Patent ID: 8385778

Claim:
An image forming apparatus including a gear, the gear comprising: a hole arranged at substantially center of the gear through which a shaft of a rotating member is engaged; an engagement portion arranged on an outer circumference of the gear to receive a drive force to rotate the gear; and a single circular ridge arranged between the hole and the engagement portion, the single circular ridge including at least two notches and at least two protruding portions extending from a surface of the gear, and arranged at a distance from the hole, the at least two notches having different lengths, wherein the gear drives a portion of the image forming apparatus, wherein the at least two protruding portions pass through a position sensor that detects a rotational position of the rotating member based on a position of the at least two protruding portions, wherein a gap is disposed between the rotating member and the gear in an axial direction of the shaft of the rotating member, and wherein lengths of each of the at least two protruding portions of the single circular ridge in a direction of rotation of the shaft of the rotating member are smaller than lengths of each of the at least two notches of the single circular ridge in the direction of rotation.