Set of ink and reaction liquid, and image forming method

摘要

A set of an ink containing a pigment dispersed by a water-soluble resin and having the surface tension of 38 mN/m or less and a reaction liquid containing a polyvalent metal ion and a surfactant, which is an ethylene oxide adduct of a higher alcohol of a linear primary or secondary alcohol or an isoalkyl alcohol, and has a HLB value of 13.0 or more as determined by the Griffin method. The content 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 of an acidic group derived from the water-soluble resin in the ink and the content of the surfactant in the reaction liquid is 0.15 times or more in terms of mass ratio as much as the total content of the pigment and water-soluble resin in the ink.

主权项

1. 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.