| 摘要 |
PROBLEM TO BE SOLVED: To prevent an electrostatic charging member from being contaminated with fogging toner produced where a toner image is not formed on a photoreceptor drum or owing to retransfer. SOLUTION: The application of a transfer bias from a transfer bias power source 6 to transfer rollers 5a, 5b, 5c, and 5d is started under the control of a controller 7 before the start of rotational drive of the photoreceptor drums 1a, 1b, 1c, and 1d resulting from the start of image forming operation and stopped after the rotational drive of the photoreceptor drums 1a, 1b, 1c, and 1d are stopped at the end of the image forming operation, and then while the photoreceptor drums 1a, 1b, 1c, and 1d are rotating, the transfer bias is applied to securely move the fogging toner sticking on the surfaces of the photoreceptor drums 1a, 1b, 1c, and 1d onto an intermediate transfer belt 8 and prevent electrostatic charging rollers 2a, 2b, 2c, and 2d from being contaminated, so that excellent images can stably be obtained for a long period. |
