SHEET TRANSPORT DEVICE, IMAGE READER INCLUDING THE SAME, AND IMAGE FORMATION DEVICE

摘要

PROBLEM TO BE SOLVED: To prevent damage of a stopper for restraining sheets from entering to a paper feed position in a sheet transport device which transports the sheets, an image reader including the sheet transport device, and an image formation device.SOLUTION: A document feeding unit 5 is attached to an upper cover unit 32U of an automatic document feeder. A pickup roller 51 and a paper feeding roller 52 transport a document sheet P placed on a document feeding tray in a sheet transport direction. A stopper 63 protrudes on or is recessed from a sheet transport path and prevents a tip of the sheet from contacting with the paper feeding roller 52. A linkage part causes the stopper 63 to change its posture between a protruding posture and a retreated posture in conjunction with rotational driving of the paper feeding roller 52. A retreat mechanism causes the stopper 63 to take the retreat posture in conjunction with change of the upper cover unit 32U from the closed state to the open state.