1. An image forming apparatus for performing an image forming operation, the image forming apparatus comprising: an image carrier on which a toner image is formed; an intermediate transfer member configured to transfer the toner image to a recording medium, the intermediate transfer member having a toner image forming area including an output image forming area and a non-output image forming area located outside of the output image forming area, the toner image forming area being wider than the output image forming area; and a detecting part configured to measure a physical quantity regarding an image quality of a first reference image formed in the output image forming area and a second reference image formed in the non-output image forming area.