Patent ID: 7876345
Filing Date: 2011-01-25
Classification: B41M,C09D

Abstract:
1. An ink set comprising: a first liquid which contains a coloring material, a polymer, and a dispersion medium composed of water and water-soluble solvent, the coloring material and the polymer being dispersed in the dispersion medium, the coloring material having properties such that when dispersed in an aqueous coloring material solution, a volume-average particle size of the coloring material is changed along with a pH change of the aqueous coloring material solution, the polymer having properties such that when dispersed in an aqueous polymer solution, a volume-average particle size of the polymer is changed along with a pH change of the aqueous polymer solution; and a second liquid which changes pH of the first liquid, wherein a condition of |α−β1|≧|α−β2| is satisfied, where α is pH of the first liquid before the first liquid is subjected to a pH change caused by the second liquid, β1 is pH of the aqueous coloring material solution at which the volume-average particle size of the coloring material reaches 1000 nm along with the pH change of the aqueous coloring material solution, and β2 is pH of the aqueous polymer solution at which the volume-average particle size of the polymer reaches 1000 nm along with the pH change of the aqueous polymer solution.