Development device

A development device comprising:

• a developer bearing member provided rotatably and configured to bear developer including toner and carrier to convey the developer to a development region facing an image bearing member;
• a first chamber configured to supply the developer to the developer bearing member;
• a second chamber configured to collect the developer having passed through the development region from the developer bearing member;
• a first communication portion configured to permit movement of the developer from the second chamber to the first chamber;
• a second communication portion configured to permit movement of the developer from the first chamber to the second chamber;
• a first conveyance screw disposed in the first chamber and configured to convey the developer in a first direction from the first communication portion toward the second communication portion, the first conveyance screw being disposed below the developer bearing member when the development device develops an electrostatic latent image formed on the image bearing member;
• a second conveyance screw disposed in the second chamber and configured to convey the developer in a second direction from the second communication portion toward the first communication portion;
• a partition wall configured to partition the first chamber and the second chamber;
• a guiding surface provided on the partition wall and configured to guide collecting the developer having passed through the development region from the developer bearing member to the second chamber;
• a developer replenish portion configured to replenish the developer;
• and
• a developer discharge portion configured to discharge a part of the developer as the developer is replenished by the developer replenish portion,
• wherein the developer discharge portion is provided on the first chamber which is disposed downstream of the second communication portion with respect to the first direction.

A development device comprising:

• a developer bearing member provided rotatably and configured to bear developer including toner and carrier to convey the developer to a development region facing an image bearing member;
• a first chamber configured to supply the developer to the developer bearing member;
• a second chamber configured to collect the developer having passed through the development region from the developer bearing member;
• a first communication portion configured to permit movement of the developer from the second chamber to the first chamber;
• a second communication portion configured to permit movement of the developer from the first chamber to the second chamber;
• a first conveyance screw disposed in the first chamber and configured to convey the developer in a first direction from the first communication portion toward the second communication portion, the first conveyance screw being disposed below the developer bearing member when the development device develops an electrostatic latent image formed on the image bearing member;
• a second conveyance screw disposed in the second chamber and configured to convey the developer in a second direction from the second communication portion toward the first communication portion;
• a partition portion configured to partition the first chamber and the second chamber, the partition portion extending to the vicinity of the developer bearing member;
• a developer replenish portion configured to replenish the developer;
• and
• a developer discharge portion configured to discharge a part of the developer as the developer is replenished by the developer replenish portion,
• wherein the developer discharge portion is provided on the first chamber which is disposed downstream of the second communication portion with respect to the first direction.

A development device comprising:

• a developer bearing member provided rotatably and configured to bear developer including toner and carrier to convey the developer to a development region facing an image bearing member;
• a first chamber configured to supply the developer to the developer bearing member;
• a second chamber configured to collect the developer having passed through the development region from the developer bearing member;
• a first communication portion configured to permit movement of the developer from the second chamber to the first chamber;
• a second communication portion configured to permit movement of the developer from the first chamber to the second chamber;
• a first conveyance screw disposed in the first chamber and configured to convey the developer in a first direction from the first communication portion toward the second communication portion, the first conveyance screw being disposed below the developer bearing member when the development device develops an electrostatic latent image formed on the image bearing member;
• a second conveyance screw disposed in the second chamber and configured to convey the developer in a second direction from the second communication portion toward the first communication portion;
• a partition portion configured to partition the first chamber and the second chamber, the partition portion is provided such that the developer having passes through the development region is able to be collected by the second chamber without passing through the first chamber from the developer bearing member;
• a developer replenish portion configured to replenish the developer;
• and
• a developer discharge portion configured to discharge a part of the developer as the developer is replenished by the developer replenish portion,
• wherein the developer discharge portion is provided on the first chamber which is disposed downstream of the second communication portion with respect to the first direction.