Writing utensils for forming thermochromic handwriting

摘要

An object of the present invention is to obtain a writing instrument excellent in handwriting density and stability with time. A ballpoint pen refill comprising a ballpoint pen tip and a ballpoint pen refill in which an ink composition for a writing instrument is filled is provided at the front end portion of the ink containing cylinder. The ink composition for writing utensil comprises at least a thermochromic ink containing a thermochromic microcapsule pigment Wherein the writing instrument is provided with a pressing mechanism for applying pressure to a rear end of the ink composition for writing utensils.