The invention relates to a pen for cosmetic, writing, drawing, sketching and/or marking purposes, having an inner part and an outer part, wherein the inner part is accommodated in the outer part at least in sections and is fastened therein. According to the invention, it is provided that a fastening device between the inner part and the outer part serves to fasten the inner part to the outer part, which fastening device is elastically deformable and is deformed in the installed state against its elastic restoring force, wherein it is supported on one side on the inner part and on the other side on the outer part by means of the elastic restoring force to fasten the inner part to the outer part.

The invention relates to a pen for cosmetic, writing, drawing, sketching and/or marking purposes, having an inner part and an outer part, wherein the inner part is accommodated in the outer part at least in sections and is fastened therein. According to the invention, it is provided that a fastening device between the inner part and the outer part serves to fasten the inner part to the outer part, which fastening device is elastically deformable and is deformed in the installed state against its elastic restoring force, wherein it is supported on one side on the inner part and on the other side on the outer part by means of the elastic restoring force to fasten the inner part to the outer part.

A method for manufacturing a ball pen tip, in which a spring for biasing a ball is assembled to the ball pen tip, includes punching the ball pen tip by a punch from a rear end of the ball pen tip along a central axis direction of the ball pen tip to form a plastic flow ridge formed by plastic flow upheaving radially inward from an inner peripheral wall surface of the ball pen tip to assemble the spring to the ball pen tip by the plastic flow ridge.

A method for manufacturing a ball pen tip, in which a spring for biasing a ball is assembled to the ball pen tip, includes punching the ball pen tip by a punch from a rear end of the ball pen tip along a central axis direction of the ball pen tip to form a plastic flow ridge formed by plastic flow upheaving radially inward from an inner peripheral wall surface of the ball pen tip to assemble the spring to the ball pen tip by the plastic flow ridge.

A thermochromic writing instrument, comprising: a writing body, storing a thermochromic ink therein, stored in a barrel; an operation body provided in the barrel to be operated to longitudinally move the writing body; a nib of the writing body configured to be capable of appearing from a front end of the writing instrument, wherein the writing instrument further includes a friction unit, rubbing handwriting in the thermochromic ink and capable of thermally changing the color of the handwriting by frictional heat generated at that time, and at least one clip body as the operation body, the friction unit is provided at a rear end of the barrel, and the clip body is provided in an area other than the rear end of the barrel.

A thermochromic writing instrument, comprising: a writing body, storing a thermochromic ink therein, stored in a barrel; an operation body provided in the barrel to be operated to longitudinally move the writing body; a nib of the writing body configured to be capable of appearing from a front end of the writing instrument, wherein the writing instrument further includes a friction unit, rubbing handwriting in the thermochromic ink and capable of thermally changing the color of the handwriting by frictional heat generated at that time, and at least one clip body as the operation body, the friction unit is provided at a rear end of the barrel, and the clip body is provided in an area other than the rear end of the barrel.

An ink reservoir unit for a writing instruments using an ink reservoir tube with which low contamination can be achieved considering environmental problems; and a writing instruments using the same. The ink reservoir tube is composed of a composite material in which a raw material is layered on a paper substrate having paper as a substrate. One end section of the ink reservoir tube is coupled to a connection part formed on a writing member or a relay member that holds the writing member to constitute the ink reservoir unit for a writing instrument. In one preferred aspect, a locking device using a male thread formed on an outer peripheral surface is provided to the connection part to be connected to the ink reservoir tube, and the ink reservoir tube is coupled to the relay member that holds the writing member by the locking device.

A pencil cutting tool 1 comprising a recess forming part 10 for boring a connecting recess 52 in an end face 51 of a pencil 50, wherein the recess forming part 10 comprises a main body 11 having a cylindrical insertion hole 12 for insertion of an end of the pencil 50 and a boring blade 40 disposed inside the insertion hole 12 so as to come into contact with the end face 41 of the pencil 50, the boring blade 40 has a semicircular cross section and a flat surface 40a extending along the axial line of the insertion hole 12, and the main body 11 has a discharge part 13 that is formed so as to face the flat surface 40a to discharge shavings from the insertion hole 12.

A writing instrument 2 includes a pen tip mechanism 20, an ink tank 40, an ink induction mechanism 50, and a regulator mechanism 60. The ink tank 40 includes first and second ink tanks 40A and 40B. The pen tip mechanism 20 includes first and second pen tips 20A and 20B. The ink induction mechanism 50 includes first and second induction cores 50A and 50B. A regulator flow path set around the first induction core 50A and the second induction core 50B is partitioned into first and second regulator flow paths by the regulator mechanism 60. The first and second regulator flow paths are temporary accommodation spaces of inks and circulation spaces for sending air from the induction cores 50A and 50B to the ink tanks 40A and 40B.

A writing instrument 2 includes a pen tip mechanism 20, an ink tank 40, an ink induction mechanism 50, and a regulator mechanism 60. The ink tank 40 includes first and second ink tanks 40A and 40B. The pen tip mechanism 20 includes first and second pen tips 20A and 20B. The ink induction mechanism 50 includes first and second induction cores 50A and 50B. A regulator flow path set around the first induction core 50A and the second induction core 50B is partitioned into first and second regulator flow paths by the regulator mechanism 60. The first and second regulator flow paths are temporary accommodation spaces of inks and circulation spaces for sending air from the induction cores 50A and 50B to the ink tanks 40A and 40B.