Paper feeding apparatus and driving method thereof for office machine

A paper feeding apparatus for feeding sheets one by one to a paper processing apparatus, said paper feeding apparatus comprising:

• a pickup roller for picking up an uppermost one of the sheets;
• a delivery roller for delivering the uppermost sheet;
• a set of feeding rollers selectively blocking or forwarding the sheet delivered from the delivery roller to the paper processing apparatus;
• a detector for detecting one of a leading edge and a trailing edge of the sheet, and generating a corresponding signal;
• a driving device, responsive to the corresponding signal, selectively driving the pickup roller, the delivery roller and the feeding roller;
• wherein the set of feeding rollers comprise an active roller and an idle roller,
• while the paper feeding apparatus starts picking up and feeding the sheets, and before the detector generates signals indicating the arrival of the leading edge of the sheet, the driving device driving the pickup roller to rotate in a first direction to pick up the uppermost sheet, driving the delivery roller to rotate in the first direction to deliver the sheet picked up by the pickup roller, and driving the active roller to rotate in a second direction, opposite to the first direction, to block the paper sheet delivered from the delivery roller;
• while the detector generates signals indicating the arrival of the leading edge of the sheet, the driving device, after a delay of short period of time, stopping driving the pickup roller, still driving the delivery roller to rotate in the first direction, and driving the active roller to rotate in the first direction to deliver the sheet delivered from the delivery roller to the paper processing apparatus.