Developing device and image forming apparatus including same

A developing device comprising:

• a developing container which includes
• a first conveyance chamber and
• a second conveyance chamber disposed above the first conveyance chamber with a partition therebetween,
• the developing container holding therein a two-component developer including a carrier and a toner;
• a first stirring-conveyance member which is rotatably supported in the first conveyance chamber and conveys the developer in the first conveyance chamber in a first direction, while stirring the developer;
• a second stirring-conveyance member which is rotatably supported in the second conveyance chamber to be parallel to the first conveyance member, and rotates in a direction opposite to a direction in which the first stirring-conveyance member rotates, to thereby convey the developer in the second conveyance chamber in a second direction which is opposite to the first direction;
• and
• a developer carrier which is rotatably supported in the developing container and carries on a surface thereof the developer in the second conveyance chamber;
• wherein
• the developing container includes
• a first communication portion which allows the first conveyance chamber and the second conveyance chamber to communicate with each other at end portions thereof on a downstream side in the first direction,
• a second communication portion
• which allows the first conveyance chamber and the second conveyance chamber to communicate with each other at end portions thereof on a downstream side in the second direction, and
• which is formed at an end portion of the partition on a side in a width direction of the developing container which is perpendicular to an axial direction of the second stirring-conveyance member, the developer on the side being made to move upward by rotation of the second stirring-conveyance member and downward by rotation of the first stirring-conveyance member, and
• a guide member which is disposed in the first conveyance chamber, and guides, to the downstream side in the first direction, the developer that is conveyed from the second conveyance chamber, passing through the second communication portion, and falls into the first conveyance chamber.