An image forming apparatus comprises at least one printer that prints inputted image data on a plurality of types of print sheets, an expiration time attribute detector that detects from the image data, data representing an expiration time attribute, and a controller that judges based on the detection result drawn by the expiration time attribute detector, on which type of print sheets the image data should be printed, among the plurality of types of print sheets, then controls the image forming apparatus itself based on the judgment.