| 摘要 |
A stencil is made by thermally perforating a stencil material by the use of a thick film thermal head. The thermal head includes an electrical insulating substrate and a glaze layer superposed on a heat radiating plate in this order, a resistance heater formed on the glaze layer to continuously extend in a main scanning direction, a plurality of electrodes of at least two lines which extend in a direction intersecting the main scanning direction in contact with the resistance heater and are alternately arranged in the main scanning direction, and a protective layer which covers exposed part of the resistance heater and the electrodes. The resistance heater is not smaller than 1 mu m and not larger than 10 mu m in thickness, and the space between each pair of adjacent electrodes in the main scanning direction is not smaller than 20% and not larger than 60% of the center distance between the adjacent electrodes. The stencil material is conveyed by a conveyor in a sub-scanning direction relative to the thermal head with the stencil material kept in contact with the thermal head. The thermal head and the conveyor are controlled so that the length in the sub-scanning direction of the resistance heater at the portion between each pair of adjacent electrodes is not smaller than 100% and not larger than 250% of the sub-scanning pitch. <IMAGE> |
