The Pilot Ink Co., Ltd.

Kabushiki Kaisha Pilot Corporation

Nobuo Sekine

Masashi Ando

Hideaki Asami

Mikiya Ido

Masahiro Kondo

Kazuo Iwase

Nobuo Matsubara

Yoshinori Imamura

Takehiko Yokosuka

Yoshiaki Okawara

Masashi Andoh

A thermochromic writing instrument contains a thermochromic ink, wherein a writing body is accommodated in a barrel movably in a longitudinal direction, an operation portion is provided on the outer surface of the barrel, a pen tip of the writing body is constituted so as to be projectable/retractable from/into a front-end hole of the barrel by operating the operation portion, the thermochromic ink is contained in the inside of the writing body, the pen tip capable of ejecting the thermochromic ink is provided at the front end of the writing tool, and a friction portion capable of thermally changing the color of the handwriting of the thermochromic ink by the frictional heat generated when the handwriting is rubbed with the friction portion is provided on the outer surface of the barrel.

Thermochromic writing instrument

A thermochromic writing instrument contains a thermochromic ink, wherein a writing bodyis accommodated in a barrelmovably in a longitudinal direction, an operation portionis provided on the outer surface of the barrel, and a pen tipof the writing bodyis constituted so as to be projectable/retractable from/into a front-end holeof the barrelby operating the operation portion. The thermochromic inkis contained in the inside of the writing body, the pen tipcapable of ejecting the thermochromic inkis provided at the front end of the writing tool, and a friction portioncapable of thermally changing the color of the handwriting of the thermochromic inkby the frictional heat generated when the handwriting is rubbed with the friction portionis provided on the outer surface of the barrel

The present invention provides the ballpoint pen that precludes the possibility of the pipe portion bending at the joint thereof can be provided even if the outer diameter D is small. In the ballpoint pen having a ballpoint pen tip at a front end thereof, the ballpoint pen tip rotatably accommodating a ball at a front end of a pipe made of metal, an outwardly projecting pipe portion having a uniform thickness throughout the length thereof is arranged at a front end of the ballpoint pen tip, and if a length of the pipe portion is L, an outer diameter of the pipe portion is D, a relational expression 'L/D.ltoreq.4.0' is satisfied.

Ballpoint pen and cap therefor

Ball-point pen

A ballpoint pen tip including a metallic pipe having a plurality of inwardly projecting portions at a neighborhood of a front end portion of the pipe at regular intervals, and a front end edge portion at a front end of the pipe, and a ball rotatably held between the front end edge portion and the plurality of inwardly projecting portions, wherein the pipe satisfies a relation of A/T.ltoreq.5.8 where A is an outer diameter of the ball and T is a thickness 10 of the pipe, and also the relation of B/T.ltoreq.2.3 where B is a diameter of a virtual inscribing circle contacting a top of the plurality of inwardly projecting portions and T is the same as above.

Ballpoint pen tip, manufacturing method therefor, and ballpoint pen

Ballpoint pen tip

Growing community of inventors

Nagoya, Japan

Nobuo Sekine