Thermal print head, thermal printer, and method for manufacturing thermal print head

A method for manufacturing a thermal print head, comprising:

• a substrate preparing step of preparing a substrate made of a single crystal semiconductor;
• a substrate processing step of processing the substrate to form an obverse surface facing in one sense of a thickness direction and a ridge that is raised from the obverse surface and extends in a main scanning direction;
• a resistive layer forming step of forming a resistive layer that is supported by the substrate and includes a plurality of heat generating parts arranged side by side in the main scanning direction;
• an insulating layer preparing step of preparing an insulating layer supported by the substrate;
• a wiring layer forming step of forming a wiring layer that is supported by the substrate and forms a conductive path to the plurality of heat generating parts;
• and
• a protective layer preparing step of preparing a protective layer covering the resistive layer and the wiring layer,
• wherein the wiring layer includes a conductive part and a heat generating sub-part for each of the plurality of heat generating parts, the conductive part having a lower resistance value per unit length in a sub-scanning direction than the heat generating part, the heat generating sub-part having a resistance value per unit length in the sub-scanning direction that falls between the respective resistance values of the heat generating part and the conductive part,
• the heat generating part, the heat generating sub-part and the conductive part are formed on the ridge,
• the heat generating sub-part is located between the heat generating part and the conductive part in the sub-scanning direction,
• the ridge includes a top part that is most distant from the obverse surface, an upstream-side first slope connected to the top part on an upstream side in the sub-scanning direction, a downstream-side first slope connected to the top part on a downstream side in the sub-scanning direction, and a downstream-side second slope connected to the a downstream-side first slope on an opposite side from the top part in the sub-scanning direction,
• the upstream-side first slope and the downstream-side first slope are inclined to the obverse surface at a first inclination angle,
• the heat generating part extends from the downstream-side first slope to the top part, and
• the insulating layer is in contact with the protective layer on the downstream-side second slope.

A thermal print head comprising:

• a substrate made of a single crystal semiconductor and including an obverse surface facing in one sense of a thickness direction;
• an insulating layer supported by the substrate;
• a resistive layer supported by the substrate and including a plurality of heat generating parts arranged side by side in a main scanning direction;
• and
• a wiring layer supported by the substrate and forming a conductive path to the plurality of heat generating parts,
• wherein the substrate includes a ridge raised from the obverse surface and extending in the main scanning direction,
• the wiring layer includes a conductive part and a heat generating sub-part for each of the plurality of heat generating parts, the conductive part having a lower resistance value per unit length in a sub-scanning direction than the heat generating part, the heat generating sub-part having a resistance value per unit length in the sub-scanning direction that falls between the respective resistance values of the heat generating part and the conductive part,
• the wiring part includes a first conductive layer and a second conductive layer,
• the conductive part is formed by a part where the first conductive layer is in contact with the insulating layer,
• the heat generating sub-part is formed by a part where the second conductive layer is in contact with the insulating layer,
• the first conductive layer and the second conductive layer partially overlap with each other as viewed in the thickness direction,
• the entire first conductive layer overlaps with the ridge as viewed in the thickness direction,
• the heat generating part, the heat generating sub-part and the conductive part are disposed on the ridge, and
• the heat generating sub-part is located between the heat generating part and the conductive part in the sub-scanning direction.