Further, each of the ink filling holes is sealed by combining a first cylindrical element, which is formed on {HEAD ~ the inner cover} encircling {TAIL ~ the opening}, and a second cylindrical element formed on the outer cover to be engaged with the first cylindrical element 
Further , each of the ink filling holes is sealed by combining a first cylindrical element , which is formed on { HEAD ~ the inner cover } encircling { TAIL ~ the opening } , and a second cylindrical element formed on the outer cover to be engaged with the first cylindrical element
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 TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH