Patent ID: 8168780

Claim:
A method for producing a polymorphic form of a titanylphthalocyanine having a peak at a Bragg angle (2θ±0.2°) in X-ray diffraction spectrum with CuK α-ray: 9.0°, 9.6°, 14.1°, 14.9°, 17.9°, 18.3°, 23.4°, 24.5° and 27.2°, which includes steps of: (I) subjecting a titanylphthalocyanine having an α-type polymorph to an acid pasting treatment to give a titanylphthalocyanine in a form of a water-containing cake; (II) stirring a dispersing aid and the resulting titanylphthalocyanine in a mixed solvent of water and an organic solvent at room temperature to prepare a polymorph, wherein the stirring conditions are set to give a required stirring power of no less than 3.0 [kg-m/sec]; and (III) filtering, washing, and drying under a reduced pressure.