Image forming apparatus

An image forming apparatus comprising image forming sections provided for respective colors, wherein each of the image forming sections includes an electrophotosensitive member, a developing unit that develops a toner image on the electrophotosensitive member, a transfer unit that applies a transfer bias and transfers the toner image formed on the electrophotosensitive member onto a belt for transferring the toner image formed on the electrophotosensitive member;

• and an electrophotosensitive member cleaning unit that removes toner remaining on the electrophotosensitive member, said image forming apparatus comprising:
• a detection unit that detects the toner image transferred onto the belt by the image forming section;
• and
• a toner discharge unit that forcedly discharges toner from the developing unit and forms the toner image on said electrophotosensitive member,
• wherein the transfer unit applies a first transfer bias with a predetermined transfer efficiency with respect to the belt, for a predetermined area part of the toner image, and applies a second transfer bias whose transfer efficiency is at least smaller than the predetermined transfer efficiency of the first transfer bias, for a part excluding the predetermined area part of the toner image.