| 摘要 |
<p>PURPOSE:To reduce the generation of trouble outside an operation region without lowering the characteristics of a printer by an increase in the load of a processor, by providing a monostable multivibrator for extending and contracting the pulse width of a printing signal corresponding to the temp. of a substrate, a monitor circuit for detecting the limit of the operation region from the temp. of the substrate to output a signal and a change-over circuit having a thermistor connected thereto. CONSTITUTION:A monostable multivibrator 3 extends and contracts the pulse width of a printing signal corresponding to the temp. of a substrate and the printing signal is inputted to a head 2 from a processor 1 through the monostable multivibrator 3. The head 2 is equipped with a thermistor 21 detecting the temp. of the substrate to change a resistance value and the output signal of the thermistor 21 is inputted to a circuit for controlling the pulse width of the monostable multivibrator 3 through the analogue switch 61 of a change-over circuit 6. A monitor circuit 5 consists of a pair of comparing circuits 51, 52 containing a circuit generating reference voltage and the output signal of the thermistor 21 is inputted to the input terminal of one of the comparing circuits 51, 52 through the analogue switch 62 of the change-over circuit 6 and, for example, the comparing circuits 51, 52 respectively detect the upper and lower limits of an operation range from the temp. of the substrate.</p> |
