supplying {HEAD ~ the additive material} to within {TAIL ~ the pockets} on the roll face of the first roller 
to within
supplying { HEAD ~ the additive material } to within { TAIL ~ the pockets } on the roll face of the first roller
OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH