Kabushiki Kaisha Pilot Corporation

Kouichi Takayama

Takumi Kajiwara

Hirotaka Masuda

Satoru Ando

Tatsuyuki Nakatani

Keishi Okamoto

Yasuyuki Sugimoto

Yuki Nitta

Susumu Yamaguchi

Kunihiro Toyota

Akihiro Shiobara

Toshihide Kawasaki

A writing ball capable of suppressing wear of a ball seat of a ballpoint pen tip and obtaining stable ink outflow, a writing ball that is a sphere, the sphere comprising, at least: a first hard component containing a first metal; a second hard component containing a second metal; and a binding component, the writing ball comprising: a first outer surface from which the first hard component is exposed, the first outer surface being an outermost surface of the sphere; and a recess including, as a bottom surface, a second outer surface from which the second hard component is exposed, the second outer surface being recessed inward from the first outer surface, wherein the first outer surface includes a smooth surface.

Writing ball, method for manufacturing writing ball, and ballpoint pen with writing ball

An oil-based ball-point pen refill includes a ball-point pen tip in which a ball is held, in which the ball-point pen tip is mounted on a leading end of an ink housing cylinder, an ink composition including a coloring agent consisting of a dye, an organic solvent, and polyvinyl butyral resin is housed in the ink housing cylinder, the arithmetic mean roughness of a surface of the ball is 0.1 to 15 nm, the content of the polyvinyl butyral resin is 50 mass % or more based on the total mass of the whole resin, and an ink viscosity is 5000 to 50000 mPa&#xb7;s. In an oil-based ball-point pen, the refill is disposed in a barrel cylinder. An oil-based ball-point pen ink composition including a specific salt-forming dye, polyvinyl butyral resin, and an aromatic alcohol can be utilized in the refill.

Oil-based ball-point pen refill, oil-based ball-point pen, and oil-based ball-point pen ink composition

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.

Ballpoint pen tip and ballpoint pen using the same

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.

Ballpoint pen tip and ballpoint pen

Growing community of inventors

Kanagawa-ken, Japan

Kouichi Takayama