Patent ID: 8744304

Claim:
A developing device comprising: a developer carrying member for carrying a magnetic developer to form a developer image on an image bearing member; a developing device frame including a first accommodating chamber for accommodating the magnetic developer and including a second accommodating chamber, in which said developer carrying member is provided, for accommodating the magnetic developer supplied from said first accommodating chamber through a first opening; a sealing member, which is provided to seal the first opening, and which is to be removed by being passed through a second opening; and a magnetic seal member, which is provided between a longitudinal end portion of said developer carrying member and said developing device frame, forming at least part of the second opening, wherein said magnetic seal member can carry the magnetic developer in a gap between an outer peripheral surface of said developer carrying member and said magnetic seal member, and can carry the magnetic developer at the second opening to suppress movement of the magnetic developer to an outside of said developing device by a magnetic force, wherein the second opening is a slit provided in said magnetic seal member.