Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A thermochromic writing instrument contains a thermochromic ink, wherein a writing body 8 is accommodated in a barrel 2 movably in a longitudinal direction, an operation portion 5 is provided on the outer surface of the barrel 2, and a pen tip 81 of the writing body 8 is constituted so as to be projectable/retractable from/into a front-end hole 31 of the barrel 2 by operating the operation portion 5. The thermochromic ink 83 is contained in the inside of the writing body 8, the pen tip 81 capable of ejecting the thermochromic ink 83 is provided at the front end of the writing tool, and a friction portion 4 capable of thermally changing the color of the handwriting of the thermochromic ink 83 by the frictional heat generated when the handwriting is rubbed with the friction portion 4 is provided on the outer surface of the barrel 2.

Abstract: There is provided a thermochromic writing instrument containing a thermochromic ink, which is capable of easily changing color of the handwriting of thermochromic ink by rubbing and also being quickly brought into a writing-capable state (pen-tip-projected state) or a stored state (pen-tip-retracted state) even when the user can use only one hand.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A key input device which forms a key switch with high reliability or an integrated keyboard with small dimensions which can produce coded signals with high reliability and a S/N ratio of high value without any encoder circuits, comprising a piezoelectric polymer film, applied as a pressure sensor, having layer electrodes on both surfaces thereof and at least one device for straining the film, the straining device defining a key.