Patent ID: 7871216

Claim:
An image forming apparatus comprising: a medium supporting member including: a plurality of ribs that support a recording medium; and an irradiation target portion that has a smooth surface, wherein the irradiation target portion is formed to have a lower surface roughness than other portions different from the irradiation target portion of the medium supporting member; and wherein the irradiation target portion is formed such that a ten-point average roughness Rz, indicating a surface roughness, is 3 microns or less; a light emitting unit that emits a light toward the irradiation target portion; a light receiving unit that detects the reflected light of the light emitted by the light emitting unit; and a diaphragm member that reflects a portion of the light which is emitted by the light emitting unit and which is not directed to the irradiation target portion, to restrict an irradiation range of the light within the irradiation target portion, wherein: a presence or absence of a recording medium in the irradiation target portion is detected based on a quantity of the reflected light; and the surface of the irradiation target portion has a slope inclined in a direction from the light receiving unit to the light emitting unit.