determining means for determining whether {HEAD ~ each pixel signal} read by the image reading means represents {TAIL ~ a white pixel} and for generating a white pixel signal representing the white pixel 
represents
determining means for determining whether { HEAD ~ each pixel signal } read by the image reading means represents { TAIL ~ a white pixel } and for generating a white pixel signal representing the white pixel
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH