Temperature control system of fixing device

Abstract

Abstract PURPOSE: To keep the heater temperature at the fixing temperature even when the conveying speed of recording paper is not uniform, by deciding the temperature change speed of the heater, and controlling the electric power to be supplied to the heater depending on the result of this decision. CONSTITUTION: A temperature detecting element is fitted in a heater 1, and the output thereof is inputted into the (+) input terminal of a comparator 6. Resistors 8aW8f make a voltage level corresponding to the reference temperature by the ratio to the resistance against a resistor 7, and voltage levels corresponding to these referance temperatures sequentially appear at the (-) terminal of the comparator 6 in time divisionally. The comparator 6 compares the two inputs in time divisionally, and the output thereof becomes high level when the temperature of the heater 1 is high, and low level when low. FF9a to 9f operate according to the signals of results of comparison obtained from the comparator 6, and counters 10W12 count the clock pulses when the outputs from FF9aW9f are high level, and the number of counting is compared with the content stored in decision circuits 22W24, thereby controlling a lighting ratio control circuit 3. COPYRIGHT: (C)1980,JPO&Japio

Inventors

• 👤 Koji Yamabe

Bibliographic Details