A developer supply container for supplying a developer to a process cartridge detachably mounted to a main assembly of an electrophotographic image forming apparatus, the process cartridge containing an electrophotographic photosensitive drum and a developing roller configured and positioned to develop an electrostatic latent image formed on the photosensitive drum with the developer, said developer supply container comprising:
- a developer accommodating portion configured to accommodate the developer;
- a first container positioning portion, provided at a leading end of said developer supply container with respect to a mounting direction in which said developer supply container is longitudinally mounted to the main assembly of the apparatus,
- said first container positioning portion being positioned relative to a first main assembly positioning portion provided in the main assembly of the apparatus when said developer supply container is mounted to the main assembly of the apparatus,
- a first container guide extending along the longitudinal direction of said developer supply container, said first container guide being disposed at one end of said developer supply container, with respect to a direction crossing the longitudinal direction of said developer supply container,
- said first container guide being guidable by a main assembly guide provided in the main assembly of the apparatus when said developer supply container is mounted to the main assembly of the apparatus,
- wherein when said first container positioning portion is positioned relative to the first main assembly positioning portion, a trailing side of said first container guide is positioned relative to the main assembly guide in the mounting direction by a leading side of said developer supply container being raised;
- a second container guide extending along the longitudinal direction of said developer supply container, said second container guide being disposed at the other end of said developer supply container, with respect to the direction crossing the longitudinal direction of said developer supply container,
- said second container guide being guidable by another main assembly guide provided in the main assembly of the apparatus when said developer supply container is mounted to the main assembly of the apparatus,
- wherein when said first container positioning portion is positioned relative to the first main assembly positioning portion, a trailing side of said second container guide is positioned relative to the another main assembly guide in the mounting direction by the leading side of said developer supply container being raised;
- a developer supply opening disposed at the leading side of said developer supply container and on the bottom surface of said developer supply container when said first container positioning portion is positioned relative to the first main assembly positioning portion,
- said developer supply opening being configured and positioned to face a toner inlet provided in the process cartridge mounted to the main assembly to permit supply of the developer into the process cartridge from said developer accommodating portion;
- and
- an elastic force receiving portion disposed at the leading side of said developer supply container and disposed at the top surface of said developer supply container when said first container positioning portion is positioned relative to the first main assembly positioning portion,
- said elastic force receiving portion being configured and positioned to receive an elastic force from an elastic member provided in the main assembly of the apparatus, urging said developer supply opening toward the toner inlet when said first container positioning portion is positioned relative to the first main assembly positioning portion.