an electrostatographic developer mixture comprising finely - divided positively charging toner particles electrostatically clinging to negatively charging carrier particles . the toner particles comprise a resin , a colorant , and a charge inducing material selected from a long chain hydrazinium compound and an alkyl pyridinium compound . the carrier particles comprise core particles having a coating of fused thermoplastic resin particles wherein the carrier particles are prepared by dry - mixing the core particles with thermoplastic resin particles until the resin particles adhere to the core particles . the mixture of core and resin particles are heated to between 320 ° f . and 650 ° f . for between 20 and 120 minutes so that the resin particles melt and fuse to the core particles . the developer mixture is employed to develop electrostatic latent images .