Oki Electric Industry Co., Ltd.

Susumu Shibata

Hideo Sawai

Kenji Kuroki

Tsutomu Nomoto

Keiji Murasugi

Taiji Tsuruoka

A heating resistor includes a conductive material, and an electrically insulating material made of a mixture of silicon carbide (SiC) and carbon (C) having a carbon content of not less than 3 wt % based on the mixture. The resistor is formed by sputtering of a target of the conductive material and the electrically insulating material having at least 5 wt % of carbon. The conductive material and the electrically insulating material may be respectively provided as separate targets. The conductive material is at least one metal selected from tantalum, niobium, titanium, tungsten, molybdenum, zirconium and chromium.

Heating resistor and method for making same

A heater element plated on a dielectric substrate through electroless plating process provides an excellent thermal head for thermally printing on a paper. Said heater element composes of nickel, one of phosphorus and boron, and some minor additive agent. That additive agent is one of tungsten and molybdenum by 2-10 weight %. Because of the addition of the additive agent, the life time and heat stress characteristics of a thermal head are considerably improved.

Thermal head

A thermal head for a thermal printer and/or a thermal ink transfer printer having a substrate, a heater layer and a conductive lead layer on the substrate in which a protection layer covering the heater layer has been improved. According to the present invention said protection layer is made of polyimide resin which includes some hard particle of filler of S.sub.i C with a weight ratio to the polyimide solid in the range between 1.1 and 3.2. Since the present protection layer is provided with low curing temperature, the substrate of the present thermal head may be polyimide resin which is not heat-proof. Because of filler in the protection layer, that protection layer is wear-proof, although polyimide layer itself is not wear-proof.

A thermal head for high speed printing with high temperature comprises a dielectric substrate, a first thin S.sub.i O.sub.2 layer on the substrate, heater layers on the first S.sub.i O.sub.2 layer, conductive layers for coupling the heater layer with an external circuit, a second thin S.sub.i O.sub.2 layer on the heater layer, and a protection layer on the second S.sub.i O.sub.2 layer. The width of the heater layer is less than 30 .mu.m, and the preferable thickness of the first and second S.sub.i O.sub.2 layers is less than 2 .mu.m. Preferably, the heater layer is made of tantalium nitride (T.sub.a2 N).

A thermal head for a thermal printer having a dielectric support and a plurality of conductive layers made of a single material has been found. Said conductive layer comprises a pair of lead lines at both the extreme ends of the same and a heater line formed in a zigzag fashion between said lead lines, and the material of the conductive layer is, for instance, nickel. A portion of said lead line is plated with a conductive material whose conductivity is better than that of the heater. Said heater line is covered with single protection layer of Al.sub.2 O.sub.3.

Growing community of inventors

Tokyo, Japan

Susumu Shibata