Patent ID: 8053570

Claim:
A method for producing an α-form titanylphthalocyanine represented by the formula (I): which has a peak at a Bragg angle (2θ±0.2°) in X-ray diffraction spectrum with CuK α-ray: 7.5°, 10.2°, 12.6°, 13.2°, 15.1°, 16.3°, 17.3°, 18.3°, 22.5°, 24.2°, 25.3° and 28.6°, wherein the method includes steps of: (I) subjecting a crude titanylphthalocyanine having an α-form polymorph to an acid pasting treatment, and then filtering and washing with water to give a water-containing wet cake, and then subjecting the wet cake to drying and crushing to give a low crystalline titanylphthalocyanine; (II) adding a dispersing aid to the low crystalline titanylphthalocyanine and dispersing at room temperature, in DMF, to prepare a polymorph; and (III) filtering, washing, and drying under a reduced pressure.