| 摘要 |
<p>PURPOSE:To provide a line thermal head protection circuit which can correspond to various kinds of abnormal situations, self-reset errors and carry out normal printing after self-resetting errors. CONSTITUTION:The variation of head load signal S2 output from a power-on control circuit 14 is sensed by a flip-flop FF1 and a NAND gate G3. If the variation is not sensed during the given time (error), error signals $6 are output by a counter CT1 and an inverter INV2, and the power-on control circuit 14 is reset by a reset signal S8. An error signal S5 is output by the flip-flop FF2 during said reset period to put a control terminal of the gate G2 on H level and put forcibly a power-on control signal S1 on H level, which means power- off. A thermal head, therefore, is protected.</p> |
