Method for producing core material of electrophotographic ferrite carrier and resin-coated ferrite carrier

Abstract

The present invention provides a method for producing a core material of an electrophotographic ferrite carrier, by charging a raw powder with an average particle size of 20 to 50 μm obtained by preparing raw materials for ferrite into a combustion flame along with a carrier gas for the raw powder, thermal-spraying the powder in atmospheric air to ferritize the powder, subsequently rapidly solidifying the thermal-sprayed particle, and sampling and collecting the particle, wherein the method satisfies the conditions comprising the following (1) to (3): (1) a mixture gas of propane and oxygen is used for the combustion flame for the thermal spraying, and a volumetric ratio of the propane to the oxygen is 1:3.5 to 6.0; (2) the carrier gas for the raw powder is air, nitrogen, oxygen or a mixture gas thereof, and the ratio (a/b) of a charged amount (a) of a raw powder (kg/hr) to a charged amount (b) of the carrier gas (kg/hr) for the raw powder is 4.8 or less; and (3) a flame flow velocity of the combustion flame is 65 to 125 m/sec.