Patent ID: 8175471

Claim:
An image forming apparatus comprising: an image carrier that supports a latent image; a latent image forming unit that forms the latent image on the image carrier; a developing apparatus that develops the latent image formed on the latent image carrier into a toner image using a developer including toner and a magnetic carrier; an image density control unit that performs control operations based on an image density control condition that is adjustably set to control an output image to have a predetermined image density; a belt member that is arranged to be in contact with the image carrier and is suspended in a tensioned state by a plurality of support members; a toner pattern detection unit that detects a toner pattern formed on the belt member; an information detection unit that detects information for determining an amount of toner exchanged between the developing apparatus and the image carrier within a predetermined period, the information detection unit detecting image area ratios of a plurality of images formed within the predetermined period; an image density control condition modifying unit that calculates a modified image density control condition based on the information detected by the information detection unit and a parameter for image density control condition calculation and sets the modified image density control condition as the image density control condition to be used by the image density control unit; and a parameter modifying unit that modifies the parameter for image density control condition calculation used by the image density control condition modifying unit based on a detection result obtained by the toner pattern detection unit, wherein the image density control condition modifying unit calculates the modified image density control condition based on a moving average of the image area ratios detected by the information detection unit.