Patent ID: 8610971

Claim:
An image forming apparatus that forms an image based on image information, comprising: a photosensitive element; an optical scanning device that includes a light source, and scans a surface of the photosensitive element in a main scanning direction with light emitted from the light source to form a latent image on the surface of the photosensitive element; a developing unit that develops the latent image; a photosensitive element period detecting sensor that detects a rotation period of the photosensitive element; a density sensor that detects a density variation of an image, which is developed by the developing unit, in a sub scanning direction orthogonal to the main scanning direction; and a processing device that corrects a driving signal of the light source according to the image information, based on an output signal of the density sensor and an output signal of the photosensitive element period detecting sensor, so as to suppress the density variation in the sub scanning direction.