| 摘要 |
PROBLEM TO BE SOLVED: To prevent a direct flow and a reverse flow of ink, blur after upward writing or impact and to prevent the direct flow of the ink even if an accident of dropping a tip ball occurs in a ballpoint pen using aqueous ink or low viscosity oily ink having shear-rate thinning with reduced viscosity. SOLUTION: A collar part 15 having a sealing surface 16 sealed with a rear end face of a tip is provided substantially at a center. An ink guide groove 14 and a small-diameter part 17 are provided on an outer periphery of a barrel 6. A dowel 13 integrally having the barrel extended rearward is provided, and a spring 22 is urged between a rear end of the collar part and an inner step 21 of the joint, the small-diameter part of the dowel is brought into contact with a back surface of a tip ball 5a so that the ball is brought into close contact with the inner edge of an enclosing part of the tip 5 end. In this state, a gap for feeding ink is formed between the rear end surface of the tip and a sealing surface of the dowel. |
