US 7,211,359 : Coating solution containing cocrystals and or crystals of a charge-generation pigment or a mixture of charge-generation pigments



Molaire, Michel Frantz (Rochester, NY, US)
Lobo, Lloyd Anthony (Rochester, NY, US) 


Eastman Kodak Company (Rochester, NY, US) 

A method for preparing a coating solution containing a cocrystallized titanyl phthalocyanine-titanyl fluorophthalocyanine, the method comprising: dry milling a charge-generation pigment or mixtures of charge-generation pigments; increasing the amorphousness of the pigment mixture as determined by X-ray crystallography using X-radiation characteristic of Cu Kα at a wavelength of 1.541 Å of the Bragg angle 2θ to provide an amorphous pigment mixture; contacting the amorphous pigment mixture with a first organic solvent having a gammachydrogen bonding parameter of less than 9, with or without the presence of a dispersant material, to produce a crystalline pigment of the charge-generation pigment prior to contacting the pigment with a second organic solvent having a gammac hydrogen bonding parameter greater than 9; mixing at least one of a second organic solvent, a dispersant and a binder with the crystalline pigment/first solvent mixture without isolating the crystalline pigment to produce a mixture; and, adjusting the concentrations of the first organic solvent, crystalline pigment, binder, dispersants and second organic solvent as required to produce the coating solution of a selected composition.