Developing apparatus

A developing apparatus configured to develop an electrostatic latent image formed on an image bearing member with toner, the developing apparatus comprising:

• a developer bearing member configured to bear and convey a developer containing the toner and a carrier;
• a developing container configured to accommodate the developer, the developing container including:
• a first chamber configured to accommodate the developer that is supplied to the developer bearing member;
• a second chamber configured to collect the developer separated from the developer bearing member;
• a partition wall configured to divide the first chamber and the second chamber, the partition wall including a first communicating portion configured to communicate between the second chamber and the first chamber such that the developer is allowed to move from the second chamber to the first chamber and a second communicating portion configured to communicate between the second chamber and the first chamber such that the developer is allowed to move from the first chamber to the second chamber;
• a first conveyance member disposed in the first chamber and configured to convey the developer in a first direction from the first communicating portion toward the second communicating portion;
• a second conveyance member disposed in the second chamber and configured to convey the developer in a second direction from the second communicating portion toward the first communicating portion;
• and
• a magnet non-rotationally disposed inside the developer bearing member and including a plurality of magnetic poles arranged in a rotational direction of the developer bearing member, the magnet being configured to generate a magnetic field that allows the developer bearing member to bear the developer,
• wherein the magnet includes a first magnetic pole and a second magnetic pole,
• wherein the second magnetic pole is positioned adjacent to the first magnetic pole on an upstream side in the rotational direction of the developer bearing member, has a same polarity as the first magnetic pole, and is configured to separate the developer on the developer bearing member by a repulsive magnetic field generated in cooperation with the first magnetic pole,
• wherein, a low magnetic force portion having a magnetic force of equal to or less than 10 milli-Tesla is formed in a region upstream of the first magnetic pole and downstream of the second magnetic pole in the rotational direction of the developer bearing member, and
• wherein the partition wall includes an opening portion formed at a position facing the low magnetic force portion with the developer bearing member interposed therebetween, and a flow path portion configured to guide air entering from the opening portion to an outside of the developing container.