| 摘要 |
PURPOSE:To perform highly safe temperature control by switching a power-on time to be detected through a temperature controller which performs power-on control over the heater of a copying machine, etc., according to the state of the heater. CONSTITUTION:The time of feeding to the heater H1 is monitored to detect abnormality of the heater H1. The time of feeding to the heater H1 is monitored by different timers in power-on operation, stand-by state, and in copying operation. This results from that it takes about 20sec to raise the surface temperature of a roller from room temperature (about 20 deg.C) to temperature in stand-by state (about 180 deg.C) while it takes about 1sec to enter the stand-by state in the stand- by mode or copying operation after the heater H1 is turned off. For the purposes, two timers are used. Further, the signal from a thermistor Th1 which monitors the surface temperature of the roller is detected and a judgement of abnormality is made when the surface temperature exceeds a specific value to blow a fuse resistance R38. |
