Developing device, image forming apparatus and cartridge

An image forming apparatus comprising:

• a developing device;
• a rotatable developer carrying member configured to carry a developer comprising a magnetic material to develop a latent image formed on an image bearing member;
• a developer accommodating chamber configured to accommodate the developer to be supplied to said developer carrying member;
• a rotatable stirring member provided inside said developer accommodating chamber configured to stir the developer while being in contact with at least a part of an inner surface of said developer accommodating chamber;
• and
• a magnetic field generating member generating a magnetic field in at lease a part of a contact region where said stirring member contacts said inner surface,
• wherein a magnetic flux density of the magnetic field at a first position in the contact region generated by said magnetic field generating member is different from that in a second position which is adjacent to the first position in a rotational axis direction of said developer carrying member.

A cartridge detachably mountable to a main assembly of an image forming apparatus, said cartridge comprising:

• a rotatable developer carrying member configured to carry a developer comprising a magnetic material to develop a latent image formed on an image bearing member;
• a developer accommodating chamber configured to accommodate the developer to be supplied to said developer carrying member;
• a rotatable stirring member provided inside said developer accommodating chamber configured to stir the developer while being in contact with at least a part of an inner surface of said developer accommodating chamber;
• and
• a magnetic field generating member generating a magnetic field in at lease a part of a contact region where said stirring member contacts said inner surface,
• wherein a magnetic flux density of the magnetic field at a first position in the contact region generated by said magnetic field generating member is different from that in a second position which is adjacent to the first position in a rotational axis direction of said developer carrying member.