| 摘要 |
PROBLEM TO BE SOLVED: To make sink marks hardly occur in a molding, restrain deviation of resin to the utmost, and prevent fine appearance from being damaged even when it is molded with a transparent resin, by making a front barrel to be an outer member at a superposed part and forming a plurality of recesses on the surface of a front part rather than on the thin part of the front barrel. SOLUTION: With respect to a superposed part 2a of a front barrel, a plurality of circumferential recessed parts 2e are formed on an outside face of a thick part 2d. This part is a holding part at the time of writing and the circumferential recessed parts 2e serve also as anti-slip parts. In this manner, by forming a plurality of recessed parts on the surface part of the thick part 2d, change of the thickness as a molding is a little and change of contraction quantity of resin at the time of molding is reduced. In an ink tank 4, a water-based pigment ink 7, a back-flow preventing composition 8 made of α-olefin, and an interface shape stabilizer 9 of the back-flow preventing composition 8 as a bottomed cylindrical body made of polypropylene are arranged. The back-flow preventing composition 8 is arranged on an interface position of the ink 7. |
