Patent ID: 7623277

Claim:
A duplex scanning apparatus for scanning images of a plurality of documents, said duplex scanning apparatus comprising: a flatbed image scanning portion including a scanning module for scanning said images of said documents in a scan region; and an automatic document feeder comprising: a sheet input tray for placing said documents thereon; a sheet ejecting tray for supporting said documents thereon; a transfer channel arranged between said sheet input tray and said sheet ejecting tray, wherein a portion of said transfer channel is disposed within the range of said scan region; a sheet pick-up roller disposed in said sheet input tray for transporting said documents into said transfer channel; a friction-enhancing stopper sustained against said documents to offer a frictional force required to transport said documents into said transfer channel such that only one of said documents is selected to feed into said transfer channel for each time; a transfer roller assembly disposed in said transfer channel for transporting said documents through said transfer channel; a first inverting region disposed between said sheet input tray and said sheet ejecting tray; a second inverting region disposed between said first inverting region and said sheet ejecting tray; an inverting channel arranged between said inverting regions and said transfer roller assembly; a first switching element arranged at the intersection between said transfer channel and said sheet ejecting tray for guiding said documents to said sheet ejecting tray or said inverting regions; a second switching element arranged at the intersection between said inverting channel and said second inverting region for guiding said documents to said first inverting region or said second inverting region; a sheet ejecting roller assembly disposed in the vicinity of said sheet ejecting tray for transporting said documents to said sheet ejecting tray; a first inverting roller assembly disposed in the vicinity of said first inverting region for transporting said documents from said transfer channel to said first inverting region or from said first inverting region to said inverting channel; and a second inverting roller assembly disposed in the vicinity of said second inverting region for transporting said documents from said transfer channel to said second inverting region or from said second inverting region to said inverting channel.