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