JPH0243065A - electrode 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 the Invention The present invention relates to an electrode head for recording electrical signals on a recording medium.

2. Description of the Related Art In recent years, office automation has required a variety of terminals. Among these, there is a great demand for recording devices that convert electrical signals into visible images, so-called printers, and recording devices using various methods have been produced in the past.

A recording device using electrical discharge breakdown recording paper consists of a metallic thin film layer, a black layer, and a base paper.A voltage-applied electrode is brought into contact with the metallic thin film layer of the electrical discharge breakdown recording paper. Recording is performed by removing the layer and exposing the underlying black layer. Conventionally, resin has often been used as a support material for fixing electrode needles in discharge recording heads, but when resin is used, electrodes made of thick and hard material are used to prevent short circuits between electrodes due to adhesion of dust generated during recording. The needle must be exposed from the support, making it difficult to produce a high-density discharge recording head. Therefore, in order to perform high-density recording, an electrode head (Japanese Patent Application No. 178537-1982) using a hexagonal boron nitride sintered body as a support for the electrode needle was proposed, and it was hoped that high-resolution printing quality could be obtained. Became.

Problems to be Solved by the Invention Hereinafter, problems with the above-mentioned conventional electrode head will be explained with reference to the drawings.

FIG. 4 is a perspective view of a conventional electrode head. In FIG. 3, 1 is an electrode needle (for example, electrolytic copper), and 2a and 2b are supports containing hexagonal boron nitride (for example, Denka boron nitride sintered body manufactured by Denki Kagaku Kogyo Co., Ltd.). , the electrode needle 1 is a support 2a containing macrogonal boron nitride.
, 2b, and the supports 2a, 2b are adhesively fixed to the metal plate 3 with an epoxy adhesive 1B.

In particular, when using epoxy adhesive, if the support is not firmly fixed to the metal plate, the tip of the support may shift when pressing the tip of the electrode head against the discharge breakdown recording paper and running the discharge breakdown recording paper. This is because the recording paper may cause the recording paper to sway or shake at a certain angle, resulting in poor contact with the recording paper and, as a result, the recording quality deteriorates.

Figure 3 is a diagram of the operating principle of discharge breakdown recording, and shows the electric signal B
An electric signal from 21 passes through the electrode needle 1 and the ground electrode 22 to remove the metal thin film layer 24 on the discharge destruction recording paper 23 by discharge destruction, and at the same time supports the electrode needle 1 in response to wear of the electrode needle 1 due to the discharge. While scraping the supports 2a and 2b containing orthogonal boron nitride, the underlying black layer 25 is exposed, and 5 prints are recorded on the discharge breakdown recording paper 23.

A support 2a containing the hexagonal boron titanide.

Since electrode needle 2b has a property of being easily abraded, it is constantly worn in such a way that the electrode needle 1 protrudes, thereby maintaining good contact with the discharge breakdown recording paper 23 and removing discharge debris adhering to the surface of the electrode needle 1. As a result, good recording characteristics can be maintained.

However, with the electrode head configuration as described above, the bond between the support and the metal plate is subject to temperature cycle tests (-20°C to +85°C) that must be guaranteed as parts to be mounted on electronic equipment.
C) caused a problem of peeling. This is because the thermal expansion coefficient of macrogonal boron nitride as a support is approximately -1:104, whereas when aluminum is used as a metal plate, its thermal expansion coefficient is 23X104, and there is a large difference between the two. . In other words, the length of the electrode head that corresponds to recording on A4 size paper is approximately 200 mm, but a temperature difference of 100"C causes a difference in thermal expansion coefficient of approximately 250 μm at the ends, and the epoxy adhesive cannot absorb this deformation. This is because the adhesive part will peel off.

An object of the present invention is to provide an electrode head constructed by bonding the tip of a support made of ceramic material and a metal plate that holds it, which is highly reliable even against temperature changes during practical use. It is an object.

Means for Solving the Problems In order to achieve the above objects, in the tti head of the present invention, the bond between the tip of the support made of ceramic material and the metal plate holding it has a large elongation at break and softens at high temperatures. It uses an adhesive material that

By using the above adhesive material, it can withstand stress due to the difference in thermal expansion coefficient between the support and the metal plate, and especially at high temperatures, the adhesive material softens and has an adhesive function, while the adhesive material itself expands greatly, absorbing stress. This is what I am trying to do.

Function: The electrode head constructed as described above has a stable bond between the support and the metal plate even during temperature changes that may occur during storage or transportation, making it possible to obtain a highly reliable electrode head. can.

EXAMPLE An example of the present invention will be described below with reference to the drawings. In FIG. ) and then photolithography and etching processes to form parallel electrical conductors in stripes at a density of 8 conductors/mm, which are sandwiched between the support 2b containing hexagonal boron nitride and the support 2a. This is bonded to the metal plate 3 with an adhesive 8. A driving TC 4 for applying a discharge recording signal to the electrode needle 1, a circuit board 5, and a connector 6 are mounted on the metal plate 3, and are electrically connected by conductor wires 7, 7' and 7''', respectively. There is.

As the adhesive 8 for bonding the support 2a and the metal plate 3, the polyester adhesive of Sample 1 (Kemit Toyo Rayon Co., Ltd.) and the silicone adhesive of Sample 2 (CY 52-228) were used as adhesives having viscoelasticity. Toray Silicone Co., Ltd.), the same silicone adhesive of sample 3 (KE-
67 Shin-Etsu Chemical Co., Ltd.), sample 4 double-sided adhesive sheet (Nitto Denko Co., Ltd.), and for comparison, a conventional epoxy adhesive sheet (Epicoat 828) was selected as sample 5.
Yuka Shell Co., Ltd.) was added to create an A4 size electrode head. The thickness of the adhesive layer is an important factor in sample conditions, but due to differences in adhesive types, the thickness cannot be the same.

Another important factor is the elongation at break of the adhesive, but by combining these conditions and the test results described below,
Record in the table.

(Margin below) As is clear from Table 1, the silicone adhesive and double-sided adhesive sheet of Samples 2 and 3.4 have high viscoelasticity at room temperature, so it was difficult to firmly hold the support in the initial pressure test. It could not be held firmly and the position shifted when pressurized. However, in the temperature cycle test, the viscoelasticity of the adhesive was effective, and no adhesive peeling occurred even after 50 cycles. Further, although the epoxy adhesive material of Sample 5 had good initial pressure test results, adhesive peeling between the support and the metal plate occurred in the first cycle of the temperature cycle test. This is because, as mentioned above, the epoxy adhesive has a low elongation at break, so it cannot absorb the stress due to the difference in thermal expansion coefficients and peels off. The electrode head using the polyester adhesive of Sample 1 showed good results in both the initial pressure test and the 50-cycle temperature cycle test. This is because the polyester adhesive is thermoplastic, so it has appropriate hardness at room temperature, but softens at high temperatures. However, since the pour point is approximately 120°C, it has been confirmed that the degree of softening does not matter within the operating temperature range of the electrode head. In addition, it has a breaking elongation of more than 700% at room temperature, which allows the support to be firmly bonded and fixed, and even under temperature cycle test conditions, it absorbs the difference in thermal expansion coefficient between the support and the metal plate, preventing peeling problems. Think of it as something.

Effects of the Invention Since the present invention is configured as described above, it exhibits the effects described below.

A polyester adhesive that has a high elongation at break and is easily softened at high temperatures is used to bond the support that holds the electrode needle that contacts the discharge breakdown recording paper and controls the recording with the metal plate that adhesively fixes the support. By using this method, the adhesion between the support and the metal plate is stable under the temperature conditions likely to be encountered during transportation and storage of electrical equipment, and an electrode head with high reliability can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the configuration of an electrode head in an embodiment of the present invention, FIG. 2 is a perspective view of an electrode head with a conventional configuration,
FIG. 3 is a diagram showing the operating principle of discharge breakdown recording. 1... Electrode needle, 2a, 2b... Support body, 3... Metal plate, 4... Drive ICl3
...Circuit board, 6...Connector, 7.7
', 7''...Conductor wire, 8...Polyester adhesive, 18...Adhesive, 21...
・Electric signal source, 22... Earth electric wire, 23...
. . . Discharge breakdown recording paper, 24 . . . Metal thin film layer, 25 . . . Black layer, 26 . . . Platen. Name of agent: Patent attorney Shigetaka Awano, 1 person, 3-44, 4-, 0, 5-11 circuit basis

Claims (2)

[Claims] (1) an electrode needle and a ceramic support that holds the electrode needle;
An electrode head consisting of a metal plate for adhesively fixing the ceramic support and a drive IC for supplying a recording signal to the electrode needle, the ceramic support and the metal plate having a breaking elongation of 50.
Electrode head using 0% or more adhesive. (2) The electrode head according to claim (1), wherein a polyester adhesive is used as the adhesive.