plate 1 can be visually observed, and the workability is improved. Next, the cavity plate 1 is placed on the lower electrode 13 (anode) of stainless steel foil, the diaphragm 9 is placed on the cavity 1, and the point electrode 12 (cathode) is brought into contact. In this state, the whole is heated to 350 to 550 ° C., and after the temperature is stabilized, about 300 V is applied between the point electrode 12 and the lower electrode 13.
Is applied. At that time, the current flows only at the initial stage after the start of the joining, decreases several minutes after the start of the joining, and ends the joining. Electron microscope observation of the joints confirmed that the joints were in a uniform joining state without any inclusions between them, and the joint strength was part of the two when the two were peeled apart. Was destroyed. In addition, since it is heated during electrostatic bonding, the conductive film 1 is different from the conventional one.
No. 1 does not require heat treatment for stabilization. Therefore, the piezoelectric element 10 (indicated by a broken line in FIG. 2) can be bonded to a predetermined portion of the upper surface of the conductive film 11 of the diaphragm 9 immediately after the electrostatic bonding, and the operation is completed by this bonding.

[0006]

In the production of an ink jet recording head, it is naturally required to improve the working efficiency and the yield rate. In the case of electrostatic bonding between a silicon substrate and a glass plate on which a conductive film is formed only at a portion where a piezoelectric element is to be fixed in advance, there are the following quality problems. In order to increase work efficiency, the temperature was rapidly increased to a predetermined temperature, and the holding time at the predetermined temperature was shortened as much as possible to perform the electrostatic bonding. Then, since the electric field strength of the portion where the conductive film is formed is increased, the joining of the portion is started quickly and progresses, but the portion without the conductive film is started with a delay and the joining is started slowly. Proceed to If the joining start time and the progress state differ depending on the location, distortion occurs between the initially joined portion and the lately joined portion, and particularly, a portion having a small contact area between the diaphragm and the cavity plate, for example, an ink reservoir. In some parts, the glass plate as the diaphragm is damaged. In order to prevent the breakage, the cavity plate and the vibration plate may be preheated and homogenized for a sufficient time, but the work man-hour is increased and the productivity is reduced accordingly.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems of the prior art and to reduce the number of steps required for electrostatic bonding between a silicon substrate as a cavity plate and a glass plate as a vibration plate, and to improve the yield rate. It is another object of the present invention to provide a method of manufacturing an ink jet recording head for achieving the above.

[0008]

According to a first aspect of the present invention, there is provided a method of manufacturing an ink jet recording head, wherein a silicon plate as a cavity plate formed as a groove communicating with an ink reservoir, an ink pressurizing chamber, and an ink jet nozzle. An ink-jet recording comprising: a substrate; and a glass plate as a vibrating plate, which is joined to the groove-side surface of the silicon substrate on one surface and a piezoelectric element is fixed on the other surface at a position facing the ink pressurizing chamber. In the method of manufacturing a head, a conductive film is formed on the entire surface of the glass plate on which the piezoelectric element is fixed; electrostatically bonding the formed glass plate and the silicon substrate; The piezoelectric element is fixed at the position on the conductive film of the glass plate that has been electrostatically bonded.

[0009]

In the method of manufacturing an ink jet recording head according to the first aspect, an electric field distribution at the time of electrostatic joining is uniformed by forming a conductive film on one entire surface of the vibration plate, and joining at each position is started. Variations in timing and joining progress are eliminated. As a result, the diaphragm is not distorted by the joining, and there is no risk of breakage. In addition, since the joining proceeds simultaneously on the entire surface of the diaphragm, the number of joining steps is reduced.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An application example of a method for manufacturing an ink jet recording head according to the present invention will be described below with reference to the perspective view of FIG. In FIG. 1, prior to electrostatic bonding between the cavity plate 1 and the vibration plate 9, a conductive film 15 is formed on the entire surface of the vibration plate 9 on the fixed side of the piezoelectric element 10. More precisely, the conductive film 15 is provided on the diaphragm 9.
Care must be taken not to protrude from the periphery to the outer periphery. The conductive film 15 is made of indium tin oxide or tin oxide having a thickness of about 0.05 to 1 [mu] m by electron beam evaporation, as in the conventional example, and both are transparent.

Next, electrostatic bonding between the cavity plate 1 and the vibration plate 9 is performed under the following conditions: (1) temperature: 300 to 450 ° C. (holding time: 1 minute or more) (2) voltage: 400 to 400 800 V (application time: within 1 minute). Compared with the conventional example of a temperature of 350 to 550 ° C. and a voltage of 300 V (application time: several minutes), the temperature is slightly lower and the voltage is considerably higher. . As a result of electrostatic bonding under the above conditions, there was no breakage of diaphragm 9 during bonding. This is a remarkable improvement as compared with the yield rate of the conventional example: 35%.

[0012]

In the method of manufacturing an ink jet recording head according to the present invention, an electric field distribution at the time of electrostatic bonding is made uniform by forming a conductive film on one entire surface of a vibration plate.
Variations in the welding start time and welding progress at each location are eliminated, and as a result, the diaphragm is not distorted by the welding, there is no risk of breakage, and the welding proceeds on the entire surface of the diaphragm at the same time. Man-hours are reduced. Therefore, it is possible to reduce the number of steps involved in electrostatic bonding between the silicon substrate as the cavity plate and the glass plate as the vibration plate, and to improve the yield rate.

[Brief description of the drawings]

FIG. 1 is a perspective view of an application example according to the invention method.

FIG. 2 is a perspective view of an application example of a conventional method.

FIG. 3 is a plan view of a recording head to which the present invention is applied;

FIG. 4 is a sectional view of the same.

[Explanation of symbols]

 Reference Signs List 1 cavity plate 9 diaphragm 10 piezoelectric element 15 conductive film

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B41J 2/16 B41J 2/045 B41J 2/055

Claims (1)

(57) [Claims] 1. A silicon substrate as a cavity plate formed as a groove through which an ink reservoir, an ink pressurizing chamber, and an ink ejecting nozzle communicate with each other; A glass plate as a vibrating plate to which a piezoelectric element is fixed at a position opposite to the ink pressurizing chamber on the other surface, wherein the piezoelectric element of the glass plate is fixed. Forming a conductive film on the entire surface on the side to be bonded; electrostatically bonding the formed glass plate and the silicon substrate; and forming the position of the electrostatically bonded glass plate on the conductive film. A method for manufacturing an ink jet recording head.