An image forming apparatus includes a drive source which is detachably mountable
to a main body, wherein the main body includes a gear which can be driven rotatable
by the drive source and which includes a coupling protrusion on a radial line.
A process cartridge includes a photosensitive drum, a process unit which acts upon
the photosensitive drum, and a coupling hole which is provided at an end part of
a radial direction of the photosensitive drum. The photosensitive drum set in the
main body rotates by receiving a drive force from the drive source via the coupling
protrusion and the coupling hole when a cover member of the main body is closed,
and the coupling protrusion and the coupling hole are fit together.
