An image forming apparatus includes: an image carrier; a developing unit which supplies a toner contained in a developer to the image carrier; a lubricant supply unit which supplies a lubricant to the image carrier; a lubricant amount detection unit which detects an amount of the lubricant which is supplied to the image carrier from the lubricant supply unit and is thereafter incorporated into the developing unit from the image carrier; and a control unit which controls the developing unit to discharge the lubricant from the developing unit according to the amount of the lubricant detected by the lubricant amount detection unit.

An image forming apparatus includes an apparatus body, an image bearing member, and a process unit attached to the apparatus body, the process unit including a frame including a storage portion configured to store developer, a developer bearing member configured to supply developer to the image bearing member to develop an electrostatic latent image; and a circuit board attached to the frame, wherein the circuit board includes a light emitting portion configured to emit light, and a light receiving portion configured to receive the light emitted from the light emitting portion and having passed through an interior of the storage portion.

An image forming apparatus includes an image forming part, a toner storage part, a toner conveyance part, a drive motor and a control part. The image forming part forms an image on a sheet using a toner. The toner storage part stores the toner replenished to the image forming part. The toner conveyance part conveys the toner. The drive motor generates a drive force by which the toner conveyance part conveys the toner. The control part generates a control signal for controlling the drive motor, based on information showing a rotational speed of the drive motor. The control part executes a determination processing for determining whether a driving of the drive motor is stopped, based on the control signal.

A toner container information acquiring method includes: measuring a toner amount contained in a resin forming a toner container; and acquiring information regarding mechanical strength of the toner container based on the measured toner amount.

An image forming apparatus includes an image carrier, a developing device, a voltage applier, a current detector, a weight detector, and a control device. The control device acts as a first measurer, a second measurer, and an estimator. The first measurer acquires a toner use amount indicating weight per unit area, of the toner that has migrated from the developing agent carrier to the image carrier, according to a detection result provided by the weight detector. The second measurer acquires the developing current from the current detector. The estimator calculates a value of decision coefficient, obtained by dividing variance of an estimated value in a regression model between the toner use amount and the developing current, by variance of a sample value, and estimates deterioration status of the toner, according to the value of the decision coefficient.

An example operation method of an image forming apparatus includes obtaining, from a sensor, an output signal corresponding to a degree of shrinkage of a transporting member that transports a developing agent in a toner cartridge, as the transporting member rotates, determining a state of the toner cartridge based on a characteristic of the output signal, and executing a recovery mode that increases a driving force delivered to the transporting member when determining that the state of the toner cartridge is an abnormal state in which toner is not normally supplied to a developing device.

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.

A remaining-toner-amount detecting device includes: first sensor disposed at a supply channel for a toner; a second sensor disposed at a location different from the supply channel; detection processing that compares a capacitance detected by the first sensor with a determination threshold value to detect a toner end; and a memory that stores a capacitance detected by the second sensor in an initial period as initial reference data, and a capacitance detected by the second sensor after part replacement as post-replacement reference data. The detection processing circuitry sets, based on the initial reference data, the determination threshold value as an initial determination threshold value in the initial period, and re-sets the determination threshold value, from the initial determination threshold value, to a value based on the post-replacement reference data, as a post-replacement reference data after the part replacement.

An example operation method of an image forming apparatus includes obtaining, from a sensor, an output signal corresponding to a degree of shrinkage of a transporting member that transports a developing agent in a toner cartridge, as the transporting member rotates, determining a state of the toner cartridge based on a characteristic of the output signal, and executing a recovery mode that increases a driving force delivered to the transporting member when determining that the state of the toner cartridge is an abnormal state in which toner is not normally supplied to a developing device.

A powder transport device includes a transport unit, a spiral first transport member, and a first driving unit. The transport unit has a transport path. The first transport member is rotatably disposed in the transport path and rotates forward to transport powder. The first driving unit drives the first transport member to rotate. The first driving unit rotates the first transport member in reverse when both (i) a non-operation time during which the first transport member is not rotated and (ii) detection information on a temperature satisfy a condition.