| 摘要 |
PURPOSE:To obtain copies of good quality without unfixed one and save energy by detecting factors for change of fixing temperature and supplying necessary electric power to the heater of a fixing device, and thereby improving response to change of temperature. CONSTITUTION:A temperature sensor detecting signal outputted from a temperature detecting circuit according to the temperature of a heater 34 is converted to a digital signal by an A/D converter 44. This is checked and the initial value of temperature of the heater 34 is monitored. Then, change of power source voltage, linear velocity of copying paper and number of continuous copying which are the factors of change of temperature of the heater 34 are monitored. Further, the result of conversion of a pattern detecting circuit 72 by the A/D converter is read out successively and white and black density ratio of the original 9 which is a factor of change of temperature of the heater 34 is monitored. Next, the amount of control of electric power is operated according to the number of copies, power source voltage, linear velocity and densitvy ratio, and power supply to the heater 34 is controlled basing on the result of operation. |
