| 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 that is rotatably arranged, that carries a developer, which includes toner and carrier, and that supplies the developer to a development region, which faces an image-bearing member; a developing chamber in which the developer is supplied to the developer-carrying member at a position facing a circumferential surface of the developer-carrying member; a collecting chamber that is positioned upstream of the developing chamber in a rotation direction of the developer-carrying member in such a manner as to face the circumferential surface of the developer-carrying member, in which the developer that has been collected from the developer-carrying member is placed, and in which a circulation path that allows the developer to circulate through communicating portions, which allow communication between the collecting chamber and the developing chamber at opposite ends of the chambers, is formed; a partitioning wall that separates the developing chamber and the collecting chamber from each other; a first screw that is rotatably arranged in the developing chamber and that conveys the developer; and a second screw that is rotatably arranged in the collecting chamber and that conveys the developer; wherein, in an axial direction of the developer-carrying member, a developer carrying area of the developer-carrying member is superposed with one of the communicating portions, which is a downstream communicating portion through which the developer is conveyed from the developing chamber to the collecting chamber, and wherein, a conveying ability of the second screw in a first area that includes an area, which is superposed with the developer carrying area of the developer-carrying member and the downstream communicating portion in the axial direction of the developer-carrying member, 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 developer-carrying member, or is zero, or a direction in which the second screw conveys the developer in the first area and a direction in which the second screw conveys the developer in the second area are opposite to each other. |
