Patent ID: 7392980

Claim:
A sheet feed device comprising: a conveyor roller that rotates in a first conveying direction to convey a sheet for conveyance; a separation roller that is pressed against the conveyor roller, to nip the sheet for conveyance at a contact area formed between the separation roller and the conveyor roller, the separation roller being rotatable in a second direction, reverse to the first, conveying direction, to convey a sheet for separation; a sheet detector that is provided at a detecting position at the contact area or downstream of the contact area, to detect a number of sheets for conveyance passing through the detecting position; a pressure generator that generates a pressure by which the separation roller is pressed against the conveyor roller; a separation torque generator that generates a separation torque by which the sheet for separation on the separation roller is conveyed in the second, reverse direction; and a controller that, if two or more sheets are detected at the sheet detector, applies at least one of the pressure and the separation torque to the separation roller to separate the sheets one by one, until the number of sheets detected at the sheet detector is decreased to be one, and that if one sheet is detected at the sheet detector or after the sheet detector detects the number of sheets to be now one, controls at least one of the pressure and the separation torque, to adjust and maintain a position of a lead edge the sheet for separation on the separation roller to a target position between the contact area and the detecting position, until conveyance of the sheet for conveyance on the conveyor roller finishes.