JPS61255863A - Ink jet head - Google Patents

Abstract

PURPOSE:To provide an inexpensive ink jet head having high density nozzles and to miniaturize said head, by providing a head upper substrate integrally having the conductor and plug forming an electric circuit for driving the elastomer forming a part of the wall of an ink pressure chamber and a head lower substrate having nozzles, ink flow passages, the ink pressure chamber and a common liquid chamber and integrally connecting the head upper and lower substrates. CONSTITUTION:An elastomer 1, the connection pad 2 connecting the elastomer 1 and a vibrator plate 5 and conductor patterns 3, 8 are formed by the photoetching of the metal part of a laminate plate consisting of a thin metal plate 16 and a polymer film 1. The material quality of the film as the elastomer and an insulator is determined according to ink to be used and the thickness thereof is determined by a displacement amount, the diameter of the elastomer and driving energy, etc. Ink jet nozzles 10, an ink pressure chamber 11, ink flow passages 12 and a common liquid chamber 13 are formed to a liquid chamber substrate (head lower substrate) 9 by using photoetching, electroforming, molding or composite processing. A head upper substrate and the head lower substrate are integrally connected.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inkjet ejection head suitable for use in an on-demand type inkjet recording apparatus.

FIG. 19 is a sectional view showing an example of an inkjet ejection head (Japanese Patent Application Laid-Open No. 168575/1983) proposed by the present applicant. In the figure, 21 is a nozzle.

22 is an ink pressurizing chamber, 23 is a vibration unit, 24 is a vibration transmission rod, 25 is an elastic body, 26 is a head lower substrate, 27 is a head upper substrate, and 28 is an ink supply port.

Reference numeral 29 denotes a support body, and one end of the vibration unit 23 is fixed to the head upper substrate 27, and the other end is fixed to the elastic body 25 via the vibration transmission rod 24. In addition, the vibration unit 23 receives a signal voltage from a drive circuit (not shown) and is displaced about the support 29, and in response to the displacement, the elastic body 25 is bent to reduce the volume of the ink pressurizing chamber 22, thereby pressurizing the ink. The pressure inside the liquid chamber increases and ink is ejected from the nozzle 21. Thus, in the inkjet ejection head, an elastic body 25 is attached to a part of the wall of the ink pressurized liquid chamber and connected to the vibration unit 23 through the indirect member of the vibration transmission rod 24, thereby freeing up the mounting space for the vibration unit. The idea is to make it easier to integrate and downsize the head by making it freely removable, but conventionally, the head upper substrate and head lower substrate are made of photosensitive glass, and the elastic body is made of stainless steel.

Vibration transmission rods are composed of members made of metal rods and other materials, and these members are joined to form a head.
Among these, the head/upper substrate, the head lower substrate, and the elastic body are joined by heat fusion bonding by heat treatment at high temperature for a long time in an inert gas or vacuum. In addition, the elastic body 25 of 14 and the vibration transmission rod 24 are connected by adhesive bonding, but the head base is made of photosensitive glass, a metal elastic body is bonded, and furthermore, the vibration transmission rod is bonded.

The problem was that it was difficult to connect to the vibration unit and the process was complicated, making it extremely difficult to mass-produce. Furthermore, to be more specific, it is expensive because photosensitive glass is used for the head base material, making it unsuitable for low-priced printers. Yields are poor in photosensitive glass etching, heat fusion bonding, etc. In a head made of photoetched and laminated SUS materials, the yield rate is poor due to deformation and breakage of the thin metal elastic body at high temperatures and pressures during thermal diffusion bonding. Both photosensitive glass and SOS heads require a rigid body with a diameter of about 0.5 to 1.0 to be joined to a thin metal elastic body (10 to 50 μm), resulting in significantly poor handling and assembly. There were drawbacks such as poor handling properties such as temporary fixing and fixing of the metal elastic body having a thickness of 10 to 50 μm, and poor automatic assembly properties.

The present invention has been made in order to solve the above-mentioned drawbacks of the conventional technology, and it is possible to reduce the size of the ink pressurized liquid chamber, and to change the vibration form of the vibration unit to be supported at one end or both ends, so that displacement can be achieved with a low driving voltage. By making it possible to obtain a large amount of ink, the area of the pressurized ink chamber can be reduced, and the head can be integrated.
Alternatively, it is possible to provide an inkjet ejection head that can be easily miniaturized and lowered in price, and furthermore, to provide an inkjet ejection head that is inexpensive and has high density nozzles for high-speed printing, and that has a miniaturized head. It was done for the purpose of

In order to achieve the above object, the present invention provides an inkjet ejection head that ejects ink droplets by changing the volume of an ink pressurized liquid chamber in an inkjet ejection head using a vibration unit, In the inkjet ejection head in which at least a part of the wall of the liquid chamber is formed of an elastic body, and the vibrating unit is supported on a plane that is not the same as the spreading direction plane of the elastic body, the elastic body and a metal foil or plate made of copper or the like are connected. It consists of laminated members stacked together, and the laminated members are shaped into a desired shape by means such as photo-etching.

A pattern is etched to form the elastic body, a connection pad that connects the elastic body forming a part of the wall of the ink pressurized liquid chamber and the vibration unit, and an electric circuit for driving the vibration unit. The head upper substrate integrally has a conductor and a plug, and the head lower substrate has a nozzle, an ink flow path, an ink pressurizing liquid chamber, and a common liquid chamber, and the head upper substrate and the head lower substrate are integrated. Alternatively, the ink may be made of a laminated member in which an elastic body and a metal foil or plate of copper or the like are laminated, and the laminated member may be etched into a desired shape or pattern by means such as photo-etching. It integrally includes the elastic body that forms part of the wall of the pressurized liquid chamber, a connection pad that connects the elastic body and the vibration unit, and a conductor and plug that form an electric circuit for driving the vibration unit. a head top board;
It has a head inner substrate having an ink flow path, an ink pressurized liquid chamber, and a common liquid chamber, and a head lower substrate consisting of a nozzle plate, and the head upper substrate, head middle substrate, and head lower substrate are integrated. It is characterized by being joined in a straight line. Hereinafter, the present invention will be explained based on examples.

FIG. 1 is a sectional view for explaining an embodiment of an inkjet ejection head according to the present invention, and FIG. 2 is a perspective view.
In the figure, reference numeral 1 denotes an elastic body whose adhesive layer is made of a polymeric film such as a polyester film, which has voltage resistance, insulation resistance, and etching resistance.

2 is a connection pad, 3 is a PZT drive pulse application conductor, 4
5 is a support body, 5 is a diaphragm, 6 is PZT, and 7 is a resin member (adhesive) for connecting the elastic body and the diaphragm.

8 is a plug, 9 is a liquid chamber board (head lower board), 10 is a jet nozzle, 11 is an ink pressurizing liquid chamber, 12 is an ink flow path,
13 is a common liquid chamber, and 14 is an ink supply hole.

15 is a lead wire for applying a PZT driving pulse, 16 is a metal layer, and there are two types of plugs and lugs 8, 09e, as shown in FIG. Therefore, the present invention relates to an improvement of an inkjet ejection head that ejects ink droplets by changing the volume of an ink pressurized liquid chamber in the inkjet ejection head using a vibration unit. At least a part of the wall is formed of an elastic body, and the vibration unit is supported on a surface that is not flush with the spreading direction surface of the elastic body, thereby making it possible to reduce the area of the ink pressurized liquid chamber.
This facilitates head integration or miniaturization.

FIG. 3 shows an elastic body 11 and a connection pad 2 for connecting the elastic body 1 and the diaphragm 5. A perspective view of the conductor pattern 3.8, FIG.
The structure shown in FIGS. 3 and 4 is a cross-sectional view taken along the line IV-IV in the figure, and as shown in FIG. It was obtained by photo-etching into a shape with one dimension. Specifically, a 35μ polyester film is used as the polymer film 1, and this is attached to a 35μ copper foil 1 with an adhesive.
6 was used. The type (material) of the film used as the elastic body and insulator is determined based on the ink used, and the thickness of the film is determined by the amount of displacement, the diameter of the elastic body (dl in Figure 6), the driving energy, etc. It is determined based on the balance between Further, in the above embodiment, the connection pad 2 serves to prevent the adhesive from sticking when connecting the diaphragm 5 and the elastic body 1 by dropping a certain amount of the adhesive 7 using a dispenser or the like and curing the adhesive 7. However, like the conventional technology,
If the vibration rod (the member that connects the vibration plate and the elastic body) is directly bonded to the elastic body using adhesive, the adhesive at the joint will spread in a concentric circle, causing the thickness of the elastic body to vary, which will have a negative impact on the jetting characteristics. effect. Therefore, management of the diameter d1 of the elastic body and the diameter do of the connection pad in FIG. 6 is one of the important items.

FIG. 7 is a cross-sectional view when the vibrating end of the diaphragm 5 is bonded to the connection pad 2 shown in FIG. Depending on the amount, it is possible to place a certain amount of adhesive 7 on the connection pad 2 in a hemispherical shape.

FIG. 8 is a perspective view showing another embodiment of the connection pad;
The figure is an enlarged sectional view, and in this embodiment, the connection pad 2 is formed into a concave shape by photoetching etc., thereby preventing the adhesive 7 from spreading and increasing the surface area and increasing the adhesive strength. This is what I did. The vibration unit is composed of a thin metal plate 5 such as a thin stainless steel plate and a PZT (electrostrictive vibrator) 16 bonded together with an adhesive or the like, and the unit is aligned on the metal layer 16 as shown in the figure. and fixed with adhesive etc.

A hole is formed at the tip of the diaphragm 5 made of the thin metal plate, and the connecting resin or adhesive 7 is dropped so as to fill the hole at the tip of the diaphragm. Amount control is required.

For this control, it is preferable to use an automatic dripping machine to drip the connection resin and adhesive 7 again after fixing and joining the vibration units.

FIG. 10 is a perspective view showing an example of the liquid chamber substrate (head lower substrate) 9. The liquid chamber substrate 9 can be processed by conventional photoetching, electroforming, molding, or a combination of photoetching and electroforming. Ink jet nozzle l using method etc.
O, ink pressurized liquid chamber 11, ink flow path 12. Common liquid chamber 1
3rd class has been formed.

FIG. 11 shows a member with a three-layer structure of metal 16-film 1-metal 9 that is photo-etched on both sides at the same time, connecting pads,
This is a perspective view of the conductor pattern, the plug, the nozzle 2 ink flow path, the ink pressurizing chamber, the common liquid chamber, etc. formed all at once. When the flat plate 18 is bonded to the metal plate 9 as shown in FIG. 14, the head base is formed. is formed.

Figure 12 shows the pressure absorbing elasticity 1jl! when the head undergoes sudden pressure fluctuations. An example is shown in which 17 is provided.
This elastic membrane part 17 is formed by cutting out a part of the thin metal plate 16, and as in the case of FIG. 11, the pressure absorbing elastic membrane part 17 can also be processed by photo-etching on both sides at the same time, so there is no need for man-hours. No adverse effects. Note that the dimensions, number, and position of the pressure-absorbing elastic membranes are determined in consideration of the head characteristics.

FIG. 13 shows a perspective view of a head substrate in the case where a plurality of inkjet ejection nozzles as described above are provided to form a multi-nozzle and used for a high-speed printer, and FIG. 14 is a perspective view of the head substrate shown in FIG. It is a perspective view when the vibration unit and the flat plate 18 are joined, and the PZT 6 and the conductor pattern 3 are electrically connected by the lead wire 15.

FIG. 15 is a perspective view showing another embodiment of multiple nozzles, and FIG. 16 is a perspective view of a nozzle plate (head lower substrate) 19. An elastic body 1. which forms part of the wall of the ink pressurizing liquid chamber, consists of a head upper substrate consisting of a head upper substrate, a head inner substrate consisting of a liquid chamber substrate 9, and a head lower substrate consisting of a nozzle plate 19. Ink pressurization chamber 11 (not shown) and nozzle 10
are arranged in a staggered manner, and as shown in FIG. 16, the nozzle plate 19 has elastic body parts l shown in FIG.
The nozzle 10 is formed in a shape corresponding to the above.

FIG. 17 is a sectional view of the main part of the head shown in FIG.
In the case of this head, ink is ejected in the same direction as the vibration direction of the elastic body 1, and in the case of the illustrated example, the head middle substrate 9 and the nozzle plate (head lower substrate) 1
9 is formed separately, but the nozzle plate 19
ink flow path.

An ink pressurizing chamber, a common liquid chamber, a nozzle, etc. may be integrally formed. The nozzle plate in which the nozzle and the ink pressurizing chamber are integrally formed can be manufactured by conventional molding, photo-etching/electroforming combined processing, etc.

FIG. 18 is a perspective view of an inkjet ejection head constructed using the head substrate shown in FIG. 15.

As is clear from the above explanation, according to the present invention, (a) elastic bodies, conductor patterns, plugs, connection pads, pressure-absorbing elastic bodies, etc. can be formed with high precision (as they can be integrally formed, contributing to a reduction in man-hours and being inexpensive). This makes it possible to provide a head that is

(b) Since each of the above-mentioned parts can be formed by means such as photo-etching, it is possible to provide an inexpensive head that is easily adaptable to multi-layer printing.

(c) Since a polymer film is used as the elastic body, it is possible to provide an inkjet ejection head that has a lower bias ratio than conventional metal elastic bodies, and is also capable of compact liquid nitriding and low driving voltage.

(d) The elastic body and the diaphragm are connected by automatic dripping of a polymer material through a connection pad, which is suitable for mass production.

There are advantages such as

[Brief explanation of drawings]

1 to 14 are diagrams for explaining an embodiment of an inkjet ejection head according to the present invention, in which FIG. 1 is a cross-sectional view, FIG. 2 is a perspective view, and FIG. 3 is a perspective view of a substrate on the head. ,
4 is a sectional view taken along line IV-IV in FIG. 3, FIG. 5 is a perspective view of the head substrate before processing, FIG. 6 is an enlarged sectional view of the connection pad portion of the head substrate, and FIG. 8 is a perspective view showing a modified example of the connection pad, FIG. 9 is a sectional view, FIG. 10 is a perspective view of the lower head board, and FIG. The figure is a perspective view of the head board, Figure 12 is a perspective view when a pressure absorbing part is provided on the head upper board, Figure 13 is a perspective view of the head board when multi-head FIGS. 15 to 18 are perspective views for explaining other embodiments of the present invention, FIG. 15 is a perspective view of a head board, FIG. 16 is a perspective view of a nozzle plate, and FIG. The figure is an enlarged sectional view of the nozzle part.
18 is an overall perspective view, and FIG. 19 is a sectional view showing an example of a conventional on-demand inkjet ejection head. 1... Elastic body, 2... Connection pad, 3... PZT
l! ! Dynamic pulse application conductor, 4... support, 5...
Diaphragm, 6... PZT, 7... Resin member (adhesive) for connecting the elastic body and the diaphragm, 8... Plug, 9...
Liquid chamber substrate, 10... Ejection nozzle, 11... Ink pressurizing liquid chamber, 12... Channel. 13... Common liquid chamber, 14... Ink supply hole, 15...
...PZT drive pulse application lead wire, 16...metal layer. 17... Vibration-resistant absorption part, 18... Flat plate, 19...
nozzle plate. Figure 1 N2 Figure 5
Figure 6 Figure 9 l110rI! J Fig. 11 Fig. 15 m

Claims (4)

[Claims] (1) An inkjet ejection head that ejects ink droplets by changing the volume of an ink pressurized liquid chamber in the inkjet ejection head using a vibration unit, the inkjet ejection head including at least a part of the wall of the ink pressurized liquid chamber. The inkjet ejection head is formed of an elastic body and the vibrating unit is supported on a surface that is not the same as the plane in the spreading direction of the elastic body, and the inkjet jet head is made of a laminated member in which the elastic body and a metal foil or plate of copper or the like are laminated, the elastic body forming a part of the wall of the ink pressurized liquid chamber by etching the laminated member into a desired shape and pattern by means such as photo-etching; a connection pad connecting the elastic body and the vibration unit; A head upper substrate that integrally has a conductor and a plug forming an electric circuit for driving the vibration unit, and a head lower substrate that has a nozzle, an ink flow path, an ink pressurizing liquid chamber, and a common liquid chamber. . An inkjet ejection head, wherein the head upper substrate and the head lower substrate are integrally joined. (2) A portion of the metal foil or plate is removed to expose a portion of the elastic body, and the exposed portion of the elastic body acts as a vibration-resistant absorber against fluctuations in ink pressure within the ink pressurized liquid chamber. Claim No. 1 (
The inkjet ejection head according to item 1). (3) An inkjet ejection head that ejects ink droplets by changing the volume of an ink pressurized liquid chamber in the inkjet ejection head using a vibration unit, the inkjet ejection head including at least a part of the wall of the ink pressurized liquid chamber. The inkjet ejection head is formed of an elastic body and the vibrating unit is supported on a surface that is not the same as the plane in the spreading direction of the elastic body, and the inkjet jet head is made of a laminated member in which the elastic body and a metal foil or plate of copper or the like are laminated, the elastic body forming a part of the ink pressurized liquid chamber by etching the laminated member into a desired shape and pattern by means such as photo-etching; a connection pad connecting the elastic body and the vibration unit; and the vibration. a head top substrate that integrally has a conductor and a plug forming an electric circuit for driving the unit; a head middle substrate that has an ink flow path, an ink pressurized liquid chamber, and a common liquid chamber;
An inkjet ejection head comprising a head lower substrate made of a nozzle plate, and wherein the head upper substrate, the head middle substrate, and the head lower substrate are integrally joined. (4) A portion of the metal foil or plate is removed to expose a portion of the elastic body, and the exposed portion of the elastic body acts as a vibration-resistant absorber against fluctuations in ink pressure within the ink pressurized liquid chamber. Claim No. 1 (
The inkjet ejection head according to item 3).