A ballpoint pen is disclosed. In the ballpoint pen, an oil-based ballpoint pen ink composition has an ink viscosity with a range of 500 mPa.Math.s to 15000 mPa.Math.s inclusive at 20° C. and a shear rate of 500 sec.sup.-1. A ball has a ball diameter of 0.5 mm or less. A tip distal end portion includes a first swaged portion and a second swaged portion. The first swaged portion has an inclination angle with a range of 90 degrees to 100 degrees inclusive. The second swaged portion is provided closer to a distal end side of a ballpoint pen tip than the first swaged portion and has an inclination angle with a range of 110 degrees to 130 degrees inclusive. An angle of a bottom wall of a ball holding chamber is the same as the inclination angle of the second swaged portion.

A ballpoint pen is disclosed. In the ballpoint pen, an oil-based ballpoint pen ink composition has an ink viscosity with a range of 500 mPa.Math.s to 15000 mPa.Math.s inclusive at 20° C. and a shear rate of 500 sec.sup.-1. A ball has a ball diameter of 0.5 mm or less. A tip distal end portion includes a first swaged portion and a second swaged portion. The first swaged portion has an inclination angle with a range of 90 degrees to 100 degrees inclusive. The second swaged portion is provided closer to a distal end side of a ballpoint pen tip than the first swaged portion and has an inclination angle with a range of 110 degrees to 130 degrees inclusive. An angle of a bottom wall of a ball holding chamber is the same as the inclination angle of the second swaged portion.

Provided is a liquid storage member for coating tools which successfully reduces plastic consumption and reduces environmental loads, by making use of materials based on paper in place of plastics such as polypropylene that has been used for liquid (e.g., ink) storage members. A liquid storage member for coating tools having at least three layers of a paper base laminate composed of an inner layer made of paper base material, and a middle layer of a metal layer or a silica deposition layer, formed on the outer peripheral side of the inner layer; and an outer layer made of the paper base material formed on the outer peripheral side of the middle layer, wherein the paper base material of the inner layer has a density of 0.8 g/cm.sup.3 or more.

Provided is a liquid storage member for coating tools which successfully reduces plastic consumption and reduces environmental loads, by making use of materials based on paper in place of plastics such as polypropylene that has been used for liquid (e.g., ink) storage members. A liquid storage member for coating tools having at least three layers of a paper base laminate composed of an inner layer made of paper base material, and a middle layer of a metal layer or a silica deposition layer, formed on the outer peripheral side of the inner layer; and an outer layer made of the paper base material formed on the outer peripheral side of the middle layer, wherein the paper base material of the inner layer has a density of 0.8 g/cm.sup.3 or more.

A refillable free ink writing instrument including a body having a rear end, a front end and an ink reservoir disposed between the rear end and the front end, a writing tip mounted on the front end and a plug mounted on the rear end, wherein the plug is configured to close an opening in fluid communication with the ink reservoir, the plug being configured to be removable from the rear end to refill the ink reservoir with water and concentrated ink refill.

A refillable free ink writing instrument including a body having a rear end, a front end and an ink reservoir disposed between the rear end and the front end, a writing tip mounted on the front end and a plug mounted on the rear end, wherein the plug is configured to close an opening in fluid communication with the ink reservoir, the plug being configured to be removable from the rear end to refill the ink reservoir with water and concentrated ink refill.

[Problems] To provided are a reversibly thermochromic composition that shows black during color development by using a fluoran derivative having a specific structure as an electron-donating color-developing organic compound, turns colorless during decoloration, and is excellent in light resistance and a microcapsule pigment encapsulating the reversibly thermochromic composition.

[Solution] Disclosed is a reversibly thermochromic composition including: (a) a fluoran derivative having a specific structure as an electron-donating color-developing organic compound; (b) a compound having a specific structure as an electron-accepting compound; and (c) a reaction medium which reversibly induces an electron transfer reaction between the component (a) and the component (b) in a specific temperature range, and a reversibly thermochromic microcapsule pigment encapsulating the reversibly thermochromic composition.

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.

The adaptation of a pocket-size pen for use by a person is provided. The pen includes a cap with internally configured male threads, and a body. The body includes a barrel with externally configured and spaced apart first set of female threads, and second set of female threads. The barrel is hollow inside with a top opening for receiving a full-sized standard ink source. The male threads of the cap engage the second set of female threads of the pen body for closing a writing tip and reducing the length of the pen for storage in the pocket of a user. The male threads of the cap engage the first set of female threads of the body for transforming the pen into an extended-length pen similar in length to a conventional pen and revealing the writing tip for comfortable writing using the pen.

The adaptation of a pocket-size pen for use by a person is provided. The pen includes a cap with internally configured male threads, and a body. The body includes a barrel with externally configured and spaced apart first set of female threads, and second set of female threads. The barrel is hollow inside with a top opening for receiving a full-sized standard ink source. The male threads of the cap engage the second set of female threads of the pen body for closing a writing tip and reducing the length of the pen for storage in the pocket of a user. The male threads of the cap engage the first set of female threads of the body for transforming the pen into an extended-length pen similar in length to a conventional pen and revealing the writing tip for comfortable writing using the pen.