| 摘要 |
PROBLEM TO BE SOLVED: To provide a multicolor image forming apparatus including image carriers for a plurality of colors individually, which satisfactorily starts control of forward current applied between the image carrier and a transfer means while suppressing mixture of developing material having different color. SOLUTION: Positive voltage or negative voltage is selectively applied to a developing roller 15 from a high-voltage power supply for development 25. If inflow current flowing into a transfer roller 7 from a photoreceptor drum 5 is equal to or above a predetermined value, at a point of time after starting positive electrification of the photoreceptor drum 5 by an electrifier 11 and before starting formation of an electrostatic latent image by an LED unit 13, the negative voltage is applied to the developing roller 15. Consequently, surface potential of the photoreceptor drum 5 is decreased, and the inflow current is also decreased. Since it is unnecessary to apply reverse current from the transfer roller 7 to the photoreceptor drum 5, the mixture of toner having different color is suppressed. COPYRIGHT: (C)2010,JPO&INPIT |
