Process cartridge, electrophotographic image forming apparatus and coupling therebetween

A process cartridge detachably mountable to a main assembly of an image forming apparatus, wherein said main assembly includes a motor, a main assembly side gear for receiving driving force from said motor and a hole defined by twisted surfaces, said hole being substantially coaxial with said side gear, said process cartridge comprising:

• an electrophotographic photosensitive drum;
• a developing roller for supplying toner to said electrophotographic photosensitive drum to develop a latent image formed on said electrophotographic photosensitive drum;
• a twisted projection engageable with said twisted surfaces, said projection being provided at a longitudinal end of said photosensitive drum, wherein when said main assembly side gear rotates with said hole and projection engaged with each other, rotational driving force is transmitted from said side gear to said photosensitive drum through engagement between said hole and said projection;
• a drum gear, disposed at one longitudinal end of said electrophotographic photosensitive drum to transmit the driving force from the electrophotographic photosensitive drum to said developing roller;
• a developing roller gear, engaged with said drum gear and disposed at one longitudinal end of said developing roller, for receiving the driving force for rotating said developing roller from said photosensitive drum;
• a magnetic seal member, disposed with a gap from said developing roller, for preventing leakage of the toner in a longitudinal direction of said developing roller, wherein magnetic force provided on a surface of said developing roller by said magnetic seal member is approximately 1000-2000 Gauss.

A process cartridge detachably mountable to a main assembly of an image forming apparatus, comprising:

• an image bearing member;
• a cartridge coupling member, provided coaxially with said image bearing member, for engaging with a main assembly coupling member provided in the main assembly of the apparatus to receive driving force for rotating said image bearing member from the main assembly of the apparatus when said process cartridge is mounted to the main assembly;
• a developing roller for supplying toner to said image bearing member to develop a latent image formed on the image bearing member, said developing roller having a magnet roller disposed therein;
• a driving force transmission member, disposed at one longitudinal end of said image bearing member to transmit the driving force from the image bearing member to said developing roller;
• a driving force receiving member, engaged with said driving force transmission member and disposed at one longitudinal end of said developing roller, for receiving the driving force for rotating said developing roller from said image bearing member;
• and
• a magnetic seal member, disposed with a gap from said developing roller, for preventing leakage of the toner in a longitudinal direction of said developing roller,
• wherein said magnetic seal member includes a magnet and a magnetic member magnetized by said magnet and provided outside and adjacent said magnet in the longitudinal direction,
• wherein said magnet roller and said magnetic seal member overlap each other in the longitudinal direction, and said magnetic seal member and said magnet roller form a first magnetic brush, and said magnet and said magnetic member form a second magnetic brush.