BALL-POINT PEN TIP AND BALL-POINT PEN USING THE SAME

PROBLEM TO BE SOLVED: To provide a ball-point pen tip and a ball-point pen using the ball-point pen tip, which provide a smooth writing condition of the pen by forming a lubricating ink layer of the wide range over the surface of a ball and the inner surface of a ball holder.SOLUTION: The ball-point pen tip includes: a ball transfer part which is transferred substantially in accordance with the curvature of the ball by pushing the inner surface of the ball holder against the surface of the ball is formed on the inner surface of a ball receiving seat part and a tip caulking part, the total area of the ball transfer part satisfying 19.0-27.0% of the surface area of the ball; and radial through-grooves as ink flow path, wherein the average surface roughness (Ra) on the ball transfer part is 5.0-14.0 nm, and the maximum-minimum height difference (Ry) is 20-100 nm, the ball-point pen tip uses an oily ink containing phosphoric acid ester-based lubricant and has 0.5 mm ball diameter.