| 摘要 |
PURPOSE:To supply proper applied energy, by a method wherein the temp. characteristic of a thermistor is corrected by a resistor network to be amplified by an operational amplifier and the output potential of the operational amplifier is set as reference potential and the charging time up to the reference potential of a condenser is outputted as a pulse width by a voltage comparing circuit to be set to the reference current supply time of a heat generating element. CONSTITUTION:A resistor network 1 corrects the temp. characteristic of a thermistor. When the values of resistors 23, 24 are set to R23, R24, the value of a condenser 10 to C10 and the output potential of an operational amplifier to Vop, a pulse width TW is determined by the potential Vop. By selecting the values of C10, R23, R24 and the value of an amplifying circuit 2, a characteristic having the change ratio of the pulse width linear to temp. change in a limited temp. range can be realized. The output of a comparing circuit 9 is transmitted to a transistor 27 for switching through an inverter buffer 25. The transistor 27 is connected to the power source supply terminal 26a of a head driver 26 and the head driver 26 becomes operable only for the time of the pulse width TW and the reference current supply time of a heat generating element 30 is determined. |
