A process cartridge removably mounted onto a main body of an image forming system including a reciprocally movable original setting glass on which an original is set, a lamp for irradiating a surface of the original set on the original setting glass, a lens for introducing a reflected light from a surface of the original to an electrophotographic photosensitive drum, a lens unit rockably supporting the lamp and the lens, original setting glass positioning members provided on the lens unit such that the original setting glass, upon moving, rides over the original setting glass positioning members, and an openable/closable cover having a mount portion for mounting said process cartridge, said lens unit being rockably provided on the openable/closable cover and the original setting glass positioning members protruding from penetration holes disposed proximate to each end of an exposure aperture formed on the openable/closable cover in a longitudinal direction thereof, said process cartridge comprising:
- an electrophotographic photosensitive drum;
- a charge roller abutted to and charging said electrophotographic photosensitive drum;
- a developing roller supplying toner to said electrophotographic photosensitive drum for developing a latent image formed on said electrophotographic photosensitive drum;
- a cleaning blade abutted to said electrophotographic photosensitive drum for removing residual toner therefrom;
- a lower frame provided with said electrophotographic photosensitive drum, said developing roller, and said cleaning blade, said lower frame being located at a lower position when said process cartridge is mounted on a mount portion provided on the openable/closable cover and when the openable/closable cover is closed;
- an upper frame provided with said charge roller and a toner container portion for containing the toner to be used by said developing roller, said upper frame being located at an upper position when said process cartridge is mounted on the mount portion provided on the openable/closable cover and when the openable/closable cover is closed, said upper frame being separably connected with said lower frame;
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- positioning members provided on said lower frame and protruding from penetration holes formed in said upper frame, for abutting and positioning the lens unit supporting the lamp and the lens when said process cartridge is mounted on the mount portion provided on the openable/closable cover and when the openable/closable cover is closed, said positioning members being provided on said lower frame at positions proximate to one and the other end of said electrophotographic photosensitive drum in a longitudinal direction thereof, said penetration holes formed in said upper frame being provided proximate to one end and the other end of an exposure aperture for irradiating the reflected light to said electrophotographic photosensitive drum.