DEVELOPING DEVICE

摘要

PROBLEM TO BE SOLVED: To enhance the copying property of a generation copy and a slender and pale original without lowering image density by preventing carrier from being attached to a developing roller by enhancing the magnetic restriction force of the developing roller as to the developing roller of an electrophotographic copying device. SOLUTION: The developing device is provided with the developing roller 3 having plural magnetic poles and constituted so that a latent image on a latent image carrier on which an electrostatic latent image is formed is developed and visualized. Then, the width of the density of magnetic flux in a normal line direction corresponding to 80% of the maximum density of the magnetic flux in the normal line direction of the main poles S1 and S2 in the roller 3 positioned so as to be faced to the latent image carrier is shaped to be >=35 deg. with the rotary shaft of the roller 3 as a central point. Besides, the main poles S1 and S2 are formed of parts where magnetic force is high and parts between them where the magnetic force is low and the magnetic force on a downstream side is stronger by 0-100G than that on the upstream side in a developing area.