| 摘要 |
A tubular nib having a beak-shaped section at one end of a tube, a slit formed in the beak-shaped section, and a slit-widening inhibiting section having a radius of curvature larger than that of the tubular part of the tubular nib at least at the section across the innermost end of the slit in the beak-shaped part of the tubular nib. |
