An electrophotographic image forming apparatus is usable with a process cartridge having an electrophotographic photosensitive member. The apparatus includes a transfer member contactable to the photosensitive member to transfer a toner image from the photosensitive member thereonto, a tray carrying the cartridge and movable between a contact position where the photosensitive member contacts the transfer member and a spaced position spaced from the transfer member, a supporting member supporting the tray for movement parallel with a tangent line between the photosensitive member and the transfer member between a first position positioning the tray at the contact position and a second position retracted from the first position away from the transfer member in a perpendicular direction perpendicular to the photosensitive-member axial direction and to the tangent line to position the tray at the spaced position, and engageable and engaging portions engageable with each other. The engaging portion regulates tray movement.