TONER PARTICLE AND ELECTROPHOTOGRAPHIC NEGATIVE CHARGE CYAN TONER CONTAINING THAT TONER PARTICLE

摘要

PROBLEM TO BE SOLVED: To obtain a cyan toner for color electrophotography having excellent electrification characteristics and moisture resistance which can form a sharp image by incorporating a copper phthalocyanine pigment having a specified content of free copper and at least a binder resin. SOLUTION: The toner particles used contain a copper phthalocyanine pigment having =2000 ppm content of free copper and at least a binder resin. Namely, since free copper remaining as an impurity in the copper phthalocyanine pigment is positively charged, by decreasing the free copper above described present in the pigment, the pigment, the toner particles containing that pigment, and the toner can be electrified into negative charges in a good state. If the content of free copper in the copper phthalocyanine pigment is larger than 2000 ppm, the electrification property of the toner decreases in a high humidity environment, which causes image defects such as fog. In this method, as to the binder resin to be used, various kinds of resin materials such as well-known styrene-acryl and polyester resin can be used.