PAPER FEEDER AND IMAGE FORMING DEVICE

PROBLEM TO BE SOLVED: To provide a paper feeder and an image forming device having the same capable of detecting a paper size in a paper feed tray without reloading the paper feed tray when a detection sensor starts the operation even if the paper in the paper feed tray is changed while the detection sensor is in a non-operating state. SOLUTION: A displacement length detection means 14 detects the total length of an exposure length Lb and a triangular piece length Lb on a crossing straight line where a first detected member 12 interlocking with a rear end regulation member 3 and a second detected member 13 interlocking with a side end regulation member 4 are crossed, and the size and the placement position of the paper P are detected according to the detection output. As a result, even if the size and the placement position of the paper P are changed while the displacement length detection means 14 is in non-operating state, the size and the placement position of the paper in the paper feed tray can immediately be detected by the displacement length detection means with a simple configuration when the image forming device starts its operation. COPYRIGHT: (C)2009,JPO&INPIT