Color toner and two-component developer containing same

Claim 1

A black developer for developing electrostatic latent images, comprising: (1d) a black toner composition containing a black toner which in turn contains at least a binder resin and two or more colorants, and hydrophobic silica fine powder and (2d) a ferrite carrier coated with a mixture of a fluorine-containing resin and a styrene type resin in a weight ratio of 90:10 to 20:80, wherein the binder resin comprises a styrene-arcylic acid ester type resin or a polyester ester, the ferrite carrier has an average particle size of 30-60 microns, and the ferrite carrier is coated with 0.01 to 5 wt. % based on the carrier of the mixture of the fluorine-containing resin and the styrene type resin; the black toner having a volume particle size of 11.0 to 14.0 microns, containing 30% by number or less of particles having sizes below 6.35 microns and containing 9% by weight or less of particles having sizes above 20.2 microns; the black toner composition having an agglomeration degree of 25% or below and an apparent density of 0.2 to 1.5 g/cm 3 ; the black toner having an apparent viscosity of 100° C. of 10 4 to 5×10 5 poise, an apparent viscosity of 90° C. of 5×10 4 to 5×10 6 poise, a DSC heat-absorption peak at 58° to 72° C., and a gloss of 5.0% or higher; the black toner having chromatically values of a*=-3.5 to 6.5, b*=-6.0 to 4.0, and L*=26.0 to 36.0; the black toner showing a triboelectric charge of -5 to -20 micro-C/g with respect to the ferrite carrier coated with the mixture of the fluorine-containing resin and the styrene type resin containing 70 wt. % or more of carrier particles having sizes of 250 mesh-pass and 350 mesh-on and the black toner having a spectral reflectance of 60% or more in an infrared region of 900 to 1,000 nm.