The valve protects the ink in the ink supply from {TAIL ~ contaminants} that can migrate up {HEAD ~ the ink line} during shut down periods 
The valve protects the ink in the ink supply from { TAIL ~ contaminants } that can migrate up { HEAD ~ the ink line } during shut down periods
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH