Image forming apparatus which cleans a transfer belt by applying a bias voltage

摘要

An image forming apparatus capable of preventing toner deposited on an image carrier from being transferred to an image transfer belt and capable of removing the toner transferred to the belt without lowering a copying speed. When an image transfer medium is absent at a nip formed by the belt and an image carrier contacting each other, a charge of the same polarity as a charge assigned to image transfer is applied from a high-tension power source to the belt.