An ink jet textile printing ink composition includes water; a color material; and a metal chelating agent. In the ink composition described above, the metal chelating agent includes at least one selected from methyl glycine diacetic acid, L-glutamate diacetic acid, L-aspartic diacetic acid, hydroxyethylimino diacetic acid, 3-hydroxy-2,2-iminodisuccucinic acid, dicarboxymethyl glutamic acid, (S,S)-ethylenediaminedisuccinic acid, and salts thereof, and the pH of the ink composition is 6 to 10.

A wash fluid for use in an inkjet recording apparatus contains water, a coconut oil fatty acid surfactant, an organic deliquescent agent, a polyhydric alcohol, and a basic inorganic compound. The polyhydric alcohol is an alkanediol. The coconut oil fatty acid surfactant is contained in an amount of at least 0.01% by mass and no greater than 3.00% by mass. The organic deliquescent agent is contained in an amount of at least 0.10% by mass and no greater than 30.00% by mass.

Disclosed is an aqueous fluorescent ink and a preparation method and use thereof. The aqueous fluorescent ink provided by the present disclosure includes 0.10%-0.14% of polystyrene micro-spheres, 0.010%-0.014% of fluorescent dyes, 0.4%-0.6% of surfactants, and the balance of water. The present disclosure uses polystyrene micro-spheres as a fluorescent dye carrier, which is colorless and transparent under ordinary daylight and completely invisible, and displays fluorescence only when irradiated by ultraviolet light and has high fluorescence intensity. The surfactant makes the polystyrene fluorescent micro-spheres uniformly dispersed in the fluorescent ink, and the stability of the fluorescent ink is improved. Water is used as a solvent, which has excellent safety and environmental friendliness. The accuracy of the printed patterns can reach 30 m, which can help realize large-format ultra-high-precision patterned anti-counterfeiting encryption printing. Through precision printing, the two-dimensional code can be implemented with one code for one object, and has excellent anti-counterfeiting ability.

A metal ink containing metal particles including silver, a protective agent A including an amine compound, and a protective agent B including a fatty acid. The metal ink is configured such that the protective agent A includes at least one C.sub.4-12 amine compound, and the protective agent B includes at least one C.sub.22-26 fatty acid. It is preferable that the amine compound content is 0.2 mmol/g or more and 1.5 mmol/g or less on a silver particle mass basis. In addition, it is preferable that the fatty acid content is 0.01 mmol/g or more and 0.06 mmol/g or less on a silver particle mass basis.

Provided are a near infrared absorbing fine particle dispersion liquid having an absorption ability in a near infrared region, a clear contrast, and applicable to offset printing, and a method for producing the same, an anti-counterfeit ink composition using the near infrared absorbing fine particle dispersion liquid and an anti-counterfeit printed matter using near infrared absorbing fine particles. Also provided are a near infrared absorbing fine particle dispersion liquid containing a solvent of one or more kinds selected from vegetable oils or vegetable oil-derived compounds; near infrared absorbing fine particles in an amount of 2 mass % or more and 25 mass % or less, selected from one or more kinds of hexaboride fine particles expressed by a general formula XB.sub.a (wherein element X is at least one or more kinds selected from a group consisting of La, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Y, Sm, Eu, Er, Tm, Yb, Lu, Sr, and Ca, satisfying 4.0a6.2); and a dispersant soluble in the solvent and having a fatty acid in its structure, wherein viscosity is 180 mPa/S or less, and an anti-counterfeit ink composition containing the near infrared absorbing fine particle dispersion liquid. Also provided is an anti-counterfeit printed matter excellent in anti-counterfeit effect due to the printed matter containing the near infrared absorbing fine particles.

Provided are a near infrared absorbing fine particle dispersion liquid having an absorption ability in a near infrared region, a clear contrast, and applicable to offset printing, and a method for producing the same, an anti-counterfeit ink composition using the near infrared absorbing fine particle dispersion liquid and an anti-counterfeit printed matter using near infrared absorbing fine particles. Also provided are a near infrared absorbing fine particle dispersion liquid containing a solvent of one or more kinds selected from vegetable oils or vegetable oil-derived compounds; near infrared absorbing fine particles in an amount of 2 mass % or more and 25 mass % or less, selected from one or more kinds of hexaboride fine particles expressed by a general formula XB.sub.a (wherein element X is at least one or more kinds selected from a group consisting of La, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Y, Sm, Eu, Er, Tm, Yb, Lu, Sr, and Ca, satisfying 4.0a6.2); and a dispersant soluble in the solvent and having a fatty acid in its structure, wherein viscosity is 180 mPa/S or less, and an anti-counterfeit ink composition containing the near infrared absorbing fine particle dispersion liquid. Also provided is an anti-counterfeit printed matter excellent in anti-counterfeit effect due to the printed matter containing the near infrared absorbing fine particles.

According to one embodiment, an ink which can be decolored upon heating is provided. Colored images can be formed with the ink by various methods, such as ink jetting or the like, then later the images can be decolored with heat. An ink according to an embodiment contains a color developable compound, a color developing agent that causes the color developable compound to develop a color, a nonaqueous solvent, and a decoloring agent that is insoluble in the nonaqueous solvent and decolors the color developable compound upon heating.

According to one embodiment, an ink which can be decolored upon heating is provided. Colored images can be formed with the ink by various methods, such as ink jetting or the like, then later the images can be decolored with heat. An ink according to an embodiment contains a color developable compound, a color developing agent that causes the color developable compound to develop a color, a nonaqueous solvent, and a decoloring agent that is insoluble in the nonaqueous solvent and decolors the color developable compound upon heating.

A near infrared absorbing-fine-particle dispersion liquid having absorption in a near infrared region, having clear contrast, and being applicable to offset printing; a method for producing the same; an anti-counterfeit ink composition using the near infrared absorbing-fine-particle dispersion liquid; and anti-counterfeit printed matter using the near infrared absorbing-fine-particles. The near infrared absorbing-fine-particle dispersion liquid contains a solvent of one or more from vegetable oils or vegetable oil-derived compounds; near infrared absorbing-fine-particles of 2 mass % or more and 25 mass % or less, selected from one or more of hexaboride fine-particles expressed by formula XB.sub.a (where X is one or more kinds of specified elements, and 4.0a6.2); and a dispersant soluble in solvent and having a fatty acid in its structure, where the viscosity is 180 mPa.Math.s or less. The anti-counterfeit printed matter is excellent in anti-counterfeit effect due to the near infrared ab sorbing-fine-particles.

A pigment dispersion containing a metal pigment, wherein the metal pigment contains plate-like particles, and in the case where the longitudinal diameter on the planar surface of the plate-like particle is X, the lateral diameter is Y, and the thickness is Z, the 50% average particle diameter R50 of a corresponding circle determined from the surface area in the X-Y plane of the plate-like particle is between 0.5 and 3 m, and the condition R50/Z>5 is satisfied.