Electrophotographic photosensitive drum, process cartridge, and electrophotographic image forming apparatus

A process cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus for forming an image on a recording material, the main assembly including a motor, a main assembly gear for transmitting a driving force from the motor, and a non-circular twisted hole having a section with a plurality of corner portions provided at a central portion of the main assembly gear, the non-circular twisted hole being rotatable integrally with the main assembly gear, said process cartridge comprising:

• (a) electrophotographic photosensitive drum;
• (b) process means actable on said electrophotographic photosensitive drum;
• and
• (c) a non-circular twisted projection provided on one longitudinal end of said electrophotographic photosensitive drum and having a section with a plurality of corner portions, said non-circular twisted projection being engageable with the hole of the main assembly of the apparatus to receive a rotational driving force for rotating said electrophotographic photosensitive drum from the main assembly of the apparatus when said process cartridge is mounted to the main assembly of the apparatus,
• wherein a recess is formed in a central portion of said projection and has a bottom portion and a side surface portion substantially perpendicular to said bottom portion,
• wherein in a state that said projection receives a pulling force toward the hole by rotation of the main assembly gear with said projection and the hole being engaged with each other, said bottom portion contacts a spherical surface portion provided at a central portion of the hole, and said side surface portion contacts the spherical surface portion, and
• wherein when said process cartridge is mounted to the main assembly of the apparatus, and said electrophotographic photosensitive drum receives the rotational driving force for rotating said electrophotographic photosensitive drum from the main assembly of the apparatus, an end of the spherical surface portion contacts said bottom portion, and the spherical surface portion contacts said side surface portion in a state that said projection receives the pulling force and that a gap is provided between a free end of said projection and a bottom portion of the hole.

An electrophotographic image forming apparatus for forming an image on a recording material, said electrophotographic image forming apparatus comprising:

• (a) a motor;
• (b) a main assembly gear configured and positioned to transmit a driving force from said motor;
• (c) a non-circular twisted hole is provided in a central portion of said main assembly gear and having a section with a plurality of corner portions, said non-circular twisted hole being rotatable with said main assembly gear;
• (d) a spherical portion provided in a central portion of said non-circular twisted hole;
• (e) a mounting portion in a main assembly of said apparatus;
• and
• (f) a process cartridge detachably mounted to said mounting portion, said process cartridge including:
• an electrophotographic photosensitive drum;
• process means actable on said electrophotographic photosensitive drum;
• a non-circular twisted projection provided on one longitudinal end of said electrophotographic photosensitive drum and having a section with a plurality of corner portions, said non-circular twisted projection being engageable with said hole to receive a rotational driving force from said main assembly of said apparatus when said process cartridge is mounted to said mounting portion of said main assembly of said apparatus,
• wherein a recess is formed in a central portion of said projection and has a bottom portion and a side surface portion substantially perpendicular to said bottom portion,
• wherein in a state that said hole receives a pulling force toward said projection by rotation of said main assembly gear with said projection and said hole being engaged with each other, said bottom portion contacts an end of said spherical surface portion, and said side surface portion contacts said spherical surface portion;
• and
• (g) feeding means for feeding the recording material,
• wherein when said process cartridge is mounted to said main assembly of said apparatus, and said electrophotographic photosensitive drum receives the rotational driving force for rotating said electrophotographic photosensitive drum from said main assembly of said apparatus, the end of said spherical surface portion contacts said bottom portion, and said spherical surface portion contacts said side surface portion in a state that said projection receives the pulling force and that a gap is provided between a free end of said projection and a bottom portion of said hole.