ABNORMAL OPERATION PREVENTING DEVICE AND METHOD FOR ELECTRIFYING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a device capable of being accurately cut off the power supply only when arc or overvoltage influential with the damage of an image and a photoreceptor is caused and also capable of eliminating short-time arcing or overvoltage not influential with the damage of the image and the photoreceptor only by a temporal element. SOLUTION: The electrifying device for electrifying the photoreceptor by corona discharge or the electrifying device for transferring a toner image stuck to the photoreceptor by high voltage applied through an electrifying roller to a printing paper side is provided with a discriminating means for discriminating the occurrence of the trouble arc or the overvoltage between the electrifying device and the photoreceptor by measuring the output voltage dropping time and the overvoltage outputting time of a high voltage generating device connected to the electrifying device. Supply of high voltage to the electrifying device is stopped by the discriminating means when the arc exerting influence on the image or the photoreceptor occurs.