US Patent 7723001 Electrophotographic toner

An electrophotographic toner includes toner parent particles containing a binder resin, a colorant and a charge control agent; and an external additive added to the surface of the toner parent particles. The toner further includes positively chargeable silica and polymer beads in addition to large particle diameter silica, small particle diameter silica and titanium oxides. Thus, the toner can maintain its charge quantity and distribution stably even during environmental changes and after long image printing times, thereby preventing the contamination of the non-image part and the filming.