1. An image forming apparatus, comprising: an image carrier; exposure unit configured to irradiate laser light onto said image carrier according to an image signal and forming an electrostatic latent image; discrimination unit configured to discriminate a low density area in which pixels having less than a predetermined density exist in succession in the image signal; and exposure control unit configured to control said exposure unit to irradiate the laser light in a first condition for a pixel to be interested of a pixel area in the low density area discriminated by said discrimination unit, and to irradiate the laser light in a second condition being different from the first condition for pixels other than the pixel to be interested in the pixel area.