Patent ID: 8099010

Claim:
An image forming apparatus having a single-side printing mode of forming an image on a single surface of a recording medium and a double-side printing mode of forming an image on a first surface of the recording medium and thereafter forming another image on a second surface of the recording medium opposite to the first surface, comprising: a plurality of photosensitive members arranged in line in a transport direction for the recording medium so that electrostatic latent images are formed thereon; a plurality of developing members, each developing member corresponding to a photosensitive member of the plurality of photosensitive members, and each developing member being supplied with a developing bias for forming a first potential difference between the developing member and the corresponding photosensitive member, for feeding a developer of a prescribed color to the corresponding photosensitive member and developing the electrostatic latent image formed on the corresponding photosensitive member into a developer image; a plurality of transfer members, each transfer member corresponding to a photosensitive member of the plurality of photosensitive members, and each transfer member being supplied with a transfer bias for forming a second potential difference between the transfer member and the corresponding photosensitive member, for transferring the developer image on the corresponding photosensitive member to the recording medium; a transfer bias set up section setting up the transfer bias applied to each transfer member so that the transfer bias applied to the transfer member corresponding to the photosensitive member on the most downstream side in the transport direction is greater than the transfer bias applied to the one or more other transfer members; and a developing bias set up section setting up the developing bias applied to each developing member to a first developing bias in the single-side printing mode while setting up the developing bias applied to each developing member in formation of the image on the first surface and in formation of the image on the second surface to a second developing bias lower than the first developing bias when the image formed on the second surface is an image formed by overlapping developer images of a plurality of colors in the double-side printing mode.