| 摘要 |
PROBLEM TO BE SOLVED: To prolong the service life of a photoreceptor by reducing the time to cause damage to the photoreceptor without impressing alternating voltage until DC voltage impressed on an electrifying roller rises to a specified value. SOLUTION: DC and alternating components impressed on the electrifying roller 2 are controlled and outputted independently, and the DC voltage is impressed on the roller 2 before starting the formation of an image. It takes 300ms to make a DC voltage value rise to -750V being a specified value. In the case only DC voltage is impressed, the surface potential of the photoreceptor is only <=20% of a desired value of electrifying the photoreceptor, so that the photoreceptor is prevented from being damaged by the electrification in the case only the DC voltage is impressed. Thereafter, the alternating voltage of 1500Vpp is impressed on the roller 2. Since it takes little time to make the alternating voltage rise, the surface of the photoreceptor 1 is electrified to -720V being a specified value for the first time. Then, DC and AC are turned off in timing that the photoreceptor 1 does not cause plastic memory after turning off the impressed voltage on a transfer roller 7. |
