DEVELOPING APPARATUS

摘要

A developing apparatus includes a developer carrying member; and a magnetic member provided inside the carrying member and having magnetic poles arranged circumferentially, wherein on a center axis of the carrying member outside an end of the magnetic member, there is a region in which a magnetic flux density of a first magnetic polarity converges toward zero; and wherein a ratio of a volume, per unit length, of a portion of the magnetic member which has a surface magnetic pole of a second magnetic polarity which is different from the first magnetic polarity in a longitudinal end portion to that in a longitudinally central portion is smaller than a ratio of a volume of a portion of the magnetic member which has a surface magnetic pole of the first magnetic polarity in a longitudinal end portion to that in a longitudinally central portion.

主权项

1. A developing apparatus comprising:
a developer carrying member for carrying a developer; and a magnetic member provided inside said developer carrying member and having magnetic poles arranged in a circumferential direction of said developer carrying member, wherein on a center axis of said developer carrying member outside an end of said magnetic member, there is a region in which a magnetic flux density of a first magnetic polarity converges toward zero; and wherein a ratio of a volume, per unit length in a longitudinal direction, of a portion of said magnetic member which has a surface magnetic pole of a second magnetic polarity which is different from the first magnetic polarity in a longitudinal end portion to that in a longitudinally central portion is smaller than a ratio of a volume, per unit length in a longitudinal direction, of a portion of said magnetic member which has a surface magnetic pole of the first magnetic polarity in a longitudinal end portion to that in a longitudinally central portion.