Image forming apparatus which accepts multiple types of test sheets for calibration of image density and geometric characteristics

An image forming apparatus comprising:

• an image forming unit configured to form an image;
• a conveying unit configured to convey a sheet on which the image is formed;
• a reader configured to read the sheet conveyed by the conveying unit;
• and
• a controller configured to:
• execute first calibration in which a density of an image to be formed by the image forming unit is controlled based on a result of reading by the reader;
• and
• execute second calibration in which a geometric characteristic of an image to be formed by the image forming unit is controlled based on a result of reading by the reader, and
• wherein the controller allows usage of a sheet of a first type in the first type of calibration,
• wherein the controller prevents usage of a sheet of a second type in the first type of calibration,
• wherein the controller allows usage of a sheet of the first type in the second type of calibration, and
• wherein the controller allows usage of a sheet of the second type in the second type of calibration.