Method of operating a document feeding mechanism to detect and recover from a multi-feed condition and an apparatus therefor

A method of operating a document feeding mechanism having a document feed path which extends through a nip defined between an advance roller disposed on one side of a document feed path and a retard roller disposed on an opposite side of the document feed path, the method comprising:

• detecting a multi-feed condition in which a first document and a second document overlapping the first document have been fed through the nip from an upstream end of the document feed path to a downstream end of the document feed path;
• halting operation of the advance roller when the multi-feed condition is detected;
• and
• reversing direction of rotation of the retard roller when the multi-feed condition is detected such that the second document which is adjacent to the retard roller is driven backwards through the nip from the downstream end of the document feed path to the upstream end of the document feed path while the first document which is adjacent to the halted advance roller is maintained in the nip between the advance roller and the retard roller.

A document feeding apparatus comprising:

• an advance roller disposed on one side of a document feed path;
• a retard roller disposed on an opposite side of the document feed path and facing the advance roller to form a nip therebetween;
• a sensor for (i) detecting a multi-feed condition in which a first document and a second document overlapping the first document have been fed through the nip from an upstream end of the document feed path to a downstream end of the document feed path, and (ii) providing a sensor signal indicative of the multi-feed condition;
• a controller for (i) providing a first control signal to halt operation of the advance roller when the sensor signal indicative of the multi-feed condition is detected, and (ii) providing a second control signal to reverse direction of rotation of the retard roller when the sensor signal indicative of the multi-feed condition is detected such that the second document which is adjacent to the retard roller is driven backwards through the nip from the downstream end of the document feed path to the upstream end of the document feed path while the first document which is adjacent to the halted advance roller is maintained in the nip between the advance roller and the retard roller.