Patent ID: 8164606

Claim:
An exposure apparatus having a light source for emitting a light beam with a light quantity corresponding to a current amount supplied, a rotating polygon mirror with a plurality of reflection planes, the rotating polygon minor rotating in a manner that the light beam emitted from the light source and reflected off a reflection plane scans on a photosensitive body, and a beam magnifying unit for expanding the light beam emitted from the light source in a manner that the light beam is irradiated onto the rotating polygon minor with a beam width exceeding a width of the reflection plane of the rotating polygon mirror in a scanning direction, comprising: a setting unit for setting a target light quantity of the light beam irradiated onto the photosensitive body; and a current supplying unit for, if a first target light quantity is set by the setting unit, supplying the light source with first correction current that will make a light quantity of the light beam irradiated onto the photosensitive body nearly constant in a main scanning direction and, if a second target light quantity is set by the setting unit, supplying the light source with second correction current that will make a light quantity of the light beam irradiated onto the photosensitive body nearly constant in a main scanning direction.