| 摘要 |
PROBLEM TO BE SOLVED: To allow a writing end to smoothly protrude or retract by providing an ink container having a relatively large sectional area, and mounting the refill of a ballpoint pen filled with water base or low viscosity oil base ink having shear-rate thinning in a dual writing instrument. SOLUTION: The refill 1 of the ballpoint pen comprises a tip 7 for enclosing an end ball 8, and a spring for always urging the ball to the inner edge of the enclosing part at the end of the tip into close contact and releasing at the time of writing. Shear-rate thinning water base ink or low viscosity oil base ink to flow out by reducing the viscosity by the rotation of the ball upon writing is charged in an ink containing tube 13 at the rear of the tip. A follower 15 made of grease-like semitransparent non-drying matter moving to follow up the consumption of the ink upon writing is charged at the rear end of the ink, and a tail plug 1 is fixed to the rear end of the tube. |
