Patent ID: 8783843

Claim:
A set of an ink and a reaction liquid for ink jet, the set having a combination of an ink comprising a pigment dispersed by a water-soluble resin, and a reaction liquid containing no coloring material but comprising a polyvalent metal ion and a surfactant, wherein a surface tension of the ink is 38 mN/m or less, a content (μmol/g) of the polyvalent metal ion in the reaction liquid is 10.0 times or more in terms of molar ratio as much as an amount (μmol/g) of an acidic group derived from the water-soluble resin in the ink, the surfactant in the reaction liquid comprises an ethylene oxide adduct of a higher alcohol selected from the group consisting of a linear primary alcohol, a linear secondary alcohol and an isoalkyl alcohol, and has a HLB value of 13.0 or more as determined by the Griffin method, and a content (% by mass) of the surfactant in the reaction liquid is 0.15 times or more in terms of mass ratio as much as the total content (% by mass) of the pigment and the water-soluble resin in the ink.