Rohm Co., Ltd.

Yutaka Tatsumi

Hideo Taniguchi

Kunio Motoyama

Teruhisa Sako

Masatoshi Nakanishi

Syunji Nakata

A thermal head producing method in which dispersion of resistance values of heating resistors in each thermal head and dispersion of the resistance values of the heating resistors per dot unit are made uniform to improve printing quality. A glaze layer is formed on a substrate and a heating resistor composed of a thin film resistor material of a mixed composition of a high melting point metal and an insulating material is formed on the glaze layer. First and second pattern conductors for providing common and separate electrodes are formed on the heating resistor and, after a protective film is formed to cover the first and second pattern conductors and the heating resistor, the heating resistor is heated so as to be a higher temperature than a dot temperature required for a printing operation. Preferably, after a resistor film formed on the glaze layer is annealed under vacuum to prepare the heating resistor, the first and second pattern conductors are formed on the heating resistor, and the protective film is formed in the same manner as described above.

Thermal head producing method

Apparatus for controlling driving of thermal printhead

The present invention provides a thermal head capable of preventing any chipping between a glaze layer and a protective film, increasing an angle of separation in a thermal transfer ribbon and eliminating any step of abrading the protective film to prevent the separation of the thermal transfer ribbon and the darkened background of the heat-sensitive sheet, and a method of making such a thermal head. The thermal head includes a glaze layer 12 formed as a heat-accumulating layer on a substrate 11, resistance and electrode layers 13, 14 and 15 formed on the glaze layer 12 and a protective film 16 formed to cover the entire surface of the thermal head. The edge of the glaze layer 12 is totally cut with the upper cut edge thereof being rounded. The protective film 16 is formed directly on the cut edge of the glaze layer and the substrate. After the glaze layer has been formed, the edge portion of the glaze layer 12 is cut until reaching the substrate 11. Thereafter, the glaze layer is heated at a temperature equal to or higher than its softening point to round the upper cut edge of the glaze layer. The other layers are then formed. The formed layers are then covered with the protective film 16. Finally, a portion of the protective film 16 adhered to the substrate is cut at a position adjacent to the upper rounded edge of the glaze layer.

Thermal head and method of making the same

A thick film type thermal head which includes an insulative substrate (2), an under-glaze layer (3) formed on the insulative substrate (2), a heat-generating resistor (6) and an electrode device for energizing the heat generating resistor (6) which are formed on the under-glaze layer (3), and an overcoating layer (7) for covering the heat-generating resistor (6). The overcoating layer (7) further includes a first overcoating layer (7a) formed by a thick film forming technique, and a second overcoating layer (7b) formed on the first overcoating layer (7a) through employment of a thin film forming technique.

Thick film type thermal head

A method for forming a thermal printing head comprising a base of electrically insulating material, a glaze layer formed on said base so as to form an elongated projection thereon, said glaze layer comprising a main portion and a portion integral with and extending from said main portion, at least one thermal printing element formed on said main portion of said glaze layer, and an area formed in said extending portion of said glaze layer to relieve said glaze layer of surface tension when glaze is sintered and then cooled to form said glaze layer on said base.

Method for forming a thermal printing head

A thermal printing head comprising a base of electrically insulating material, a glaze layer formed on said base so as to form an elongated projection thereon, said glaze layer comprising a main portion and a portion integral with and extending from said main portion, at least one thermal printing element formed on said main portion of said glaze layer, and an area formed in said extending portion of said glaze layer to relieve said glaze layer of surface tension when glaze is sintered and then cooled to form said glaze layer on said base.

Growing community of inventors

Kyoto, Japan

Yutaka Tatsumi