Image forming apparatus that performs shading correction to maintain print position accuracy

An image forming apparatus comprising:

• an image forming unit configured to form an image on a sheet of a plurality of sheets based on received image data, form an adjustment image in an area of the sheet to be cut, and convey the sheet on a conveyance path;
• a reading sensor configured to read the image on the sheet which passes a reading area of the conveyance path;
• a reference member that is read by the reading sensor for performing a shading correction for the reading sensor;
• a controller configured to:
• switch operation of the image forming apparatus between a productivity priority mode and an image quality priority mode;
• control a positional relationship between the reading sensor and the reference member to be a first positional relationship in a case where the reading sensor reads the image;
• control the positional relationship between the reading sensor and the reference member to be a second positional relationship that is different from the first positional relationship in a case where the reading sensor reads the reference member;
• control, in the productivity priority mode, in a case where an execution condition for executing reading of the reference member by the reading sensor is satisfied during a period in which both the image and the adjustment image are formed on the sheet of the plurality of sheets, the positional relationship between the reading sensor and the reference member to be the second positional relationship while continuing conveyance of the plurality of sheets including the sheet on which the image and the adjustment image have been formed to pass the reading area,
• wherein the reading sensor and the reference member are arranged such that the positional relationship between the reading sensor and the reference member is switched from the first positional relationship to the second positional relationship by moving either the reference member or the reading sensor while continuing conveyance of the plurality of sheets on which the image and the adjustment image have been formed along a same conveyance path in both the first positional relationship and the second positional relationship;
• and
• adjust, in the image quality priority mode, in the case where the execution condition for executing reading of the reference member by the reading sensor is satisfied during the period in which both the image and the adjustment image are formed on the sheet of the plurality of sheets, a timing for forming the adjustment image on the sheet and control the positional relationship between the reading sensor and the reference member to be the second positional relationship while continuing conveyance of the plurality of sheets to pass the reading area such that the sheet on which the image and the adjustment image have been formed passes the reading area after the shading correction has been performed.