The document 10 is moved in direction 14 so that all portions of the document are eventually illuminated by the line of light, or scan line 16, which is produced by {HEAD ~ the illuminating devices} of {TAIL ~ the scanner} 
The document 10 is moved in direction 14 so that all portions of the document are eventually illuminated by the line of light , or scan line 16 , which is produced by { HEAD ~ the illuminating devices } of { TAIL ~ the scanner }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL