Abstract: Disclosed is a water based ink composition for a rollerball pen that includes at a least colorant, a water-soluble organic solvent, water, a shear thinning viscosity property-providing agent, a lubricant, and a bubble suppressant. The ink composition includes a phosphate-ester based surfactant having a structure of general formula 1 as the lubricant, and an erythorbic acid or a derivative thereof as the bubble suppressant (n represents an integer of 1 or more, R represents an alkyl group having carbon numbers of 12 to 15, and R? represents H or R—(C2H4O)n—).

Abstract: The present invention relates to a rotating retractable writing instrument, which is constituted in a simpler way and can thrust a mouthpiece and a writing core element smoothly to positions ready for writing. The writing instrument by the present invention comprises a rear outer cylinder 2, an inner sheath 4 unrotatably accommodated in the rear outer cylinder 2, a front outer cylinder 10 from which a mouthpiece 12 and a writing core element 13 can be thrust. A protrusion 45 for restraining rotating range, a refill sliding cam 42 and a mouthpiece sliding cam 43 are formed in the inner sheath 4. A refill sliding element 6 and a mouthpiece sliding element 7 are accommodated in the inner sheath 4. The mouthpiece sliding element 7 is connected to the refill sliding element 6. Further a connecting element 9 is connected to the inner sheath 4.

Abstract: A reversal magnetic display panel where the numbers of writes/erases repeated until the micro magnets in a dispersion liquid sealed in multiple small cells formed between substrates sediment in the lower part of the small cells by repeated writes/erases when the reversal magnetic display panel is used in a vertical position are increased and a favorable display/erase performance is achieved. Between substrates, a dispersion liquid containing a dispersion medium and a thickening agent as main components and further containing micro magnets the both sides of each of which are differently colored are sealed in. Writing is constituted by difference in contrast between the color of the reversed micro magnets and the color of the non-reversed ones. Hollow particles are mixed with the micro magnets so as to reduce the ratio of the specific gravity of the micro magnets to that of the liquid. The residual magnetization per unit mass of the micro magnets is 1.0 to 23.

Abstract: In order to obtain an ink for oil-based ballpoint pens and an oil-based ballpoint pen which are excellent in handwriting sharpness, handwriting dryness, handwriting and feeling of writing, an ink composition includes an oil-soluble dye, water, an organic solvent whose vapor pressure at 20° C. is 0.5 mmHg or more and which dissolves the water, and an organic solvent whose vapor pressure at 20° C. is 0.1 mmHg or less and which dissolves the organic solvent whose vapor pressure at 20° C. is 0.5 mmHg or more. A total of these three components is 20 to 75% by mass based on an entire mass of the ink composition. A content of the water is 3.0 to 15.0% by mass based on the entire mass of the ink composition. An ink viscosity at 20° C. is 100 to 5,000 mPa·s. The water and the other components are formulated, mixed and stirred to produce the ink. A ballpoint pen refill with low vapor permeability is used.

Abstract: A ballpoint pen including: an ink accommodation cylinder; a ballpoint pen tip in which a ball is rotatably held, the pen tip being attached to a tip end of an ink-accommodation cylinder directly or through a tip holder; and ballpoint oil-based ink comprising at least a coloring agent, organic solvent, a lubricant comprising organic acid and phosphoric ester, and organic amine, the ink having ink viscosity at shearing speed 6.8 sec?1 of 500 to 6000 mPa·s (20° C.) and directly being accommodated in the ink-accommodation cylinder, wherein the ballpoint pen satisfies 2.5×10?3?Z?1.0×10?3 where ink amount per 1 mm2 is Z mg/mm2 which is calculated from Y=X×105×Z where writing width of the ballpoint pen is X mm and ink consumption per 100 m is Y mg.

Abstract: Disclosed is a ballpoint pen including: an ink accommodation cylinder; a ballpoint pen tip in which a ball is rotatably held, the pen tip being attached to a tip end of an ink-accommodation cylinder directly or through a tip holder; and ballpoint oil-based ink comprising at least a coloring agent, organic solvent, a lubricant comprising organic acid and phosphoric ester, and organic amine, the ink having ink viscosity at shearing speed 6.8 sec?1 of 500 to 6000 mPa·s (20° C.) and directly being accommodated in the ink-accommodation cylinder, wherein the ballpoint pen satisfies 2.5×10?3?Z?1.0×10?3 where ink amount per 1 mm2 is Z mg/mm2 which is calculated from Y=X×105×Z where writing width of the ballpoint pen is X mm and ink consumption per 100 m is Y mg.

Abstract: Disclosed is a water based ink composition for a rollerball pen that includes at a least colorant, a water-soluble organic solvent, water, a shear thinning viscosity property-providing agent, a lubricant, and a bubble suppressant. The ink composition includes a phosphate-ester based surfactant having a structure of general formula 1 as the lubricant, and an erythorbic acid or a derivative thereof as the bubble suppressant (n represents an integer of 1 or more, R represents an alkyl group having carbon numbers of 12 to 15, and R? represents H or R—(C2H4O)n—).

Abstract: In order to obtain an ink for oil-based ballpoint pens and an oil-based ballpoint pen which are excellent in handwriting sharpness, handwriting dryness, handwriting and feeling of writing, an ink composition includes an oil-soluble dye, water, an organic solvent whose vapor pressure at 20° C. is 0.5 mmHg or more and which dissolves the water, and an organic solvent whose vapor pressure at 20° C. is 0.1 mmHg or less and which dissolves the organic solvent whose vapor pressure at 20° C. is 0.5 mmHg or more. A total of these three components is 20 to 75% by mass based on an entire mass of the ink composition. A content of the water is 3.0 to 15.0% by mass based on the entire mass of the ink composition. An ink viscosity at 20° C. is 100 to 5,000 mPa·s. The water and the other components are formulated, mixed and stirred to produce the ink. A ballpoint pen refill with low vapor permeability is used.

Abstract: An ink composition for oil-based ballpoint pens is comprised of a solvent, a colorant and an anti-corrosive wetting agent. The solvent is a water containing water-in-oil-type organic solvent. The colorant is a combination of a dye and a pigment, wherein the pigment is dispersed in the ink with a nonionic surfactant. The anti-corrosive wetting agent is a phosphate based surfactant. An oil-based ballpoint pen using the above ink is also included.