IRON POWDER DEVELOPING CARRIER AND THE MANUFACTURING METHOD OF THE SAME, DEVELOPER CONTAINING SAID CARRIER AND METHOD OF FORMING VISIBLE IMAGE BY USING SAID DEVELOPER

摘要

An iron powder developing carrier for developing an electrostatic latent image, a manufacturing method thereof, a developer containing said developing carrier and a method of forming a visible image by using said developer. Said iron powder developing carrier has the apparent density from 1.5 to 2.5. Said manufacturing method comprises the steps of sintering a raw iron powder having been ground to particles of not larger than 50 microns in diameter without using any binder agent at the temperature from 900 to 1200.degree.C to form a sintered body, grinding and classifying said sintered body into an intermediate iron powder having the particle diameter from 50 to 200 microns, then treating said intermediate iron powder to oxidize at the temperature from 280 to 390.degree.C, and adjusting the resultant iron powder so as to have the apparent density from 1.5 to 2.5.