Leakproof fountain pen with ballbearing tip

摘要

A leakproof fountain pen with a ballbearing tip includes an upper casing threadedly engaged to an ink flow guide. An ink reservoir has an open end received by an annular base of the ink flow guide. The upper casing combines with the ink flow guide to form a chamber for collecting ink which may flow from the ink reservoir. The ink flow guide further comprises an axial vent hole communicated with the atmosphere; an axial ink hole to serve as a path for ink flowing to and from the chamber and the ink reservoir; and an axial control hole having a flow portion with a bigger diameter. A gravity post is movably disposed inside the flow portion and can block the passage of ink between the ink reservoir and the control hole. A plug unit acts as a support for the gravity post. A first end of the ink flow guide is substantially V-shaped with the lowest point at the opening of the ink hole to direct the collected ink from the chamber towards the ink hole when the pen is held upright. The air inside the ink reservoir is communicated with the atmosphere through the vent hole and the ink hole.