Patent ID: 8393726

Claim:
A set of a reaction liquid that has a buffering action against pH change and exhibits a pH of 3.5 or more and 5.5 or less, and an ink that has a higher pH than the reaction liquid, wherein the ink comprises a pigment, wherein a basic group that forms a cation form at the pH of the reaction liquid is bonded to the surface of the pigment, wherein an amount of basic groups bonded to the surface of the pigment based on 1 g of pigment is 0.01 mmol/g or more and 0.1 mmol/g or less, wherein the pigment does not have an acidic group having a pKa equal to or less than the pH of the reaction liquid, and wherein the pigment is dispersed by a water-soluble polymer that has an acidic group having a pKa equal to or more than the pH of the reaction liquid and equal to or less than the pH of the ink.