Reaction solution, set of reaction solution and ink, ink jet recording apparatus and image recording method

A set of an ink and a reaction solution comprising the ink containing a coloring material in a dissolved or dispersed state, and the reaction solution capable of destabilizing the dissolved or dispersed state of the coloring material in the ink in contact with the ink,

• wherein the reaction solution contains a polyvalent metal ion and an organic solvent, has a pH of 2 or higher, and has a buffering action for variations in pH, wherein the buffering action means it can maintain pH variation within the range of 0.5 before and after the addition of 1.0 ml of a 0.1 N aqueous lithium hydroxide solution to 50 ml of the reaction solution.

An inkjet recording apparatus comprising a recording head for discharging an ink containing a coloring material in a dissolved or dispersed state, an ink cartridge having an ink storage unit containing the ink, ink supply means for supplying the ink from the ink cartridge to the recording head, and means for supplying a reaction solution capable of destabilizing the dissolved or dispersed state of the coloring material in the ink in contact with the ink,

• wherein the reaction solution contains a polyvalent metal ion and an organic solvent, has a pH of 2 or higher, and has a buffering action for variations in pH, wherein the buffering action means it can maintain pH variation within the range of 0.5 before and after the addition of 1.0 ml of a 0.1 N aqueous lithium hydroxide solution to 50 ml of the reaction solution.

An image recording method comprising a step of coating a recording medium with a reaction solution capable of destabilizing the dissolved or dispersed state of a coloring material in an ink in contact with the ink containing the coloring material in a dissolved or dispersed state, and a step of coating the ink on the recording medium by the ink-jet method,

• wherein the reaction solution contains a polyvalent metal ion and an organic solvent, has a pH of 2 or higher, and has a buffering action for variations in pH, wherein the buffering action means it can maintain pH variation within the range of 0.5 before and after the addition of 1.0 ml of a 0.1 N aqueous lithium hydroxide solution to 50 ml of the reaction solution.