The dithering of one side edge while continuing {HEAD ~ the advance} of the opposite side edge continues until the other of the fiducial marks is detected after which the advance of {TAIL ~ the sheet} is resumed 
The dithering of one side edge while continuing { HEAD ~ the advance } of the opposite side edge continues until the other of the fiducial marks is detected after which the advance of { TAIL ~ the sheet } is resumed
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH