CO-PRECIPITATION OF HYDROXYGALLIUM AND TITANYL PHTHALOCYANINE POLYMORPHS
Original Publication Date: 1996-Aug-31
Included in the Prior Art Database: 2004-Apr-07
Xerox Disclosure Journal
Disclosed is a co-precipitation of hydroxygallium and titanyl phthalocyanine polymorphs. It is known that the Type I1 crystal form of titanyl phthalocyanine, which is of moderate photosensitivity, and the Type V crystal modification of hydroxygallium phthalocyanine, which is highly photosensitive, are isomorphous, having identical crystal lattice parameters. When mixtures of the two respective precursor pigments were dissolved in sulfuric acid and precipitated in aqueous ammonia and the resultant material milled in dimethylformamide solvent (the process used to prepare Type V HOGaPc) the product, regardless of the composition, had an X-ray diffraction pattern identical to that of the pure Type V (HOGaPc) or Type I1 (TiOPc) pigments. The products are homogeneous mixtures having the two pigment molecules in the same crystal lattice rather than a mixture of the individual crystals of each pigment and as photoreceptor generator material, have a tunable range of photosensitivities spanning about S=170 to 300 V cm2/erg. The material remains stable during subsequent milling processing and act as a single photogenerator pigment.