| 摘要 |
PURPOSE:To accurately detect and control the temperature of a heater controller from a low temperature to a high temperature by changing the resistance value of a resistor in accordance with the signal from an electric temperature detector. CONSTITUTION:A certain voltage Vcc is impressed to one end of an electric temperature detector (thermistor) 3 provided in the vicinity of a fixing heater 2, and the other end of the thermistor 3 is connected to the connection point of analog switches SA to SC, and resistors R1 to R3 are connected to analog switches SA to SC. Analog switches SA to SC are turned on or off in accordance with a temperature detection voltage Va of the thermistor 3, and resistors R1 to R3 connected to the thermistor 3 are switched in accordance with this turning-on/off to change the resistance values of resistors connected to the thermistor 3. Thus, the temperature of the heater controller is accurately detected and controlled from a low temperature to a high temperature. |
