IMAGE FORMING APPARATUS

A density correction unit calculates a density change rate to a change in an exposure amount as a first density change rate based on a difference between a density of a part of reference patch images, in which a position in a main scanning direction is identical to a position of a first patch image. As for a second patch image, the density correction unit similarly calculates a second density change rate. A light amount when forming the first patch image is smaller than a reference light amount. A light amount when forming the second patch image is larger than the reference light amount. The density correction unit uses the first or the second density change rate based on whether a density of each position of the reference patch images in the main scanning direction higher or lower than a target density to correct the exposure amount