A waste toner collecting device includes an intermediate collection box, a conveying path, a conveying screw, an exhaust path and a floating toner collection chamber. The conveying path is provided in the intermediate collection box. The conveying screw is rotatable in the conveying path. Through the exhaust path, air containing a floating toner is sucked and passed. The floating toner collection chamber is provided on a part of the exhaust path in the intermediate collection box. The floating toner collection chamber has a discharge opening opened to an inside of the intermediate collection box and a discharge door. Rotation of the conveying screw in a normal direction turns the discharge door into a storage position where the discharge opening is closed. Rotation of the conveying screw in a reverse direction turns the discharge door into a discharge position where the discharge opening is opened.

A developing device includes a developer container, a developer carrier, and first and second members for stirring/conveying. The developing container has a first partition wall between first and second chambers, communication portions through which those chambers communicate at opposite ends of the first partition wall, a developer supply port, and a developer discharge portion. The first member stirs and conveys developer in the first chamber in a first direction. The second member stirs and conveys developer in the second chamber in a second direction and includes a regulating portion and a discharging blade. The developer container includes a second partition wall between the first chamber and the regulating portion. The second partition wall is lower than the first partition wall, and an upper end part of the second partition wall is between upper and lower end parts of the rotary shaft of the second stirring/conveying member.

A replenishment conveyance screw portion is provided in a replenishment conveyance path and configured to convey the replenishment developer in a third direction. The replenishment conveyance screw portion includes a first blade portion, a second blade portion, and, a third blade portion. The third blade portion is continuously formed in a region between a terminal end of the first blade portion with respect to the third direction and a starting end of the second blade portion with respect to the third direction, the region being displaced in a circumferential direction of the replenishment conveyance screw portion from the terminal end of the first blade portion and the starting end of the second blade portion.

A developer container includes: a case that stores developer and in which a developer outlet for discharging the developer is formed; a conveying spiral that is rotatably disposed in the case and rotates to convey the developer toward the developer outlet in an axial direction of the conveying spiral; a guide wall that is disposed along the conveying spiral and guides the developer in the axial direction of the conveying spiral; and a push member that is attached to the conveying spiral and rotates with the conveying spiral to push the developer into the developer outlet. A cutout is formed at a portion of the guide wall corresponding to the push member to form a guide portion that guides the developer to the developer outlet.

A developing device includes a holding body that holds a developer; an agitating unit that agitates the developer; a supply unit that supplies the developer that flows in from the agitating unit to the holding body; a filling portion provided above the agitating unit and filled with the developer; a closing portion that closes a lower portion of the filling portion, and causes the developer to drop from the filling portion into the agitating unit in a case where the closing portion is removed; and a duct portion that connects a space in the filling portion and a portion above the holding body.

A developing device includes a developer container, a developer carrier, and first and second members for stirring/conveying. The developing container has a first partition wall between first and second chambers, communication portions through which those chambers communicate at opposite ends of the first partition wall, a developer supply port, and a developer discharge portion. The first member stirs and conveys developer in the first chamber in a first direction. The second member stirs and conveys developer in the second chamber in a second direction and includes a regulating portion and a discharging blade. The developer container includes a second partition wall between the first chamber and the regulating portion. The second partition wall is lower than the first partition wall, and an upper end part of the second partition wall is between upper and lower end parts of the rotary shaft of the second stirring/conveying member.

A developing device includes a developer bearer and a stirring conveyor. The stirring conveyor includes a first conveying chamber including a conveying member and a second conveying chamber to receive the developer from an end of the first conveying chamber. The conveying member includes a forward winding blade, a reverse winding blade, and a shaft portion on which the forward winding blade and the reverse winding blade are mounted with a space therebetween. A circumferential phase of the conveying member at a start position of the reverse winding blade is different from a circumferential phase of the conveying member at an end position of the forward winding blade. The conveying member is disposed in the first conveying chamber so that the space is opposite a portion at which the second conveying chamber receives the developer from the end of the first conveying chamber.

Provided is a developing device having a first transport member and a second transport member that are disposed in a first transport path and a second transport path provided at an upper side and a lower side in a gravitational direction. The transport members transport a developer so as to cause the developer to circulate between the first transport path and the second transport path. A partition wall that separates the first transport path and the second transport path from each other and has an opening including an open-close member that opens and closes the opening.

A developing device includes a developer container including first and second chambers between which the developer is circulated, first and communication portions to permit the developer to communicate with the first and second chambers, first and second screws provided in the first and second chambers, respectively, and a developer discharging portion. The developer discharging portion is provided in a passage continuous with the first chamber of an upstream of the second communication portion. In the developing device, a discharging method includes a step for inserting a shield member into the second communication portion via an inserting opening of the developer container, and a step for discharging the developer from the developing device via the developer discharging portion, by rotating the first and second screws in a direction opposite to a direction of rotating during a developing operation in a state where the shielding member is inserted into the second communication portion in the inserting step.

A developer discharging method includes inserting a shielding member into a second communication portion via an inserting opening of a developer container to shift the second communication portion from an opening state for opening the second communication portion to a shielding state for shielding the second communication portion, and discharging the developer from a developing device via a developer discharging portion by rotatably driving a first conveying screw in a direction opposite to a direction of rotatably driving the first conveying screw during a developing operation of developing an electrostatic image formed on an image bearing member when the shielding member is inserted into the second communication portion and by rotatably driving the second conveying screw in a direction opposite to a direction of rotatably driving the second conveying screw during the developing operation when the shielding member is inserted into the second communication portion.