Method for producing organic pigment microparticles

A method of producing organic pigment microparticles, comprising the following steps:

• Step 1 of precipitating organic pigment microparticles by mixing an organic pigment raw material liquid in which an organic pigment raw material is mixed with a solvent, and a precipitation solvent for precipitating microparticles of the organic pigment from the organic pigment raw material liquid in a thin film fluid formed by introducing the organic pigment raw material liquid and the precipitation solvent in a space between at least two processing surfaces which are disposed so as to face each other, being capable of approaching to and separating from each other, at least one of which rotates relatively to the other;
• and
• Step 2 of coating at least a part of each of the organic pigment microparticles individually with an oxide coating, in order to suppress particle growth and/or aggregation of the precipitated organic pigment microparticles;
• wherein the oxide coating is optically colorless and transparent, and
• after Step 1, Step 2 is completed at a predetermined time until the organic pigment microparticles grow and/or aggregate, and thereby particle growth and/or aggregation of the precipitated organic pigment microparticles are suppressed.

A method of producing organic pigment microparticles, comprising the following steps:

• Step 1 of precipitating organic pigment microparticles by mixing an organic pigment raw material liquid in which an organic pigment raw material is mixed with a solvent, and a precipitation solvent for precipitating microparticles of the organic pigment from the organic pigment raw material liquid in a thin film fluid formed by introducing the organic pigment raw material liquid and the precipitation solvent in a space between at least two processing surfaces which are disposed so as to face each other, being capable of approaching to and separating from each other, at least one of which rotates relatively to the other;
• and
• Step 2 of coating at least a part of each of the organic pigment microparticles individually with an inorganic oxide coating, in order to suppress particle growth and/or aggregation of the precipitated organic pigment microparticles;
• wherein Step 1 and Step 2 are performed out continuously in the thin film fluid, and
• after Step 1, Step 2 is completed at a predetermined time until the organic pigment microparticles grow and/or aggregate, and thereby particle growth and/or aggregation of the precipitated organic pigment microparticles are suppressed.