| 摘要 |
PROBLEM TO BE SOLVED: To prevent developer left after transfer (toner) from adhering to a contact electrifying member and to stably and uniformly electrify an image carrier even after the long service of an image forming apparatus of a contact electrification type and a cleaner-less system. SOLUTION: By performing control to change the control value of DC voltage applied to a toner electrification amount control means 7 and a toner-left-after-transfer uniformizing means 8 so that the values of DC currents flowing to the toner electrification amount control means 7 and the toner-left-after-transfer uniformizing means 8 may be respectively constant, the electrification amount of the toner left after transfer can be controlled even when the toner electrification amount control means 7 and the toner-left-after-transfer uniformizing means 8 are deteriorated due to the accumulation of toner and external additive or the like after the image forming apparatus is used over a long term, whereby the adhesion of the toner left after transfer to an electrifying roller 2 and the faulty collection of the toner left after transfer in a developing device 4 can be prevented. Furthermore, the surface of a photoreceptor drum 1 is uniformly/stably electrified even when the electrifying roller 2 is deteriorated. COPYRIGHT: (C)2008,JPO&INPIT
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