PURPOSE: To provide a developing device obtaining satisfactory developing characteristics and stable excellent image quality even by using the DC bias power source of a low cost in the case of adopting a non-contact developing system in the developing device whose structure is simple and which uses one-component magnetic developer where the reduction of a cost is facilitated.
CONSTITUTION: This device is provided with a developing sleeve 31, a magnet roller fixed and arranged at the inside of the developing sleeve 31 and having plural magnetic poles, a miniagitator 5 supplying toner at the inside of a toner hopper 6 on the developing sleeve 31, a blade 4 charging by friction while controlling the layer thickness of the toner on the developing sleeve 31 and a developing bias power source 8. A developing magnetic pole fixed and arranged at a position opposite to a developing area out of plural magnetic poles is constituted by making magnetic flux density in the direction of the normal line of the surface of the developing sleeve 31 at the developing area lower than the magnetic flux density in the direction of the normal line of the surface of the developing sleeve 31 on the downstream side of the developing area in a toner carrying direction on the developing sleeve 31, and a toner supplying magnetic pole is fixed and arranged at the position opposite to a toner supplying part made of a toner supplying member.
SUGINO YOICHIRO
SAWADA AKIRA
SAITO HIROSHI
BABA SATOHIKO
