| 摘要 |
PROBLEM TO BE SOLVED: To provide an image forming apparatus, wherein when switching to constant current control as time passes, control is performed so that an application voltage is increased in the case that the resistance of a primary transfer means is high in the constant current control, contrarily in the case that the resistance of the primary transfer means is lowed as times passes, the constant current control is applied at first, and the constant current control is switched to constant voltage control as time passes. SOLUTION: The first primary transfer means 51 is connected to an operating time storage mechanism 62 which stores an operating time. A transfer power source 61 to the primary transfer means 51 is controlled by primary transfer bias control means, which are a switchable constant voltage control section 63 for performing constant voltage control and a switchable constant current control section 64 for performing constant current control. Switching between the control sections 63 and 64 is carried out when the operating time of the primary transfer means 51 stored by the operating time storage mechanism 62 exceeds a prescribed value. COPYRIGHT: (C)2008,JPO&INPIT
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