Patent ID: 8754921

Claim:
An image forming apparatus, comprising: an image carrier; a charger that charges a surface of said image carrier; a light source that emits a light modulated in response to an image signal and irradiates the light on the surface of said charged image carrier; a storage unit that stores a plurality of location data as coordinates comprising a main-scanning position and a sub-scanning position on the surface of said image carrier and stores data of a charging electric potential associated with the plurality of location data, wherein the plurality of location data and the data of the charging electric potential comprise local maximums of the data of the charging electric potential at coordinates of the plurality of location data associated with the local maximums, and further comprises local minimums of the data of the charging electric potential at coordinates of the plurality of location data associated with the local minimums; a determination unit that determines from the data of the charging electric potential, which has been read out from said storage unit, one or more correction values of a light power of said light source to be applied so as to reduce a charging electric potential of coordinates on the surface of said image carrier or a charging electric potential unevenness of coordinates on the surface of said image carrier; and a correction unit that uses the determined correction value(s) to correct the light power of said light source so as to mitigate an influence of charging unevenness at each of the coordinates on the surface of said image carrier, wherein the local maximums and the local minimums of the data of the charging electric potential stored in said storage unit exclude at least some in which a difference between a local maximum and a local minimum having neighboring coordinates is less than a prescribed value.