| 摘要 |
A ballpoint pen tip which, even if ink having less outflow characteristics, such as ink containing large particles or ink having high viscosity, is used, does not cause a written trace to be faint, does not cause the ink to drop, and does not impair the outflow characteristics. Ink grooves (31) are formed around an ink guide hole (30) at equally distributed places, said ink guide hole (30) connecting a ball house (26) and a back hole (28) of a holder (21) for holding the writing ball (35), and the ink grooves (31) radially penetrate through from the ball house (26) side to the front end portion (29) of the back hole (28). Inward protrusions (32) which protrude inward are formed at positions which are respectively in contact with the rear ends of the ink grooves (31). If the inner diameter of the ink guide hole (30) is A, the inner diameter of the front end portion (29) of the back hole (28) is B, the diameter of the circle circumscribing the ink grooves (31) is C, and the diameter of the circle inscribing the inward protrusions (32) is D, the relationships of A < B < C, and D < B are satisfied. |
