Abstract: A printing ink jet ink composition of the present disclosure is an ink composition which includes an acidic dye; a water-soluble organic solvent; a lactam compound; and water, the acidic dye includes at least one selected from the group consisting of C.I. Acid Black 172 and C.I. Acid Black 52:1, a content of the acidic dye with respect to a total mass of the ink composition is 10 percent by mass or more, the water-soluble organic solvent includes a glycol ether compound having a standard boiling point of 195° C. to 290° C., the lactam compound includes at least one selected from the group consisting of 1-(2-hydroxyethyl)-2-pyrrolidone and ?-caprolactam, and a mass ratio of the lactam compound to the glycol ether compound is 3.5 to 20.

Abstract: An ink jet textile-printing ink composition according to the present disclosure contains an acidic dye having water solubility of 30 g/L or less at 20° C., a water-soluble organic solvent, and water, wherein a glycol-based solvent and a cyclic-amide-based solvent are contained as the water-soluble organic solvent, and the cyclic-amide-based solvent contains one or both of ?-caprolactam and N-hydroxyethyl-2-pyrrolidone.

Abstract: An ink set includes a first ink containing the compound represented by formula (y-1) or its salt, a second ink containing one or two or more of the compound represented by formula (m-1) or its salt, the compound represented by formula (m-2) or its salt, a compound represented by formula (m-3) or its salt, and the compound represented by formula (m-4) or its salt, and a third ink containing one or two or more of a compound represented by formula (c-1) or its salt, the compound represented by formula (c-2) or its salt, the compound represented by formula (c-3) or its salt, a compound represented by formula (c-4) or its salt, and the compound represented by formula (c-5) or its salt.

Abstract: An ink set includes a pigment ink, containing a pigment, and a dye ink containing the compound represented by formula (y-1) below or a salt thereof.

Abstract: An ink jet recording apparatus includes an ink composition, an ink encasement in which the ink composition is encased, a recording head that ejects the ink composition, and a carriage configured to move the recording head back and forth. The carriage carries the ink encasement, with the ink encasement integrated with the carriage. The ink encasement has an ink fill port that opens and shuts as a port through which the ink composition is loaded. The ink composition contains a disperse colorant, with the volume-average particle diameter of the disperse colorant being 110.0 nm or more and 200.0 nm or less, and also contains at least one organic solvent with an SP of 9 or more, with the percentage thereof being 10.0% by mass or more.

Abstract: An ink jet recording apparatus includes an ink composition, an ink encasement in which the ink composition is encased, a recording head that ejects the ink composition, and a carriage configured to move the recording head back and forth. The carriage carries the ink encasement, with the ink encasement integrated with the carriage. The ink encasement has an ink fill port that opens and shuts as a port through which the ink composition is loaded. The ink composition contains a water-soluble dye and a polyhydric alcohol with a normal boiling point of 270° C. or above, with the percentage of the polyhydric alcohol being 26.0% by mass or less of the total amount of the ink composition.

Abstract: An ink jet recording apparatus includes an ink composition, an ink encasement in which the ink composition is encased, a recording head that ejects the ink composition, and a carriage configured to move the recording head back and forth. The carriage carries the ink encasement, with the ink encasement integrated with the carriage. The ink encasement has an ink fill port that opens and shuts as a port through which the ink composition is loaded. The ink composition contains a disperse colorant, with the volume-average particle diameter of the disperse colorant being 105.0 nm or less.

Abstract: An ink jet recording apparatus includes an ink composition, an ink encasement in which the ink composition is encased, a recording head that ejects the ink composition, and a carriage configured to move the recording head back and forth. The carriage carries the ink encasement, with the ink encasement integrated with the carriage. The ink encasement has an ink fill port that opens and shuts as a port through which the ink composition is loaded and also has a detector that detects the amount of ink composition encased. The ink composition contains a surfactant with an HLB of 6 or less.

Abstract: An ink jet recording apparatus includes an ink composition, an ink encasement in which the ink composition is encased, a recording head that ejects the ink composition, and a carriage configured to move the recording head back and forth. The carriage carries the ink encasement, with the ink encasement integrated with the carriage. The ink encasement has an ink fill port that opens and shuts as a port through which the ink composition is loaded. The ink composition contains a water-soluble dye and a polyhydric alcohol with a normal boiling point of 270° C. or above, with the percentage of the polyhydric alcohol being 26.0% by mass or less of the total amount of the ink composition.

Abstract: An ink jet recording apparatus includes an ink composition, an ink encasement in which the ink composition is encased, a recording head that ejects the ink composition, and a carriage configured to move the recording head back and forth. The carriage carries the ink encasement, with the ink encasement integrated with the carriage. The ink encasement has an ink fill port that opens and shuts as a port through which the ink composition is loaded. The ink composition contains a disperse colorant, with the volume-average particle diameter of the disperse colorant being 110.0 nm or more and 200.0 nm or less, and also contains at least one organic solvent with an SP of 9 or more, with the percentage thereof being 10.0% by mass or more.

Abstract: An ink jet recording apparatus includes an ink composition, an ink encasement in which the ink composition is encased, a recording head that ejects the ink composition, and a carriage configured to move the recording head back and forth. The carriage carries the ink encasement, with the ink encasement integrated with the carriage. The ink encasement has an ink fill port that opens and shuts as a port through which the ink composition is loaded. The ink composition contains a disperse colorant, with the volume-average particle diameter of the disperse colorant being 105.0 nm or less.

Abstract: An ink jet recording apparatus includes at least one aqueous ink composition, at least one ink encasement in which the aqueous ink composition is encased, a recording head that ejects the aqueous ink composition, and a carriage configured to move the ink encasement and the recording head back and forth. The carriage carries the ink encasement, with the ink encasement integrated with the carriage. The ink encasement has an ink fill port that opens and shuts as a port through which the aqueous ink composition is loaded, and the maximum external length of the ink encasement in the direction parallel with the direction in which the carriage moves back and forth is 30.0 mm or less.

Abstract: An ink jet recording apparatus includes an ink composition, an ink encasement in which the ink composition is encased, a recording head that ejects the ink composition, and a carriage configured to move the recording head back and forth. The carriage carries the ink encasement, with the ink encasement integrated with the carriage. The ink encasement has an ink fill port that opens and shuts as a port through which the ink composition is loaded and also has a detector that detects the amount of ink composition encased. The ink composition contains a surfactant with an HLB of 6 or less.

Abstract: An ink set includes a first ink containing the compound represented by formula (y-1) or its salt, a second ink containing one or two or more of the compound represented by formula (m-1) or its salt, the compound represented by formula (m-2) or its salt, a compound represented by formula (m-3) or its salt, and the compound represented by formula (m-4) or its salt, and a third ink containing one or two or more of a compound represented by formula (c-1) or its salt, the compound represented by formula (c-2) or its salt, the compound represented by formula (c-3) or its salt, a compound represented by formula (c-4) or its salt, and the compound represented by formula (c-5) or its salt.

Abstract: An ink set includes a pigment ink, containing a pigment, and a dye ink containing the compound represented by formula (y-1) below or a salt thereof.

Abstract: An ink composition contains dyes A and B. Dye A has a width at a half height of the largest peak in the absorption spectrum between 380 nm and 780 nm that is 50 nm or less. Dye B has a corresponding width at the half height that is 70 nm or more. Dye A is present in an amount of 40% by mass or more and 90% by mass or less of the total mass of the dyes.

Abstract: An ink composition of the invention is an ink composition to be charged in an ink storage container which includes an ink composition-replenishable ink chamber and an ink inlet, and the ink chamber is able to communicate with outside air. The ink composition includes a pigment; an organic compound; and water, and a resolubility index is 0.5 to 10 minutes, the resolubility index indicating a time required for that after the mass of the ink composition is decreased by 50%, the viscosity thereof is returned to an ink viscosity before the mass is decreased by addition of water in an amount equivalent to the decreased mass.

Abstract: An ink composition contains dyes A and B. Dye A has a width at a half height of the largest peak in the absorption spectrum between 380 nm and 780 nm that is 50 nm or less. Dye B has a corresponding width at the half height that is 70 nm or more. Dye A is present in an amount of 40% by mass or more and 90% by mass or less of the total mass of the dyes.

Abstract: An ink composition of the invention is an ink composition to be charged in an ink storage container which includes an ink composition-replenishable ink chamber and an ink inlet, and the ink chamber is able to communicate with outside air. The ink composition includes a pigment; an organic compound; and water, and a resolubility index is 0.5 to 10 minutes, the resolubility index indicating a time required for that after the mass of the ink composition is decreased by 50%, the viscosity thereof is returned to an ink viscosity before the mass is decreased by addition of water in an amount equivalent to the decreased mass.

Abstract: An ink composition is provided which has excellent initial filling characteristics and continuous printing stability even in the case of an ink composition (for example, dissolved nitrogen is equal to or greater than 5 ppm) which is almost not deaerated or an ink composition (for example, dissolved nitrogen is equal to or greater than 7 ppm) which is not deaerated at all. The ink composition includes an alkylene oxide adduct (A) of acetylenic glycol in which a main chain has 12 or more carbon atoms, acetylenic glycol (B) in which a main chain has 10 or more carbon atoms, and polyoxyalkylene alkyl ether (C).