| 摘要 |
<p>PURPOSE: To obtain an oily ink ball point pen combined with oily ink having viscosity within a range appropriate to each of ball point pens in which the diameter of points varies from extrafine to very thick diameter. CONSTITUTION: In a ball point pen in which a ball is held between a ball seat formed close to the end and the end margin, a metal pipe chip 2 having a straight cylindrical hole ink passage 3 is provided, and free organic solvent base oily ink is packed, the proper viscosity range of the oily ink has a lower limit of 1.3Pa.s and an upper limit is a value which is calculated from an equation of logη=a.d<2> /l+b which is related with the diameter (d) of the cylindrical hole ink passage 3 of the chip 2 and the length (l) of a shaft, in whichηis viscosity, (a) and (b) are constants, respectively.</p> |
