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