An image forming apparatus which comprises an image reading unit which reads a document and outputs the image data corresponding to the document; an image processing unit which processes by a given method the image data supplied from the image reading unit, and outputs the printing image data; a printer unit which prints on a recording sheet the image corresponding to the printing image data supplied by the image processing unit; and an image attaching unit which attaches the identifying information for representing the image formation apparatus to the recording sheet on which the image is formed by the printer unit.
