| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent a handwriting from becoming blurred or disabled when a pen is used for continuous writing with a ball point facing upward. <P>SOLUTION: In this ball-point pen, a ball 3 is rotatably embraced by an inwardly facing tip edge part 21 formed at the apex of a tip main body 2 and a ball receiving seat 22 behind the tip edge part 21. In addition, ink and a follower are accommodated inside an ink accommodation cylinder, and the straight part 81 of a spring is inserted through an inner hole 5 running in the axial direction of the ball receiving seat 22. Next, an ink circulating gap 6 is formed between the internal surface of an inner hole 5 and the external surface of the straight part 81. The minimum transverse area S of the ink circulating gap 6 is set to 0.02 to 0.15 mm<SP>2</SP>. The viscosity of the ink at 20°C is set at 1 to 50 mPa s and the viscosity at a rotational frequency of 100 rpm and 20°C is 3 to 160 mPa s and also the shear-rate thinning index is 0.80 to 0.99. <P>COPYRIGHT: (C)2004,JPO&NCIPI |
