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