Image forming apparatus using various kinds of correction processes

An image forming apparatus comprising:

• a toner image forming portion including an exposure portion that forms an electrostatic latent image on an image bearing member, a developing portion that renders the electrostatic latent image visible to form a toner image, and a transfer roller that transfers the toner image onto a transfer belt;
• an information acquisition portion that acquires optical information on the toner image within a time after the toner image is transferred onto the transfer belt until the toner image is fixed on a paper sheet;
• and
• a control portion, wherein
• the control portion carries out:
• (i) a process that causes the toner image forming portion to form, as a test image, at least either one of a toner image of single dot and a toner image of dot line consisting of single dots arranged in one or more rows in a predetermined direction, and then causes the information acquisition portion to acquire optical information on the formed test image;
• and
• (ii) a process that corrects a condition for forming the toner image in the toner image forming portion, based on a state of the test image obtained from the optical information acquired by the information acquisition portion.