| 摘要 |
PURPOSE:To make favorable printing efficiency and the property for contact with a paper, by controlling the ratio of the width of a glazed glass to be provided to the width of a printing dot to within a specified range, and controlling the ratio of the width of the glazed glass to the thickness of the glazed glass to within a specified range. CONSTITUTION:The dot width Dw in a cross-sectional view of the part of a glazed glass 12 of a thermal head is necessarily determined by the construction of characters to be printed. Once the dot width Dw is determined, the width (w) of the glazed glass 12 and the thickness (t) thereof suitable for eliminating an air gap can be calculated. Thus, the ratio Dw/w must be not less than 0.15, and the ratio t/w must be not less than 0.038. In view of a heat-accumulating effect and restrictions on manufacture, the upper limits of Dw/w and t/w are determined to be 0.25 and 0.08, respectively. With this arrangement, the surface of a heating element makes favorable contact with a paper or a ribbon, leading to a higher printing efficiency and contributing to enhancement of printing quality. |
