| 摘要 |
PURPOSE:To obtain a control device which is used to the temperature display control and other purposes of the electrophotographic copier or the like with the steady operation ensured. CONSTITUTION:With switch-on of the power supply, the balance is lost for the bridge comprising resistors 9, 10 and 11 plus thermistor 6 in case the ambient temperature is low. And input terminal (2) features a higher potential than (3) for amplifier 12, and then the oscillation circuit has oscillations. As a result, the output of transformer 17 is transmitted to the gate of two-way thyristor 20 via diode 18 and resistance 19 to turn on the gate. Thus heater 2 is switched on, and the fixing unit is heated up with the temperature starting to rise up. When the temperature rises up and thermistor 6 reaches the set temperature, the output of the bridge composed of resistances 23 and 24 plus thermistor 6 becomes 0. And the output of amplifier 26 also becomes 0. |
