US Patent 7579128 Toner compositions including styrene containing external additives

Toner compositions of toner particles including additive particles upon an external surface of the toner particles, wherein the additive particles include crosslinked styrene containing polymer particles, exhibit reduced sensitivity to relative humidity. The crosslinked styrene containing polymer particles have an average particle size of from about 30 nm to about 300 nm, and may include styrene homopolymer particles, styrene copolymer particles or mixtures thereof. A process of reducing the relative humidity sensitivity of toner using such external surface additive is also described.