Patent ID: 7693470

Claim:
An image forming apparatus comprising: a plurality of rollers; an endless belt looped around the plurality of rollers so that a bridging portion is formed between rollers and both ends of the bridging portion are supported on the rollers, the endless belt being insulative and driven in a predetermined driving direction so as to convey a record sheet; a photosensitive element positioned outside of and facing an outer peripheral surface of the bridging portion of the endless belt, the photosensitive element forming developer images when electrostatically charged developer is deposited thereon; and a transfer element positioned opposite of the photosensitive element with the bridging portion interposed therebetween, and to which a transfer bias is applied so as to transfer the developer from the photosensitive element to the record sheet, wherein the plurality of rollers includes an upstream-side roller for supporting an upstream end of the bridging portion that is interposed between the photosensitive element and the transfer element as seen in the driving direction of the endless belt; and wherein an inner peripheral surface of the endless belt is made of a material which has greater tendency to be charged in a polarity that is the same as the developer in triboelectric series than an outer peripheral surface of the upstream-side roller.