| 摘要 |
<p>PURPOSE:To eliminate manual adjusting work by providing a thermal head with a heat generating resistor for detecting the same in the resistance value as a heat generating resistor for recording and automatically adjusting supply power of the thermal head indirectly detecting the resistance value thereof. CONSTITUTION:Heat generating resistors 11 for detection with a resistance value R is provided across a heat generating resistor 10 for recording of a thermal head 4. A circuit is provided to adjust a voltage VD to be applied to the heat generating resistor 10 for recording from a constant voltage circuit 1 depending on the resistance value of the resistor 11. When a reference voltage V3 for detection is applied to a reference resistance 14 connected in series to two resistors 11 for detection, divided voltages V1 and V2 develop therein and are applied to input terminals A and B of a voltage adder 5. A signal of the result (V1+V2) is inputted into an A/D converter 6 and converted to a pit parallel logic signal to be inputted into a CPU circuit 8. Based on informations from a PROM12 and an RAM13, a control signal is emitted from the CPU circuit 8 to control the output voltage of the constant voltage power circuit 1 via an A/D converter 7.</p> |
