| 摘要 |
PROBLEM TO BE SOLVED: To provide a ballpoint pen of a low cost without diffusing an ink due to a temperature or atmospheric pressure change without bringing about a backflow or direct flow of the ink by maintaining a draught resistance of a writing tip in the pen immediately filled with an aqueous ink having a low viscosity. SOLUTION: In the ballpoint pen comprising a tip 13 having a tip ball 14 always urged to an inner edge of a ball embracing part 13d of the tip end front of a barrel 1 so that the contact state is released at the time of writing, an aqueous low viscosity ink having a viscosity of several to several tens mPa.S charged in rear of the barrel, and a follower 20 for preventing an evaporation of the ink at an end of the ink and moving by following to consumption of the ink; a valve chamber 9 having a guide hole 8 for communicating a valve disc seat 5 with an ink container 1a is provided rear of the tip 13, a valve disc 11 is urged by a spring 12 in the chamber 9 to be brought into close contact with the seat 5 to always block the hole 8 to release the close contact state of the disc 11 with the seat 5 by a negative pressure at the time of writing to discharge the ink to the tip side. |
