Dry composite blended magnetic developer of resin encapsulated fine magnetite and resin encapsulated coarse magnetite

摘要

Disclosed is a dry composite magnetic developer consisting essentially of a particulate shaped article of a composition comprising a binder resin medium and a powdery magnetic material dispersed in the binder resin medium, wherein said developer is formed by dry blending (A) a first particulate shaped article comprising a non-pulverizing agglomerate of cubic particles of magnetite having a number average particle size of 1 to 10 mu m as measured by an electron microscope with (B) a second particulate shaped article comprising magnetite particles having a particle size of 0.2 to 1 mu m at an (A)/(B) weight ratio of from 95/5 to 10/90, especially from 95/5 to 30/70.