Rotational force transmitting part

An image forming apparatus comprising:

• a process cartridge including:
• a casing;
• a cylinder having a photosensitive layer at an outer periphery thereof, the cylinder having an axis L1;
• a flange provided at one end of the cylinder that is coaxial with the axis L1, the flange including a plurality of projections provided inside the flange that project radially inward of the flange with a space diametrically between the projections, wherein a radially inner part of each projection has an overhang, and wherein the flange is rotatably supported in the casing to permit rotation about the axis L1;
• and
• a coupling member having an axis L2, the coupling member having (i) a first end portion connected to the flange, (ii) a second end portion, and (iii) a connecting portion connecting the first end portion and the second end portion,
• wherein the coupling member is movable between a first position in which the axis L2 of the coupling member is coaxial with the axis L1 of the flange, and a second position in which the axis L2 of the coupling member is inclined with respect to the axis L1 of the flange, and
• wherein, when the coupling member is in the second position, an angle of inclination of the axis L2 with respect to the axis L1 is about 20 degrees to about 60 degrees;
• a driving motor;
• a driving shaft engageable with the second end portion of the coupling member of the process cartridge and having a rotational axis L3;
• a guide portion configured to guide insertion of the process cartridge into the image forming apparatus along a direction that is substantially perpendicular to the rotational axis L3 of the driving shaft;
• and
• an urging member movable between an urging position and a retracted position retracted from the urging position,
• wherein, when the process cartridge is mounted to the image forming apparatus, the coupling member is inclined toward the driving shaft by being urged by an elastic force of the urging member restoring to the urging position after being temporarily retracted to the retracted position by being contacted by the coupling member.