Patent ID: 7920800

Claim:
An image forming apparatus, comprising: a plurality of toner image forming devices for forming toner images of a plurality of mutually different colors; a toner image carrying member for carrying on a surface thereof the toner images of the plurality of colors to be transferred onto a recording medium at one time; an adhesion amount detection device for detecting a toner adhesion amount of each of the toner images of the plurality of colors formed and carried on the surface of the toner image carrying member, the adhesion amount detection device being located at one end of the toner image carrying member; and a failure detection device for detecting signs of failure in the toner image forming devices, wherein the failure detection device detects signs of failure in one of the toner image forming devices on the basis of information based on adhesion amount detection results obtained through detection by the adhesion amount detection device of toner adhesion amounts of toner images formed on the surface of the toner image carrying member by other toner image forming devices.