Patent ID: 7769309

Claim:
An image forming apparatus, comprising: an image forming section haying at least an image bearing member on which surface an electrostatic latent image is formed, the image forming section being used for printing an image by supplying a toner to the electrostatic latent image on the image bearing member to form a toner image and transferring and fixing the toner image onto a recording medium; a patch forming section structured to control the image forming section so as to form on the image bearing member a plurality of toner patches whose toner densities are different from each other in sequence, by changing toner patches forming conditions; a patch density detecting section structured to detect patch densities which are the toner densities of the plurality of the toner patches formed on the image bearing member; a toner density adjusting section structured to adjust a density of the toner image formed by the image forming section, depending on the patch densities detected by the patch density detecting section; an operation detecting section structured to detect whether or not the patch density detecting section is operating properly; and a patch printing section structured to control the image forming section, when the operation detecting section detects that the patch density detecting section is not operating properly, so as to form a plurality of patch images by printing on the recording medium the plurality of the toner patches which are formed on the image bearing member and different in density from each other in sequence.