Patent ID: 8724163

Claim:
An image forming apparatus comprising: a light source configured to output a light beam; a rotational polygonal mirror configured to deflect the light beam output from the light source such that the light beam scans on a a photosensitive member; an optical unit configured to guide the light beam deflected by the rotational polygonal mirror onto the photosensitive member; a storage unit configured to store a plurality of correction data corresponding to a plurality of reference current values respectively, the plurality of correction data to corrects light amount of the light beam guided onto the photosensitive member by the optical unit to target light amounts corresponding to a plurality of positions in a scanning direction in which the light beam scans on the photosensitive member; a setting unit configured to set a light amount setting value of the light beam; a data generating unit configure to generate a first interpolation data or a second interpolation data for the plurality of positions, the first interpolation data being an approximate expression of degree n for interpolating correction data between the plurality of reference current values based on the plurality of correction data corresponding to the plurality of reference current values stored in the storage unit, and the second interpolation data being a linear expression for interpolating between a previous light amount setting value to be changed by the setting unit and a reference current value; and a control unit configured to control light amount of the light beam to a target light amount for the plurality of positions in the scanning direction based on the first interpolation data and the light amount setting value in a case where an image is formed by a first mode, and control light amount of the light beam to a target light amount for the plurality of positions in the scanning direction based on the second interpolation data and the light amount setting value in a case where an image is formed by a second mode, wherein image quality of an image formed by the first mode is higher than image quality of an image formed by the second mode.