An image forming apparatus measures, using a toner concentration sensor installed in a developing apparatus of the image forming apparatus, a toner concentration of a developer stored in the developing apparatus to obtain an output waveform. The image forming apparatus calculates, based on the output waveform, a first characteristic value corresponding to a volume of the developer. Based on a result of comparing the first characteristic value with a reference value calculated from a reference output waveform obtained in an initial state of the developing apparatus, the image forming apparatus determines whether to execute a discharge mode for discharging the developer from the developing apparatus and to control an amount of the developer. The image forming apparatus discharges, according to a result of the determining, a portion of the developer from the developing apparatus by controlling a driving speed of the developing apparatus when the discharge mode is executed.

A developing device includes a developing case, a toner concentration sensor, and a positioner. The developing case stores a developer containing toner and carrier to develop a latent image on a surface of an image bearer. The developing case includes at least a part of a conveyance path of the developer. The toner concentration sensor detects a toner concentration of the developer in the developing case. The positioner engages with an engaging portion at a center of a sensor main section of the toner concentration sensor to determine a position of the sensor main section in the developing case.

An image forming apparatus includes a motor, a container detection sensor, and a controller. When a toner container is attached, the motor generates a driving force for rotating a toner conveying member in the toner container. The container detection sensor is arranged at a position where the container detection sensor comes into contact with an outer periphery of a cam connected to the toner conveying member when the toner container is attached. The controller distinguishes between at least three attachment states of the toner container based on a sensor signal of the container detection sensor.

The control unit executes a mode of detecting the image density of the toner image for control. The control unit sets the target toner density so that the target toner density becomes smaller than before execution of the mode and also set the target transfer current so that the target transfer current becomes smaller, in a case where the image density detected in the mode is higher by a predetermined threshold or more than a reference density.

A print apparatus is disclosed. The print apparatus comprises a container-receiving unit for receiving a reusable print agent container; a print agent reservoir for storing print agent to be consumed by the print apparatus during a printing operation; a pump for transferring print agent between a reusable print agent container positioned in the container-receiving unit and the print agent reservoir; and processing circuitry. The processing circuitry is to operate the pump to transfer print agent of a first concentration from the reusable print agent container to the print agent reservoir; and, responsive to determining that a volume of print agent of the first concentration in the reusable print agent container has fallen below a threshold volume, operate the pump to transfer a volume of print agent of a second, lower concentration from the print agent reservoir to the reusable print agent container. A method and a machine-readable medium are also disclosed.

An image forming apparatus includes an image carrier, a developer, a toner conveyer, a toner replenisher, a toner, and a processor. The image carrier is configured to hold an electrostatic latent image. The developer is configured to form a toner image by causing toner to adhere to the electrostatic latent image. The toner conveyer is configured to convey the toner in the developer. The toner replenisher is configured to replenish the developer with the toner. The toner concentration sensor is configured to detect a concentration of the toner in the developer. The processor configured to: determine a toner replenishment amount; determine an estimated toner concentration value from the toner replenishment amount; receive the concentration from the toner concentration sensor; determine a measured toner concentration value based on the concentration; and cause the toner replenisher to replenish the developer with the toner replenishment amount.

An image forming apparatus includes: an image carrier configured to carry an image; a developing unit configured to develop the image carried by the image carrier with a developer; and a developer replenishing unit configured to supply the developer to the developing unit, the developer replenishing unit being configured to predict, in advance, an amount of developer consumed by the image carrier at a start or an end of image formation apart from developer consumed in the image formation, to replenish the predicted amount of the developer.

An image forming apparatus includes: an image carrier that carries an image; a developing device that develops a latent image formed on the image carrier into a visible image formed of powder; an intermediate transfer body to which the visible image is transferred from the image carrier and that temporarily transports the visible image; a transfer device that transfers the visible image on the image carrier to the intermediate transfer body; a first cleaning device that cleans the image carrier by collecting powder that remains on the image carrier; a first collection container that receives the powder collected by the first cleaning device; a second cleaning device that cleans the intermediate transfer body by collecting powder that remains on the intermediate transfer body; a second collection container that receives the powder collected by the second cleaning device; a feeding device that supplies a transfer-process bias to the transfer device; and a changing unit that changes the transfer-process bias supplied by the feeding device when a waste powder image is formed on the image carrier, the transfer-process bias being changed so as to adjust amounts of powder in the waste powder image received by the first collection container and the second collection container.

In an example, a printing device may include a cartridge including a print substance, a belt, and a controller including a processing resource and a memory resource. The processing resource may execute instructions to deposit a plurality of patches of the print substance from the cartridge onto the belt to determine a cartridge density based on a density of a sub-set of patches of the plurality of patches; and adjust a print substance output of the cartridge based on the determined density of the print substance in the cartridge.

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.