whereby the expansion of said pressure transmitting medium by said driving means is concentrated at said elastic wall portion, to move said {HEAD ~ elastic wall portion} to drive said {TAIL ~ printing element} 
to drive
whereby the expansion of said pressure transmitting medium by said driving means is concentrated at said elastic wall portion , to move said { HEAD ~ elastic wall portion } to drive said { TAIL ~ printing element }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL OTH TAIL TAIL TAIL TAIL TAIL TAIL