Developing device

A developing device comprising:

• a first chamber configured to accommodate a developer including toner and a carrier;
• a second chamber partitioned from the first chamber by a partition wall;
• a first rotatable member to which the developer accommodated in the first chamber is supplied and which carries and feeds the developer to a developing position where an electrostatic latent image formed on an image bearing member is developed;
• a first magnet provided non rotatably and stationarily inside the first rotatable member, wherein the first magnet includes a first magnetic pole provided opposed to the image bearing member in the developing position, a second magnetic pole provided downstream of the first magnetic pole with respect to a rotational direction of the first rotatable member, and a third magnetic pole provided downstream of the second magnetic pole and adjacent to the second magnetic pole, with respect to the rotational direction of the first rotatable member, and having the same magnetic polarity as that of the second magnetic pole, with a repelling magnetic field being generated between the second magnetic pole and the third magnetic pole;
• a second rotatable member provided opposed to the first rotatable member and to which the developer is delivered from the first rotatable member by a magnetic field generated by the first magnet, wherein the second rotatable member carries and feeds the developer for collecting the developer, after the electrostatic latent image is developed, into the second chamber;
• and
• a second magnet provided non rotatably and stationarily inside the first second rotatable member, wherein the second magnet includes a plurality of magnetic poles including a fourth magnetic pole having a magnetic polarity different from that of the second magnetic pole, a fifth magnetic pole provided downstream of the fourth magnetic pole with respect to a rotational direction of the second rotatable member, and a sixth magnetic pole provided downstream of the fifth magnetic pole and adjacent to the fifth magnetic pole, with respect to the rotational direction of the second rotatable member, and having the same magnetic polarity as that of the fifth magnetic pole, with a repelling magnetic field being generated between the fifth magnetic pole and the sixth magnetic pole, and the fourth magnetic pole being a magnetic pole, of the plurality of magnetic poles, provided closest to the second magnetic pole,
• wherein the rotational direction of the second rotatable member, in a position where on an outer peripheral surface of the second rotatable member, the second rotatable member is closest to the first rotatable member, is the same as the rotational direction of the first rotatable member in a position where on an outer peripheral surface of the first rotatable member, the first rotatable member is closest to the second rotatable member, and
• wherein with respect to the rotational direction of the second rotatable member, a maximum position where a magnetic flux density of the fourth magnetic pole in a normal direction relative to the outer peripheral surface of the second rotatable member is maximum is positioned downstream of the position where on the outer peripheral surface of the second rotatable member, the second rotatable member is closest to the first rotatable member, and is positioned upstream of the fifth magnetic pole.