A system and method for cooling electrostatic process units includes an impeller in communication with a shaft associated with a rotating component of the electrostatic process unit such as a toner mixer, a waste auger, a developer, or a photoconductive drum. When the shaft rotates, the impeller rotates and causes air to be directed into a cooling duct. The cooling duct directs the air over one or more components of the electrostatic process unit such as the developer or a doctor blade. The air directed over the components cools the electrostatic process unit.

A feeding screw for feeding a developer includes a rotation shaft, a first blade portion helically formed on an outer peripheral surface of the rotation shaft to feed the developer in one direction, a second blade portion helically formed on the outer peripheral surface to feed the developer in the one direction, and a third blade portion helically formed on the outer peripheral surface to feed the developer in the one direction. The first blade portion and the second blade portion overlap with each other with respect to a rotational axis direction of the feeding screw, the second blade portion and the third blade portion do not overlap with each other with respect to the rotational axis direction, and the third blade portion and the first blade portion overlap with each other with respect to the rotational axis direction.

A developing device includes a developer carrier, first and second chambers, first and second communication portions, first and second conveyance screws, a pair of sealing members, and a drive transmission gear. The developer carrier carries developer containing toner and carrier for developing an electrostatic image formed on an image carrier. The second chamber is partitioned from the first chamber. The first conveyance screw conveys the developer in a first direction from the first communication portion toward the second communication portion. The second conveyance screw conveys the developer in a second direction from the second communication portion toward the first communication portion. The sealing member pair seals the first and second communication portions to store initial developer in the second chamber. The drive transmission gear includes a fitting portion to which a tool to input a driving force for rotating the second conveyance screw to the drive transmission gear is fitted.

An image forming apparatus includes an apparatus body, a developer container, a data recording medium, a contact terminal, a detector, and control circuitry. The developer container is detachably attached in the apparatus body. The data recording medium is on the developer container. The contact terminal is disposed in the apparatus body and contacts the data recording medium. The detector detects a communication failure between the data recording medium and the apparatus body. The control circuitry executes a control mode to vibrate the data recording medium when the detector detects the communication failure.

A transport device includes a transport path that includes an opening through which a developer flows into the transport path, an opening and closing portion that is provided to be movable along the transport path and that opens and closes the opening, and a transport body that is disposed in the transport path, that includes a blade formed in a spiral shape on an outer periphery of a shaft portion, that transports the developer flowing into the transport path through the opening and moves the opening and closing portion to an opening position with the blade by rotating forward, and that idly rotates with respect to the opening and closing portion moved to the opening position in a case of forward rotation.

A toner cartridge includes a cartridge case, a stirring paddle and a stirring sheet. In the cartridge case, a toner stirring chamber is formed. The stirring paddle is rotatably installed in the stirring chamber. The stirring sheet is rotatable together with the stirring paddle in the stirring chamber. The cartridge case has a toner supply port. The stirring sheet protrudes outward in a radial direction from a rotational locus drawn by a tip end of the stirring paddle. When the stirring paddle is positioned at a specific rotational phase, the stirring sheet blocks the supply port.

A development device includes a development container, a first conveying member, a second conveying member, a toner concentration sensor, and a developer carrier. The first and second conveying members are equal to each other in outer diameter and shaft diameter, the outer diameter being 1.3 times the shaft diameter or more but 1.6 times the shaft diameter or less. Where L represents an axial length of the first conveying member, K represents a distance of a center position of the sensing surface of the toner concentration sensor from a downstream end of a first conveying chamber of the development container in the first direction, P represents a pitch of the conveying blade of the first conveying member, and R represents a rotational speed of the first conveying member, formula (1) is satisfied: 30000<(PRL)/K<45000 (1).

A development device includes a development container, a first conveying member, a second conveying member, a toner concentration sensor, and a developer carrier. The toner concentration sensor is arranged at a wall portion of the first conveying chamber in which the first conveying member is arranged. The first and second conveying members are equal to each other in outer diameter and shaft diameter, the outer diameter being 2.3 times the shaft diameter or more but 3.0 times the shaft diameter or less. Where D represents the shaft diameter of the first conveying member, L represents an axial length of the first conveying member, and K represents a distance of a center position of a sensing surface of the toner concentration sensor from a downstream end of the first conveying chamber in the first direction, formula (1) is satisfied: 500<(L.sup.2K)/D.sup.4<2500 (1).

In one embodiment, a toner container comprises a toner container body in which toner is stored, a cover portion configured to cover the toner container body, and a projection. The projection is provided in the vicinity of a rear end portion in a longitudinal direction of the cover portion or a longitudinal direction of the toner container body, and projecting toward a rear side of the toner container.

A toner case includes a case main body, a conveying member and a transmitting member. The case main body is configured to store a toner and has a discharge port for the toner. The conveying member is configured to rotate around a rotation axis extending along a rotation axis direction and to convey the toner in the case main body to the discharge port. The transmitting member is configured to transmit rotation to the conveying member. The conveying member is movable along the rotation axis direction with respect to the transmitting member between a coupling position where the conveying member is coupled to the transmitting member and a release position where a coupling of the conveying member to the transmitting member is released.