| 摘要 |
<p>PURPOSE:To enable a thermal head to be used for a long period of time, by setting a voltage supplied to heat generating elements of the thermal head to a low level in a period in which a controlling circuit is reset. CONSTITUTION:A terminal voltage Vc of a capacitor C in a resetting circuit 18 is inputted to a minus input terminal of a comparator 23, while a voltage Vref obtained by voltage division by resistors R2, R3 is inputted to a plus input terminal of the comparator 23. While the terminal voltage Vc of the capacitor C is lower than the comparative voltage Vref, an output voltage of the comparator 23 is at a high level (+5V), and an output from an inverter buffer 24 is at a low level. Therefore, an electric current passed from the point of +5V to a resistor R6 wholly flows into an output part of an inverter,and a transistor Q1 is turned OFF. Where the transistor Q1 is turned OFF, a transistor Q2 is also turned OFF, and a supply voltage V0 for heat generating resistors of a thermal head is not outputted.</p> |
