JPH0429850A - Ink-jet head - Google Patents

Abstract

PURPOSE:To make minutely spaced arrangement of nozzles possible for a nozzle plate by a method wherein the nozzle plate is made up by bonding two board- like members, and etching is applied in different shapes, one in oval and the other in circle, respectively on each of the board-like members. CONSTITUTION:An oval resist R1 is selectively formed on a relatively thick board member (the member that is to be a fist board-like member) by photolityographic processing. Etching is applied by ferric chloride aquenous solution and an oval hole 19 is formed therewith. Then the resist R1 is peeled off. Thereby the first board-like member 16A is formed. A circular resist R2 is selectively formed on thin board member (the member that is to be a second board-like member) by photolityographic processing. The etching is applied by ferric chloride aqueous solution, and thereby an circular hole 19B having highly accurate hole diameter is formed. Then the resist R2 is peeled off. Thereby the second board-like member 16B is formed. The first board-like member 16A and the second barod-like member 16B are precisely positioned each other and are bonded together by thermal diffusion method.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an inkjet head, and particularly to an inkjet head that drives a pressure transducer in ink and discharges ink from a nozzle opening to perform printing. .

[Prior Art] Methods for manufacturing a nozzle plate having a plurality of nozzle openings include electroforming, etching, wire discharge,
etc. have been proposed. Furthermore, electroforming methods include photoelectroforming, in which a plate-like member is formed after selectively resisting a conductor plate, and master electroforming, in which a master shape is created and then transferred to form the shape. There is a law. and,
Nozzle plates manufactured by these methods have conventionally been composed of a single plate-shaped member.

[Problems to be solved by the invention] Conventional nozzle plates were made of a single plate-like member, so when manufactured by photoelectroforming or etching, the shapes of the inlet and outlet sides of the nozzle were similar. Therefore, there was a problem that it was difficult to arrange the nozzle intervals precisely. Further, when manufacturing the master by the electroforming method, there is a problem that the manufacturing of the master requires a huge amount of cost, and furthermore, the master has a short lifespan, making it very expensive.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and provide an inexpensive inkjet head in which nozzle intervals on a nozzle plate can be arranged finely.

[Means for Solving the Problems] An inkjet head of the present invention includes a piezoelectric transducer disposed in ink opposite to a nozzle plate having a plurality of nozzle openings at a certain interval, and the piezoelectric transducer is disposed in ink. In the on-demand type inkjet head, which operates at a pressure of ink near the nozzle opening to eject ink droplets from the nozzle opening, the nozzle plate has a structure in which two plate-like members are bonded together, Each of the plate-like members is etched into a different shape, one of which is elliptical and the other circular.

[Function] According to the inkjet head of the present invention, since the nozzle plate has a structure in which two plate-like members are pasted together, the nozzle shape is an ellipse on the ink inlet side and the oval shape on the ink outlet side. It is possible to inexpensively make a circle with a diameter equal to or smaller than the short axis of the ellipse, and by arranging the nozzles in the direction of the short axis of the ellipse, it is possible to create a high-density inkjet array. .

[Example] Next, embodiments of the present invention will be described based on the drawings.

FIG. 1 is a perspective view showing the configuration of a printing and recording apparatus using an inkjet head according to the present invention.

In the drawing, reference numeral 9 denotes an inkjet head, which is mounted on a carriage 8 that is guided by a guide shaft 6.7 and moves in the width direction of the recording medium 1 (in the direction of arrow 10).

2 and 3 are paper feed rollers that move the recording medium 1 in the direction of arrow 5. 4 is a platen.

Although FIG. 2 is a sectional view showing one embodiment of the inkjet section of the inkjet head of the present invention, the present invention is not limited thereto. In the figure, reference numeral 13 indicates a plurality of rod-shaped piezoelectric transducers arranged in parallel to each other. 1
Reference numeral 4 denotes a support substrate, on which a protrusion 15 for fixing the rod-shaped piezoelectric transducer 13 with adhesive is formed. 1
Reference numeral 6 denotes a nozzle plate, which has a nozzle opening 19 arranged opposite to the piezoelectric transducer 13. 17 is a flexible substrate that transmits an operating electrical signal to the piezoelectric transducer 13. The piezoelectric transducer 13 is displaced by voltage application to increase the pressure of the ink near the nozzle opening 19 .
eject more ink droplets.

The support substrate 14 and the nozzle plate 16 are the piezoelectric transducer 1
It is made of a 36% Ni-Fe alloy as a material that has a thermal expansion similar to that of No. 3.

FIG. 3 is a front cross-sectional view of the nozzle plate 16 of this embodiment (
a) and a side sectional view (b), in which a first plate member 16A having oval holes 1 and 9A and a second plate member 16B having a circular hole 19B are joined. It is composed of Ink is supplied from the upper surface of the first plate member 16A, and is ejected from the lower surface of the second plate member 16B.

The diameter of the pores on the surface from which ink is ejected has a great effect on print quality, so high precision is required. For this purpose, it is necessary to make the second plate member 16B as thin as possible and reduce the amount of side etching. Furthermore, in order to reduce the ink flow path resistance, it is desirable that the second plate member 16B be made as thin as possible.

On the other hand, the nozzle plate 16 due to the pressure of ink during ejection
The nozzle plate 16 must be thick in order to prevent vibration, deformation, deformation when the nozzle plate is joined, deformation due to external force such as contact with paper, etc. In this embodiment, a thick member in which holes 19A larger than holes 19B on the ink ejection side are formed, that is, a second plate-like member 16A, is joined to the ink supply side to form a laminated structure, thereby solving the conflicting problem described above. points have been resolved.

Furthermore, in order to provide an inexpensive inkjet head with high print quality, it is necessary to arrange the nozzles at a high density. In this embodiment, the first plate-shaped member 16A serving as the ink supply side is formed into an oval shape as shown in FIG. 3, and is arranged as shown in FIG. 4, thereby increasing the density of the nozzles. ing.

Next, one embodiment of a method for manufacturing the nozzle plate 16 will be described with reference to FIG. In this embodiment, a 36% Ni--Fe alloy is used as the material for the nozzle plate 16, but the material is not limited to this, and any material can be selected depending on the required characteristics.

1) An elliptical resist R1 is selectively formed on a relatively thick plate member (a member that will become the first plate-like member) by a photolithography process.

2) Etching is performed using a ferric chloride aqueous solution to form an oblong hole 19A.

3) Peel off the resist R1. Thereby, the first plate member 16A is formed.

4) A circular resist R2 is selectively formed on a thin plate member (a member that will become the second plate-like member) by a photolithography process.

5) Etching is performed using a ferric chloride aqueous solution to form a circular hole 19B with a highly accurate hole diameter.

6) Peel off resist R2. Thereby, the second plate member 16B is formed.

7) The first plate-like member 16A and the second plate-like member 16B are precisely aligned and joined by thermal diffusion. The joining method is not limited to this example, but
In cases where adhesive or solder is used, the adhesive or solder flows and the holes become clogged, so in this example, thermal diffusion bonding, which does not cause flow, is used.

[Effects of the Invention] As described above, according to the present invention, the shape of the nozzle on the ink supply side of the nozzle plate can be made into an oval shape, and the shape of the nozzle on the ink discharge side can be made into a highly accurate random circular shape. By realizing a dense nozzle arrangement without increasing ink flow path resistance, an inkjet head with excellent print quality can be provided at a low cost.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing one embodiment of a recording apparatus equipped with an inkjet head of the present invention, FIG. 2 is a sectional view showing an inkjet section of this embodiment, and FIG. 3 is a diagram of a nozzle section of a nozzle plate of the present invention. Detailed sectional view, Figure 4 is nozzle layout,
FIGS. 5 1) to 7) are diagrams showing one embodiment of a nozzle plate manufacturing method. ... Recording medium 3 ... Feed roller ... Platen 7 ... Guide shaft ... Carriage ... Inkjet spatula ... Piezoelectric ceramic ... Metal layer ... Piezoelectric transducer ... Support substrate...protrusions...nozzle plate...flexible substrate...adhesive and above Applicant Seiko Epson Co., Ltd. Agent Patent attorney Kizobe Suzuki and 1 other person Figure 3(b) Figure 5

Claims (1)

[Claims] A nozzle plate having a plurality of nozzle openings is 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 to increase the pressure of the ink near the nozzle openings. In the on-demand inkjet head that ejects ink droplets from the nozzle opening, the nozzle plate has a structure in which two plate-like members are bonded together, and each of the two plate-like members is etched into a different shape. An inkjet head characterized in that one of the inkjet heads has an elliptical shape and the other has a circular shape.