| 摘要 |
<p>PURPOSE:To obtain a simple head protective circuit, by providing a timer for counting a predetermined period of time after restarting for each energization period, and a means for making valid energization data for a thermal head during the counting of the predetermined period and making invalid the energization data after completion of the counting. CONSTITUTION:A latch circuit 2 comprises a RESET terminal which is reset at 0V. With a time pulse 26 inputted, energization data 21 are effectively latched during a period T1 to output an ON/OFF signal 23. During a resetting period T2 from the end of the period T1 to the next latch pulse, the latch circuit 2 is reset, and a terminal Q is maintained at 0V. Since the latch pulse 22 is inputted to each latch circuit 2 at an energization period T0 irrespective of the presence or absence of the energization data, when a timer 4 is set for a period of time not longer than the period T0, the timer 4 is restarted for each of the latch pulses 22, and a resetting operation is repeated. Accordingly, even when data becomes longer than the energization data 21 due to a noise (n), resetting is effected after a predetermined period of time T1.</p> |
