| 摘要 |
In a developing device, the conveying ability of a second screw in a first area that includes an area, which is superposed with, in an axial direction of a developing sleeve, a developer carrying area of the developing sleeve and a downstream communicating portion through which a developer is conveyed from a developing chamber to a collecting chamber, is lower than the conveying ability of the second screw in a second area, which is positioned further downstream than the first area in a direction in which the developer is conveyed and which is superposed with the developer carrying area of the developing sleeve. |
| 主权项 |
1. A developing device comprising:
a developer-carrying member configured to carry a developer and to develop a latent image; a first chamber configured to accommodate a developer to be supplied to the developer-carrying member, the first chamber including a first opening, which is formed at a position facing a circumferential surface of the developer-carrying member and through which a developer can be supplied to the developer-carrying member; a second chamber arranged next to the first chamber, the second chamber including a second opening, which is formed at a position facing the circumferential surface of the developer-carrying member and through which a developer carried by the developer-carrying member can be collected; a partitioning wall configured to separate the first chamber and the second chamber from each other; a first communication portion that is formed at one side of the partitioning wall in an axial direction of the developer-carrying member, and that allows communication between the first chamber and the second chamber; a second communication portion that is formed at the other side of the partitioning wall in the axial direction of the developer-carrying member, and that allows communication between the first chamber and the second chamber; a first screw that is rotatably arranged in the first chamber and that conveys the developer in a first direction from the first communication portion toward the second communication portion; and a second screw that is rotatably arranged in the second chamber and that conveys the developer in a second direction which is an opposite direction from the first direction, wherein, in the axial direction of the developer-carrying member, a developer carrying area of the developer-carrying member is superposed with the second communicating portion, wherein the second screw has a first area that is superposed with both of the developer carrying area of the developer-carrying member, and the second communication portion in the axial direction of the developer-carrying member, and a second area that is positioned further downstream than the first area in the second direction and that is superposed with the developer carrying area of the developer-carrying member, and wherein a helical blade for conveying the developer is not formed in the first area of the second screw while at least one a helical blade for conveying the developer in the second direction is formed in the second area of the second screw. |
