A developing device includes a storage portion storing a developer, a conveying portion stirring and conveying the developer in the storage portion, a sensor, an acquisition processing portion, and a correction processing portion. The sensor outputs an electrical signal in accordance with magnetic permeability at a predetermined detection position in a conveyance path of the developer. The acquisition processing portion acquires a specific value based on the electrical signal outputted during a rotation period of the conveying portion. The correction processing portion corrects the specific value based on a rotation speed of the conveying portion when a fluctuation width of the electrical signal outputted during the rotation period of the conveying portion is less than a predetermined threshold, and corrects the specific value based on the rotation speed of the conveying portion and the fluctuation width when the fluctuation width is equal to or greater than the threshold.

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.

A developing device includes a storage portion storing a developer, a conveying portion stirring and conveying the developer in the storage portion, a sensor, an acquisition processing portion, and a correction processing portion. The sensor outputs an electrical signal in accordance with magnetic permeability at a predetermined detection position in a conveyance path of the developer. The acquisition processing portion acquires a specific value based on the electrical signal outputted during a rotation period of the conveying portion. The correction processing portion corrects the specific value based on a rotation speed of the conveying portion when a fluctuation width of the electrical signal outputted during the rotation period of the conveying portion is less than a predetermined threshold, and corrects the specific value based on the rotation speed of the conveying portion and the fluctuation width when the fluctuation width is equal to or greater than the threshold.

An image forming apparatus includes a sensor configured to detect a remaining amount of a recording agent in a cartridge mounted in the image forming apparatus, an output device configured to output at least one of visual and audio information, and a controller. The controller is configured to, upon a first cartridge being dismounted, store, as a previous remaining amount, a remaining amount of a recording agent in the first cartridge detected by the sensor. The controller is also configured to, upon a remaining amount of a recording agent in a second cartridge that has been mounted in the image forming apparatus after the first cartridge is dismounted decreasing to or below a first threshold value as detected by the sensor, control the output device to output information that varies based on a value of the previous remaining amount.

A logic circuitry package for a print apparatus component includes an interface to communicate with a print apparatus logic circuit, and at least one logic circuit. The at least one logic circuit is configured to receive, via the interface, a command series addressed to a first default address and a second default address, and transmit, via the interface, at least one response in response to at least one command of the command series. The at least one logic circuit is configured to receive, via the interface, an other command series addressed to an other first default address and subsequently, the second default address, and transmit, via the interface, at least one other response in response to at least one other command of the other command series.

An image forming device may comprise: an attaching unit to which a removable toner bottle is attached; a toner storage that stores toner supplied from the toner bottle attached to the attaching unit; a detector that detects an empty state of toner in the toner storage; and a hardware processor that: supplies toner to the toner storage from the toner bottle when the toner bottle attached to the attaching unit is new; and switches a state of the toner bottle to an old state from a new state if the empty state detected by the detector is released.

A developing device develops an electrostatic latent image formed on a photosensitive drum. A bottle rotation sensor detects rotation of a toner bottle that stores toner. A bottle motor drives the toner bottle for rotation to thereby discharge toner from the toner bottle. A hopper-internal toner sensor detects presence/absence of toner stored in a hopper that stores toner discharged from the toner bottle. A replenishment unit replenishes toner stored in the hopper to the developing device. Which of failure of the bottle rotation sensor and rotation failure of the toner bottle has occurred is determined based on a detection result of the bottle rotation sensor and a detection result of the hopper-internal toner sensor.

An image forming apparatus includes a sheet cassette, a waste developer container, a capacitance sensor, a partition conductor, and a state determination unit. The waste developer container is disposed adjacent to the sheet cassette, and the capacitance sensor is disposed between the waste developer container and the sheet cassette. The partition conductor partitions between the sheet in the sheet cassette and the capacitance sensor, and is grounded. The state determination unit determines an amount of the waste developer in the developer container, based on a detection signal of the electrostatic capacitance sensor.

An image forming apparatus includes a sheet cassette, a waste developer container, a capacitance sensor, a partition conductor, and a state determination unit. The waste developer container is disposed adjacent to the sheet cassette, and the capacitance sensor is disposed between the waste developer container and the sheet cassette. The partition conductor partitions between the sheet in the sheet cassette and the capacitance sensor, and is grounded. The state determination unit determines an amount of the waste developer in the developer container, based on a detection signal of the electrostatic capacitance sensor.

An approach is provided for monitoring and reporting capacity of a toner cartridge in a printing device. The printing device determines estimated toner levels based on actual toner levels obtained from a toner sensor of the printing device. The estimated toner levels are determined based on a first actual toner level and a second actual toner level obtained from the toner senor and print usage between the two actual toner levels. The estimated toner levels are determined for levels below the second actual toner level and are mapped to synthetic toner levels. Visual indications of the synthetic toner levels are displayed on the printing device.