Patent ID: 8417144

Claim:
An image forming apparatus capable of forming an image on a recording medium, said apparatus comprising: a main assembly frame; an exposure unit; a rotatable belt; and a supporting member, movably supported by said main assembly frame, for demountably supporting a first cartridge and a second cartridge and for moving electrophotographic photosensitive members, said supporting member being movable between (i) a latent image formation position in which said electrophotographic photosensitive members are contacted to said rotatable belt, and a retracted position in which said electrophotographic photosensitive members are spaced from said rotatable belt inside said main assembly frame, and (ii) the retracted position and an outer position in which said first cartridge and said second cartridge are detachably mountable outside of said main assembly frame, said supporting member having a mounting portion on which said first cartridge and said second cartridge are detachably mountable, wherein, the first cartridge is mounted on the most downstream side of said mounting portion in a drawing direction in which said supporting member is drawn out from said retracted position to said outer position, the second cartridge is mounted on an upstream side of the first cartridge in the drawing direction, and the first cartridge is larger than the second cartridge, wherein, between said exposure unit and said rotatable belt in an orthogonal direction with respect to the drawing direction, said supporting member, with said first cartridge and said second cartridge mounted thereon, is movable between the latent image formation position and the retracted position.