Image forming apparatus and image forming method

摘要

An intermediate transfer belt comprises a plurality of layers including a conductive layer, and has a transfer area and a transfer protection area. A CPU 111 sends a control signal to a primary transfer bias generating circuit 116, and applies a primary transfer bias upon the conductive layer of the intermediate transfer medium through a bias applying member 31A. The CPU 111 changes an output value of the primary transfer bias in accordance with a predetermined bias change condition when secondary transfer is not ongoing and when a non-image area, in which there is no toner image transferred on the intermediate transfer belt, such as the transfer protection area is passing the primary transfer part.