JPH0441247A - Ink jet head - Google Patents

Abstract

PURPOSE:To reduce dispersion of thickness and thermal deformation by using an etched plate material as a metal layer for constituting a piezoelectric transducer. CONSTITUTION:A piezoelectric transducer 1 is constituted of a piezoelectric ceramic 13, an electrode layer 14 made of a thin film metal layer such as Au, and a metal plate 12 of Ni-Fe alloy. A nozzle formation member 8 has a nozzle opening 9 arranged opposing to the piezoelectric transducer 1. The piezoelectric ceramic 13 is stuck to the etched Fe-Ni alloy 12 by a conductive adhesive 10. The Fe-Ni allay is used as the metal plate 12 so as to obtain a thermal expansion equivalent to the piezoelectric ceramic 13. As the Fe-Ni alloy is used, a piezoelectric transducer which does not make displacement dependent on temperature can be obtained even if the heat curing conductive adhesive 10 is used. The Fe-Ni alloy is heat-treated before an etching in order to stabilize the thermal expansion. For example, when a median of a thickness of the metal plate 12 is made to be 50mu, it is easy to confine thickness dispersion within 1% by a roller.

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. Related to printer head structure.

[Conventional Technique #T] The conventional method for constructing the metal layer of a piezoelectric transducer is to selectively plate a large piece of piezoelectric ceramic, attach it to a base substrate, and then divide it for use. It was getting worse. In some cases, a metal plate processed into a predetermined shape is bonded to the divided piezoelectric ceramics, and the piezoelectric ceramics are individually bonded to a base substrate.

[Problems to be Solved by the Invention] In the conventional method of forming a metal layer by plating, the thickness varies due to the so-called etch effect when plating is applied. Furthermore, the thermal expansion coefficients of metals that can be applied by plating, such as Ni, Cu, Cr SA u , and Ag, are several times to several tens of times larger than those of piezoelectric ceramics.

For this reason, there is a problem in that the piezoelectric transducer warps when it is plated, bonded with a thermosetting adhesive, or heated during use. Furthermore, in the method of joining a metal plate to divided piezoelectric ceramics, the performance as a piezoelectric transducer varies depending on positioning accuracy.

[Means for Solving the Problems] A plurality of nozzle openings are provided with piezoelectric transducers disposed in ink facing each other at a certain interval, and the piezoelectric transducers are operated in ink to The on-day ink jet head ejects ink droplets from the nozzle opening by increasing the pressure of ink near the nozzle opening, and is characterized in that an etched plate material is used as the metal layer constituting the piezoelectric transducer.

[Function] According to the configuration of the present invention, the metal layer has good thickness accuracy;
Materials with a thermal expansion coefficient equivalent to piezoelectric ceramics can be selected. Furthermore, since the piezoelectric ceramics are processed after the metal plates are bonded, highly accurate positioning is possible.

[Example] FIG. 1 shows a main cross-sectional perspective view of an inkjet head according to the present invention. A plurality of piezoelectric transducers l arranged parallel to each other include a piezoelectric ceramic 13, an electrode layer 14 made of a thin film metal such as Au formed on one side of the piezoelectric ceramic 13, and an electrode layer 14 made of a thin film metal such as Au formed on one side of the piezoelectric ceramic 13, and an electrode layer 14 formed on the opposite side of the electrode layer 14. It is composed of three members, including a metal plate 12 made of a Ni-Fe alloy. 8
is a metal nozzle forming member, and has a nozzle opening 9 disposed facing the piezoelectric transducer 1 . The nozzle forming member 8 is bonded to the piezoelectric transducer 1 with a conductive adhesive 10. On the upper side of the base substrate 11 (not conductive), there is an electrode layer 15 patterned in a stripe shape so as to correspond to the piezoelectric transducer 1. Then, the piezoelectric transducer 1 is fixed to this electrode layer 15 with a conductive adhesive 10.

Here, the electrode layer 15 plays a role in transmitting an external operating electric signal to the piezoelectric transducer 1, and is electrically connected to the thin film electrode 14 via the adhesive layer 10.

The nozzle forming member 8 also serves as a common electrode. Similar structures are arranged in two symmetrical rows and are integrated by a common nozzle forming member 8 and base substrate 11.

A space between the piezoelectric transducer 1 and the nozzle forming member 8 is filled with ink (not shown). Ink is supplied from the side of the piezoelectric transducer 1 opposite to the nozzle forming member side. The piezoelectric transducer 1 is displaced by an operating electric signal from the outside, increases the ink pressure near the nozzle opening 9, causes an ink droplet to be ejected from the nozzle opening 9, and causes the piezoelectric transducer 1 to eject paper or the like (not shown) adjacent to the nozzle forming member 8. An ink image is formed on the recording medium.

In such an inkjet head, the displacement characteristics of the piezoelectric transducer 1 have a great effect on ink ejection, so it is important to keep it uniform and constant.The displacement characteristics of the voltage-electric transducer 1 are mainly It is determined by the piezoelectric characteristics of the piezoelectric ceramic, the conditions of the electric signal, and the dimensions of each part of the piezoelectric transducer 1, such as length and thickness.

FIG. 2 shows a conceptual diagram showing the manufacturing process of one embodiment of the present invention. In (a) of the figure, two large piezoelectric ceramics 13 are etched into the Fe-Ni alloy 12,
Paste with conductive adhesive 10.

Here, electrode layers 14 are formed on both sides of the large piezoelectric ceramic. Moreover, the reason why Fe-Ni alloy is used as the metal plate is because it can obtain thermal expansion equivalent to that of piezoelectric ceramics, and by using Fe-Ni alloy, the thermosetting type conductive adhesive layer 10 A piezoelectric transducer that does not change due to temperature during use can be obtained. Fe-Ni alloy is
It is manufactured by a rolling method, and is heat treated before etching to stabilize thermal expansion. In this embodiment, the median thickness of the metal plate 12 was set to 507, but it is easy to keep the thickness variation within 1% by rolling. However, the metal layer is manufactured by plating.
In this case, it is difficult to reduce the variation to the same level. In FIG. 2(b), the base substrate 11 and piezoelectric ceramics are bonded using a conductive adhesive 10. In FIG. In (C), the connection portion of the metal plate 12 is separated. Further, the piezoelectric ceramic 13 is divided into pieces according to the etching pattern of the metal plate 12 to obtain individual piezoelectric transducers 1. (In dl, the nozzle forming member 8 and the piezoelectric transducer 1 are bonded together using a conductive adhesive 10.

Although the embodiment shown in FIG. 2 has been described above, the present invention is not limited to this embodiment, and it is also possible to use materials such as molybdenum and tungsten for the metal plate. Moreover, although the piezoelectric ceramic and the metal plate were bonded to the base substrate and then divided, the piezoelectric ceramic and the metal plate may be divided before being bonded to the base substrate. Further, the present invention can be easily applied not only to an inkjet head having a cantilever structure but also to a double-end structure.

[Effects of the Invention] According to the present invention, a metal layer can be formed without using a plating method, so there is little variation in thickness. Furthermore, it has become easier to construct a piezoelectric transducer with less thermal deformation. Furthermore, positional deviation with piezoelectric ceramics can be reduced. Therefore, it has become possible to manufacture a piezoelectric transducer with stable displacement characteristics.

[Brief explanation of the drawing]

FIG. 1 is a main cross-sectional perspective view of an inkjet head according to the present invention. FIG. 2 is a conceptual diagram of the manufacturing process of the inkjet head in the present invention. 8 Nozzle forming member 11 Base substrate 12 Metal layer Figure 7 Piezoelectric ceramic electrode layer and above Applicant Seiko Epson Co., Ltd. Agent Patent attorney Mitsuru Suzuki Mibu ft! ! 1 person (a) (b) (C) Cd)! ,'s 2 fig.

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, characterized in that an etched plate material is used as a metal layer constituting a piezoelectric transducer.