Patent ID: 8081172
Filing Date: 2011-12-20
Classification: G06F

Abstract:
1. A pen unit comprising: a unit body defining an inner space extending from an opening in one direction; a pen having a portion with a first diameter and a larger diameter member extending outward from a peripheral surface of the portion by a predetermined amount; a retention member configured to temporarily hold the pen in the inner space after being received through the opening; a driving mechanism configured to apply a driving force to the pen to direct the pen toward the opening; and a narrowed path member placed within the inner space at a position spaced from the larger diameter member, between the larger-diameter member and the opening, when the retention member holds the pen, the narrowed path member restricts the opening and interferes with the larger-diameter member when the pen is released from the retention member, but still allowing the larger-diameter member to be removed from the inner space.