Constant spacing document feeder

An improved document feeder employs sets of rollers between which it feeds documents of different lengths to generate and maintain gaps of equal length between the documents while transporting them at a constant speed. A first group of rollers separate stacked documents and start the documents moving at a low speed along the track. A second group of rollers, operated at a higher speed, receive documents from the first group of rollers and increase the speed of the first document relative to a second document, still in contact with the first group of rollers, thereby providing an initial gap which continues to lengthen until the second document reaches the second group of rollers. A third group of rollers receives the documents after they leave the second group, imparting a constant system transport speed to them. The first and second groups of rollers are then able to further adjust the gap by changing the speed of a second document, and after the desired gap has been established, reverting to transport speed before transferring the second document to the third group of rollers.