Patent ID: 8646772

Claim:
A sheet feeder for feeding sheets from a sheet stack containing a plurality of sheets one sheet by one sheet in a sheet feeding direction, the one sheet being an uppermost sheet of the sheet stack, the sheet feeder comprising: a sheet stacker for accommodating the sheet stack therein; a side fence arranged inside the sheet stacker to regulate side ends of the sheets and movable in a direction perpendicular to the sheet feeding direction; a slide shaft arranged in the side fence and extending in a vertical direction; a link member that swings as the side fence moves, a first end of the link member configured to be slidable along the slide shaft, and a second end of the link member configured to be pivotable about a pivot point, which is arranged on a side wall of the sheet stacker at a position lower than the first end; and a swing stopper unit to stop swinging of the link member, wherein the swing stopper unit is an anti-slide lock mechanism arranged at the first end of the link member to lock the first end of the link member relative to the slide shaft when in a locked state, and wherein swinging of the link member is stopped when the anti-slide lock mechanism is in a locked state.