| 摘要 |
PROBLEM TO BE SOLVED: To obtain a mold for smoothly molding a seating surface in the case of injection molding of a plastic ballpoint pen tip. SOLUTION: A core mold 50 for forming an inner surface of a ballpoint pen tip 80 is divided into a fixed side core 60 of a tip end side, and a movable side core 70 of a rear end side. The core 60 molds a ball holding part 81. A rear end of the core 60 is formed as a conical convex surface 61 for molding a seating surface 82. An end of the core 70 molds an ink hole 83 and an ink groove 84, and the end is formed in a conical recess surface 76 to be engaged with the surface 61. |
