JPS62212159A - Preparation of ink jet head - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing an ink-on-demand type inkjet head of an inkjet recording apparatus.

[Conventional technology]

Conventionally, when manufacturing an inkjet head made by bonding a diaphragm and a piezoelectric element, the bonding process is performed by heating to high temperatures using a eutectic alloy such as a solder alloy, or by using a tactile adhesive for a long period of time. They were joined by heating at high temperatures.

[Problem that the invention seeks to solve]

When bonding using a eutectic alloy of metals such as industrial solder, there is a large difference in the coefficient of thermal expansion of the piezoelectric element and the material to be bonded. Due to the residual stress, the piezoelectric element is often damaged after bonding, or due to deformation of the piezoelectric element when an electric signal is applied.

Furthermore, when bonding is performed using an epoxy adhesive, since the adhesive itself is an insulator, the 1! In order to ensure the electrical connection, it is safe to make the thickness of the adhesive layer sufficiently thin so that the slightly uneven convex portions on the surface of the pressure TrL element come into contact with the surface of the diaphragm. The appropriate thickness of the adhesive layer is about 5 to 10 μm; if it is thinner than this, unbonded parts are likely to occur, while if it is thicker than this, the electrical connection will become unstable. Generally, epoxy adhesives have a high viscosity, so the thickness of the adhesive layer is made thin as described above.
It is difficult to achieve uniformity, and the vibration of the diaphragm due to the deformation of the piezoelectric element when an electric signal is applied is unstable, so the characteristics of each nozzle differ greatly, which may cause printing holes. In addition, in order to harden the epoxy adhesive, it is necessary to heat it to a high temperature for a long time, and the epoxy resin 14, which is temporarily softened by heating, is heated as shown in Figure 3. There were many defects in which electrical continuity could not be established due to protrusion like α and the formation of an insulating layer. Furthermore, the head itself was often damaged due to heating. [Means for solving the problem] The present invention eliminates these drawbacks, and ensures reliable adhesion and electrical connection between the bottom surface of the piezoelectric element and the diaphragm. ,
The aim is to stabilize the manufacturing process and provide an even more reliable inkjet head.

〔Example〕

A cross-sectional view of the piezoelectric element portion of the inkjet head of the present invention is shown in FIG. An ink flow path 3 and a nozzle 4 are formed by welding a plastic substrate 1 having grooves corresponding to the flow path and a substrate 2 made of the same material. The substrate 2 and the metal diaphragm 8 are bonded together via an adhesive 9, and a piezoelectric element 7 is placed thereon.
is glued. When an electric signal is applied to the piezoelectric element 7, pressure is applied to the pressure chamber 5 through the substrate 2, and an ink droplet 6 is ejected from the tip of the nozzle 4.

The feature of the present invention is that the piezoelectric element 7 and the metal diaphragm 8 are bonded together using an anaerobic adhesive 10, and the process will be explained using FIG. 2.

The adhesive 10 is 358 manufactured by LOOTLTK (viscosity 2
000, C, P, S, Shore D75) was used.

First, as shown in Fig. 2 (α), it was chucked by vacuum tweezers 12, and the size was 4 cm long x 2 m wide x 3 mm thick.
A sponge-like impregnated material 13 sufficiently permeated with the anaerobic adhesive 10 is coated onto the 1 mm piezoelectric element 7 by a transfer method.

As shown in FIG. 2(h), the piezoelectric element 7 uniformly coated with the adhesive is stacked at a predetermined position on the metal diaphragm 8 and lightly pressed. Since the adhesive 10 is anaerobic and self-reacting, only the portion where air is blocked has a
It hardens and completes adhesion in ~3 seconds. Further, since curing occurs only at the joint, even if the adhesive 10 protrudes excessively, it can be removed by simple cleaning, and there is no fear of forming an insulating layer on the top surface of the piezoelectric element 7. The adhesive strength of this bonded portion was examined by an L-shaped crimp test and a shear adhesive force measurement, but in both cases, the piezoelectric element 7 was destroyed and no abnormality was observed in the bonded portion. In addition, as a result of examining the durability of the head, we found that
It was found that this method is superior to the method of bonding the t-shirt 7 and the metal diaphragm with an epoxy adhesive. moreover,
In the unlikely event that water-based or oil-based ink sticks,
The adhesive 10 is not attacked by ink and has sufficient reliability. In another embodiment, when the material of the substrates 1 and 2 is a highly elastic material such as glass or ceramic, 2 is welded to form an ink flow path, and a thin film electrode is deposited on the ink flow path, and then an anaerobic adhesive is applied to the substrate 2 corresponding to the pressure chamber in the flow path in the same manner as in [Example 1]. Glue the applied piezoelectric element.

Furthermore, as another implementation side, it is also possible to use an anaerobic adhesive that is cured by ultraviolet light instead of the adhesive 10, and by irradiating the excess protrusion that occurs during bonding with ultraviolet light, it can be effectively cured. can.

〔Effect of the invention〕

As described above, according to the present invention, the pressure 'F! When joining the L element and the diaphragm, by using an anaerobic adhesive, all of the problems described in the section [Problems to be solved by the invention] can be solved, and a head with stable printing characteristics can be produced. In particular, compared to the case where an epoxy adhesive was used to bond the piezoelectric element and the diaphragm, the electrical connections between the piezoelectric element and the diaphragm, and between the piezoelectric element and the wiring board are made more easily. This has the advantage of eliminating the occurrence of defects related to scraping and providing extremely high reliability.

Furthermore, since anaerobic adhesives generally have a low viscosity, they can be easily applied in fixed quantities and can be fully automated, and they can be adhesively fixed instantly, making it easy to streamline the manufacturing process and reduce manufacturing costs.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the vicinity of a piezoelectric element of an inkjet head manufactured by the manufacturing method of the present invention. FIGS. 2(α) to (C) are explanatory diagrams of the bonding process of the pressure M1 element of the inkjet head of the present invention. FIG. 3 is a cross-sectional view of the vicinity of a piezoelectric element of a conventional inkjet head. Applicant: Seiko Epson Co., Ltd. 9-term entry system Figure 1 10 Moxibustion-resistant sea bream @ ((Z) (b) (C) Figure 2

Claims (1)

[Claims] A flow path is formed by welding a first substrate integrally molded with a groove to become an ink flow path and a second substrate, and a diaphragm made of a highly elastic material is laminated to correspond to the pressure chamber on the diaphragm. 1. A method of manufacturing an inkjet head, characterized in that an anaerobic adhesive is used to bond the diaphragm and the piezoelectric element in the inkjet head comprising a piezoelectric element disposed at a position.