When the image forming device receives a print job including a print condition in its header, an operation control section extracts the print condition from the header, and makes an inquiry to a server. The server extracts an order table, indicative of a priority based on the extracted print condition, from a setting table in which a priority of sheets has been set in advance in accordance with the extracted print condition, and sends the order table by return to the image forming device. In the image forming device, a tray selection section generates a tray selection signal in accordance with the received order table and a detection signal, outputted from a tray detection section, which functions as sheet storage information of a sheet feeding tray section, so as to send the tray selection signal by return to the sheet feeding tray section. The sheet feeding tray section supplies a sheet, corresponding to the print condition, from a tray selected in accordance with the tray selection signal to a printer engine. Thus, it is possible to select an appropriate sheet in accordance with the print condition and to print an image on the appropriate sheet.