Abstract: An aqueous ink for ink jet recording contains a titanium oxide particle containing titanium oxide, at least part of the surface of the titanium oxide being covered with alumina and silica in specific proportions, and a compound serving as a dispersant for the titanium oxide particle, the compound being represented by the following general formula (1): where in general formula (1), R1, R2 and R3 are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, each R4 is independently an alkylene group having 2 to 4 carbon atoms, X is a single bond or an alkylene group having 1 to 6 carbon atoms, n is 6 to 24, a is 1 to 3, b is 0 to 2 and a + b = 3.

Abstract: An aqueous ink for ink jet recording includes a titanium oxide particle containing titanium oxide, at least part of the surface of the titanium oxide being covered with alumina and silica in specific proportions, in which the titanium oxide particle is dispersed at least by the action of the silica, and the ratio (?1/?1,000) of the viscosity (?1) of the aqueous ink at a shear rate of 1 (1/s) to the viscosity (?1,000) at a shear rate of 1,000 (1/s) is 1.10 times or less.

Abstract: An aqueous ink contains a titanium oxide particle, poly(acrylic acid) and potassium ions, in which the titanium oxide particle contains titanium oxide, at least part of the surface of the titanium oxide is covered with alumina and silica, and the poly(acrylic acid) content is 0.05 times or more to 0.40 times or less the alumina content in terms of a mass ratio.

Abstract: To provide an ink jet recording method which can record an image on a recording medium irrespective of what material is selected therefor. The ink jet recording method is a method of recording an image on a recording medium with a colorless transparent aqueous ink and includes a step of applying, to the recording medium, the aqueous ink containing a mineral acid and having a pH of 1.0 or less; and a step of forming carbon by making use of the mineral acid.

Abstract: An inkjet recording method of the present disclosure is an inkjet recording method of recording an image on a recording medium using an aqueous ink. Coating wax on a transfer body; applying an aqueous reaction solution containing a reaction agent reacting with the aqueous ink to the transfer body; forming an intermediate image by applying the aqueous ink to the transfer body; and transferring the intermediate image by bringing the intermediate image into contact with the recording medium are included in this order, and a surface temperature Ta (° C.) of the transfer body at a position where the intermediate image contacts the recording medium, a surface temperature Tb (° C.) of the transfer body at a position where the intermediate image is separated from the transfer body and a melting point Tm (° C.) of the wax satisfy a relationship of Tb<Tm?Ta.

Abstract: To provide an ink jet recording method capable of recording a high-quality image excellent in optical density and water resistance and at the same time, suppressing peeling-off of an image caused by contact heating of a recording medium. The ink jet recording method has a step of ejecting an aqueous ink containing a resin particle from a line head and applying the aqueous ink to a predetermined position of a recording medium having ink absorbability and a step of bringing a heating roller into contact with the aqueous ink applied to the recording medium to heat it and fixing it at the predetermined position. The dynamic surface tension of the aqueous ink at the time when the heating roller is brought into contact with the aqueous ink applied to the recording medium is higher than the surface tension of the heating roller.

Abstract: To provide an ink jet recording method which can record an image on a recording medium irrespective of what material is selected therefor. The ink jet recording method is a method of recording an image on a recording medium with a colorless transparent aqueous ink and includes a step of applying, to the recording medium, the aqueous ink containing a mineral acid and having a pH of 1.0 or less; and a step of forming carbon by making use of the mineral acid.

Abstract: To provide an ink jet recording method capable of recording a high-quality image excellent in optical density and water resistance and at the same time, suppressing peeling-off of an image caused by contact heating of a recording medium. The ink jet recording method has a step of ejecting an aqueous ink containing a resin particle from a line head and applying the aqueous ink to a predetermined position of a recording medium having ink absorbability and a step of bringing a heating roller into contact with the aqueous ink applied to the recording medium to heat it and fixing it at the predetermined position. The dynamic surface tension of the aqueous ink at the time when the heating roller is brought into contact with the aqueous ink applied to the recording medium is higher than the surface tension of the heating roller.

Abstract: Provided is an aqueous ink that can record an image excellent in color developability and is excellent in sticking recovery property. The aqueous ink for ink jet includes: a pigment; and a surfactant, wherein the pigment includes a self-dispersible pigment in which at least one functional group selected from the group consisting of (i) an anionic group and (ii) a group in which another atomic group and an anionic group are bonded to each other is bonded to a surface of a particle of carbon black and a density of the functional group is 0.10 ?mol/m2 or more to 0.48 ?mol/m2 or less and wherein the surfactant includes an amino acid type surfactant in which a nitrogen atom capable of becoming a cation has a structure of a secondary amine or a tertiary amine.

Abstract: An ink jet recording method is provided for recording an image by ejecting an ink from a recording head including a member defining an ejection orifice through which the ink is ejected, an ejection element configured to generate an energy used for ejecting the ink, and a first flow path communicating with a portion between the ejection orifice and the ejection element. The method includes ejecting an ink through the ejection orifice, and moving the ink from the first flow path to the portion between the ejection orifice and the ejection element separately from the ejecting of the ink. In this method, the ink is an aqueous ink containing a coloring material and a compound containing a chain hydrocarbon having a carbon number of 8 or more to 18 or less substituted by a hydroxy group or an anionic group.

Abstract: Provided is an aqueous ink that can record an image excellent in color developability and is excellent in sticking recovery property. The aqueous ink for ink jet includes: a pigment; and a surfactant, wherein the pigment includes a self-dispersible pigment in which at least one functional group selected from the group consisting of (i) an anionic group and (ii) a group in which another atomic group and an anionic group are bonded to each other is bonded to a surface of a particle of carbon black and a density of the functional group is 0.10 ?mol/m2 or more to 0.48 ?mol/m2 or less and wherein the surfactant includes an amino acid type surfactant in which a nitrogen atom capable of becoming a cation has a structure of a secondary amine or a tertiary amine.

Abstract: A liquid discharge apparatus has a liquid discharge head having a recording element board that includes a plurality of discharge orifices configured to discharge liquid, a plurality of pressure chambers internally provided with a recording element configured to generate energy used to discharge liquid, the plurality of pressure chambers each communicating with the plurality of discharge orifices via discharge channels, a liquid supply channel configured to supply liquid to the plurality of pressure chambers, and a liquid recovery channel configured to recover liquid from the plurality of pressure chambers, and a tank configured to store liquid supplied to the liquid discharge head. The plurality of pressure chambers communicate between the liquid supply channel and the liquid recovery channel so that liquid flows through the plurality of pressure chambers, and the specific permittivity ?r of the liquid stored in the tank satisfies the relationship of ?r?65.

Abstract: An ink jet recording method is provided for recording an image by ejecting an ink from a recording head including a member defining an ejection orifice through which the ink is ejected, an ejection element configured to generate an energy used for ejecting the ink, and a first flow path communicating with a portion between the ejection orifice and the ejection element. The method includes ejecting an ink through the ejection orifice, and moving the ink from the first flow path to the portion between the ejection orifice and the ejection element separately from the ejecting of the ink. In this method, the ink is an aqueous ink containing a coloring material and a compound containing a chain hydrocarbon having a carbon number of 8 or more to 18 or less substituted by a hydroxy group or an anionic group.

Abstract: A liquid discharge apparatus has a liquid discharge head having a recording element board that includes a plurality of discharge orifices configured to discharge liquid, a plurality of pressure chambers internally provided with a recording element configured to generate energy used to discharge liquid, the plurality of pressure chambers each communicating with the plurality of discharge orifices via discharge channels, a liquid supply channel configured to supply liquid to the plurality of pressure chambers, and a liquid recovery channel configured to recover liquid from the plurality of pressure chambers, and a tank configured to store liquid supplied to the liquid discharge head. The plurality of pressure chambers communicate between the liquid supply channel and the liquid recovery channel so that liquid flows through the plurality of pressure chambers, and the specific permittivity ?r of the liquid stored in the tank satisfies the relationship of ?r?65.

Abstract: The invention provides an aqueous ink containing a self-dispersible pigment having a carboxylic acid group bonded directly or through another atomic group to a particle surface of a pigment and a lactone group bonded to the particle surface of the pigment, wherein, as determined by a selective neutralization method, an introduced amount of the carboxylic acid group is 0.60 mmol/g or more and a ratio of an introduced amount (mmol/g) of the lactone group to the introduced amount (mmol/g) of the carboxylic acid group is 0.20 time or less.

Abstract: The present invention preferably provides an ink including an organic pigment, a water-soluble resin and a surfactant that allows images having high color developability to be obtained independently of the type of recording medium, even when a small amount of ink is applied. Preferably, the organic pigment is a phosphonic acid-type self-dispersible pigment, the acid value of the water-soluble resin is 100 mg KOH/g to 160 mg KOH/g, the surfactant is an ethylene oxide adduct of a higher alcohol selected from the group consisting of a linear primary alcohol, a linear secondary alcohol and an isoalkyl alcohol, the HLB value of the surfactant as determined by the Griffin method is 13.0 or more, and the mass ratio of the content (% by mass) of the surfactant in the ink to the content (% by mass) of the water-soluble resin in the ink is 0.07 to 0.70.

Abstract: The invention provides an aqueous ink containing a self-dispersible pigment having a carboxylic acid group bonded directly or through another atomic group to a particle surface of a pigment and a lactone group bonded to the particle surface of the pigment, wherein, as determined by a selective neutralization method, an introduced amount of the carboxylic acid group is 0.60 mmol/g or more and a ratio of an introduced amount (mmol/g) of the lactone group to the introduced amount (mmol/g) of the carboxylic acid group is 0.20 time or less.

Abstract: A water-based ink of the present invention includes water, a plurality of different water-soluble organic solvents, and a water-insoluble coloring material, wherein the above water-soluble organic solvents consist of a good solvent to the above water-insoluble coloring material and a poor solvent to the above water-insoluble coloring material, and the total amount (% by mass) of the good solvents in the ink is represented by A and the total amount (% by mass) of the poor solvent in the ink is represented by B, the ratio of A to B ranges from 10:5 to 10:30 both inclusive, and when the respective Ka values of the above water-soluble organic solvents are determined by the Bristow method and compared with each other, a water-soluble organic solvent having the largest Ka value is the poor solvent. The pigment ink has a sufficiently large area factor even with a small amount of ink and provides an image of high OD.

Abstract: A water-based ink of the present invention comprises water, a plurality of different water-soluble organic solvents, and a water-insoluble coloring material, wherein the above water-soluble organic solvents consist of a good solvent to the above water-insoluble coloring material and a poor solvent to the above water-insoluble coloring material, and the total amount (% by mass) of the good solvents in the ink is represented by A and the total amount (% by mass) of the poor solvent in the ink is represented by B, the ratio of A to B ranges from 10:5 to 10:30 both inclusive, and when the respective Ka values of the above water-soluble organic solvents are determined by the Bristow method and compared with each other, a water-soluble organic solvent having the largest Ka value is the poor solvent. The pigment ink has a sufficiently large area factor even with a small amount of ink and provides an image of high OD.

Abstract: A water-based ink of the present invention includes water, a plurality of different water-soluble organic solvents, and a water-insoluble coloring material, wherein the water-soluble organic solvents consist of a good solvent to the water-insoluble coloring material and a poor solvent to the water-insoluble coloring material, and the total amount (% by mass) of the good solvents in the ink is represented by A and the total amount (% by mass) of the poor solvent in the ink is represented by B, the ratio of A to B ranges from 10:5 to 10:30 both inclusive, and when the respective Ka values of the above water-soluble organic solvents are determined by the Bristow method and compared with each other, a water-soluble organic solvent having the largest Ka value is the poor solvent. The pigment ink has a sufficiently large area factor even with a small amount of ink.