| 摘要 |
<p>A retention member holds a tip of a pen received in an inner space of a unit body through an opening. A narrowed path member is placed within the inner space at a position between a large-diameter member of the pen and the opening, when the retention member holds the pen. The large-diameter member expands outward from the outer peripheral surface of the pen by a predetermined amount. The narrowed path member contacts the large-diameter member when the pen is released from the retention member, and creates enough interference to prevent the pen from falling out of the unit body, but otherwise allows the pen to be drawn out of the opening.</p> |
