Abstract: This invention provides an electrophotographic carrier comprising hard ferrite particles, said particles having a coating comprising a silicone resin and a colloidal silica.

Abstract: A method of modifying the triboelectric charging propensity electrostatographic developer carrier particles, comprising the steps of:(A) providing a carrier particles that is uncoated or polymer coated;(B) mixing the carrier particles with either (i) an aqueous basic solution or (ii) an aqueous solution containing from 0.1 to 5.0 weight percent of a soluble acidic metal salt, based on the weight of the carrier particles to form a mixture; and(C) contacting the mixture with the solution, (i) or (ii), not used in step (B) thereby causing a precipitate of an insoluble salt to deposit on the carrier particles wherein the insoluble salt is(a) strontium carbonate;(b) insoluble metal hydroxides;(c) insoluble metal hydrated oxides; or(d) a mixture of two or more of (a), (b) and (c);provided that when a soluble strontium metal acid salt is used in step (B) (ii) and the carrier coating is other than a polyfluorocarbon, a reagent that provides a source of carbonate ions is also used in step (B).

Abstract: Carrier particles for use in negative electrostatographic developers wherein said particles bear, based on the weight of the carrier particles, from 0.1 to 2 weight percent of deposits selected from the group consisting of (a) strontium carbonate, (b) insoluble metal hydroxides, (c) an insoluble metal hydrated oxide, and (d) mixtures thereof; provided that when the said carrier particles bear a polymeric flurocarbon coating the deposit is other than strontium carbonate.

Abstract: This invention relates to supersensitizing dye combinations useful for organic photoconductive compositions comprising: at least one cyanine, merocyanine, rhodacyanine or styryl spectral sensitizing dye which1. has an anodic polarographic half-wave potential less than +1.0 volts;2. has an anodic polarographic half-wave potential and a cathodic polarographic half-wave potential which, when added together, give a sum more negative than -0.10 volts; and3. desensitizes negative silver bromide emulsions, containing 99.35 mole percent bromide, less than 0.4 log E at radiation of 365 nm. when incorporated therein at a concentration of 0.2 millimole of dye per mole of silver halide; and at least one electron-accepting dye such as a pyrylium or thiapyrylium salt as the supersensitizer.