An image forming apparatus includes a photoreceptor formed by a transparent support member, a transparent conductive layer, an optical semiconductor layer, and an insulation layer stacked in this order, as well as developing units corresponding to black, yellow, magenta, and cyan provided at an outer periphery thereof. Exposure units corresponding to respective developing units are provided in the photoreceptor. Fixing units are arranged near respective developing devices at the outer periphery of the photoreceptor. Feeding units are provided for feeding a sheet A along the outer periphery of the photoreceptor from a paper feeding cassette to a first developing device and between the developing devices. Paper ejection units are provided corresponding to respective fixing units and sheet A is fed or ejected by switching the position of the fixing unit.