Abstract: The present invention can sufficiently suppress curling phenomenon of a recorded product and facilitate handling of a printed product produced by using plain paper, in particular. The present invention provides a printing medium coating solution including water and a water-retentive, water-soluble organic compound, wherein the water-soluble organic compound includes only a water-soluble organic compound showing a difference of 36% or less between the water retention ability at a temperature of 23° C. and a humidity of 45% and the water retention ability at a temperature of 30° C. and a humidity of 80%; and the content of the water-soluble organic compound is 15 mass % or more with respect to the total amount of the printing medium coating solution.

Abstract: The present invention relates to a water-based fluorescent ink for the purpose of measurement or judgment of the fluorescence emission in a visible light region by an excitation wavelength in a predetermined ultraviolet range, containing water, a coloring material dissolved or dispersed in water, and an organic solvent, having a plurality of fluorescent groups in the coloring material structure of the coloring material, and using a water-soluble coloring material having a sulfonic acid group as the water-soluble group in the state of a free acid, capable of improving the water resistance and the light resistance, dramatically increasing the content of the fluorescent coloring material in the ink, which has conventionally been included only by a small amount in the ink due to the concentration quenching problem, obtaining preferable fluorescence emission and water resistance of the recorded image, and providing preferable adhesion resistance to the recording medium of the coloring material and reliability.

Abstract: An object of the present invention is to provide an ink jet ink capable of suppressing bleeding and excellent in color developability, a method of producing the ink with an aid of a unit preferable in terms of economy and environmental protection, and an ink jet recording method providing an image which can suppress the occurrence of bleeding and which is excellent in color developability. The ink jet ink comprises water, coloring materials, and a water-soluble organic solvent, in which the coloring materials comprise at least one dye selected from the group consisting of C.I. Direct Yellow 86, C.I. Acid Yellow 23, C.I. Direct Yellow 173, C.I. Direct Yellow 132, and C.I. Direct Yellow 59, and C.I. Pigment Yellow 74; the water-soluble organic solvent comprises a poor medium for C.I. Pigment Yellow 74; and a surface tension of the ink is 34.0 mN/m or more.

Abstract: An object of the present invention is to provide an ink jet ink capable of suppressing bronzing phenomenon in which a reflected light of an image looks red, is excellent in color developability, and gives an image with suppressed bleeding even when formed adjacent to an image formed with a black ink. The ink jet ink comprises water, coloring materials, and a water-soluble organic solvent, in which the coloring materials comprise at least one dye selected from the group consisting of C.I. Direct Blue 199, C.I. Direct Blue 86, and C.I. Acid Blue 9, and a pigment having a copper phthalocyanine skeleton; the water-soluble organic solvent comprises a poor medium for the pigment having the copper phthalocyanine skeleton; and a content of the pigment having the copper phthalocyanine skeleton in the ink is less than 1 mass % with respect to a total mass of the ink jet ink.

Abstract: The present invention relates to a water-based fluorescent ink for the purpose of measurement or judgment of the fluorescence emission in a visible light region by an excitation wavelength in a predetermined ultraviolet range, containing water, a coloring material dissolved or dispersed in water, and an organic solvent, having a plurality of fluorescent groups in the coloring material structure of the coloring material, and using a water-soluble coloring material having a sulfonic acid group as the water-soluble group in the state of a free acid, capable of improving the water resistance and the light resistance, dramatically increasing the content of the fluorescent coloring material in the ink, which has conventionally been included only by a small amount in the ink due to the concentration quenching problem, obtaining preferable fluorescence emission and water resistance of the recorded image, and providing preferable adhesion resistance to the recording medium of the coloring material and reliability.

Abstract: An ink set is provided which can prevent the occurrence of a new color mixing phenomenon in which a different ink comes into the insides of particular ink channels. The ink set is constituted of plurality of inks. The plurality of inks constituting the ink set is stored respectively in ink cartridges each having an ink storage portion which is brought into a hermetically-closed state. The difference in specific gravity between a first ink having the largest specific gravity and a second ink having the smallest specific gravity among the inks constituting the ink set is less than 0.020.

Abstract: The present invention provides a fluorescence ink having a high fluorescence intensity, and an ink jet recording method using the same. The ink contains a first fluorescent coloring material that emits fluorescence at a predetermined fluorescence wavelength to be used for measurement or determination with excitation at a predetermined excitation wavelength, a second fluorescent coloring material that emits fluorescence on excitation at the predetermined excitation wavelength, where the excitation spectrum of the first coloring material in the ink to obtain the fluorescence at the predetermined emission wavelength has a peak wavelength range next to the predetermined fluorescence wavelength, and the emission fluorescence spectrum of the second coloring material has an emission wavelength region substantially including at least the above peak wavelength range.

Abstract: A pigment ink is provided which has good ink reliability and storage stability and can achieve superior scratch resistance of images at such a level that coloring materials are hardly scraped off even when images are scratched with finger nails under application of such strong pressure as to scratch a recording medium at its non-recorded areas. The pigment ink contains a pigment, a modified siloxane compound having a specific structure, and a polymer whose acid value and hydrogen bond parameter (?h) are specified.

Abstract: A liquid composition which can achieve superior scratch resistance of images at such a level that coloring materials are hardly scraped off even when images are scratched with finger nails under application of such strong pressure as to scratch a recording medium at its non-recorded areas. The liquid composition contains at least a modified siloxane compound having specific structure and a polymer whose acid value and hydrogen bond parameter (?h) are specified.

Abstract: The present invention aims to provide an ink which has a sufficiently large area factor even in a small ink droplet quantity and can obtain images having a high image density, and further has a superior storage stability. According to the present invention, a cyan ink is provided which is used in an ink set having four kinds of aqueous inks consisting of a cyan ink, a magenta ink, a yellow ink and a black ink in which each ink comprises at least water, a water-insoluble coloring material, and a plurality of water-soluble organic solvents having a good medium or good mediums for the water-insoluble coloring material and a poor medium or poor mediums for the water-insoluble coloring material, wherein, the ratio B1/A1 is from 0.5 or more to 3.

Abstract: An aqueous ink comprising water, a water-soluble organic solvent and at least two pigments. The aqueous ink is used together with a reaction liquid containing a reactive component that reacts with the aqueous ink to cause aggregation or gelation of the aqueous ink. The at least two pigments have a difference in precipitation value to the reaction liquid of 0.2 or less.

Abstract: A recording head and a recording unit are provided achieving both the reliability of ejection stability and storage stability and the prevention of a new color mixing phenomenon. The recording head has ejection orifice lines each of which ejects each of the inks constituting an ink set. The plurality of inks is stored respectively in ink cartridges each having an ink storage portion being brought into a hermetically-closed state. At least three types of inks among the inks are different in specific gravity from one another, and at least two types of inks among the at least three types of inks are different in specific gravity by 0.020 or more. The ejection orifice lines are arranged so that the total sum of differences in specific gravities between the inks to be ejected from ejection orifice lines adjacent to each other among the inks to be ejected from the ejection orifice lines becomes minimal.

Abstract: An aqueous ink to be used in an ink jet recording containing a green pigment having a copper phthalocyanine skeleton, wherein a proportion of the K?-line intensity of a chlorine atom to the K?-line intensity of a bromine atom obtained by subjecting the green pigment to X-ray fluorescence analysis is 3.3 or more to 10.0 or less.

Abstract: The invention provides an aqueous ink that can prevent clogging at an orifice due to drying of the ink though the ink contains a pigment, and can achieve high-level ejection stability required in recent years. The aqueous ink contains at least water, a water-soluble organic solvent and carbon black particles, the carbon black particles including carbon black particles having a particle size of 0.5 ?m or more, wherein a proportion made up by the volume of carbon black particles having a particle size of 0.2 ?m or more and less than 0.5 ?m is 0.3% or less based on the total volume of all the carbon black particles in the ink, a number of carbon black particles having a particle size of 0.5 ?m or more and less than 5.0 ?m is 1.0×107 or less per mL of the aqueous ink, and an average particle size value of the carbon black particles is from 0.060 ?m or more to 0.130 ?m or less.

Abstract: An aqueous ink, by which stable ink-jet recording can be conducted irrespective of printing environment, a substantially even image having abrasion resistance can be formed, no image soiling is caused even upon double-side printing, and a high-quality image improved in unclearness at a contour portion of the image and free from occurrence of color bleed can be provided, is provided. The aqueous ink is an aqueous ink used in a system that a reaction liquid containing at least a polyvalent metal and an aqueous ink containing at least a pigment dispersion, in which a pigment is dispersed with an anionic polymer dispersant, are used to form an image, wherein the aqueous ink satisfies specific condition.

Abstract: A reaction solution to be used for image recording with an ink containing a coloring material in a dissolved or dispersed state in order to achieve a high level of image density with stability, wherein the reaction solution contains a polyvalent metal ion and an organic solvent to destabilize the dissolved or dispersed state of the coloring material in the ink in contact with the ink, has a pH of 2 or higher, and has a buffering action for pH, wherein the buffering action means it can maintain pH variation within the range of 0.5 before and after the addition of 1.0 ml of a 0.1 N aqueous lithium hydroxide solution to 50 ml of the reaction solution.

Abstract: An ink to be used in an ink jet recording method of ejecting an ink from a recording head through action of thermal energy can improve the ink ejection stability and shows a high storage stability and a high color developability. An ink to be used in an ink jet recording method of ejecting an ink from a recording head through action of thermal energy is characterized in that the ink comprises a pigment represented by the general formula (1), a dispersant, a water-soluble organic compound and an aggregation inhibiting substance for inhibiting aggregation after dispersion breakdown of the pigment, and the content (mass %) of the aggregation inhibiting substance with respect to the total mass of ink is 0.4 times or more to less than 1.

Abstract: An ink to be used in an ink jet recording method of ejecting an ink from a recording head through action of thermal energy can improve the ink ejection stability. An ink to be used in an ink jet recording method of ejecting an ink from a recording head through action of thermal energy is characterized in that the ink comprises a pigment represented by the general formula (1), a dispersant and a water-soluble organic compound, and the pigment substantially shows neither an exothermic peak nor an endothermic peak in the range 25° C. or more to 200° C.

Abstract: Disclosed is an aqueous ink comprising at least water, a plurality of water-soluble organic solvents and a coloring material. The coloring material is a pigment, and, it contains a pigment particle having at least one ionic group bonded to a surface of the pigment particle directly or via another atomic group. The plurality of water-soluble organic solvents have a good medium or good mediums for the pigment and a poor medium or poor mediums for the pigment. The poor medium does not solvate perfectly or substantially the pigment. The ionic group undergoes perfectly or substantially no ionic dissociation in the poor medium. Also, among the respective Ka values of the plurality of water-soluble organic solvents as determined by the Bristow method, the Ka value of the poor medium is maximum.

Abstract: An aqueous ink to be used in an ink jet recording method that an ink is ejected from a recording head by the action of thermal energy, wherein the ink contains a pigment, a polymer and a water-soluble organic solvent, the hydrophilicity ?m of the pigment falls within a range of from 21.5 or more to 23.5 or less, and the content (mass %) of the water-soluble organic solvent is from 5.0 mass % or more to 17.5 mass % or less with respect to the whole mass of the aqueous ink.