Page numbers on original document volumes that have been read are deleted from the read image information as a part of image processing, and page information sorted with the original document pages of multiple read original document volumes as a single document is superimposed onto the image information from which the page numbers have been deleted, following which the pages are printed out. The pages are thus provided with serial page numbers according to the sorting thereof, and situations wherein both original and new page numbers are present on the pages can be avoided.