Cartridge, image forming apparatus, and drum attaching method

An image forming apparatus for forming an image on a recording material, said image forming apparatus comprising:

• a photosensitive drum having a shaft provided adjacent to one axial end;
• a frame that is provided with:
• (i) a first bearing portion supporting a circumference of said shaft, and
• (ii) a second bearing portion supporting a circumference of said shaft, said second bearing portion being spaced from said first bearing portion with respect to the axial direction and being disposed at a side opposite from said first bearing portion with respect to a plane including an axis of said shaft at the time when said shaft is supported by said first bearing portion, and said second bearing portion being disposed outside of said first bearing portion with respect to the axial direction;
• a first clearance space provided at a position opposite to said first bearing portion with respect to the plane, said first clearance space being disposed outside of a contact portion of said second bearing portion relative to said shaft with respect to a radial direction of said photosensitive drum and inside of said second bearing portion with respect to the axial direction;
• and
• a second clearance space provided at a position opposite to said second bearing portion with respect to the plane, said second clearance space being disposed outside of a contact portion of said first bearing portion relative to said shaft with respect to the radial direction and outside said first bearing portion with respect to the axial direction,
• wherein, in a process of causing said shaft to be supported by said first bearing portion, said shaft is capable of entering said first clearance space, and
• wherein in a process of causing said shaft to be supported by said second bearing portion, said shaft is capable of entering said second clearance space.

A mounting method for manufacturing a cartridge that is detachably mountable to an image forming apparatus, the cartridge including a photosensitive drum having a shaft provided adjacent to one axial end;

• a frame being provided with (i) a first bearing portion supporting a circumference of the shaft and (ii) a second bearing portion supporting a circumference of the shaft, with the second bearing portion being spaced from the first bearing portion with respect to the axial direction and being disposed at a side opposite from the first bearing portion with respect to a plane including an axis of the shaft at the time when the shaft is supported by the first bearing portion;
• the second bearing portion being disposed outside of the first bearing portion with respect to the axial direction;
• a first clearance space provided at a position opposite to the first bearing portion with respect to the plane, wherein in a process of causing the shaft to be supported by the first bearing portion, the shaft is capable of entering the first clearance space, the first clearance space being disposed outside of a contact portion of the second bearing portion relative to the shaft with respect to a radial direction of the photosensitive drum and inside of the second bearing portion with respect to the axial direction;
• and a second clearance space provided at a position opposite to the second bearing portion with respect to the plane, wherein in a process of causing the shaft to be supported by the second bearing portion, the shaft is capable of entering the second clearance space, the second clearance space being disposed outside of a contact portion of the first bearing portion relative to the shaft with respect to the radial direction and outside the first bearing portion with respect to the axial direction, the method comprising:
• a first step of moving the photosensitive drum such that a part of the shaft enters the first clearance space in a state that the photosensitive drum extends in a direction crossing the axis;
• a second step, after the first step, of moving the photosensitive drum such that a part of the shaft enters the second clearance space in a state that the photosensitive drum extends in a direction crossing the axis;
• and
• a third step of moving such that the shaft is brought into contact to the first bearing portion and the second bearing portion from a state that the photosensitive drum extends in a direction crossing the axis.