{TAIL ~ The shape} around the optical axis of {HEAD ~ the scanning lens} is concave, convex and concave from the first surface in the scan direction and concave, convex, concave and convex in the sub scan direction 
{ TAIL ~ The shape } around the optical axis of { HEAD ~ the scanning lens } is concave , convex and concave from the first surface in the scan direction and concave , convex , concave and convex in the sub scan direction
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD 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