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