Patent ID: 7571905

Claim:
An automatic document feeding device comprising: a document feed tray where documents are stacked; a shaft rotatably disposed on the document feed tray; an automatic document feeding roller rotatably coupled to the shaft and transporting the documents one by one; a bracket rotatably coupled to the shaft; a pick-up roller rotatably coupled to the bracket and picking up the documents stacked on the document feed tray by using a rotating force received from the shaft; a document stopper disposed to be able to rotate about the same axis as the pick-up roller rotates about and limiting a movement of the documents stacked on the document feed tray; a latch arm locking the document stopper to limit the movement of the documents and prevent the document stopper from rotating; and a flag rotatably coupled to the shaft and pushing the latch arm to unlock the document stopper, wherein the automatic document feeding device further comprises a cover disposed near the bracket and having a protrusion proximate to the latch arm, and the latch arm is rotatably coupled to the cover, and wherein the latch arm further comprises a leaf that collides with the protrusion of the cover to restrict rotation of the latch arm in a counter-clockwise direction, wherein the automatic document feeding device further comprises a clutching unit comprising: a clutch spring inserted into a bushing fixed to the shaft and a flange formed in the bracket to have a pressing force, rotating the bracket in a direction in which the pick-up roller descends when the shaft rotates in a predetermined direction, and having one end inserted into a first insertion groove formed in the bracket; and a clutch sleeve being a pipe-type member surrounding the clutch spring and comprising a second insertion groove into which the other end of the clutch spring is inserted, and the flag protrudes from an outer circumferential surface of the clutch sleeve.