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