Patent ID: 8408533

Claim:
A sheet feeder, comprising: a feed tray configured to contain a stack of sheets; an air blower near a topmost sheet on top of the sheets stacked in the feed tray; a sheet suction unit that sucks the topmost sheet on top of the sheets stacked in the feed tray by a negative pressure generated at a position facing a top surface of the topmost sheet; an air suction unit that is connected to the sheet suction unit via an air flow passage and that sucks air from a sheet suction unit side to generate the negative pressure in the sheet suction unit; a sheet conveying unit that includes a conveying member and that attracts the topmost sheet sucked by the sheet suction unit on the conveying member and conveys the topmost sheet toward a pair of carriage rollers located in a downstream side in a conveying direction and disposed parallel to the sheet conveying unit; and a positive pressure generating unit that generates a positive pressure in the sheet suction unit, the positive pressure generating unit includes: an air releasing mechanism that opens the air flow passage between the sheet suction unit and the air suction unit to atmosphere, and an air release control unit that controls the air releasing mechanism to be opened and closed, wherein when the feeding operations ends, the respective driving sources of the air blower, the air suction unit, the sheet conveying unit, and the pair of carriage rollers are stopped and the air release control unit immediately controls the air releasing mechanism to be opened.