Patent ID: 8934819
Filing Date: 2015-01-13
Classification: G03G

Abstract:
1. A developing apparatus comprising: a developer carrying member for carrying a developer; and a magnetic member including a plurality of magnet pieces disposed inside said developer carrying member along a circumferential direction of said developer carrying member, wherein said magnetic member includes one or more first magnet pieces having a first magnetic polarity at a surface opposing an inner surface of said developer carrying member, and one or more second magnet pieces having a second magnetic polarity, which is opposite of the first magnetic polarity, at a surface opposing the inner surface of said developer carrying member, wherein in a longitudinally central portion of said magnetic member, a ratio of a total sum of volumes occupied by said one or more first magnet pieces per unit length is larger than a ratio of a total sum of volumes occupied by said one or more second magnet pieces per unit length, and wherein the ratio of the total sum of the volumes occupied by said one or more first magnet pieces per unit length in a longitudinally end portion is smaller than that in the longitudinally central portion.