Abstract: A magnetic toner comprising a binder resin a magnetic substance is disclosed, the toner containing from 2 to 20% by weight of a polyolefin, preferably polyethylene, having a dispersed particle size of from 0.01 to 0.5 .mu.m. The particle size distribution of the polyolefin preferably has a coefficient of variation of from 20 to 40%. The magnetic toner is fixable with low heat energy, hardly causes offset and smudge, and has a reduced abrasive action on a photoreceptor. It is therefore suitable for use in a fixing means with no cleaning mechanism, a machine with a double side copying function, or an organic photoreceptor.

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.

Abstract: In a process for producing an olefinic resin foam which comprises the steps of forming a composition comprising an olefinic resin, a chemical blowing agent and a crosslinking agent into an unfoamed sheet-like or rod-like shaped article and foaming it by heating, the improvement wherein the heat-forming step is carried out in an oxygen-free atmosphere or in an atmosphere containing not more than 10% of oxygen.