PURPOSE: To prevent a double feed and increase the life by detecting an output torque of a motor to apply a torque to a return roller, and controlling the output torque of the motor to be constant based on detected information.
CONSTITUTION: A pickup roller 1 is put by its own weight on a sheet P mounted on a supply paper tray 4, and a roller 1 and a feed roller 2 are driven to rotate clockwise, while a return roller 3 receives a torque clockwise by a DC motor 30. The roller 3 is applied to the upper roller 2 through an oscillation member 18 by the spring force of a tension spring 20 at a constant pressure. If the sheet P is put between the rollers 2 and 3, the roller 3 rotates counterclockwise to discharge the sheet P to a guide plate 7. However, if two sheets P are put between the rollers 3 and 3, the roller 3 rotates in the direction to return the sheet P because a friction resistance between the upper and lower sheets is small, and the output torque is reduced. This is detected by a torque detector 40, and the output torque is increased and controlled to be constant, so the paper P is returned.