After ink is filled through {HEAD ~ the ink filling hole} 42 on the inner cover 40, a cylindrical element 72 formed on {TAIL ~ the outer cover} 70 is fitted in the cylindrical element 42 a encircling the ink filling hole 42, thereby sealing up the ink filling hole 42 
After ink is filled through { HEAD ~ the ink filling hole } 42 on the inner cover 40 , a cylindrical element 72 formed on { TAIL ~ the outer cover } 70 is fitted in the cylindrical element 42 a encircling the ink filling hole 42 , thereby sealing up the ink filling hole 42
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL 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 OTH OTH OTH OTH OTH