US 7,011,919 : Self-dispersing titanyl phthalocyanine pigment compositions and electrophotographic charge generation layers containing same

Inventors:

Molaire, Michel F. (Rochester, NY, US)
Sorriero, Louis J. (Rochester, NY, US) 

Assignee:

Eastman Kodak Company (Rochester, NY, US) 

In a process for forming a self-dispersing crystalline phthalocyanine pigment composition of monodisperse nanoparticles, a mixture containing titanyl fluorophthalocyanines, unsubstituted titanyl phthalocyanine, and an organic monomeric dispersant but substantially free of organic solvents or inorganic salts is dry milled, thereby forming a substantially amorphous phthalocyanine pigment composition. The substantially amorphous composition is contacted with an organic solvent having a hydrogen bonding parameter gammac lower than about 8, thereby forming a self-dispersing cocrystalline phthalocyanine pigment composition of monodisperse nanoparticles containing titanyl fluorophthalocyanines and titanyl phthalocyanine, which can be used to form the charge generation layer of an electrophotographic element.
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