Abstract: A negatively electrifiable, non-magnetic and single component developer comprising a binder resin, a carbon black and a charge control agent, wherein the carbon black has an average primary particle diameter of 20 to 50 nm and a pH of 2 to 5, and the charge control agent comprises a compound represented by the following formula: ##STR1## wherein M represents a metal atom selected from the group consisting of zinc, iron, nickel and cobalt, and R.sub.1 and R.sub.2 each represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. An image forming process using the developer is also disclosed. This one-component developer, which is suitable for use as a black toner in color image formation, can be stably charged and transported over long to give images free from fogging and having evenness of density and hardly poses problems such as dirts and color mixing over long.

Abstract: A magnetic toner comprising a binder resin having dispersed therein a magnetic powder is disclosed, wherein the magnetic toner has a volume average particle diameter (D.sub.50) of from 4 to 9 .mu.m, the magnetic powder has a number average particle diameter of from 0.15 to 0.25 .mu.m (hereinafter simply referred to as a particle diameter), a BET specific surface area of from 6 to 8 m.sup.2 /g, and a residual magnetization of from 7 to 10 emu/g, the magnetic powder is present in an amount of from 30 to 70% based on the total weight of the magnetic toner, and the magnetic toner has adhered to the surface thereof silica powder having been rendered hydrophobic. The magnetic toner exhibits superior performance in terms of image density, definition, dot and fine line reproducibility, and environmental stability.