Patent ID: 7485400

Claim:
A developer comprising a carrier and a toner, wherein the toner comprises toner particles of at least one binder, at least one colorant, and external additives including a first silica, a second silica, a titania, an optional cerium oxide, and an optional zinc stearate, wherein the developer has a trimmer clogging value in relation to toner triboelectric charge and toner cohesion expressed according to the equation (−0.80+0.039×(% toner cohesion)+0.026×(toner triboelectric charge) (μC/g)) of less than or equal to about 3.2, wherein the first silica is about 0.5% to about 2.5% by weight of the toner particles, the second silica, differing at least in an average diameter from the first silica, is about 0.5% to about 2% by weight of the toner particles, the titania is about 0.5% to about 2% by weight of the toner particles, the optional cerium oxide, when present, is about 0.2% to about 1% by weight of the toner particles, and the optional zinc stearate, when present, is about 0.1% to about 1% by weight of the toner particles, and wherein a surface area coverage of the toner particles by the external additives is from about 20% to about 60%.