| 摘要 |
PROBLEM TO BE SOLVED: To prevent fogging at a developing part due to electrifying failure, caused by the sticking of residue toner, after transferring or the increase of its content. SOLUTION: The residue toner, after transferring remaining on the surface of a photoreceptor drum 1a without being transferred to a recording material when being transferred, is detected by a concentration sensor 15. Transfer bias applied to a transfer electrifying device 5a by a transfer bias applying power source 5e is controlled, based on the detected result by a control means 20. Thus, the quantity of transfer residue toner is decreased, and the developing part is prevented from fogging due to the change in electrical resistance of an electrifying member caused by the residue transfer toner being stuck to the electrifying member and is mixed into the toner. |
