JPS61139455A - Thermal head - Google Patents

Abstract

PURPOSE:To achieve the improvement of wear resistance and power resistance, by forming a protection film with the insulation layer for which the first insulating matter and the second insulating matter are alternately deposited. CONSTITUTION:A resisting film 12 and a conductor film 13 are successively adhered onto a substrate 11 and respectively formed in required shapes to compose a heating resistor. Then, for example, silicon dioxide 14 of 1,000 Angstrom in thickness as the first insulating matter is adhered onto the heating resistor. Then, for example, tantalum pentaoxide 15 of 4,000 Angstrom in thickness as the second insulating matter is adhered thereonto. Thereafter, the protection film of 5 micron in thickness is constructed by alternately depositing the first and second insulating matter. Further, any one of silicon dioxide, alumina and tantalum pentaoxide as the first insulating matter and any one of tantalum pentaoxide, silicon nitride, silicon carbide, silicon boride and alumina as the second insulating matter should be preferably selected.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to the structure of a thermal head, and particularly provides a thermal head that is fully equipped with a resistor protection film that enhances the power durability and abrasion resistance of the heating resistor. It's about doing.

[Conventional technology]

Conventionally, this type of thermal head uses a mixture of silicon dioxide and tantalum pentoxide as a protective film, or a 92-layer film in which tantalum pentoxide is deposited on silicon dioxide, as described in, for example, Utility Model Publication No. 59-75052. Then, as shown in FIG. 2, a resistive film 22 and a conductive film 23 are layered on a substrate 21 and formed into a desired shape.
It was then covered with the protective film 24 in a desired shape.

[Problem that the invention seeks to solve]

However, in a thermal head using the above-mentioned mixture as a protective film, the protective film wears out at a high rate due to the running of the recording paper during printing, and although the heat resistance of the heating resistor is high, The resulting thermal head has the disadvantage of a short lifespan. In conventional thermal heads, in which tantalum pentoxide is deposited on silicon dioxide to a thickness of several microns, when high power is applied to the heating resistor, tantalum pentoxide crystallizes, and the manufactured thermal head is manufactured using a heating resistor. The disadvantage is that the body has a low power resistance.

[Means to solve all problems]

The thermal head of the present invention removes the drawbacks of the above-mentioned protective film and easily provides a protective film with excellent wear resistance and power resistance. It is formed by forming an insulating layer in which two insulating materials are alternately deposited.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a schematic cross-sectional view showing essential parts of a thermal head according to an embodiment of the present invention. Reference numeral 11 denotes a substrate, on which a resistive film 12 and a conductive film 13 are sequentially attached and each formed into a desired shape to constitute a heating resistor. Silicon dioxide 14 with a thickness of 100 OA is deposited on the 7 heating resistors as a first insulating material, then tantalum pentoxide 15 with a thickness of 4000 Å is deposited as a second insulating material, and the first and second The insulating material is alternately deposited to form a 5 micron thick protective film.

In the present invention, the first insulating material and the second insulating material are alternately deposited as a protective film for the heating resistor to provide a thermal head with excellent wear resistance and electrical resistance of the heating resistor. This is what we provide.

According to the present invention, a modification of the protective film structure allows direct contact with the heating resistor. It is also possible to carry out the entire invention by depositing only the first layer of the first insulating material to a particularly thick layer (e.g. 5000 to 1 AO00A); as another variation, the third insulating layer is deposited on the heating resistor. After that, the multilayer deposited insulating film described in the embodiment 81!1 can be used as a protective film. An insulating film in which three or more types of insulating materials are alternately deposited can also be used as a protective film. Furthermore, Makyu,
The present invention can also be practiced by performing active sputtering or active vapor deposition of a single or multiple types of insulating materials in an atmosphere containing nitrogen, oxygen, or the like.

〔Effect of the invention〕

As described above, in the thermal head of the present invention, since at least the first insulating material and the second insulating material are alternately deposited with a thin film thickness as a protective film, crystallization of these insulating materials is prevented. The temperature is rising. Therefore, in a thermal head using a protective film of this configuration, the protective film does not crystallize even when high power is applied to the heating resistor, or the crystallization temperature is 50 to 200% higher than that of conventional protective films.
'0 is high, so the power durability of the resistor is high. Furthermore, since the first and second insulating materials are not mixtures, the functions of these insulating materials can be differentiated. That is, for example, the first insulating material can function as an oxidation-preventing film of the resistor, and the second insulating material can function as a wear-resistant film. As stated in the first example, the wear rate of the tantalum oxide film is 1/1 that of the silicon dioxide film.
10 or less, and the wear rate of the mixture insulating film is 1
/3 or less. Therefore, the protective film of the present invention has excellent wear resistance, and the manufactured thermal head has a long life.

In addition to the above-described effects of the present invention, the thermal head is not limited in any way to the shape and material of the substrate, heating resistor, conductor, etc., construction method, mounting/connection method of the driving IC, etc. According to experiments, the first insulating material is one of silicon dioxide, alumina, and tantalum pentoxide.
The second insulating material is preferably one of tantalum pentoxide, silicon nitride, silicon carbide, silicon boride, and alumina, but the materials of these @1 insulating materials and the second insulating material It goes without saying that there should be no restrictions on the thickness of each film to be deposited, the thickness of the entire protective film, or the number of times the first and wc2 insulating materials are deposited.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view showing essential parts of a thermal head according to an embodiment of the present invention, and FIG. 2 is a schematic sectional view showing a conventional thermal head. 11...Substrate, 12...Resistive film, 13
. . . Conductor film, 14 . . . First insulating film (
silicon dioxide), 15... second insulating film (tantalum pentoxide). Ahxm-A m-+ ,,,, ~-
4.

Claims (2)

[Claims] (1) A thermal head characterized in that an insulating layer formed by alternately depositing a plurality of different types of insulating materials is attached on a resistor. (2) In the thermal head according to claim 1, the first insulating material is one selected from silicon dioxide, alumina, and tantalum pentoxide, and the second insulating material is tantalum pentoxide and nitride. A thermal head characterized by being made of one selected from silicon, silicon carbide, silicon boride, and alumina.