An apparatus includes a photoconductor, an exposure device, a developing device, a toner concentration sensor, a supply motor, and a processor. The exposure device exposes the photoconductor based on image data. The developing device forms a toner image on the photoconductor with toner supplied from a toner cartridge. The toner concentration sensor detects a toner concentration in the developing device. The supply motor supplies the toner from the toner cartridge to the developing device based on the toner concentration. The processor detects a toner container supply abnormality based on a toner supply rate and a print rate of the image data, the toner supply rate being calculated based on a pixel count value that is an integrated value of pixel values of the image data and a supply motor count value that is an integrated value of drive times of the supply motor.

According to one embodiment, an image forming apparatus includes a printer and a controller. The printer performs image formation on a sheet at a first speed relating to a speed of image formation or at a second speed slower than the first speed. The controller acquires information on deterioration of developer contained in an own apparatus, and controls the printer to perform image formation at the first speed when the information does not satisfy a predetermined condition indicating that the developer is deteriorated and to perform image formation at the second speed when the information satisfies the predetermined condition.

An image forming apparatus includes: an image bearing member; a developing device that develops an electrostatic latent image formed on the image bearing member; an attachment portion to which a developer supply container containing developer is attached; an information reading portion that reads information on the developer supply container stored in an information storage portion disposed in the developer supply container; a conveyance portion that communicates with a discharge port for discharging developer of the developer supply container and the developing device and conveys developer discharged from the developer supply container attached to the attachment portion to the developing device; a discharge mechanism that discharges developer from the developer supply container; and a controller that controls an operation of the discharge mechanism to reach a set discharged developer quantity using the information read by the information reading portion.

An apparatus includes a photoconductor, an exposure device, a developing device, a toner concentration sensor, a supply motor, and a processor. The exposure device exposes the photoconductor based on image data. The developing device forms a toner image on the photoconductor with toner supplied from a toner cartridge. The toner concentration sensor detects a toner concentration in the developing device. The supply motor supplies the toner from the toner cartridge to the developing device based on the toner concentration. The processor detects a toner container supply abnormality based on a toner supply rate and a print rate of the image data, the toner supply rate being calculated based on a pixel count value that is an integrated value of pixel values of the image data and a supply motor count value that is an integrated value of drive times of the supply motor.

According to an aspect of the invention, a developing device includes a developing container that accommodates a two-component developer, a toner concentration detecting unit that detects a toner concentration of the developer by a detecting unit exposed to an inner wall of the developing container, a transport member that is disposed within the developing container and stirs and transport the developer with a transport blade having a pitch that is equal to or less than a size of the detecting unit of the toner concentration detecting unit, and a plurality of gap holding members that is provided at a position facing the toner concentration detecting unit of the transport member and holds a gap such that a tip thereof is abutted against the inner wall of the developing container.

A developing device includes a developer holding member that holds a developer, a supplying member that supplies the developer to the developer holding member, a transport member that transports the developer while passing the developer onto the supplying member through a passing member, the transport member including a discharge unit that discharges excess developer and that is provided downstream of the passing member in a transport direction, a detecting unit that is provided upstream of the discharge unit in the transport direction and that detects a toner concentration, and a retaining member that includes a non-application portion that prevents action of a force for transporting the developer radially outward and that retains the developer in a region corresponding to the detecting unit of the transport member.

An image forming apparatus includes a development device, a toner storage part, a drive unit, a control unit, and an image carrying member. The development device includes a development casing, a developer carrying member, a first stirring transport member, a second stirring transport member, a discharge impeller, and a reverse transport impeller. The development casing includes a first partition wall, a communication part, a developer replenishment port, and a developer discharge part. The first stirring transport member includes a first rotation shaft and a first transport impeller. The second stirring transport member includes a second rotation shaft and a second transport impeller. The control unit can perform a developer discharge mode, in which the first rotation shaft and the second rotation shaft are rotated reversely during a non image formation period, so that the developer around the reverse transport impeller is discharged through the developer discharge part.

According to one embodiment, an image forming apparatus includes a printer and a controller. The printer performs image formation on a sheet at a first speed relating to a speed of image formation or at a second speed slower than the first speed. The controller acquires information on deterioration of developer contained in an own apparatus, and controls the printer to perform image formation at the first speed when the information does not satisfy a predetermined condition indicating that the developer is deteriorated and to perform image formation at the second speed when the information satisfies the predetermined condition.

An image forming apparatus includes a rotatable image bearing member; a developing device including a rotatable developer carrying member, a toner content detecting portion, an electrostatic capacity detecting portion, and a switching portion configured to switch a developing condition on the basis of an output of the toner content detecting portion and an output of the electrostatic capacity detecting portion so that the developing condition is changed when the electrostatic capacity detected by the electrostatic capacity detecting portion reaches first electrostatic capacity at a first toner ratio and so that the developing condition is changed when the electrostatic capacity reaches second electrostatic capacity larger than the first electrostatic capacity at a second toner ratio smaller than the first toner ratio.

An image forming apparatus includes an image bearing member configured to carry an image, a developing device configured to develop a latent image with a developer including toner and carrier, and a toner content sensor configured to detect a ratio of the toner to the developer in the developing device. A toner container contains the toner to be supplied to the developing device, and a notifying portion notifies necessity for exchange of the toner container when the ratio indicated by the output of the sensor reaches a set level lower than the predetermined range. A controller controls an image forming condition so as to change, on the basis of the output of the toner content sensor, a development contrast wherein the controller sets the development contrast at a level higher than that when the ratio is in the predetermined range, at least in part of a period from when the ratio indicated by the output of the toner content sensor becomes lower than the predetermined range to when the ratio indicated by the output of the toner content sensor reaches a first set level.