Patent ID: 8672315

Claim:
A sheet feeder comprising a pair of sheet feeding units, each of the sheet feeding units including a paper tray for holding paper therein, a pickup roller configured to pick up the paper from the paper tray, a feed roller configured to convey the picked up paper out from the paper tray, a separation roller configured to be in press contact with the feed roller to be rotated via a torque limiter in a direction in which the separation roller returns the paper back to the paper tray, a conveying roller configured to convey the paper conveyed out from the paper tray by the feed roller, a driving source configured to rotate selectively in a forward direction and a backward direction, wherein the feed roller of a first sheet feeding unit of the pair of sheet feeding units is driven to rotate when the driving source of the first sheet feeding unit rotates in the forward direction, and the conveying roller of a second sheet feeding unit of the pair of sheet feeding units is driven to rotate when the driving source of the first sheet feeding unit rotates in the backward direction, a first torque transmission mechanism configured to transmit a torque generated by the driving source of the first sheet feeding unit to the feed roller of the first sheet feeding unit via a first torque transmission path, a second torque transmission mechanism configured to transmit the torque generated by the driving source of the first sheet feeding unit to the conveying roller of the second sheet feeding unit via a second torque transmission path, a first one-way clutch arranged on the first torque transmission path, the first one-way clutch being put in a locked state when a torque generated by forward rotation of the driving source is applied to the first one-way clutch, the first one-way clutch being put in a free-wheeling state when a torque generated by backward rotation of the driving source is applied to the first one-way clutch, and a second one-way clutch arranged on the second torque transmission path, the second one-way clutch being put in a free-wheeling state when the torque generated by forward rotation of the driving source is applied to the second one-way clutch, the second one-way clutch being put in a locked state when the torque generated by backward rotation of the driving source is applied to the second one-way clutch.