Modified silica particles

A negatively charged toner composition consisting essentially of resin, pigment, optional negative inducing charge additive and a flow aid surface additive comprised of hydrophobic silica of a size diameter of from about 5 to about 40 nanometers, and which silica contains adsorbed on its surface a hydrocarbon layer originating from a long chain aliphatic alcohol, wherein said long chain aliphatic alcohol is selected from the group consisting of C16H33OH and C18H37OH, and wherein there is generated a protective coating on said silica by the attachment and interaction of hydrocarbon chains present on said aliphatic alcohol and wherein the hydroxy group on said alcohol molecules forms hydrogen bonds with the silica surface.

A developer comprised of carrier particles and a negatively charged toner consisting essentially of resin, pigment, negative inducing charge additive and a flow aid surface additive comprised of hydrophobic silica of a size diameter of from about 5 to about 40 nanometers, and which silica contains adsorbed on its surface a hydrocarbon layer originating from a long chain aliphatic alcohol;

• and wherein said long chain aliphatic alcohol is selected from the group consisting of C16H33OH and C18H37OH, and wherein there is generated a protective coating on said silica by the attachment and interaction of hydrocarbon chains present on said aliphatic alcohol and wherein the hydroxy group on said alcohol molecules forms hydrogen bonds with the silica surface.

A toner consisting of resin, pigment and modified silica particles, which particles contain a protective coating thereon formed from the adsorption on said silica of a long chain aliphatic alcohol;

• and wherein said long chain aliphatic alcohol is C16H33OH, and wherein there is formed a hydrophobic protective layer on said silica wherein said OH is anchored on the silica surface by hydrogen bonding while the hydrocarbon components of said alcohol interacts with each other on the silica surface by Van der Waals forces to form or generate said protective coating.

A process for the preparation of improved toner compositions which comprises adding to said compositions modified silica particles, which particles contain a protective coating thereon formed from the adsorption on said silica of a long chain aliphatic alcohol;

• and wherein said long chain aliphatic alcohol is selected from the group consisting of C16H33OH and C18H37OH, wherein a hydrophobic protective layer is formed on said silica, and wherein the OH of said alcohol is anchored on the silica surface by hydrogen bonding, and wherein said hydrocarbon chains of said alcohol interact with each other on the surface of the silica by Van der Waals forces to generate said protective layer.

A negatively charged toner composition consisting essentially of resin, pigment, optional negative inducing charge additive and a flow aid surface additive comprised of hydrophobic silica of a size diameter of from about 5 to about 40 nanometers, and which silica contains adsorbed on its surface a hydrocarbon layer originating from a long chain aliphatic alcohol, wherein said long chain aliphatic alcohol is C18H37OH, and wherein there is generated a protective coating on said silica by the attachment and interaction of the hydrocarbon chains present on said aliphatic alcohol, and wherein the hydroxy group on said aliphatic alcohol molecules forms hydrogen bonds with the silica surface, and wherein the toner tribo at 20 percent relative humidity is a −26.9 microcoulombs per gram, and the toner tribo at 80 percent relative humidity is a −8.4 microcoulombs per gram.