| 摘要 |
PROBLEM TO BE SOLVED: To provide an image forming apparatus which is capable of suppressing a maldistribution of toner electric charge in a primary transfer part to prevent the occurrence of abnormal images and is capable of sufficiently utilizing the advantage of a superposition system for increasing a transfer rate. ! SOLUTION: A primary transfer roller 13 as a primary transfer nip forming member brought into contact with a photoreceptor drum 20 via an intermediate transfer belt 11 includes a metallic core bar 132 and a conductive sponge layer 131 as an elastic layer fixed on the surface of the core bar. In order to prevent the occurrence of discharge when a transfer bias in which an AC component and a DC component are superposed is applied at a secondary transfer nip, a diameter of the metallic core bar 132 is set to such a size (10.4 mm or larger) that a maldistribution of toner electric charge at the time of primary transfer can be suppressed. That is, the diameter is set to such a size (rigidity) tha |
