Patent ID: 9658573
Date: 2017-05-23
CPC Classifications: G03G

Claim:
1. A developing unit comprising: a developer carrier configured to bear a developer including a toner and a carrier on a developer carrying area; a first chamber configured to face at least a part of the developer carrier and receive the developer falling from the developer carrier; a second chamber provided next to the first chamber; a partition configured to be disposed between the first chamber and the second chamber to separate the first chamber from the second chamber; a first conveying member, disposed rotatably in the first chamber, configured to convey the developer in the first chamber in a first direction; a second conveying member, disposed rotatably in the second chamber, comprising a spiral blade portion conveying the developer in the second chamber in a second direction opposite to the first direction, and a reverse spiral blade portion disposed downstream of the spiral blade portion in the second direction and configured to convey the developer in the first direction; a discharging portion, provided in the second chamber and downstream of the reverse spiral blade portion in the second direction, configured to discharge the developer; and a plurality of communication portions communicating the first chamber and the second chamber with each other, and comprising a first communication portion, disposed downstream in the second direction, through which the developer is conveyed from the second chamber to the first chamber, and a second communication portion, disposed upstream in the second direction, through which the developer is conveyed from the first chamber to the second chamber among the plurality of communication portions, wherein a distance between an upstream end, in the second direction, of the first communication portion and a center, in a rotational axis direction of the developer carrier, of the developer carrier is greater than a distance between a downstream end, in the second direction, of the second communication portion and the center of the developer carrier.