MANUFACTURING METHOD FOR FINE ORGANIC PIGMENT

The present invention relates to [1] a process for producing a fine organic pigment, including step 1 of kneading a mixture prepared by compounding a raw material organic pigment, a water-soluble inorganic salt and a water-soluble organic solvent; and step 2 of subjecting the kneaded mixture obtained in the step 1 to cleaning treatment with an aqueous solvent and then to filtration treatment, in which before or after kneading the mixture in the step 1 and before subjecting the kneaded mixture to filtration treatment in the step 2, a sulfonic acid salt dispersant is compounded in an amount of not less than 0.8 part by mass and not more than 8.0 parts by mass on the basis of 100 parts by mass of the raw material organic pigment; [2] a process for producing a dispersion, including step 3 of subjecting a pigment mixture containing the fine organic pigment obtained by the production process according to the above [1], an organic solvent and water to dispersion treatment; and [3] a process for producing an ink, including step 4 of mixing the dispersion obtained by the production process according to the above [2] with at least one medium selected from the group consisting of water and an organic solvent.