Patent ID: 8248627

Claim:
An image forming apparatus comprising: a control panel configured to receive an instruction for forming an image on a first side and a second side of a paper sheet; a scanner configured to read a plurality of originals; a memory configured to store image data of a first page and a second page; a printer configured to form the image; and a controller configured to judge whether a size of the first page and that of the second page are the same before forming the image on the paper sheet based on the image data of the first page and the second page, form the image of the first page and the image or the second page on the first side and the second side of a first paper sheet, respectively, by the printer if the sizes of the first and second pages are the same, and form the image of the first page on the first paper sheet and form the image of the second page on a second paper sheet by the printer if the sizes of the first and second pages are different.