Drive transmitting device and image forming apparatus incorporating the drive transmitting device

A drive transmitting device comprising:

• a drive source configured to apply a driving force;
• a drive transmitting body having a press-in target portion, the drive transmitting body configured to receive the driving force from the drive source;
• and
• a rotary shaft including a press-in portion mounted on one end of the rotary shaft in an axial direction of the rotary shaft, the press-in portion configured to press into the press-in target portion of the drive transmitting body, the press-in portion including:
• a flat face extending parallel to the axial direction of the rotary shaft;
• and
• a plurality of circular arc faces disposed parallel to the axial direction of the rotary shaft, having distances different from each other from an axial center of the rotary shaft, and extending parallel to the axial direction of the rotary shaft,
• the plurality of circular arc faces each being disposed at a same position in the axial direction of the rotary shaft as at least a portion of the flat face in the axial direction of the rotary shaft,
• the plurality of circular arc faces including a first circular arc face and a second circular arc face, the first circular arc face being on an upstream side of the second circular arc face in an attaching direction of the drive transmitting body and having a radius of curvature, the second circular arc face being on a downstream side of the first circular arc face in the attaching direction of the drive transmitting body and having a radius of curvature,
• the radius of curvature of the second circular arc face being greater than the radius of curvature of the first circular arc face.