abstract |
A magnetic toner capable of exhibiting stablenchargeability regardless of environmental change isnformed of magnetic toner particles each comprising atnleast a binder resin, an iron oxide and a sulfur-containingnpolymer, and inorganic fine powder blendednwith the magnetic toner particles. The magnetic tonernis also provided with good developing performance andnhigh transferability by satisfying a weight-averagenparticle size (D4) of 3 - 10 µm, an averagencircularity of at least 0.970, and a magnetization ofn10 - 50 Am 2 /kg (emu/g) at a magnetic field of 79.6nkA/m (1000 oersted). The magnetic toner is furtherncharacterized in that the magnetic toner particlesnretain carbon in an amount of A and iron in an amountnof B at surfaces thereof as measured by X-raynphotoelectron spectroscopy, satisfying: B/A < 0.001,nand the magnetic toner contains at least 50 % bynnumber of magnetic toner particles satisfying anrelationship of D/C ≦ 0.02, wherein C represents anprojection area-equivalent circle diameter of eachnmagnetic toner particle, and D represents a minimumndistance between a surface of the magnetic tonernparticle and iron oxide particles contained in thenmagnetic toner particle. |