Abstract: An image forming apparatus includes a photoreceptor drum having a toner image formed on its surface, a transfer drum having a dielectric layer, a semiconductive layer and a conductive layer arranged orderly, a power source section applying a predetermined voltage to the conductive layer, and a ground roller which is grounded and comes in contact with the surface of the dielectric layer through a transfer paper. In addition, in the image forming apparatus, a foaming body having elastic property is used for the semiconductive layer, and a diameter of foams in the semiconductive layer is controlled within the range of between 200 .mu.m and 400 .mu.m. Alternatively, the average micro-gap (which is obtained by equalization of a micro-gap formed between the semiconductive layer and the dielectric layer) may be controlled within the range of between 20 .mu.m and 50 .mu.m.