JPH02164557A - Electrothermal transfer recording head - Google Patents

Abstract

PURPOSE:To suppress degradation of print quality and to reduce fusion of resistance layer by coating the surfaces of an electrode substrate and a recording electrode except the end face for supplying power with a conductive material having higher volume resistivity than the resistance layer on an ink film. CONSTITUTION:A recording electrode 2 is formed on an electrode substrate 1 then the tip section 3 of the upper face thereof contacting with an ink film is coated with a conductive material 4 having sufficiently higher volume resistivity than a resistance layer. Since conductive coating agent is employed, discharge is suppressed even if a small gap is formed with respect to the upper face of the electrode section so long as the upper face is contacting with the film, thus suppressing abrasion due to discharge. Since there is no recess to be adhered with fused resistance layer in the faces at the tip of the electrode substrate 1 and the recording electrode 2, the resistance layer does not adhere to the recording head even if power is fed to a portion of the resistance layer on the ink film having quite low resistance and the resistance layer is fused due to abnormal heating.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to a recording head used in an electrically conductive thermal transfer recording device.

(Prior Art 1) In the structure of a conventional current-carrying type thermal transfer recording head, the surfaces of the electrode substrate and the recording electrodes except for the end surfaces related to current-carrying are coated with epoxy resin, which is an insulating material.

[Problems to be Solved by the Invention] The head structure described above has the following problems.

As shown in FIG. 3, if the coating material 4 is made of epoxy resin, the coating agent at the tip of the electrode part will retreat due to heat generation during recording and mechanical wear, causing minute damage to the surface of the resistor M10 of the ink film 7. Due to the unevenness, when the ink film 7 and the recording paper 9 move in the direction of the arrow in FIG. 3, the electrical contact between the resistive layer 10 and the recording electrode 2 is unstable in areas A and B in FIG. 4. As a result, a discharge occurs between the resistance layer 10 and the recording electrode 2, and the recording electrode 2 is destroyed by discharge as shown in part 0 of FIG. 4, resulting in a durable deterioration of printing quality.

In addition, as shown in Figure 3, apart from the unevenness of resistance [10],
Electrode wear due to discharge in the small gap between the top surface 11 of the tip of the tffi section and the ink film 7 could not be avoided by coating with an insulating material such as epoxy resin.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the current-carrying type thermal transfer recording head of the present invention uses a conductive material instead of the conventional coating agent of an insulating material.

1 Effect 1 According to the above structure of the present invention, the electrode portion and the ink film are hardly discharged during printing.

[Example 1] Hereinafter, an example according to the present invention will be described based on the drawings, but the present invention is not limited thereto.

In FIG. 1, a recording electrode 2 is formed on an electrode substrate 1 based on ceramic such as alumina, glass, or resin such as polyimide by a thin film method such as sputtering, a plating method, or a thick film method such as printing. Form.

A conductive material 4 is coated on the tip portion 3 that contacts the ink film on the upper surface. Here, the coating method of this conductive material may be a coating method using a dispenser or a brush, a plating method, a dipping method, a printing method, or the like. Furthermore, the same effect can be obtained by protecting only the recording electrode 2 as shown in FIG. 2, or by protecting the recording electrode 2 and the space between the recording electrodes 5 as shown in FIG. 1. However, considering the simplification of the manufacturing process and mass productivity, it is preferable to protect both the recording electrode and the area between the recording electrodes.

Based on the above, the current-carrying type thermal transfer head shown in FIG. 1 will be explained below.

The material for the conductive material 4 to be coated is preferably a material that is hard, has excellent heat resistance, and has a higher electrical resistance than the ink film (T i N, Si C + ZrB).
2nd grade conductive ceramic etc. are suitable.

A printing mechanism using the current-carrying type thermal transfer recording head 6 constructed as described above is shown in FIG.

In FIG. 3, the tip surface 1-a of the electrode substrate 1 and the tip surface 2-a of the recording electrode 2, which is involved in energization, are not coated, and only the ink film 7 that contacts the tip surface 2-a of the recording electrode is coated. is mainly energized, and the coating [4] in contact with the ink film 7 is slightly energized because of its high resistance. The platen 8 is pressed against the recording head 6 via the ink film 7 and the recording paper 9, and the pressing portion 8-a is deformed by a sufficient amount so that the entire tip surface 2-a of the recording electrode 2 comes into contact with the resistance layer 10. doing. Here, the thickness of the coating layer is determined by the pressing force and
The film thickness is extremely thin compared to the amount of deformation of the platen suppressing portion 8-a so as not to impair the contact property. A few μm
For the recording electrode 2 having a thickness of about 20 .mu.m, it is appropriate that the deformation amount of the platen suppressing portion 8-a is 100 .mu.m to 200 .mu.m, and the thickness of the coating layer 4 is 10 .mu.m or less.

According to this current-carrying type thermal transfer recording head 6, the recording electrode 2
Comparing the discharge that occurs in the small gap between the top surface of the electrode tip and the ink film with a conventional head coated with an insulating material such as epoxy resin, the discharge that occurs in the small gap between the top surface of the electrode part and the ink film is caused by the coating agent. Because it is a conductive material, as long as the coating agent is in contact with the film, even if there is a slight gap between the top surface of the 'FhN part and the ink film, the amount of discharge can be suppressed compared to conventional methods. Electric discharge wear can be suppressed.

In addition, as with conventional heads coated with an insulating material such as epoxy resin, even if electricity is applied to the part of the ink film 7 where the resistance value of the resistor N10 is extremely low and the resistor layer 10 melts due to abnormal heat generation, the tip surface of the electrode substrate 1-a and the recording electrode tip surface 2-a have no recesses to which the molten resistor N10 would adhere, so it will not be welded to the recording head 6.

[Effects of the Invention] As described above, by using the current-carrying thermal transfer recording head according to the present invention, it is possible to suppress the deterioration of printing quality due to discharge breakdown of the recording electrode, and it is possible to reduce the welding of the resistive layer. .

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the structure of the current-carrying type thermal transfer head of the present invention. FIG. 2 is a diagram showing an embodiment of the present invention. FIG. 3 is a diagram showing a printing mechanism equipped with the current-carrying type thermal transfer recording head of the present invention. FIG. 4 is a diagram for explaining problems in the prior art. 1 ・ 2 ・ 3 ・ ・Coating layer at the tip of the electrode substrate, recording electrode, ink film, electrically conductive material between the recording electrodes Current-carrying type thermal transfer recording head Ink film platen Recording paper 10 ・ 11 ・ ・Resistance layer ・ Top surface of the tip of the electrode part and above Application Person Seiko Epson Co., Ltd. Representative Patent Attorney Kizobe Suzuki (and 1 other person) jfl1 Figure 2

Claims (1)

[Scope of Claims] 1) An ink film having at least a resistance layer and a heat-melting ink layer, and a recording paper are disposed between a recording head having a plurality of recording electrodes arranged in parallel on the side edges of an electrode substrate and an elastic member. The elastic member is compressed so as to be slightly deformed, and a voltage is applied between adjacent recording electrodes to energize the resistance layer and generate heat to melt the hot melt ink layer and transfer it to the recording paper, forming a desired pixel. In the current-carrying type thermal transfer recording device, the surfaces of the electrode substrate and the recording electrode other than the end surfaces related to current-carrying are coated with a conductive material having a volume resistivity sufficiently higher than at least a resistive layer formed on the ink film. An energized thermal transfer recording head characterized by: 2) The current-carrying thermal transfer recording head according to claim 1, wherein the coating material is a conductive ceramic. 3) The current-carrying thermal transfer recording head according to claim 1, wherein the coating film thickness is extremely thin compared to the amount of deformation of the elastic member.