Moving a reading position of an image reading devices based on a reading magnification of pattern images

An image forming apparatus, comprising:

• a processor configured to:
• convey a sheet to a reading surface;
• read, by an image reading device, predetermined pattern images formed on the sheet conveyed by the conveyance unit for each of a plurality of reading candidate positions on the reading surface which are different from each other in a conveyance direction of the sheet;
• move a reading position of the image reading device in the conveyance direction on the reading surface by moving the image reading device based on reading magnification of each of the predetermined pattern images read for each of the reading candidate positions;
• and
• form an image read at the reading position on another sheet.

An image forming method, comprising:

• conveying a sheet to a reading surface;
• reading predetermined pattern images formed on the conveyed sheet for each of a plurality of reading candidate positions on the reading surface which are different from each other in a conveyance direction of the sheet;
• and
• moving a reading position of an image reading device in the conveyance direction on the reading surface by moving the image reading device based on reading magnification of each of the predetermined pattern images read for each of the reading candidate positions.