Patent ID: 7929876

Claim:
An image forming apparatus, comprising: a forming portion capable of forming a mark on a surface of a bearing member; a light projecting portion capable of irradiating a light onto the surface of the bearing member with light irradiating a portion of the surface of the bearing member with the mark and a portion of the surface of the bearing member without the mark; a light receiving portion capable of receiving a reflection light from the portion of the surface of the bearing member without the mark and from the portion of the surface of the bearing member with the mark, and outputs a received light signal in accordance with the received light amount; a judging portion capable of judging the existence or non-existence of a mark on the bearing member based on the received light signal; an evaluating portion capable of evaluating a reflection state of the bearing member; and an adjusting portion capable of adjusting a light receiving sensitivity of the light receiving portion at a time of a judgment by the judging portion, in accordance with an evaluation of the evaluating portion, wherein the adjusting portion adjusts the light receiving sensitivity such that the received light signal reaches a saturation level, where the received light signal corresponds to a reflection light from the portion of the surface of the bearing member without the mark.