| 摘要 |
PURPOSE:To prevent abnormal thermal runaway of the heat fixing device even when an accident, etc., break out in a sensor, etc., for detecting the surface temp. of the heat fixing device. CONSTITUTION:A signal SG01 from an IR sensor and a signal SG02 from a temp. sensor for correction are inputted to an operation amplifier and are superposed, by which the surface temp. of a heat roller 9a is corrected and is detected as a signal SG10. A microcomputer 12 controls an SSR 13 to on and off in accordance therewith and maintains the heat roller 9a at a prescribed temp. The output signal SG22 from a comparator inverts to a low level when the temp. sensor for correction detects an abnormal temp. rise. As a result, a heater lamp 9d is held turned off by the SSR 13. |
