In general, an image forming apparatus according to the present embodiment comprises an image forming section, a reading section and a controller. The image forming section forms an image on a sheet. The reading section reads the image on the sheet to generate scan image information. The controller generates background image information obtained by excluding extraction image information from the scan image information and forms the background image information, first identification information of the sheet and orientation information indicating orientation of the sheet on the sheet through the image forming section.