| 摘要 |
PROBLEM TO BE SOLVED: To form an image stabilized for a long term by surely performing development and suppressing fogging improvement in picture quality. SOLUTION: A bias for development to be applied across a photoreceptor 4 and a development sleeve 102 is an alternating electric field of which the half cycle is a part of a sinusoidal wave and another half cycle has a flat potential, and when the surface potential of the photoreceptor 4 electrified to be of a fixed polarity by a electrification device 6 is defined as a dark potential and the potential dropped by image-exposing the photoreceptor 4 electrified at the dark potential is defined as a bright potential, the peak potential of the sinusoidal wave is made higher than dark potential in the case of reversal development, and it is made lower than the bright potential in the case of normal development. |
