IMAGE FORMING DEVICE AND IMAGE FORMING DEVICE CONTROL METHOD

摘要

PROBLEM TO BE SOLVED: To prevent image forming accuracy from being deteriorated due to occurrence of color shift and the like caused by the torque variation of a transfer part being passed to an image carrier in a case where the image carrier and the transfer part are individually driven.

SOLUTION: An image forming device comprises an image carrier for carrying a toner image; a transfer part which can come into pressure contact with and separate from the image carrier and transfers a toner image carried on the image carrier to paper by pressure contact with the image carrier; a transfer part-drive part for rotatingly driving the transfer part; and a control part allowing constant-speed control for rotatingly driving the transfer part at a constant speed and constant-torque control for rotatingly driving the transfer part-drive part at a constant torque. The control part carries out constant-torque control in the above pressure contact state according to a torque detected in the constant-speed control in the above separation state so that variation in the torque given to the image carrier can be remarkably reduced when the paper is passed, and occurrence of a color shift is prevented in image forming.

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