Hitachi Koki Co., Ltd.

Koutara Yamada

Yasuyuki Tsuji

Hiroshi Ueno

Kunitomo Takahashi

Youji Hirose

Koji Doi

Shuuho Yokokawa

Hidenori Iwanaga

Youichi Takeuchi

A developing device in an electrophotographic apparatus, wherein a pole c.sub.1 which is a delivering magnetic pole of the second developing roll for delivering the developer to the first developing roll and a pole d.sub.1 which is a receiving magnetic pole of the second developing roll for receiving the developer from the first developing roll are set so as to be the same in polarity, whereas a pole a.sub.2 which is a receiving magnetic pole of the first developing roll for receiving the developer from the second developing roll and a pole g.sub.2 which is a delivering magnetic pole of the first developing roll for delivering the developer to the second developing roll are set to be equal in polarity, wherein each of an angle between the poles c.sub.1 and d.sub.1 and an angle between the poles a.sub.2 and g.sub.2 is set so as to be in a range of from 70.degree. to 120.degree., and wherein the magnetic flux density of each of a reaction pole induced between the poles c.sub.1 and d.sub.1 and a reaction pole induced between the poles a.sub.2 and g.sub.2 is set so as to be less than or equal to 0.015 tesla.

Developing device in electrophotographic apparatus including developing

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Ibaraki, Japan

Koutara Yamada