PURPOSE: To restrain and prevent the deterioration in discharging characteristic even in the case that a device is arranged in a comparatively small space by arranging plural corotrons at intervals.
CONSTITUTION: 1st and 2nd pre-transfer devices 21 and 22 are arranged near a photosensitive drum 11 at a prescribed interval in an area which lies between a developing machine 12 and a transfer corotron 18, and these corotron wires are commonly connected to a high voltage power supply 23. As to the corotron device 24 having such a constitution, the high voltage which is obtained by superposing AC and DC is impressed on the corotron wires of the 1st and 2nd pre-transfer devices 21 and 22 by the high voltage power supply 23. In this case, the output voltage of the high voltage power supply 23 is set slightly lower than that of a conventional high voltage power supply. By discharging by both of the pre-transfer devices 21 and 22, respective discharging quantities can be reduced.
YAMASHITA YUJI
KUBO SHINGO
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