Mitsubishi Pencil Company, Limited

Mitsubishi Pencil Kabushiki Kaisha

Yoshihide Ishii

Kazuhiko Furukawa

Kiyoshi Fujisawa

Saki Hanatani

Yoshihisa Osano

Misao Ooyama

Daisen Kato

A ballpoint penincludes: a ballpoint pen tiphaving a writing balland a holderholding the writing ball; a shaft tubeto which the rear end part of the ballpoint pen tipis mounted; and inkaccommodated in the shaft tube. The holderhas an ink guiding holeformed from the rear end thereof toward the head end thereof and a ball houseformed with the inner circumference near the head end of the holderexpanded. The writing ballis formed of a zirconia sintered body with the content of an aluminum element being less than 0.1 weight %, and the inkcontains inorganic particles

Ballpoint pen

A ballpoint pen tip in which ink grooves are formed around an ink guide hole at equally distributed places, the ink guide hole connecting a ball house and a back hole of a holder for holding the writing ball, and the ink grooves radially penetrate through from the ball house side to the front end portion of the back hole. Inward protrusions are formed at positions which are respectively in contact with the rear ends of the ink grooves. If the inner diameter of the ink guide hole is A, the inner diameter of the front end portion of the back hole is B, the diameter of the circle circumscribing the ink grooves is C, and the diameter of the circle inscribing the inward protrusions is D, their relationships are A&#x3c;B&#x3c;C, and D&#x3c;B.

Ballpoint pen tip, ballpoint pen refill, and ballpoint pen

Provided are a ballpoint pen tip which can, even if ink having properties which assures that the amount of supply of the ink to the pen tip by shear of a writing ball is sufficient is adopted, prevent partially faint written traces from occurring and provide smooth writing, a ballpoint pen refill, a ballpoint pen, and a method of manufacturing a ballpoint pen tip. A triangular pyramid-shaped recess () gradually tapered toward an ink guide hole () is provided in the bottom of a ball housing (), and troughs () formed in the recess () are utilized as ink reservoirs and ink paths. Because the troughs () have sufficient length, width, and depth, the amount of containment of the ink and the amount of supply of the ink are increased. Also, even if ink which is supplied to the pen point mainly by shear of a writing ball (A) is adopted, the supply of the ink to the pen point is not interrupted, the occurrence of partially faint written traces of ink is sufficiently prevented, and friction between the writing ball and a ball receiving seat surface can be reduced.

Ballpoint pen tip, ballpoint pen refill, ballpoint pen, and method of manufacturing ballpoint pen tip

A writing point assembly and an ink tube and/or a holder can be welded appropriately at a predetermined area without using ultrasonic waves, so as to be able to prevent dislodging of the writing point assembly, ink leakage and the like. The rear end part, of a metallic writing point assembly as a part of a writing instrument, is inserted into a joint, and is heated at the predetermined area (at least the fitted area in contact with the front end part of the joint), so as to weld the predetermined area of the writing point assembly to the surrounding part of the joint.

Growing community of inventors

Yokohama, Japan

Yoshihide Ishii