| 摘要 |
PROBLEM TO BE SOLVED: To provide a thermochromic retractable ball point pen capable of easily changing a color at a desired location only, the pen including a friction body at a rear end part of a shaft tube.SOLUTION: A retractable ball point pen includes a friction body having rubber-like elasticity at a rear end part of a shaft tube, the friction body being capable of rubbing handwriting of thermochromic ink and thermally changing a color of the handwriting of the thermochromic ink with frictional heat caused from rubbing. The maximum diameter of the rear end part of the shaft tube is at or less than 1.0 to 1.5 times the maximum diameter of the friction body, and the maximum width of an operation part in a circumferential direction is smaller than the maximum diameter of the friction body. A tangent line between the friction body and the operation part forms an angle at or larger than 60 degrees to a writing surface when the friction body is directed downward and an axis of the shaft tube is perpendicular to the writing surface. |
