| 摘要 |
PURPOSE:To gradually lower the resistance value of a heat generating resistor, by mounting a pulse generation circuit and a resistance meter and connecting the heat generating resistor to the above mentioned resistor when a definite time was elapsed after the application of a voltage pulse. CONSTITUTION:When a voltage application start signal START is received from a calculation part 12, a pulse generation circuit 10 returns an ENABLE prohibiting signal to the calculation part 12 and a switch 9 is changed over to the side of the pulse generation circuit 10. When a definite time T is elapsed after the START signal was applied, the pulse generation circuit 10 applies (n) pulses with a peak value Vs to the heat generating resistor of a thermal head 7 through a change-over connection circuit consisting of the switch 9 and a relay network 8. When a time T2 is elapsed after the application of pulse voltage was completed, the switch 9 is changed over to the side of a resistance meter 11. After the voltage pulse was perfectly distincted, the switch 9 is changed over and the voltage pulse can be applied certainly and the resistance value of the resistor can be successively lowered. |
