| 摘要 |
PROBLEM TO BE SOLVED: To prevent an increase in viscosity of ink and drying of the ink caused by evaporation of water in the ink from a clearance of a tip end of a chip when coated resin which is heated and molten is attached on the tip end of the chip and heat of the coated resin is transferred into the chip, and suppress writing blurring caused by intrusion of air into the chip occurring when a pressure increases in a seal member by fitting operation by the seal member.SOLUTION: A ballpoint pen body is provided with a ballpoint pen chip formed of at least a ball as a writing member and a ball holder, which partially projects the ball from a tip end opening part of a through hole and holds, on a tip end, and is connected to an ink storage part directly or through a connection member. A cylindrical member formed of thermoplastic material covers the ballpoint pen body so as to cover at least a tip end of the ballpoint pen chip in a press-fitting state. Then, a non press-fitting end part of the cylindrical member is adhered by heat and is closed liquid-tightly and air-tightly. |
