Patent ID: 7369785

Claim:
An image forming apparatus for forming an image on a front surface of a sheet based on image data inputted from one of a plurality of input sources that communicate therewith, comprising: an image forming unit for forming an addition image on a back surface of a sheet opposite to a front surface of said sheet on which an image is formed based on said inputted image data; a storage for previously storing a plurality of pieces of addition image information, each piece of said addition image information being specific to a corresponding one of said plurality of input sources of said inputted image data; an identification unit for identifying the one of said plurality of said input sources from which said inputted image data on which said image formed on said front surface of said sheet is based is inputted; and a controller for controlling when it is confirmed that specific addition image information corresponding to the one of said plurality of input sources identified by the identification unit is stored in said storage, a reading out from said storage said specific addition image information corresponding to the one of said plurality of input sources identified by said identification unit; and a forming of said addition image based on said specific addition image information on said back surface of said sheet.