Magnetic brush developing process and developer

A developing process which comprises

• (i) preparing a two-component developer by mixing toner particles and spherical ferrite carrier particles wherein diameter D.sub.50 of the weight average particle size corresponding to 50% of the weight of entire carrier particles is in the range of from 80 to 100 microns, the difference between the diameter D.sub.25 of the weight average particle size corresponding to 25% of the weight of entire carrier particles and the diameter of D.sub.75 of the weight average particle size corresponding to 75% of the weight of entire carrier particles is in the range of from 5 to 20 microns, and particles having a particle size smaller than 250 mesh occupy less than 8% by weight of the entire particles, and wherein the weight ratio of magnetic carrier to toner is less than 95/5, and the saturation magnetization of the carrier is in the range of 50 to 65 emu/g,
• (ii) feeding said two-component developer onto a developing sleeve equipped with magnetic poles and forming a magnetic brush of said two-component developer on the surface of said sleeve,
• (iii) applying a bias voltage of 250 to 350 V between a positively chargeable organic photosensitive material drum having a surface voltage of 750 to 850 V and said developing sleeve so that the development voltage difference is no greater than 500 V, wherein the photosensitive material drum and the developing sleeve are maintained at a distance apart of less than 1.2 mm, and
• (iv) contacting said magnetic brush of said two-component developer with the surface of the photosensitive material drum to form a toner image on the surface of said drum.