PURPOSE: To provide an improved process for producing α-form oxytitanium phthalocyanine to be used for producing an electrophotographic photoreceptor having excellent suitability for electrophotography.
CONSTITUTION: Oxytitanium phthalocyanine is added to an acid or an acid- containing organic solvent to give a solution or slurry. In the case of an acid only, the phthalocyanine is crystallized from a water-soluble organic solvent or a mixed solvent consisting of water and an organic solvent. In the case of an acid-containing organic solvent, the phthalocyanine is crystallized from water, a water-soluble organic solvent, or a mixed solvent consisting of water and an organic solvent. Thus, crystals are formed whose X-ray diffraction spectrum has a maximum peak at a Bragg angle (2θ±0.2°) of 27.3°. The crystals are then stirred or milled in an organic solvent, thereby yielding oxytitanium phthalocyanine crystals whose X-ray diffraction spectrum has peaks at Brag angles (2θ±0.2°) of 7.6°, 10.2°, 12.6°, 13.2°, 15.1°, 16.3°, 17.3°, 18.3°, 22.5°, 24.2°, 25.3°, and 28.6°.
IIJIMA MASAKAZU
DAIMON KATSUMI
SAKAGUCHI YASUO
