1. An image forming apparatus comprising: an image forming section which forms an image on paper; a plurality of image reading sections each of which is operable to read the image formed on the paper, and is connectable to the image forming apparatus; a storage section which stores connection information on a connection state between each of the image reading sections and the image forming apparatus; and a control section which selects a test image reading section from among the image reading sections based on the connection information, performs control for the selected test image reading section to read a test image formed by the image forming section, and performs image quality adjustment based on the read test image.