A paper feeder, comprising:
- a separation roller that separates a plurality of stacked documents, one by one;
- a pick-up roller that is disposed upstream of the separation roller in a document feeding direction, and that feeds the documents toward the separation roller;
- a frame member through which a rotating shaft for the separation roller passes, the frame member supporting a rotating shaft for the pick-up roller;
- and
- a lifting member that turns the frame member in a direction away from a document positioning portion, so as to move the pick-up roller away from the document positioning portion, by transmitting a rotation of the rotating shaft for the separation roller, to the frame member, when the rotating shaft for the separation roller rotates opposite to a direction to feed the documents in the document feeding direction, wherein the lifting member includes:
- a frame collar that projects from the frame member at an insertion portion of the rotating shaft for the separation roller in the frame member, the frame collar guiding the rotating shaft for the separation roller therethrough;
- a first collar that is disposed near the frame collar and rotatably inserted over the rotating shaft for the separation roller;
- a second collar that is disposed near a first collar end opposite to the frame collar, and fixedly inserted over the rotating shaft for the separation roller;
- a first clutch member that connects the frame collar and the first collar, wherein when the rotating shaft for the separation roller rotates in the direction to feed the documents in the document feeding direction, the first clutch member causes the frame collar and the first collar to separately and independently act, and when the rotating shaft for the separation roller rotates opposite to the direction to feed the documents in the document feeding direction, the first clutch member causes the frame collar and the first collar to act as one-piece;
- and
- a second clutch member that connects the first collar and the second collar therein, wherein when the rotating shaft for the separation roller rotates in the direction to feed the documents in the document feeding direction, the second clutch member causes the first collar and the second collar to act as one-piece, and when the rotating shaft for the separation roller rotates opposite to the direction to feed the documents in the document feeding direction, the second clutch member causes the first collar and the second collar to act as one-piece, until a predetermined torque is produced on the rotating shaft for the separation roller, and the second clutch member causes the first collar and the second collar to separately and independently act, as a torque equal to or greater than the predetermined torque is produced on the rotating shaft for the separation roller, when the rotating shaft for the separation roller rotates opposite to the direction to feed the documents in the document feeding direction.