A first ink composition includes: water; a water-soluble organic solvent; and a color developing agent. The color developing agent includes a pH indicator. The water-soluble organic solvent includes at least one water-soluble organic solvent having a SP value of 16 or less and 11 or more. An amount of the water-soluble organic solvent having a SP value of 16 or less and 11 or more in the first ink composition is 15 wt % or more. A second ink composition includes: water; a water-soluble organic solvent; and a color developing agent. The color developing agent includes a pH indicator. The water-soluble organic solvent includes at least one water-soluble organic solvent having a SP value of 16 or less. An amount of the water-soluble organic solvent having a SP value of 16 or less in the second ink composition is 15 wt % or more. The second ink composition is a water-based ink for ink-jet recording.

A first ink composition includes: water; a water-soluble organic solvent; and a color developing agent. The color developing agent includes a pH indicator. The water-soluble organic solvent includes at least one water-soluble organic solvent having a SP value of 16 or less and 11 or more. An amount of the water-soluble organic solvent having a SP value of 16 or less and 11 or more in the first ink composition is 15 wt % or more. A second ink composition includes: water; a water-soluble organic solvent; and a color developing agent. The color developing agent includes a pH indicator. The water-soluble organic solvent includes at least one water-soluble organic solvent having a SP value of 16 or less. An amount of the water-soluble organic solvent having a SP value of 16 or less in the second ink composition is 15 wt % or more. The second ink composition is a water-based ink for ink-jet recording.

A liquid discharge apparatus includes: an ink composition containing 2-pyrrolidone and an alcohol having a main chain having 6 or less carbon atoms; a liquid discharge unit configured to discharge the ink composition from a nozzle formed in a nozzle surface; and a wiping unit configured to wipe the nozzle surface. The wiping unit includes a wiping member including protrusion-shape fibers. Each of the protrusion-shape fibers has a protruded portion in a cross-section orthogonal to a fiber axis thereof. The protruded portion is continuous in a direction along the fiber axis.

A liquid discharge apparatus includes: an ink composition containing 2-pyrrolidone and an alcohol having a main chain having 6 or less carbon atoms; a liquid discharge unit configured to discharge the ink composition from a nozzle formed in a nozzle surface; and a wiping unit configured to wipe the nozzle surface. The wiping unit includes a wiping member including protrusion-shape fibers. Each of the protrusion-shape fibers has a protruded portion in a cross-section orthogonal to a fiber axis thereof. The protruded portion is continuous in a direction along the fiber axis.

An ink composition contains a semi-drying solvent; a pigment; an alkyd resin; and an amine-based polymeric dispersant. The composition contains 5 wt% or more of the alkyd resin, based on the total weight of the composition, and 5 wt% or more of the amine-based polymeric dispersant, based on the total weight of the composition.

An ink composition contains a semi-drying solvent; a pigment; an alkyd resin; and an amine-based polymeric dispersant. The composition contains 5 wt% or more of the alkyd resin, based on the total weight of the composition, and 5 wt% or more of the amine-based polymeric dispersant, based on the total weight of the composition.

An ink composition including water, a pigment, a pigment dispersion polymer A, and a water-soluble polymer B different from the pigment dispersion polymer A, in which the water-soluble polymer B contains a specific acid group and a constitutional unit represented by Formula (1), an ink set, and an image recording method. R.sup.1, R.sup.11, Y.sup.1, and Y.sup.2 each independently represent a hydrogen atom or a monovalent substituent, and L.sup.1 and L.sup.2 each independently represent a divalent linking group or a single bond. Y.sup.1 and Y.sup.2 may be bonded to each other to form a nitrogen-containing heterocycle with L.sup.1, L.sup.2, and N.

##STR00001##

An ink composition including water, a pigment, a pigment dispersion polymer A, and a water-soluble polymer B different from the pigment dispersion polymer A, in which the water-soluble polymer B contains a specific acid group and a constitutional unit represented by Formula (1), an ink set, and an image recording method. R.sup.1, R.sup.11, Y.sup.1, and Y.sup.2 each independently represent a hydrogen atom or a monovalent substituent, and L.sup.1 and L.sup.2 each independently represent a divalent linking group or a single bond. Y.sup.1 and Y.sup.2 may be bonded to each other to form a nitrogen-containing heterocycle with L.sup.1, L.sup.2, and N.

##STR00001##

A compound represented by formula (1) or a salt thereof, and an ink including the same. In formula (1), each Q independently represents a halogen atom; R.sup.11 and R.sup.12 independently represent an alkyl group substituted by an ionic hydrophilic group; and A.sup.1 represents a C1-C3 alkoxy-substituted alkylamino group ##STR00001##

A compound represented by formula (1) or a salt thereof, and an ink including the same. In formula (1), each Q independently represents a halogen atom; R.sup.11 and R.sup.12 independently represent an alkyl group substituted by an ionic hydrophilic group; and A.sup.1 represents a C1-C3 alkoxy-substituted alkylamino group ##STR00001##