Preparation of conductive toners using fluidized bed processing equipment

Abstract

A method for making conductive toner particles includes (A) heat treating in fluidized bed processing equipment a mixture of non-conductive toner particles containing a thermoplastic resin and a colorant, and an effective amount of conductive powder blended with and coated on surfaces of the non-conductive toner particles, wherein the heat treatment is carried out at a temperature at or above the glass transition temperature of the resin for a period of time at least sufficient to fuse the conductive powder onto the surfaces of the non-conductive toner particles, and then (B) cooling the heated conductive toner particles to a temperature below the glass transition temperature of the resin. The final toner particles have a conductivity of at least about 10.sup.-8 ohm.sup.-1 -cm.sup.-1 and preferably from about 10.sup.-4 to about 10.sup.-8 ohm.sup.-1 -cm.sup.-1.

Dependencies are inferred from the claim text.