Disclosed are a knock type direct liquid pen refill assembly and a writing pen. The pen refill assembly comprises an ink cylinder assembly (100), a pen tip (200) and an elastic member (300). An ink guide core (150) is provided in the ink cylinder assembly. The pen tip (200) is arranged at one end of the ink cylinder assembly (100). An ink duct (210) is formed inside and passes through the pen tip (200). A ball member (230) is provided at an ink outlet end of the ink duct (210). The ink guide core (150) partially passes through the ink duct (210), and one end of the ink guide core (150) is abutted against the ball member (230). The elastic member (300) is sleeved at the periphery of the ink guide core (150) and positioned inside the ink duct (210). The elastic member is abutted against the ball member to exert a force, such that the ball member is closely attached to an inner wall of the ink outlet end, the ball member forms sealed contact with the inner wall of the ink outlet, and ink volatilization and leakage are avoided.

A method of manufacturing a metallic ball pen tip for a writing instrument comprising a feeding passage extending in an axial direction, the feeding passage reaching in a housing configured to receive a ball, the housing being defined by a cylindrical wall and a wall, the method comprising the steps providing a preform of the metallic ball pen tip comprising the feeding passage and the housing, the housing being defined by the cylindrical wall and a wall, machining the wall so as to obtain a stepped wall, broaching feeding grooves in the stepped wall and coining the stepped wall with a spherical die so as to obtain the ball seat, and a metallic ball pen tip obtained by the method.

Provided are a reversibly thermochromic aqueous ink composition having excellent writability and few problems such as aggregation of a colorant, an increase in viscosity of the composition, or a decrease in handwriting density, and a refill or an aqueous ballpoint pen using the reversibly thermochromic aqueous ink composition.

A reversibly thermochromic composition is a reversibly thermochromic aqueous ink composition containing a reversibly thermochromic microcapsule pigment encapsulated in a microcapsule formed from an organic resin, an N-vinyl-2-pyrrolidone polymer, glycerin, and water, in which when contents (% by mass) of the reversibly thermochromic microcapsule pigment, the N-vinyl-2-pyrrolidone polymer, and the glycerin with respect to a total mass of the ink composition are P.sub.MC, P.sub.PVP, and P.sub.G, respectively, 0.3≤P.sub.MC/(P.sub.PVP+P.sub.G)≤4, and 0.2≤P.sub.PVP/P.sub.G≤5, and a refill or an aqueous ballpoint pen incorporating the reversibly thermochromic aqueous ink composition.

Provided are a reversibly thermochromic aqueous ink composition having excellent writability and few problems such as aggregation of a colorant, an increase in viscosity of the composition, or a decrease in handwriting density, and a refill or an aqueous ballpoint pen using the reversibly thermochromic aqueous ink composition.

A reversibly thermochromic composition is a reversibly thermochromic aqueous ink composition containing a reversibly thermochromic microcapsule pigment encapsulated in a microcapsule formed from an organic resin, an N-vinyl-2-pyrrolidone polymer, glycerin, and water, in which when contents (% by mass) of the reversibly thermochromic microcapsule pigment, the N-vinyl-2-pyrrolidone polymer, and the glycerin with respect to a total mass of the ink composition are P.sub.MC, P.sub.PVP, and P.sub.G, respectively, 0.3≤P.sub.MC/(P.sub.PVP+P.sub.G)≤4, and 0.2≤P.sub.PVP/P.sub.G≤5, and a refill or an aqueous ballpoint pen incorporating the reversibly thermochromic aqueous ink composition.

A metallic ball pen tip for a writing instrument comprising a feeding passage extending in an axial direction, the feeding passage reaching in a recess configured to receive a ball, the recess being defined by a cylindrical wall and a ball seat, wherein the ball seat comprises a plurality of feeding grooves and wherein the ball seat is textured, the texture comprising a plurality of blind holes having a depth equal to or smaller than 50 μm, preferably equal to or smaller than 10 μm, more preferably equal to or smaller than 5 μm, more preferably equal to or smaller than 1 μm, the blind holes having a total surface equal to or greater than 20% of the ball seat, preferably 60% and equal to or smaller than 90% of the ball seat, preferably 85%. A method of manufacturing a metallic ball pen tip.

A ballpoint pen tip comprises: a ball having a diameter of 0.5 mm or less; and a tip body, wherein the tip body has a ball holding chamber, a rear hole, an ink flow hole, and an ink flow groove opening to the ball holding chamber, and not reaching the rear hole. A ratio of an ink consumption per 100 m of handwriting to a diameter of the ball is 200 mg/mm or more and 800 mg/mm or less, and when a front end of the ink flow groove is set as a start point and a position of 0.3 mm rearward from the front end of the ink flow hole is set as an end point, a volume of a first space in the ink flow hole and the ink flow groove from the start point to the end point is 0.02 mm.sup.3 or more.

An ink composition contains a carbon black and/or an organic pigment, water, a polysaccharide, two or more of diols, and particles of an acrylic resin. The two or more of diols include a first diol having from 5 to 7 carbon atoms and a second diol having from 1 to 4 carbon atoms, and a content of the first diol in the ink composition is 0.05 wt % or more.

A molten gold writing apparatus is disclosed. The molten gold writing apparatus includes a barrel extending from a top end to an open bottom end. A heating element is positioned within the barrel and includes a rechargeable battery. A cartridge includes a refillable chamber configured to hold a solid gold refill and dimensioned to fit within the heating element. The heating element melts the gold refill and allows it to flow to a tip end of the cartridge. A grip is configured to selectively engage the bottom end of the barrel to cover all but the tip end of the cartridge.

A molten gold writing apparatus is disclosed. The molten gold writing apparatus includes a barrel extending from a top end to an open bottom end. A heating element is positioned within the barrel and includes a rechargeable battery. A cartridge includes a refillable chamber configured to hold a solid gold refill and dimensioned to fit within the heating element. The heating element melts the gold refill and allows it to flow to a tip end of the cartridge. A grip is configured to selectively engage the bottom end of the barrel to cover all but the tip end of the cartridge.

The invention is directed to a paint pen having a squeezable paint reservoir, a flexible and resilient tube connected at one end to the reservoir and at the other end to a tip comprising an absorbent and permeable material (relative to the paint in the reservoir). The pen operates by squeezing the tube to provide paint through the tube to the tip at which point it can be applied to a surface. The flexibility and resilience of the tube enables uniform application of the paint to rough surfaces.