Source : Free On-Line Dictionary of Computing

sprocket feed
     
         (Or "tractor feed", "pin feed") A method some
        {printers} use to move paper by rotating wheels with pins or
        studs (tractors) that engage holes along the sides of the
        (usually fanfold) paper.  A sprocket feed printer does not
        slip unless the paper jams, but cannot feed standard typing
        paper or work with a {sheet feeder} like {friction feed}.
     
        Some paper for sprocket feed printers has the edge strips with
        the holes in detachable from the rest of the paper.  These
        strips are known as {chad} (and other names).
     
        (1997-06-29)