JPH0441248A - Ink jet head - Google Patents

Abstract

PURPOSE:To make deformation of a nozzle formation member small so as to unify clearance between a piezoelectric transducer and the nozzle formation member and make its value constant by providing a spacer integral with the nozzle formation member. CONSTITUTION:A nozzle formation member 8 is connected to a piezoelectric transducer 1 by a spacer 8a integral with the nozzle formation member. An adhesive 10 is contained to a surface roughness in order to make use a precise thickness of the spacer effectively. Therefore, a stress generated at a coupling layer is exceedingly small. An insulating resist 201 corresponding to a periphery and a nozzle opening is formed on an electroformed substrate 202 by a photolithographic method. An Ni plating layer 203 is grown, an insulating resist film is laminated on the whole surface, the resist film at the spacer is eliminated by the photolithography, and a plating layer is further laminated. Lastly, after the resist film is eliminated, it is stripped off from the substrate 202 so as to obtain the nozzle formation member 8.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to inkjet recording, and in particular to an inkjet recording device that performs printing by driving a pressure generator in ink and ejecting ink from a nozzle opening. Regarding printer head structure.

[Prior Art] Conventional inkjet heads use highly precisely classified synthetic resin balls or glass fiber powder with a controlled diameter to ensure a gap between the nozzle forming member and the piezoelectric transducer. Adhesives mixed with interstitial materials were used.

[Problems to be Solved by the Invention] However, the above-mentioned conventional technology requires a complicated process of uniformly dispersing the interstitial material in the adhesive. Further, when using synthetic resin balls, the degree of deformation of the synthetic resin balls changes due to the pressure applied to the members to be joined, and the gap changes. When glass fiber powder is used as a gap material, the length cannot be strictly controlled during the manufacturing process of glass fiber powder, so the powder may be several times to several tens of times the diameter. When used as a gap material, the relatively short ones stand upright in a columnar shape, and the long ones overlap, making it difficult to ensure a high precision gap. Furthermore, the bonding layer whose thickness is regulated by the gap material has the function of disturbing the flatness of the nozzle forming member due to contraction during curing.

Therefore, the present invention aims to solve these problems.
The purpose is to provide an inkjet head in which the gap between the nozzle opening and the piezoelectric transducer is ensured with high precision.

[Means for Solving the Problems] The inkjet head of the present invention includes piezoelectric transducers disposed in the ink at a plurality of nozzle openings facing each other at a certain interval, and the piezoelectric transducers are disposed in the ink. Run it with
The inkjet head that increases the pressure of ink near the nozzle opening to eject ink droplets from the nozzle opening is characterized by including a spacer integrated with a nozzle forming member.

[Operation 1] According to the configuration of the inkjet head of the present invention, the thickness of the bonding layer can be made as thin as the surface roughness of the members to be bonded without using a gap material. Furthermore, the gap can be controlled by adjusting the thickness of the spacer.

[Example] FIG. 1 shows a schematic diagram of an inkjet head according to the present invention. A plurality of piezoelectric transducers 1 arranged in parallel to each other include a piezoelectric ceramic 13, an electrode layer 14 formed of a thin film metal such as Au on one side, and a metal such as Ni-Fe alloy on the opposite side of the electrode layer 14. It is composed of three members: layer 12. A nozzle opening 9 arranged opposite to the piezoelectric transducer 1
A metal nozzle forming member 8 having a metal nozzle forming member 8 is bonded to the piezoelectric transducer 1 by a conductive bonding layer 10 via an integrated spacer. On the upper side of the base substrate 11 (not conductive), there is an electrode layer 15 patterned in a stripe shape to correspond to the piezoelectric transducer 1, and a conductive bonding layer 1
0 fixes the piezoelectric transducer l. Here, electrode layer 1
5 plays a role in transmitting an operating electric signal from the outside to the piezoelectric transducer 1. A similar configuration includes nozzle forming members 8 arranged in two symmetrical rows and serving as a common electrode,
They are integrated by a base substrate 11 connected in the shape of an opening.

The operation will be explained with reference to FIG. 2, which is a sectional view of the inkjet head of the present invention. Ink (not shown) is swirled between the piezoelectric transducer 1 and the nozzle forming member 8, and the ink is supplied from the side of the piezoelectric transducer 1 opposite to the nozzle forming member. The piezoelectric transducer 1 is displaced by an operating electric signal transmitted from the outside through the flexible printed circuit board 16, increases the ink pressure near the nozzle opening 9, causes an ink droplet to be ejected from the nozzle opening 9, and is moved adjacent to the nozzle forming member 8. An ink image is formed on a recording medium such as paper (not shown). In this way, in an inkjet head that tightens the ink pressure and ejects ink droplets by displacement of the piezoelectric transducer 1, the gap between the nozzle opening 9 and the piezoelectric transducer 1 has a large influence on the ink flying characteristics, and it is necessary to maintain a uniform and constant gap. It is important to set it as a value.

FIG. 3 shows a sectional view of an example of an inkjet head not according to the present invention. The nozzle forming member 8 is a gap material 10
The pressure W and the transducer L are bonded to each other by an epoxy adhesive 20 in which 1 is dispersed. Due to the deformation that occurs, it is difficult to maintain a constant gap with the piezoelectric transducer 1 around the nozzle opening 9.

Returning to FIG. 2, an embodiment of the present invention will be described. The nozzle forming member 8 is joined to the piezoelectric transducer 1 by an integrated spacer portion 8a. The surface roughness of the adhesive 10 is suppressed to effectively utilize the thickness accuracy of the spacer. Therefore, the stress generated in the bonding layer is extremely small.

FIG. 4 shows a method of manufacturing a nozzle forming member used in an example of the present invention by electroforming. - Electroformed substrate 20 in Figure 4a
2, an insulating resist 201 corresponding to the outer periphery and the nozzle opening is formed using a photolithography method. A Ni plating layer 203 is grown here in step b, and an insulating resist film is laminated on the entire surface in step C. After removing the resist film in the photoresist layer and spacer area, a plating layer is further laminated in step d. do. Finally, after removing the resist film in step e, the substrate 202
Then, the nozzle forming member 8 is obtained.

Fig. 4 shows an example of manufacturing a nozzle forming member that is integrated with a spacer using Ni electroforming, but the invention is not limited to this.
Copper electroforming can also be manufactured using a similar process. A similar nozzle forming member can also be obtained by forming a nozzle forming part and a spacer part by etching stainless steel or the like, and then integrating them by thermal diffusion bonding. It is not limited.

[Effects of the invention] By using a spacer integrated with the nozzle forming member, the complicated work of dispersing the gap material in the adhesive used can be eliminated, and instability factors such as deformation and overlapping of the gap material can be eliminated. can be eliminated. Furthermore, since the bonding layer is made thinner, the stress caused by curing shrinkage generated by the bonding layer can be minimized.
The deformation of the nozzle forming member is small, the gap between the piezoelectric transducer and the nozzle forming member can be easily maintained at a uniform and constant value, and it has become possible to obtain an inkjet head with stable ink flight characteristics.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an inkjet head according to the present invention. FIG. 2 is a main sectional view of the inkjet head according to the present invention. FIG. 3 is a main cross-sectional view of a conventional inkjet head. FIG. 4 is a schematic diagram showing an example of a method for manufacturing a nozzle forming member according to the present invention. Piezoelectric transducer nozzle forming member Base substrate Electrode layer Gap material Resist Resist film Applicant Seiko Epson Corporation Agent Patent attorney Kizobe Suzuki and 1 other person 7 fftt Pincer No. 21A Fig. 1 (b) (C) d) δ

Claims (1)

[Scope of Claims] A plurality of nozzle openings are provided with piezoelectric transducers disposed in the ink so as to face each other at a certain interval, and the piezoelectric transducers are operated in the ink so that the piezoelectric transducers in the vicinity of the nozzle openings are An inkjet head that ejects ink droplets from the nozzle opening by increasing the pressure of ink, the inkjet head comprising a spacer integrated with a nozzle forming member.