PURPOSE: To simply sort recording paper sheets after image forming without cost increase and waste of resources.

CONSTITUTION: Recording media 1 of the same shape each of which an identification drawing 1a is recorded to identify each medium or to identify them depending on pictures recorded on the media are used for recording media for image forming. Or picture data sent from an external device or a scanner and identification drawing data used to identify each recording medium or kinds of picture data respectively generated by a pattern equipment being an identification drawing data generating means are synthesized to form a synthesized picture onto each recording medium.