| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a ball point pen tip capable of preventing a direct current caused by deformation of an inner periphery of a calking part because a shoulder of the calking part does not contact a paper surface. <P>SOLUTION: The ball point pen tip 20 is equipped with a first tapered surface 22 formed by tapering off an outer periphery of a tip of a holder 21; a connection surface 23 in which an angle measured outside a first tapered surface 22 on its tip side is more than 180 degrees; a second tapered surface 24 wherein an angle measured outside a connection surface 23 on its tip side is less than 180°C; and a calking part 25 wherein a tip part of a second tapered surface 24 is calked inside to hold a writing ball 35 inserted into a ball house 29. When a boundary of the first tapered surface 22 to the connection surface 23 is set as a first shoulder part 26 and a boundary of a second tapered surface 24 and the calking part 25 is set as a second shoulder part 27, the second shoulder part 27 is positioned inside of a virtual tangential line 41 of the first shoulder part 26 and the writing ball 35. <P>COPYRIGHT: (C)2008,JPO&INPIT |
