| 摘要 |
PURPOSE:To prevent a thermal head from overheat by a method wherein on a thermal head array making a thermosensitive printing by a dot matrix are equipped shift registers to control heating of each thermal head and gate circuit. CONSTITUTION:In order to control heating of each thermal head of a thermal head array 1 made up by arranging a plurality of thermal heads is provided a shift register 3 having respective parallel outputs. In addition, gate circuits are provided so that input signals to a series input terminal D are arrested to each of cross pulses at optional integral times as long as a bit length of the shift register 3 which is connected with the series input terminal D of said shift register 3, for a period of the cross pulse equal to the bit length and accordng to the logic of series output of the shift register. Thus, heating electric power is given continuously to the same thermal heads to prevent them from excessive rise of temperature. |
