Abstract: A writing instrument includes: a replacement ink cartridge including a bottomed cylindrical container that has an opened front end and a closed rear end and a plug fitted into an inner circumferential surface of an opening of the container; and a projection inserted into the opening of the container to press the plug rearward, thereby opening the plug of the ink cartridge, wherein the projection and the plug are fitted when the plug is press opened, and when the cartridge is replaced, the fitting between the projection and the plug is released and the plug is locked again in the opening of the container.

Abstract: The invention aims at providing a solid writing material that does not adversely affect the color changing property of script and can obtain sufficient strength. This aim is achieved by the solid writing material that includes: a reversible thermochromic microcapsuled pigment encapsulating a temperature-sensitive color-changeable color-memorizing composition; an excipient; and a resin; the temperature-sensitive color-changeable color-memorizing composition including at least (a) an electron-donating coloring organic compound, (b) an electron accepting compound and (c) a reaction medium effecting reversibly an electron transfer reaction between the (a) and (b) components in a specific temperature range; wherein the excipient or the resin includes a styrene-structure-containing polymer.

Abstract: An oil-based ink composition for a writing instrument, comprising a dye, an organic solvent and a phenolic compound of the following general formula (1): wherein R is each independently hydrogen or an alkyl group having 1 to 5 carbon atoms, R1 is any of an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, a phenyl group, a hydroxyphenyl group, and an alkyl group having 1 to 5 carbon atoms substituted by a hydroxyphenyl group, and R2 is any of a halogenated alkyl group having 1 to 5 carbon atoms, a phenyl group, a hydroxyphenyl group, and an alkyl group having 1 to 5 carbon atoms substituted by a hydroxyphenyl group. The oil-based ink composition for a writing instrument can form handwriting having excellent water resistance in which no bleeding occurs on written surfaces of various materials with a dye retaining color development.

Abstract: Disclosed is a decolorizable electrophotographic toner, including: a binder resin; and a colorant which contains at least a color developable compound and a color developing agent and is covered with an outer shell so as to have a capsule structure, wherein the number ratio of particles having an equivalent circle diameter of 0.6 ?m or more and 2.5 ?m or less of the toner when measured using a flow particle image analyzer after the toner is dispersed in an aqueous medium at a ratio of 0.08% by weight and the resulting dispersion is subjected to a stirring treatment in which stirring is performed at 5000 rpm for 30 minutes using a homogenizer (T-25 digital ULTRA-TURRAX (manufactured by IKA Japan K.K., provided with a shaft generator S25N-10G)) is 30% by number or less.

Abstract: A writing instrument includes: a writing instrument body and an ink cartridge. The ink cartridge includes a bottomed cylindrical container with an opened front end and a plug fitted into an inner circumferential surface of an opening of the container. The writing instrument body includes a projection that opens the ink cartridge when inserted into the opening to press the plug rearward and an air tight connecting portion, formed separately from the projection, that surrounds the projection. The opening is divided into a plurality of openings by air tight fitting the opening in the air tight connecting portion. A plurality of longitudinal channels are formed on an outer periphery of the projection. At least one of the plurality of channels serves as an ink channel and at least one of the other channels serves as an air intake path.

Abstract: 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.

Abstract: In order to improve the endurance of this internal solution for a reference electrode beyond that in the prior art, the solution is made to contain a copolymerized material of a crosslinker having a plurality of non-acrylamide functional groups, and a non-acrylamide monofunctional hydrophilic monomer.

Abstract: An ink composition for a reversibly thermochromic stamp including a reversibly thermochromic microencapsulated pigment encapsulating a reversibly thermochromic composition including: Component (A): an electron-donating color-developing organic compound, Component (B): an electron-accepting compound, and Component (C): a reaction medium causing reversibly an electron transfer reaction between the Component (A) and the Component (B) in a specific temperature range, water and a thickener.

Abstract: There is provided a friction body which is adapted to rub a thermochromic image or handwriting formed on a paper surface by use of thermochromic ink to thermally discolor the thermochromic image or handwriting by frictional heat resultant from rubbing, a thermal conductivity of a friction portion of the friction body is set to be within 0.05 W/(m·K) to 50 W/(m·K).

Abstract: Disclosed here is a method for producing a decolorizable electrophotographic toner, comprising mixing a first dispersion liquid in which a colorant is dispersed in an amount such that the content of the colorant in the toner is from 5% to 35% by weight, with a second dispersion liquid in which particles containing at least a binder resin and having a volume average particle diameter of 500 nm or less are dispersed, aggregating the colorant and the particles containing at least the binder resin, thereby obtaining aggregated particles, fusing the aggregated particles at a temperature lower than a completely decolorizing temperature of the colorant to obtain the toner, and measuring the number ratio of particles having an equivalent circle diameter of 0.6 ?m or more and 2.5 ?m or less of the toner using a flow particle image analyzer after the toner is subjected to a stirring treatment.

Abstract: A rotating-operation type of writing tool is provided in which a front axial cylinder and a rear axial cylinder are separable and a tip portion of the writing tool is caused to protrude from a front portion of the front axial cylinder by a rotating operation of the rear axial cylinder. When the rear axial cylinder (3) is rotated, the cam cylinder (17) is also rotated, thereby the cam protrusion (18a) moves forward due to the functions of the cam groove (17a) and the slit (18b), so that the slider (18) moves forward to cause the writing body (14) to move forward against a biasing force by the biasing member (15). The slider (18) has the hollow body (18m), the coil spring (18c) and the flange body (18f). The O-ring (19) is provided on the outer circumference of the flange body (18f).

Abstract: A writing instrument includes a pen point retaining member, a pen point that is attached to a first end of the pen point retaining member, an ink tank that is attached to a second end of the pen point retaining member, and an ink that is accommodated in the ink tank. The ink includes a lubricating interface layer-forming compound, and a carbonaceous film is formed on at least one of a surface of the ball or a contact portion of the ball holding portion with the ball.

Abstract: [Problem to be Solved] Provided are: an oil-based ball-point pen refill having the excellent concentration of a written trace, excellent performance against ink dripping, and an excellent feeling of writing; an oil-based ball-point pen using the oil-based ball-point pen refill; and an ink composition that is preferably used in the oil-based ball-point pen refill and the oil-based ball-point pen. [Solution] An oil-based ball-point pen refill includes a ball-point pen tip in which a ball is held, in which the ball-point pen tip is mounted on a leading end of an ink housing cylinder, an ink composition including a coloring agent consisting of a dye, an organic solvent, and polyvinyl butyral resin is housed in the ink housing cylinder, the arithmetic mean roughness of a surface of the ball is 0.1 to 15 nm, the content of the polyvinyl butyral resin is 50 mass % or more based on the total mass of the whole resin, and an ink viscosity is 5000 to 50000 mPa·s.

Abstract: A ballpoint pen tip is provided in which a curved contact surface, which has a curvature different from a curvature of the ball, is provided on the bottom wall of the ball holding chamber, and the ball is in contact with a contact part which is a part of the contact surface; and between the ball and the contact surface, a first gap is formed to extend from a side of the ink circulation hole up to the contact part such that the first gap gradually narrows from the side of the ink circulation hole, and a second gap is formed to extend from a distal side of an ink circulation groove up to the contact part such that the second gap gradually narrows from the distal side of the ink circulation groove.

Abstract: Provided are: an oil-based ink composition for a ball-point pen having a favorable feeling of writing, the favorable deepness of a written trace, favorable light resistance, favorable ink stability over time, and favorable pigment dispersibility; and an oil-based ball-point pen refill using the oil-based ink composition. An oil-based ink composition for a ball-point pen comprising at least a dye, a pigment, and an organic solvent, wherein the dye is at least one salt-forming dye selected from the group consisting of salt-forming dyes of alkylbenzene sulfonic acids and xanthene-based basic dyes, salt-forming dyes of alkylbenzene sulfonic acids and triarylmethane-based basic dyes, and salt-forming dyes of alkylbenzene sulfonic acids and azomethine-based basic dyes.