Sensors are provided so that the rotational position of each worm gear can be determined thereby indicating {HEAD ~ the position} of {TAIL ~ the print wheels} 
Sensors are provided so that the rotational position of each worm gear can be determined thereby indicating { HEAD ~ the position } of { TAIL ~ the print wheels }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL