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 7:9 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.

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 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: In an ink set, which is an ink set (A) obtained by combining a plurality of aqueous inks (a) and used together with an aqueous ink (B) containing a water-insoluble coloring material, respective aqueous inks constituting the ink set (A) contain at least one water-soluble organic solvent serving as a poor solvent for the water-insoluble coloring material contained in the aqueous ink (B), and among the water-soluble organic solvents which are respectively contained in the aqueous ink (a) and serve as a poor solvent, at least one water-soluble organic solvent has a vapor pressure at 20° C. that is lower than the vapor pressure of water at 20° C. The ink set can form a full-color image in which occurrence of bleeding at boundaries between different adjacent color regions of the image has been suppressed.

Abstract: The present invention relates to an aqueous ink, particularly an aqueous ink suitable for ink jet recording. The ink is an aqueous ink comprising a modified pigment having organic groups chemically attached to the surface of a particle of the pigment and an aqueous medium which is a dispersant of the pigment, wherein the above-described organic group includes a reaction product of a functional group chemically attached to the surface of the pigment directly or via another atomic group with a copolymer of an ionic monomer and a hydrophobic monomer.

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 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: 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 comprising at least water, a water-soluble organic solvent and a colorant. The colorant comprises a pigment containing a pigment particle having at least one ionic group bonded to a surface of the pigment particle directly or via another atomic group. The organic solvent undergoes completely or substantially no solvation with the pigment and the ionic group of the pigment particle undergoes completely or substantially no ion dissociation in the organic solvent.

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: The present invention relates to an aqueous ink, particularly an aqueous ink suitable for ink jet recording. The ink is an aqueous ink comprising a modified pigment having organic groups chemically attached to the surface of a particle of the pigment and an aqueous medium which is a dispersant of the pigment, wherein the above-described organic group includes a reaction product of a functional group chemically attached to the surface of the pigment directly or via another atomic group with a copolymer of an ionic monomer and a hydrophobic monomer.

Abstract: An ink set, which is an ink set (A) obtained by combining a plurality of aqueous inks (a) and is used together with an aqueous ink (B) containing a water-insoluble coloring material, wherein respective aqueous inks constituting the ink set (A) contain at least one water-soluble organic solvent serving as a poor solvent for the water-insoluble coloring material constituting the aqueous ink (B), and among the water-soluble organic solvents which are respectively contained in the aqueous ink (a) and serve as a poor solvent, at least one water-soluble organic solvent has a vapor pressure at 20° C. lower than the vapor pressure of water at 20° C. It is possible to obtain an image in which occurrence of the bleeding at the boundaries between different color regions has been suppressed in the case where a full-color image in which the respective color-regions are situated adjacently to one another is formed.

Abstract: The present invention relates to an aqueous ink, particularly an aqueous ink suitable for ink jet recording. The ink is an aqueous ink comprising a modified pigment having organic groups chemically attached to the surface of a particle of the pigment and an aqueous medium which is a dispersant of the pigment, wherein the above-described organic group includes a reaction product of a functional group chemically attached to the surface of the pigment directly or via another atomic group with a copolymer of an ionic monomer and a hydrophobic monomer.

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: An aqueous ink comprising at least water, a water-soluble organic solvent and a colorant.

Abstract: The present invention relates to an aqueous ink, particularly an aqueous ink suitable for ink jet recording. The ink is an aqueous ink comprising a modified pigment having organic groups chemically attached to the surface of a particle of the pigment and an aqueous medium which is as a dispersant of the pigment, wherein the above-described organic group includes a reaction product of a functional group chemically attached to the surface of the pigment directly or via another atomic group with a copolymer of an ionic monomer and a hydrophobic monomer.