Patent ID: 8422909

Claim:
A developing apparatus comprising: a developer carrying member for carrying a developer containing magnetic particles and for developing a latent image formed on an image bearing member; a magnetic member, provided in said developer carrying member, for magnetic confinement of the developer on a surface of said developer carrying member, wherein said magnetic member has a set of repelling poles including a first magnetic pole and a second magnetic pole which have the same magnetic polarity; and a magnetic seal provided opposed to said developer carrying member at a side remote from said image bearing member; wherein said magnetic seal has a third magnetic pole having a magnetic polarity opposite to that of the magnetic polarity of the first magnetic pole and disposed at a position closest to a peak position of the first magnetic pole on a surface of said magnetic seal opposing to said developer carrying member, a fourth magnetic pole having a magnetic polarity opposite that of the magnetic polarity of the second magnetic pole and disposed at a position closest to a peak position of the second magnetic pole on the surface of said magnetic seal opposing to said developer carrying member, and a fifth magnetic pole as an only one magnetic pole provided between the third magnetic pole and the fourth magnetic pole, the fifth magnetic pole having a polarity opposite to that of the third magnetic pole and the fourth magnetic pole.