Patent ID: 6934497

Claim:
An image forming apparatus that forms an image by forming toner images and fixes the toner images on a recording medium, the apparatus comprising: a plurality of sensitized bodies arranged in a row and including a black sensitized body adapted to carry a black image formed thereon and a plurality of color sensitized bodies adapted to carry respective images of different colors other than black formed thereon, the black sensitized body being disposed at one of the opposite ends of the row of sensitized bodies; a belt adapted to move round on a course, sequentially passing by or coming into contact with the plurality of sensitized bodies, the belt directly receiving thereon or receiving on a recording medium carried by the belt the toner images formed on the plurality of sensitized bodies; a first roll secured in position between the black sensitized body and the immediately adjacent color sensitized body and adapted to cause the belt to come into contact with the black sensitized body; and at least one retractable roll adapted to locate between the two of the color sensitized bodies in one end of the row, wherein one of the two color sensitized bodies is disposed immediately adjacent to the black sensitized body, or one of the two color sensitized bodies is disposed at an opposite end of the row, and adapted to shift from a position for holding itself in contact with the belt to a position for separating itself from the belt and vice versa to change the course of round movement of the belt; a plurality of transferring members positioned directly opposite to the plurality of sensitized bodies and adapted to nip the belt with at least one of the sensitized bodies; and two second rolls at the opposite ends of the row of sensitized bodies and held at the opposite ends of the course of round movement of the belt, each of the two second rolls having an axis of rotation stationary with respect to the plurality of sensitized bodies, wherein the at least one retractable roll is adapted to actively position each of the plurality of transferring members such that attachment and detachment of the belt is exclusively under control of the at least one retractable roll.