| 摘要 |
PROBLEM TO BE SOLVED: To accurately control image density or the like and to unnecessitate the change of the rotational speed of a photoreceptor drum or the like by measuring the dark decay of potential at a potential sensor and a developing position and controlling electrifying potential. SOLUTION: The photoreceptor drum 1 is rotated, and an eraser 4, a discharging lamp 9 and an electrifying charger 2 are turned on. Then, residual potential VR is detected by a surface potential sensor 11, and the electrifying potential V0 of an image part on the surface of the photoreceptor drum 1 is detected when the eraser 4 is turned off, so that the electrifying potential V0 is temporarily adjusted to the residual potential VR+770V±20V. The lamp 9 and the electrifying charger 2 or the like are turned off, and the electrifying potential V0' is detected at the measuring position of the electrifying potential V0 on the photoreceptor drum 1 after the photo-receptor drum 1 is rotated once. The difference of the potential ΔV0=V0-V0' is calculated from a detected value, and the difference ΔV0 is stored in a RAM 25, and the lamp 9 and the electrifying charger 2 or the like are turned on and the photoreceptor drum 1 is stopped. |
