METHOD FOR ADJUSTING ELECTRIFICATION VOLTAGE OF ELECTRIFYING DEVICE IN IMAGE FORMING APPARATUS

摘要

PROBLEM TO BE SOLVED: To provide a method for adjusting electrification voltage of an electrifying device in an image forming apparatus, wherein an image having stable image quality is formed over a long term by always keeping constant potential by electrification of a photoreceptor drum even when an electrifying roller is formed of ion conductive rubber such as epichlorohydrin rubber and a resistance value of the electrifying roller is changed due to change with time or change of ambient temperature.;SOLUTION: Target voltage and target current to be applied to the electrifying roller necessary to electrify the surface of the photoreceptor drum to fixed potential, for example, 300V are obtained in advance. When adjusting electrifying voltage of the photoreceptor drum, the target voltage is applied to the electrifying roller to measure current flowing therein. In both cases where the measured current is more than the target value and where it is less than the target value, the voltage to be applied to the electrifying roller from a bias power supply is adjusted to either a voltage value at which the current flowing in the electrifying roller is more than the target current or a voltage value at which it is lower than the target value, and then the current flowing in the electrifying roller is adjusted to the target current.;COPYRIGHT: (C)2010,JPO&INPIT