a document feeder for broad - width originals having a document path in which a moving document is scanned by a stationary scanner . the document feeder is typically mounted to a copier . the document path is either a recycling path or a reciprocating path ; the recycling path having a closed loop path and the reciprocating path having an open loop path . a selector is mounted in the document path and selects one of the recycling path and the reciprocating path . a sensor is mounted in the document path for detecting a length of the document . when the length of the document detected by the sensor is not longer than a predetermined length , the recycling path is selected by the selector . when the length of the document detected by the sensor is longer than the predetermined length , the reciprocating path is selected by the selector .