Abstract: A water base ink for ink-jet recording contains 0.1% by weight to 4.0% by weight of C.I. Direct Yellow 132; not less than 0.5% by weight of glycol ether having a melting point of not more than ?45°C.; and a water-soluble organic solvent in which a solubility of C.I. Direct Yellow 132 at 20° C. is not less than 5%. The ink satisfies 0.2?B/A and 3?C/A. B/A represents a weight ratio of the glycol ether to the C.I. Direct Yellow 132 contained in the ink, and C/A represents a weight ratio of the water-soluble organic solvent to the C.I. Direct Yellow 132 contained in the ink. The stability in long-term storage after the evaporation of water or at low temperatures can be obtained even when C.I. Direct Yellow 132 is used in the water-base ink for the ink-jet recording.

Abstract: A water base ink set for ink-jet recording includes a black ink containing water, a black pigment and a water-soluble organic solvent and a color ink containing water, a dye, and a water-soluble organic solvent. The black pigment is a negatively-chargeable and self-dispersible pigment. The dye has a fluorescein structure. The color ink further contains an alkylamine ethylene oxide adduct. The water-soluble organic solvent contained in the black ink is same as that contained in the color ink. With the ink set, not only the bleeding hardly occurs but also satisfactory discharge stability is obtained even when an ink-jet recording is performed on a regular paper.

Abstract: An ink set for ink-jet recording includes a pigment-based ink containing a negatively chargeable and self-dispersible pigment as a coloring agent and a dye-based ink containing an anionic dye as a coloring agent, and the ink set satisfies the following expression (1): Dci<1.1×Pci+0.0001??(1) wherein “Dci” represents an amount of counter ion (mol/g) of the anionic dye contained in the dye-based ink, and “Pci” represents an amount of counter ion (mol/g) of the self-dispersible pigment contained in the pigment-based ink. The pigment aggregation can be greatly suppressed, and the high quality printing can be stably performed when the ink set for ink-jet recording composed of the pigment-based ink and the dye-based ink is carried on an ink-jet printer provided with a conventional maintenance system that is simple and at low cost.

Abstract: A water base ink for ink-jet recording includes carbon black as a coloring agent and water. The content of chlorine ion contained in the ink is not more than 8 ppm. The ink may be added with 1,2,3-benzotriazole as a rustproofing agent. Even when oxygen is contained in an amount of about 9 ppm in the ink, the corrosion of a discharge section, which would be otherwise caused by chlorine ion, can be avoided even in the case of the use for a printer which uses a metal member for the discharge section.

Abstract: A water base ink set for ink-jet recording includes a black ink containing a negatively charged self-dispersing black pigment and a water-soluble polyvalent alcohol alkyl ether; and a yellow ink containing a water-soluble anionic yellow dye in which a number of counter ion or ions per one molecule is not more than 3, a surfactant based on amine represented by the following general formula (1), and a water-soluble polyvalent alcohol alkyl ether; R—N—(CH2CH2O)xH(CH2CH2O)yH??(1) wherein R represents an alkyl group or an alkenyl group having a number of carbons of 8 to 18, and x+y is 5 to 15. Accordingly, the water ink set in which no bleeding or no coagulation of the pigment occur is provided.

Abstract: A water base ink for ink-jet recording comprises water, a coloring agent, a water-soluble organic solvent, and a benzotriazole-based metal-inactivating agent and alkanolamine. When the ink is used in an ink-jet recording apparatus which has the metal member containing nickel or nickel alloy in an ink supply passage, nickel is eluted from the metal member in an amount of not more than 50 ppm. The ink makes it possible to perform stable jetting operation for a long term without causing any deterioration of metal members of a discharge head due to the metallic corrosion and the elution of nickel into the ink.

Abstract: A water base ink for ink-jet recording contains an amine compound selected from the group consisting of N-n-butylethanolamine, 1,4-bis(3-aminopropyl)piperazine, benzylamine, and an amine compound represented by a specified structural formula, a surfactant having a specified structural formula, a coloring agent, and water. It is possible to obtain a satisfactory rub resistance and a high printing quality with a sharp outline without causing any feathering on a recorded image. Further, it is possible to obtain a long term nozzle discharge stability by suppressing any corrosion on a metal member of a discharge head unit of an ink-jet recording apparatus.

Abstract: A fluorescent water base ink for ink-jet recording contains a fluorescent dye having a xanthene skeleton, and a glycol. In the fluorescent dye, the difference in hydrophilic index log P is not less than 2.6 between a substituent bonded to C-9 carbon atom of the xanthene skeleton and other portion of the fluorescent dye than the substituent bonded to the C-9 carbon atom. The glycol has a distance between hydroxyl groups substantially equivalent to or longer than an interatomic distance between atoms directly bonded to C-3 and C-6 carbon atoms of the xanthene skeleton of the fluorescent dye, respectively. It is assumed that the glycol is coordinated with the xanthene skeleton in a bridge form to increase the fluorescence intensity by increasing the electron density of the xanthene skeleton. The ink having high fluorescence intensity and in which the fluorescence intensity is not lowered in a time-dependent manner is provided.

Abstract: A fluorescent water base ink for ink-jet recording contains a first fluorescent dye and a second fluorescent dye. The first fluorescent dye has a first ultraviolet absorption wavelength region in an absorption spectrum and a first fluorescence emission wavelength region in a fluorescence spectrum. The second fluorescent dye has a second ultraviolet absorption wavelength region which is different from the first ultraviolet absorption wavelength region in an absorption spectrum and a second fluorescence emission wavelength region in a fluorescence spectrum. The first fluorescent dye further has an absorption wavelength region which is different from the first ultraviolet absorption wavelength region and which overlaps at least a part of the second fluorescence emission wavelength region.

Abstract: An ink set for ink-jet recording includes a first ink which contains glycerol and a first coloring agent, and a second ink which contains a water-soluble organic solvent incompatible with glycerol and a second coloring agent and which does not contain glycerol. The first ink and the second ink are mixed with each other at a low speed. Therefore, the inks permeate into the paper before the inks are mixed with each other. Thus, it is possible to avoid the color bleeding.

Abstract: A fluorescent water base ink for ink-jet recording to be used for an ink-jet printer contains water, a pigment, a compound having primary or secondary amide group, and a fluorescent dye represented by the following formula (1): wherein R1 represents OH or N(R3)R4, R2 represents hydrogen atom or halogen atom, and each of R3 and R4 represents hydrogen atom or alkyl group. A sufficient OD value and a fluorescence value are obtained while securing the vivid color development and the excellent water resistance principally in accordance with the interaction of the fluorescent dye and the compound having the amide group.

Abstract: A water base ink set for ink-jet recording comprises a black ink which contains a black pigment, water, and a water-soluble organic solvent, and a color ink which contains a dye, water, a water-soluble organic solvent, and at least one compound represented by the following formulas (1) to (3), wherein the nozzle clog-up at an ink-jet head and the malfunction of a purging pump, which would be otherwise caused by the aggregation of the black ink, can be avoided: R1—O—(CH2CH2O)x—SO3.Na??(1) wherein R1 represents a straight chain alkyl group having a number of carbon atoms of 16 to 22, and x=20 to 30 is satisfied in the formula (1); wherein l+m+n+o+p+q=20 to 100 is satisfied in the formula (2); and wherein R2 represents a straight chain alkyl group having a number of carbon atoms of 16 to 22, and y=100 to 300 is satisfied in the formula (3).

Abstract: A water base ink set for ink-jet recording includes a water base ink which contains an acid dye, and a water base ink which contains a basic dye. The water base ink contains a polymer which has an average molecular weight of 3,000 to 20,000 and which is represented by the following formula (1): wherein X represents H or COONa, and Y represents H, COONa, SO3Na, or CH2OR in the formula (1). R represents a substituted group having SO3Na with carbon atom or atoms of a number of 1 to 5. When the ink containing the acid dye and the ink containing the basic dye are mixed with each other, then the head discharge section is prevented from any clog-up, and it is possible to perform the stable jetting operation.

Abstract: A water base ink set for ink-jet recording comprises a first ink which contains an anionic dye, and a second ink which contains a cationic dye. At least one of the first and second inks contains at least two glycols selected from the group consisting of diethylene glycol, triethylene glycol, and polyethylene glycol, polyvinyl pyrrolidone, and water. The ink set makes it possible to stably discharge the ink by means of an ink-jet head, and it realizes vivid recording which is highly reliable and highly accurate and which provides good color balance.

Abstract: In a water base ink set for ink-jet recording, a pigment ink has a total ion concentration of lithium ion, potassium ion, and sodium ion of not less than 60 ppm and a total ion concentration of divalent or multivalent metal ion or ions of not more than 10 ppm, and a dye ink has a total ion concentration of lithium ion, potassium ion, and sodium ion of not more than 1,800 ppm and a total ion concentration of divalent or multivalent metal ion or ions of not more than 10 ppm, wherein the total ion concentration of lithium ion, potassium ion, and sodium ion of the dye ink is 3 to 25 times that of the pigment ink. Accordingly, the water base ink set in which the pigment ink and the dye ink can be reliably used in combination without complicating a maintenance system is provided.

Abstract: An ink set for ink-jet recording comprises a pigment ink and a dye ink containing a pigment and a dye as coloring agent, respectively. The pigment ink contains water, a water-soluble organic solvent, and a negatively charged pigment wherein potassium ion and sodium ion have a total ion concentration of not more than 200 ppm, and divalent or multivalent metal ion or ions have a total ion concentration of not more than 10 ppm. The dye ink contains water, a water-soluble organic solvent, and a dye associated with a counter ion of lithium ion wherein potassium ion and sodium ion have a total ion concentration of not more than 400 ppm, and divalent or multivalent metal ion or ions have a total ion concentration of not more than 10 ppm. In the ink set, the pigment and dye inks can be used in combination without complicating a maintenance system.

Abstract: A water base ink for ink-jet recording comprises water, self-dispersing type carbon black, an anionic surfactant, and a nonionic surfactant. The anionic surfactant is a surfactant represented by the formula (1) and/or a surfactant represented by the formula (2). The nonionic surfactant is a surfactant represented by the formula (3) or a mixture of a surfactant represented by the formula (4) and a surfactant represented by the formula (5). No ink discharge failure occurs, the long term stability is excellent, and it is possible to obtain a high quality image without any feathering.

Abstract: An ink for ink-jet recording is provided, in which an amount of water X (% by weight) in the ink and a saturation viscosity Y satisfy Y≦4.5e0.09X. The saturation viscosity Y is a viscosity (mPa·s) obtained when an ink residual liquid, which is obtained by evaporating volatile components of the ink until a change in weight of the ink is less than 0.05 g/day per 50 g of ink under a condition of a temperature of 60° C. and a humidity of 40%, is cooled to a temperature of 25° C. in an environment of a humidity of 40%. X satisfies 50≦X≦75. The ink exhibits satisfactory jetting stability when the ink is normally used. Further, the ink is easily restored to give a normal jetting state even after undergoing an abnormal condition, for example, when the ink is left to stand without any nozzle cap.

Abstract: A water base pigment ink for ink-jet recording contains a pigment, water, and at least one of polyethylene glycol and diglycerol. The ink is solidified into a solid matter when the water is evaporated. Further, the solid matter is redissolved in the unsolidified water base pigment ink for ink-jet recording. When the ink is used, then neither clog-up of a nozzle nor discharge failure is caused, no load is imposed by the solidified ink on the maintenance system such as the wiping equipment, and the sticking performance on the paper is satisfactory.

Abstract: A water base ink for ink-jet recording contains a dispersible coloring agent, a propylene glycol ether, and a surfactant composed of a random copolymer represented by the following general formula (1):