Abstract: An image forming apparatus includes a developing cartridge and rotatable member having a cartridge mounting portion with an engaging portion engageable with a portion of the cartridge. The cartridge includes a developing roller for developing a latent image formed on an image bearing member. The rotatable member is rotatable for moving the mounting portion between a mounting and demounting position for mounting and demounting the cartridge and another position. The engaging portion is movable between a regulating position, in which disengagement of the cartridge from the mounting portion is suppressed, and a permitting position in which the disengagement of the cartridge from the mounting portion is permitted. When the mounting portion is at the another position, the engaging portion is regulated at the regulating position. When the mounting portion is at the mounting and demounting position, the engaging portion is movable from the regulating position to the permitting position.

Abstract: A process cartridge detachably mountable to a main assembly of an image forming apparatus includes an image bearing member; a cleaning member for removing a developer from the image bearing member; a frame provided with an opening; a developer accommodating portion for accommodating the developer which was removed by the cleaning member and has passed through the opening; a sheet member, contacting the image bearing member, for preventing the developer from leaking out of the developer accommodating portion; a supporting portion, provided to the frame, for supporting the sheet member; a reinforcing portion, provided to the frame, connecting a one end-side portion of the frame located upstream of the opening with the other end-side portion of the frame located downstream of the opening, with respect to a rotational direction of the image bearing member; and a space, provided downstream of the reinforcing portion with respect to a direction from the opening toward the developer accommodating portion, for permit