| 摘要 |
PROBLEM TO BE SOLVED: To solve the conventional problem that ink spreads longitudinally and crosswise in a combtooth-shape space, by a capillary force, from a tail end longitudinal slit which is an air circulating hole of a temporary ink reservoir member, when an impact is applied to a writing utensil itself or an internal air pressure of an ink tank rises due to a temperature increase and that when the ink reservoir member can no longer hold the ink beyond its storage capacity because the accumulated ink is only retained by the capillary force, the ink leakage occurs from an open part to the outside of the air circulation hole communicating with the outside. SOLUTION: At the open part 15 to the outside of the air circulating hole near a border between a pen point holder part 2 and a temporary ink reservoir part 3, a porous filter 14, simultaneously showing oil repellency, resistance to oil and water and air permeability (an oleobend filter formed of a polytetrafluoroethylene treated for water repellency and oil resistance, manufactured by the Japan Goatechs Co.) is mounted on a combtooth-shape wall like an 0-ring so as to block the air circulating hole after being cut to a hollow disc shape. Thus, the air passage is allowed for air replacement but passage of the overflowing ink which tends to leak to the outside from the air circulating hole beyond the storage capacity of the ink reservoir member is not allowed. |
