| 摘要 |
PURPOSE:To prevent the abnormal lighting of a copying lamp by a method wherein an operating means outputs an on-signal only for the specified period of time. CONSTITUTION:A pulse signal is outputted from an AND circuit 46 to the driving part of the copying lamp when a CLPWM signal turns to an H and a CLE signal to an H. The copying lamp is kept lighted when the CLPWM signal is kept output by the malfunction of a CPU. The voltage of the 6pin of a differential amplifier 45 turns higher than the voltage of the 7pin after the time of the time constant of a resistor R160 and a capacitor C115 from the point of the time when the CLE signal turns to the H when the CLE signal attains the state of the H and, therefore, the output from the 1pin turns to an L. The CLPWM signal to the AND circuit 46 turns to the H and the CLE signal to the L and the output from the AND circuit 46 turns to the L. Since the CLPWM signal to the driving part is the L, the copying lamp is not lighted. |
