Abstract: Modified silicas, having the following physicochemical parameters: a CTABmod of <200 m2/g, a BETMP of 50-500 m2/g, a CTABmod-BETMP of <0 m2/g, a carbon content of >0.5% by weight, a modemod from CPS particle size determination of >50 nm, a d75mod from CPS particle size determination of 20-150 nm, a Rmin from Hg pore size determination, pressurized of <10 nm, and a sulfur content of ?1.50% by weight.

Abstract: The invention relates to a hydrophobic silica powder which is unprecedentedly insensitive to environmental humidity with which electrophotographic toner can possess stable electro static charge that leads to stable quality of printed image. The hydrophobic silica powder has the following physicochemical properties; average primary particle size (D) is 30-2000 nm, B*D<430 nm, while B stands for weight % of adsorbed water vapor on silica (100 weight %) when the partial pressure of water to the equilibrium vapor pressure of water at 25° C. is 80% and D stands for average primary particle size (nm) of the silica powder, B/C<2.7, while C stands for weight % of adsorbed water vapor on silica (100 weight %) when the partial pressure of water to the equilibrium vapor pressure of water at 25° C. is 20%, and carbon content>0.30 wt.-%.

Abstract: The invention relates to a hydrophobic silica powder which is unprecedentedly insensitive to environmental humidity with which electrophotographic toner can possess stable electro static charge that leads to stable quality of printed image. The hydrophobic silica powder has the following physicochemical properties; average primary particle size (D) is 30-2000 nm, B*D<430 nm, whilst B stands for weight % of adsorbed water vapor on silica (100 weight %) when the partial pressure of water to the equilibrium vapor pressure of water at 25° C. is 80% and D stands for average primary particle size (nm) of the silica powder, B/C<2.7, whilst C stands for weight % of adsorbed water vapor on silica (100 weight %) when the partial pressure of water to the equilibrium vapor pressure of water at 25° C. is 20%, and carbon content >0.30 wt.-%.