Electrographic toner containing resin-compatible quaternary ammonium compound

A method of imaging comprising forming an electrostatic latent image, contacting the image with a developer composition comprised of a carrier a toner resin, and a pigment which is coated with from about 0.1 to about 10 percent of a quaternary ammonium compound thereby causing the toner to become positively charged, said quaternary ammonium compound being of the formula:

• ##STR4## in which at least two R radicals are hydrocarbon radicals having from about 8 to about 22 carbon atoms and each other R is selected from hydrogen and hydrocarbon radicals having from 1 to about 8 carbon atoms, and A is an anion selected from sulphate, sulphonate, nitrate, borate, chlorate, chloride, iodide, and bromide, subsequently transferring the developed image to a paper substrate, and permanently forming the image thereon.

A method for imparting a substantially high positive charge to a toner resin which is used in a developer composition comprised of a carrier, a pigment and said toner resin, which comprises adding these materials together with the pigment which is coated with from about 0.1 to about 10 percent of a quaternary ammonium compound of the formula:

• ##STR5## in which at least two R radicals are hydrocarbon radicals having from about 8 to about 22 carbon atoms and each other R is selected from hydrogen and hydrocarbon radicals having from 1 to about 8 carbon atoms, and A is an anion selected from sulphate, sulphonate, nitrate, borate, chlorate, chloride, iodide, and bromide.

A developer composition comprised of about 3 parts by weight of toner comprising about 10 percent of carbon black containing a coating of distearyl dimethyl ammonium chloride in an amount of from 0.5 percent to 1 percent and a copolymer of styrene/n-butylmethacrylate resin, in an amount of from 85 percent to 90 percent, and 100 parts per weight of a steel carrier coated with vinylidene fluoride.

A developer composition comprised of about 3 parts by weight of toner comprising about 10 percent of carbon black containing a coating of dimethyl di(hydrogenated tallow) ammonium chloride in an amount of from 1 percent to 2 percent, and a copolymer of styrene/isobutylmethacrylate resin, in an amount of from 85 percent to 90 percent, and 100 parts per weight of a steel carrier coated with vinylidene fluoride.