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 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: Disclosed herein is an ink comprising (i) first and second organic compounds which are incompatible with each other; (ii) at least one of a compound exhibiting fluorescence properties and a coloring material exhibiting fluorescence properties; and (iii) a liquid medium dissolving or dispersing the components (i) and (ii) therein.

Abstract: The invention provides an aqueous ink comprising a polymer having hydroxyl groups and a pigment, which can provide images excellent in scratch resistance and highlighter resistance and can inhibit the seeping out phenomenon of the polymer and the deterioration of ejection characteristics even when it is stored for a long period of time. The aqueous ink comprises a polymer having hydroxyl groups, a pigment and a water-soluble organic solvent, wherein the water-soluble organic solvent comprises a polyhydric alcohol having a value of number of hydroxyl groups/number of carbon atoms in its molecule of 0.50 or less.

Abstract: The invention provides an aqueous ink comprising a polymer having hydroxyl groups and a pigment, which can provide images excellent in scratch resistance and highlighter resistance and can inhibit the seeping out phenomenon of the polymer and the deterioration of ejection characteristics even when it is stored for a long period of time. The aqueous ink comprises a polymer having hydroxyl groups, a pigment and a water-soluble organic solvent, wherein the water-soluble organic solvent comprises a poor medium for a polymer that is not adsorbed on the pigment of the polymer having hydroxyl groups, and wherein when the segment constituting the polymer that is not adsorbed on the pigment of the polymer having hydroxyl groups is comprised of a segment A having hydroxyl groups and a segment B having no hydroxyl group, at least one of the poor medium is a good medium for either one of the segment A and the Segment B.

Abstract: The invention provides an aqueous ink comprising a polymer having hydroxyl groups and a pigment, which can provide images excellent in scratch resistance and highlighter resistance and can inhibit the seeping out phenomenon of the polymer and the deterioration of storage stability and ejection characteristics even when it is stored for a long period of time. The aqueous ink comprises a polymer having hydroxyl groups and a pigment, wherein a proportion of a content of a polymer that is not adsorbed on the pigment out of the polymer having hydroxyl groups to the content of the pigment in the ink is 2.0 mass % or more, and a content (mass %) of the polymer that is not adsorbed on the pigment out of the polymer having hydroxyl groups is 0.20 mass % or less based on the total mass of the ink.

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: Disclosed herein is an ink-jet recording method comprising a step of applying thermal energy to an ink to generate bubbles thereby ejecting the ink from an ejecting portion to record, wherein the relationship among a cloud point (T) of a liquid obtained by removing coloring material from the ink, a temperature T0 of the ink before formation of the bubbles in a portion in which the bubbles are generated and a temperature T1 of a part of the ink, which includes a portion in contact with the bubbles and surrounds the bubbles, satisfies T0<T<T1.

Abstract: A recording method including the step of providing an ink from a recording head to a recording medium through a gap provided between the recording head and the recording medium, the ink being supplied to the recording head from an ink tank including an ink contact member and the ink contacting the ink contact member, wherein the ink comprises: (i) a fluorescent coloring material; (ii) a nonionic surfactant; (iii) a compound which is not compatible with (ii); and (iv) a liquid medium for dissolving or dispersing (i), (ii) and (iii), and wherein the ink contact member comprises at least one compound selected from the group consisting of polyacetate and polyolefin.

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: 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: 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: Disclosed herein is an ink including (i) first and second organic compounds which are incompatible with each other; (ii) at least one of a compound exhibiting fluorescence properties and a coloring material exhibiting fluorescence properties; and (iii) a liquid medium dissolving or dispersing the components (i) and (ii) therein.

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 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. or less of a DSC curve obtained by means of a differential scanning calorimeter (DSC).

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 1.3 times of the content (mass %) of the pigment with respect to the total mass of ink.

Abstract: A reaction liquid containing a reactive substance that reacts with at least one component in an ink composition containing a coloring material in a dispersed state, in which the reactive substance is a polyvalent metal compound having multiple reactive sites in one molecule, a set of ink and a reaction liquid, and an image recording method for performing image recording by means of the set.

Abstract: A novel fluorescent ink is provided which contains at least a coloring material and an aqueous liquid medium for dissolving the coloring material, wherein the coloring material comprises C.I. Acid Red 52 and at least one direct dye, the content of the C.I. Acid Red 52 ranging from 0.1 to 0.4% by weight based on the total amount of the ink, and the content of the direct dye ranging from 0.15 to 0.4% by weight based on the total amount of the ink, and the weight ratio of the direct dye to the C.I. Acid Red 52 is not higher than 1.6. This fluorescent ink is capable of forming prints with fluorescence of high intensity and with high water resistance.

Abstract: A recording method is provided which enables formation of an image with high image density and low graininess. The recording is conducted by using a recording method using a first aqueous ink for higher-density recording and a second aqueous ink for lower-density recording, characterized in that the first aqueous ink comprises at least water, a water-insoluble coloring material, and plurality of water-soluble organic solvents, the plurality of water-soluble organic solvents including 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, the ratio B/A in the second aqueous ink being less than the ratio B/A the first aqueous ink, where A denotes the total content (mass %) of good medium based on the total mass of the aqueous ink and B denotes the total content (mass %) of poor medium based on the total mass of the aqueous ink; and the second aqueous ink has the same hue as the first aqueous ink.

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.