Abstract: A ballpoint pen tip comprises: a ball having a diameter of 0.5 mm or less; and a tip body, wherein the tip body has a ball holding chamber, a rear hole, an ink flow hole, and an ink flow groove opening to the ball holding chamber, and not reaching the rear hole. A ratio of an ink consumption per 100 m of handwriting to a diameter of the ball is 200 mg/mm or more and 800 mg/mm or less, and when a front end of the ink flow groove is set as a start point and a position of 0.3 mm rearward from the front end of the ink flow hole is set as an end point, a volume of a first space in the ink flow hole and the ink flow groove from the start point to the end point is 0.02 mm3 or more.

Abstract: A mechanical pencil has: a shaft tube; a ferrule unit supported by the shaft tube; a lead holding unit having a chuck configured to relatively move with respect to the ferrule unit to eject lead held by the same; and an indication body provided movably in an axial direction. The indication body delimits from rearward a lead storage space formed rearward the chuck in the shaft tube. The indication body located at least at a predetermined position is viewable from outside the shaft tube. A length along the axial direction between a rear end of the lead storage space and a front end of the ferrule unit, in a state where the indication body has moved most rearward along the axial direction, is equal to or more than twice a length of spare lead to be stored in the lead storage space.

Abstract: A writing instrument excellent in handwriting density and temporal stability. The writing instrument includes a ball-point pen tip attached to the front end portion of the ink storage cylinder; and a ball-point pen refill having an ink composition for a writing instrument loaded therein. The ink composition for the writing instrument is a thermochromic ink containing at least a thermochromic microcapsule pigment. The writing instrument includes a pressurization mechanism for applying a pressure to the back end of the ink composition for the writing instrument.

Abstract: A mechanical pencil including: a body cylinder; a lead releasing unit configured to release a writing lead and having a rear region supported inside the body cylinder such that a front region thereof is flexurally deformable or tiltable inside the body cylinder; and a stretchable elastic body arranged between the lead releasing unit and a body cylinder, in which the lead releasing unit has a pressed portion on an outer circumferential surface of the front region, the body cylinder has a pressing portion in a front region, the pressing portion and the pressed portion abut on each other before the front region of the lead releasing unit is flexurally deformed or tilted, and the pressing portion causes the pressed portion to relatively move to the rear side with respect to the body cylinder when the front region of the lead releasing unit is flexurally deformed or tilted.

Abstract: A writing instrument excellent in handwriting density and temporal stability. The writing instrument includes a ball-point pen tip attached to the front end portion of the ink storage cylinder; and a ball-point pen refill having an ink composition for a writing instrument loaded therein. The ink composition for the writing instrument is a thermochromic ink containing at least a thermochromic microcapsule pigment. The writing instrument includes a pressurization mechanism for applying a pressure to the back end of the ink composition for the writing instrument.

Abstract: A mechanical pencil including: a body cylinder; a lead releasing unit configured to release a writing lead and having a rear region supported inside the body cylinder such that a front region thereof is flexurally deformable or tiltable inside the body cylinder; and a stretchable elastic body arranged between the lead releasing unit and a body cylinder, in which the lead releasing unit has a pressed portion on an outer circumferential surface of the front region, the body cylinder has a pressing portion in a front region, the pressing portion and the pressed portion abut on each other before the front region of the lead releasing unit is flexurally deformed or tilted, and the pressing portion causes the pressed portion to relatively move to the rear side with respect to the body cylinder when the front region of the lead releasing unit is flexurally deformed or tilted.

Abstract: A ballpoint pen tip is provided in which a curved contact surface, which has a curvature different from a curvature of the ball, is provided on the bottom wall of the ball holding chamber, and the ball is in contact with a contact part which is a part of the contact surface; and between the ball and the contact surface, a first gap is formed to extend from a side of the ink circulation hole up to the contact part such that the first gap gradually narrows from the side of the ink circulation hole, and a second gap is formed to extend from a distal side of an ink circulation groove up to the contact part such that the second gap gradually narrows from the distal side of the ink circulation groove.

Abstract: The present invention is a ballpoint pen tip in which a tip end portion of a tip body, which includes a ball holding chamber configured to hold a ball, an ink circulation hole formed in a center of a bottom wall of the ball holding chamber, and a plurality of ink circulation grooves extending radially from the ink circulation hole, is caulked inside, so that a part of the ball held in the ball holding chamber projects from a tip end edge and the ball is rotatably held, wherein: a curved contact surface, which has a curvature different from a curvature of the ball, is provided on the bottom wall of the ball holding chamber, and the ball is to be in contact with a contact part which is a part of the contact surface; and between the ball and the contact surface, a first gap is formed to extend from a side of the ink circulation hole up to the contact part such that the first gap gradually narrows from the side of the ink circulation hole, and a second gap is formed to extend from a distal side of an ink circulat

Abstract: A ballpoint pen tip includes a ball and a ball holder for rotatably holding the ball. The ball includes a ball body and a first carbonaceous film formed so as to cover a surface of the ball body. The first carbonaceous film has carbon atoms and oxygen atoms bonded to some of the carbon atoms. The ratio of carbon atoms bonded to oxygen atoms to the total carbon atoms at a surface of the first carbonaceous film is equal to or greater than 0.1.