MAGNETIC TONER FOR DEVELOPING ELECTROSTATIC CHARGE IMAGE

摘要

PROBLEM TO BE SOLVED: To remove a product and a toner film on a latent image carrier without damaging the carrier and to suppress scattering from the carrier by fixing fine tungsten carbide powder by a direct carbonization method on the surface of a toner matrix contg. a bonding resin and a magnetic material. SOLUTION: Fine tungsten carbide powder of 0.1-1.0μm particle diameter by a direct carbonization method is fixed on the surface of the toner matrix by 0.1-1.0 pt.wt. to 100 pts.wt. magnetic toner matrix for developing an electrostatic charge image contg. a bonding resin and a magnetic material. Tungsten carbide obtd. by such the direct carbonization method that tungsten oxide is directly carbonized with carbon powder at a high temp. is a highly hard and highly strong superfine particulate tungsten-carbon alloy almost free from other metals. Since the tungsten carbide is fixed on the surface of the toner matrix and the specific gravity of the tungsten carbide is close to that of the toner matrix, the tungsten carbide does not separate from the toner matrix.