Image forming apparatus

An image forming apparatus comprising:

• an image forming section having 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 for controlling 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 the toner patches forming conditions;
• a patch density detecting section for detecting 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 for adjusting density of the toner image formed by the image forming section, depending on a result detected by the patch density detecting section;
• an operation detecting section for detecting whether or not the patch density detecting section operates properly;
• and
• a patch printing section for controlling the image forming section, when a result detected by the operation detecting section is such that the patch density detecting section does not properly operate, so as to form a plurality of patch images by printing on a 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.