The comparator 92 compares the image data, in units of {HEAD ~ dot signals}, with {TAIL ~ the reference data} supplied from the main controller 71 
The comparator 92 compares the image data , in units of { HEAD ~ dot signals } , with { TAIL ~ the reference data } supplied from the main controller 71
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH