An image forming apparatus includes a rotatable photosensitive member; a charging device for electrically charging the photosensitive member; a developing device for developing with toner an electrostatic latent image formed on the photosensitive member electrically charged by the charging device; a transfer device for transferring a toner image from the photosensitive member onto an image-receiving member; and an auxiliary charging device for electrically charging untransferred toner on the photosensitive member to a normal charge polarity before the photosensitive member is electrically charged by the charging device; wherein effective widths W.sub.PM, W.sub.CD, W.sub.TD, and W.sub.ACD of the photosensitive member, the charging device, the developing device, the transfer device, and the auxiliary charging device satisfy: W.sub.PM>W.sub.CD>W.sub.ACD.gtoreq.W.sub.TD>W.sub.DD.