Electrophotographic image forming apparatus

An electrophotographic image forming apparatus for forming an image on a recording material, wherein a plurality of process cartridges are detachably mountable to said electrophotographic image forming apparatus along a substantially vertical line, the process cartridges each having an electrophotographic photosensitive drum, process means actable on the electrophotographic photosensitive drum, a drum shutter rotatably supported on a cartridge frame configured to move between a first position for covering an exposure portion so as not to expose the electrophotographic photosensitive drum through the cartridge frame and a second position, retracted from the first position, for uncovering the exposure portion to expose the electrophotographic photosensitive drum, said apparatus comprising:

• mounting portions configured and positioned to detachably mount the process cartridges;
• an opening for permitting passage of the process cartridges into said image forming apparatus;
• a covering member configured and positioned to cover said opening and being movable between a close position for closing said opening and an open position, retracted from said close position, for opening said opening;
• a pressing member configured and positioned to abut the drum shutter to move the drum shutter to the second position thereof when said covering member moves from the open position to the close position, wherein the angle of rotation of the drum shutter rotated by said pressing member from the first position to the second position in one of the process cartridges that takes a bottommost position among the process cartridges is larger than the angle of rotation of the drum shutter rotated by said pressing member from the first position to the second position in another one of the process cartridges.