An image forming apparatus includes first and second image forming portions. A first conveying pipe conveys a first developer discharged from a first developing unit to a collection portion, and a second conveying pipe conveys a second developer discharged from a second developing unit to the collection portion. A first detection unit detects a toner content of the first developer in the first conveying pipe, and a second detection unit detects a toner content of the second developer in the second conveying pipe. The first developing unit can be removed from the image forming apparatus in a state that the first conveying pipe and the first detection unit remain in the image forming apparatus, and the second developing unit can be removed from the image forming apparatus in a state that the second conveying pipe and the second detection unit remain in the image forming apparatus.

An electrophotographic image forming apparatus includes a driving device including a first gear and a second gear, a power transmitter configured to transfer a rotational force applied in one direction from the motor to the first and second gears; a cam configured to set the power transmitter to one of a release mode in which the motor is disconnected from the first and second gears, a first connection mode in which one of the first and second gears is connected to the motor, and a second connection mode in which the other of the first and second gears is connected to the motor; and a clutch configured to selectively transfer the rotational force applied in the one direction from the motor to the cam.

An electrophotographic image forming apparatus includes a driving device including a first gear and a second gear, a power transmitter configured to transfer a rotational force applied in one direction from the motor to the first and second gears; a cam configured to set the power transmitter to one of a release mode in which the motor is disconnected from the first and second gears, a first connection mode in which one of the first and second gears is connected to the motor, and a second connection mode in which the other of the first and second gears is connected to the motor; and a clutch configured to selectively transfer the rotational force applied in the one direction from the motor to the cam.

An image forming apparatus includes: an image bearing member; a developing unit; a discharge portion which is provided in the developing unit and configured to discharge a developer in the developing unit to the outside of the developing unit; a collection portion which collects the developer discharged from the discharge portion; a conveying pipe which is separable from the developing unit, includes a conveying screw therein, and conveys the developer discharged from the discharge portion to the collection portion; and a toner density sensor which detects toner density in the conveying pipe and of which a detection surface is positioned below a rotational axis of the conveying screw in a vertical direction, wherein the developing unit is removed from the image forming apparatus in a state in which the conveying pipe and the toner density sensor remain in the image forming apparatus.

An image forming apparatus includes a body frame, a cartridge movable to an attached position and a retracted position, a moving device configured to move the cartridge, a driving device configured to drive the moving device and to perform a first operation of driving the moving device to move the cartridge from the attached position toward the retracted position and a second operation of driving the moving device to move the cartridge from the retracted position toward the attached position, and a controller configured to control the driving device and to cause the driving device to perform the second operation in a case where the cartridge has not reached the retracted position even after elapse of a predetermined time since the driving device is caused to start the first operation in a state in which the cartridge is positioned at the attached position.

A developing device includes a developer holder that supplies developer to an image carrier on which an electrostatic latent image is formed. The developing device further includes a removing member that removes the developer that has not been supplied to the image carrier and remains on the developer holder and a transport unit that includes a helical rotating body, the transport unit rotating the rotating body to transport the developer and supply the developer to the developer holder. The developing device further includes an accommodating unit that accommodates the developer holder, the removing member, and the transport unit; and a drive mechanism that operates the developer holder and the transport unit together in a first operation mode for image formation and operates the developer holder and the transport unit individually in a second operation mode for cleaning an inside of the accommodating unit by removing the developer.

An image forming apparatus configured such that a cartridge that stores a developer is attachable to and detachable from the image forming apparatus includes a rotary that is rotatable and that is configured to store the developer supplied from the cartridge; a tray that removably supports the cartridge and that moves with respect to the rotary to a retraction position in which the cartridge is located outside the rotary and to a mount position in which the cartridge is located inside the rotary; and a control unit that controls the movement of the tray. In a case that an elapsed time since the tray is located at the retraction position exceeds a predetermined length, the control unit controls the movement of the tray such that the tray moves from the retraction position to the mount position.