Aqueous ink, ink jet recording method, ink cartridge, recording unit and ink jet recording apparatus

摘要

The invention provides an aqueous ink comprising a polymer having hydroxyl groups and a pigment, which can provide images excellent in scratch resistance and highlighter resistance and can inhibit the seeping out phenomenon of the polymer and the deterioration of ejection characteristics even when it is stored for a long period of time. The aqueous ink comprises a polymer having hydroxyl groups, a pigment and a water-soluble organic solvent, wherein the water-soluble organic solvent comprises a polyhydric alcohol having a value of number of hydroxyl groups/number of carbon atoms in its molecule of 0.50 or less.

主权项

1. An aqueous ink comprising:
a polyvinyl alcohol type polymer; a pigment; and a plurality of water-soluble organic solvents, wherein the polyvinyl alcohol type polymer is a copolymer composed of a segment having hydroxyl groups and a segment having no hydroxyl group, wherein at least one of the plurality of water-soluble organic solvents comprises a polyhydric alcohol having a value of (number of hydroxyl groups/number of carbon atoms) in its molecule of 0.40 or less, wherein at least one of the plurality of water soluble organic solvents is a good medium and at least one of the plurality of water soluble organic solvents is a poor medium for the polyvinyl alcohol type polymer that is not adsorbed on the pigment out of the polyvinyl alcohol type polymer, and wherein a content (mass %) of the poor medium based on the total mass of the aqueous ink is more than a content (mass %) of the good medium based on the total mass of the aqueous ink.