| 摘要 |
PROBLEM TO BE SOLVED: To prevent the generation of a problem for a synthetic resin injection molded product by forming a rib working as a tip component moving guide for a main body with a cap on a vent hole. SOLUTION: A cap of a writing instrument is constituted of an outer cap 1 with both ends open and an inner cap 2 as a closed-end cylindrical body with one end closed. An opening of the inner cap 2 works as a connecting section 3 of the outer cap 1, and the connecting section 3 forms an annular inclined section opened spreadingly toward the opening side. A guide rib 8 for controlling the moving direction of a pen point and preventing the pen point from sinking into a vent hole 7 is formed on the connecting section 3. The guide rib 8 is disposed on the open side of the vent hole 7. A rib 9 continuing to the guide rib 8 disposed on the cap opening side of the vent hole 7 and guiding the vent hole 7 is formed on the position of the vent hole 7. The flow of synthetic resin is uniformized by the rib 9 to control the moving direction of the pen point. The generation of a problem for a synthetic resin injection molded product can be prevented by the arrangement while protecting a main body end component from sinking into the vent hole. |
