IMAGE FORMING APPARATUS

摘要

PURPOSE: An image forming apparatus is provided to detect toner concentration degree formed on the phase retaining body of an endless belt by restricting the deformation of the endless belt shape. CONSTITUTION: A photoconductor drum(5) is placed on a plurality of rolls. A detecting apparatus detects the concentration degree of the toner image formed on the photoconductor drum based on the quantity of reflected light from the photoconductor drum. The detection length which performing detection operation along the moving route of the photoconductor drum is longer than the length of the deformed photoconductor drum moving route.