Patent ID: 8447208

Claim:
An image forming apparatus comprising: a main assembly; a cartridge, which is detachably mountable to said main assembly and includes a photosensitive member on which a toner image is to be formed, that operates so as to form the toner image on a sheet material in a state in which said cartridge is mounted in said main assembly; and a fixing unit, capable of retracting from a position inside said main assembly to a position outside said main assembly, for fixing the toner image on the sheet material at the position inside said main assembly, wherein when said fixing unit is retracted to the position outside said main assembly, said cartridge is demountable from said main assembly, wherein a cross-sectional area of said cartridge viewed from a mounting and demounting direction of said cartridge is smaller than that of said fixing unit, and wherein when said cartridge is demounted from said main assembly, said cartridge is demountable from said main assembly by passing a whole of said cartridge through a space to be occupied by said fixing unit.