Then, {HEAD ~ an original light image} is exposed to the thus charged surface of the drum 1 through {TAIL ~ an exposure system} 4 thereby forming an electrostatic latent image 
is exposed through
Then , { HEAD ~ an original light image } is exposed to the thus charged surface of the drum 1 through { TAIL ~ an exposure system } 4 thereby forming an electrostatic latent image
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL OTH OTH OTH OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH