Patent ID: 7334788

Claim:
A sheet feeder, comprising: a sheet feed member which feeds recording sheets; a separating member which forms a nip portion by pressing against the sheet feed member, rotates following the sheet feed member when only one recording sheet to be fed is inserted into the nip portion, and rotates reversely when a double-fed recording sheet is inserted while being stacked under the recording sheet to be fed; a sheet detection unit which detects that each recording sheet fed out of a sheet feed tray has been inserted between the sheet feed member and the separating member; a direction detection unit which detects a change of a rotation direction of the separating member; and a separating force adjusting unit which gradually increases a reverse rotation torque of the separating member from a predetermined initial torque after the sheet detection unit detects the recording sheet, and stops the increase of the reverse rotation torque to maintain the reverse rotation torque when the direction detection unit detects reverse rotation of the separating member.