CONTROLLING METHOD FOR TEMPERATURE OF FIXING DEVICE IN ELECTROPHTOTGRAPHIC COPYING MACHINE

摘要

PURPOSE:To eliminate oveshooting while maintaining stability to absorption of heat from a fixing device by transfer paper by controlling the temp. of the fixing device by proportional control unitl the temp. of the fixing device attains a set value after starting of heating of the fixing device and controlling the temp. of the fixing device by integral control after the set value is attained. CONSTITUTION:The signal from a thermistor 26 for detecting the temp. of the fixing device is amplified with an amplifier 24 and is applied to the input terminal of an anaglog gate G0. The gate G0 opens the gate according to the gate control signal from the output port S0 of an MPU 12 and applies the signal from the amplifier 24 to an ADC input port which is the input terminal of an analog to digital converter of the MPU 12. The MPU 12 converts the analog signal inputted thereto to a digital signal and outputs the control signal for on and off controlling of a triac 16 through the output port P, thereby controlling the conduction of electricity to a heater 18 a fixing device. Proportional control is used since the start of heating of the fixing device (point of time A) until the point of time B when the temp. of the fixing device attains a set value (T0), and the temp. of the fixing device is controlled by integral control after the point of time B.