The trough shaped reflectors are moved in synchronism with the scanning movement of the beams so that {HEAD ~ the images} of {TAIL ~ the lamp filaments} remain in one dimensional focus throughout scanning of the flat document plane 
of
The trough shaped reflectors are moved in synchronism with the scanning movement of the beams so that { HEAD ~ the images } of { TAIL ~ the lamp filaments } remain in one dimensional focus throughout scanning of the flat document plane
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH