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