Apparatus is provided for comparing the difference in the signals between {HEAD ~ the superimposed document} and for analyzing {TAIL ~ the difference} to provide a signal related to the copy quality 
Apparatus is provided for comparing the difference in the signals between { HEAD ~ the superimposed document } and for analyzing { TAIL ~ the difference } to provide a signal related to the copy quality
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH