PURPOSE: To prevent the feeding of document sheets fixed by a staple or a clip in a document feeder by causing a staple detector to prevent the feeding of the staple fixed documents before the feeding thereof in response to the presence of a staple or a paper grip in the documents.

CONSTITUTION: A metal detecting coil 91 is located on the same plane as that of the bottom part 15 of a tray 16, directly connected to a proper or usual metal detecting circuit 92, its output terminal is connected to a controller 100 and, when an inquiry is made by the controller 100, a signal is generated to indicate the detection of a metallic staple located in the limited place of the coil 91. Then, based on this staple detection, a document handling device 20 and a related printer or a copying device are prevented from performing cycling up or an operation until a group of the documents including the staple is eliminated from the tray 16.