Patent ID: 7653947

Claim:
An image forming system comprising: a storage unit that stores document data once having been printed, in association with a sheet identifier recorded on a print sheet on which the document data has been printed; an authentication unit that authenticates a user based on an entered user identifier; an operating unit that accepts an operation command issued by a user; a reading unit that reads the sheet identifier from the print sheet when the operating unit has accepted a copy command issued by the user authenticated by said authentication unit; a printing unit that reads out the document data associated with the sheet identifier read by said reading unit, from said storage unit, and prints the document data; and an inhibition unit operable when the sheet identifier has not been read from the print sheet based on the accepted copy command over a predetermined time period, to inhibit the document data associated with the sheet identifier from being printed by said printing unit, wherein when the user, who has been authenticated by said authentication unit and has issued the copy command via said operating section, also has instructed the printing unit to print the document data on the print sheet having recorded thereon the sheet identifier read by said reading unit when the copy command is issued, said inhibition unit allows the document data associated with the sheet identifier to be printed by said printing unit, wherein said storage unit stores an immediately preceding printing time and the document data in association with the sheet identifier, and wherein said inhibition unit comprises a determination unit that determines whether or not the sheet identifier has not been read from the print sheet over the predetermined time period, based on a present time and the immediately preceding printing time stored in said storage unit.