pens with ball tip and ink compositions for such pens

摘要

A pressurized roller pen includes a thixotropic viscoelastic ink that is a gel at rest, but becomes a thin liquid under the shearing action of the pen's revolving ball-point, and comprises at least one polyelectrolyte polymer, at least one highly polar solvent, at least one solvent of low or medium polarity, and colloidal silica, together with pigments, dyes, surfactants and/or pH modifiers.