Patent ID: 8308155
Filing Date: 2012-11-13
Classification: B65H

Abstract:
1. A retard roller of an automatic document feeder for providing a frictional force to separate a first document and a second document from each other, said first document lying on said second document, said retard roller being disposed in a feeder cover of said automatic document feeder, said feeder cover comprising a retard roller receptacle and a receiving structure beside said retard roller receptacle, said retard roller comprising: a rotating shaft disposed within said retard roller receptacle and rotatable with respect to said feeder cover; a switching wheel disposed beside said rotating shaft, connected to said rotating shaft, and synchronously rotated with said rotating shaft, wherein said switching wheel has a first locking region and a second locking region; a stopping rod disposed within said receiving structure, and comprising a confining part, wherein said confining part is inserted into said first locking region or said second locking region of said switching wheel, and said confining part is blocked by a blocking part, so that said stopping rod is hindered from rotating in a first rotating direction; a retard sleeve member sheathed around said rotating shaft, and having a first contact surface exposed outside said retard roller receptacle, wherein when said first document and said second document are transported into said automatic document feeder, said retard sleeve member is contacted with said second document to generate said frictional force, wherein when said second document is moved in a sheet-feeding direction, said stopping rod is blocked by said blocking part to hinder said rotating shaft from rotating in said first rotating direction, so that said first contact surface is still exposed outside said retard roller receptacle, wherein when said rotating shaft is rotated in a second rotating direction reverse to said first rotating direction, said stopping rod is rotated in said second rotating direction in response to rotation of said rotating shaft, and said confining part is moved from said first locking region to said second locking region, so that a second contact surface is exposed outside said retard roller receptacle, wherein said switching wheel comprises: wherein said plural locking posts comprise a first locking post, a second locking post, a third locking post and a fourth locking post, wherein said first locking post and said second locking post collectively define said first locking region, said second locking post and said third locking post collectively define said second locking region, said third locking post has a first mark, and said fourth locking post has a second mark, wherein when said first mark is aligned with a cover mark of said feeder cover, said first contact surface of said retard sleeve member is exposed outside said retard roller receptacle, and when said second mark is aligned with said cover mark of said feeder cover, said second contact surface is exposed outside said retard roller receptacle.