| 摘要 |
<p>PURPOSE:To prevent a thermal head from being thermally destroyed due to temperature rise by providing a circuit to latch print data to be supplied to the thermal head, starting a timer circuit by running the latched data and shutting off power supply to the thermal head using an output from the timer circuit. CONSTITUTION:Print data 4 is entered to a thermal head 1 and at the same time, it is entered to a print data latch circuit 2. The data latched by the print data latch circuit 2 is entered to a timer circuit 3. If the operating time set by the timer circuit 3 reaches a time for the oversupply of power to the thermal head 1, the timer circuit 3 connects a clear signal to the print data latch circuit 2, disconnecting, a strobe signal tb, the thermal head 1. The strobe signal controls the power supply to the thermal head. If the strobe signal is disconnected, the current to the thermal head 1 is shut off. This action prevents thermal breakdown of the thermal head 1 due to the oversupply of power for printing.</p> |
