An image forming apparatus is provided, including an image forming mechanism which executes a printing process; an object data memory which stores image data as an object of the printing process when a printing instruction is received; a re-formation condition memory which stores a type of a printing function and whether or not image data is an object of image re-formation in correlation with each other; an object judging mechanism which judges whether or not the image data as a source of the image formation is the object of the image re-formation; and a data deleting mechanism which deletes the image data as the source of the image formation from the object data memory if the image data as the source of the image formation is not the object of the image re-formation.