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.

A fluid application device including a reservoir intended to contain a free fluid and a fluid delivery device, wherein the reservoir is sealed by a valve having a self-healing material. The fluid application device includes a tubular means for piercing the valve and for simultaneously placing fluid from the reservoir in communication with the fluid delivery device.

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 thermochromic writing instrument including 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 1 further includes a friction unit, for 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 10 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 including 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 1 further includes a friction unit, for 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 10 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 including 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 1 further includes a friction unit, for 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 10 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 including 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 1 further includes a friction unit, for 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 10 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 writing tool includes a refill having an ink reservoir tube formed to be a straight cylinder whose wall thickness is less than 0.56 mm; and a writing tip or a relay member holding the writing tip attached to a first end of the ink reservoir tube, wherein the refill is detachably attached to a barrel, wherein in the refill, amounting strength between the writing tip or the relay member holding the writing tip and the ink reservoir tube is set higher than a mounting strength between the barrel and a connecting portion of the ink reservoir tube. There is provided a writing tool that can prevent the occurrence of a problem such as leakage of ink at a time of replacement of refills and perform replacement of refills smoothly.

A writing tool includes a refill having an ink reservoir tube formed to be a straight cylinder whose wall thickness is less than 0.56 mm; and a writing tip or a relay member holding the writing tip attached to a first end of the ink reservoir tube, wherein the refill is detachably attached to a barrel, wherein in the refill, amounting strength between the writing tip or the relay member holding the writing tip and the ink reservoir tube is set higher than a mounting strength between the barrel and a connecting portion of the ink reservoir tube. There is provided a writing tool that can prevent the occurrence of a problem such as leakage of ink at a time of replacement of refills and perform replacement of refills smoothly.