An amount-of-remaining-toner detecting device includes: a toner housing portion in which a toner bottle is housed, the toner bottle having a bottle body that is cylindrical and in which toner is housed, and a cap that is attached to one end of the bottle body in an axial direction of the bottle body and from which the toner housed in the bottle body is discharged; and circuitry configured to detect an amount of remaining toner in the toner bottle housed in the toner housing portion. The toner housing portion includes a first pair of electrodes facing each other with the bottle body interposed between the first pair of electrodes, and a second pair of electrodes facing each other with the bottle body interposed between the second pair of electrodes, at respective positions closer to the cap than the first pair of electrodes are. The circuitry detects the amount of remaining toner in the bottle body, based on at least one of a capacitance value between the first pair of electrodes or a capacitance value between the second pair of electrodes.

An image forming apparatus includes a plurality of light sources, a light source control unit that controls turning on and off of the plurality of light sources, a first detection unit that detects an accumulated amount of waste toner with respect to the total capacity of the first waste toner container, and a second detection unit that detects an accumulated amount of waste toner with respect to the total capacity of the second waste toner container. The light source control unit turns on one of the plurality of light sources, based on detection results of the first detection unit and the second detection unit.

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 method of operating an image forming apparatus includes measuring a toner concentration supplied to a developing apparatus and increasing a driving speed of the developing apparatus based on the toner concentration not reaching a target toner concentration. The toner concentration is measured in a state where the driving speed of the developing apparatus is increased, and, based on the toner concentration not reaching the target toner concentration based on the driving speed of the developing apparatus being increased, an operating state of the image forming apparatus is determined based on a remaining amount of toner.

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.

An apparatus is configured to obtain operating information related to an operation amount of an image forming apparatus through the communication circuit, obtain another operating information related to another operation amount of another image forming apparatus located in a same installation location at which the image forming apparatus is located, determine, based on the operating information and the another operating information, a replacement timing for replacing a consumable component used in the image forming apparatus, and output the replacement timing.

A developing device includes a developing container, a detecting unit including a base portion and a detecting portion, a feeding path, a feeding screw, and a recessed portion provided on a side wall of the developing container. The recessed portion is disposed so as to project toward the feeding screw in the feeding path. The side wall includes a projected region projected toward the screw portion in the feeding path by the recessed portion and a region other than the projected region. The feeding screw includes a first screw portion opposing the projected region and a second screw portion opposing the region other than the projected region. The first screw portion includes a rotation shaft which includes a portion having a shaft diameter smaller than a shaft diameter of a rotation shaft of the second screw portion.

An image forming apparatus includes a mounting portion, a lock mechanism, an image forming unit, a first detection processing unit, a second detection processing unit, a first release processing unit, and a second release processing unit. The first detection processing unit detects a first state where a remaining amount of the developer is less than a predetermined first reference amount. The second detection processing unit detects a second state where the remaining amount of the developer is equal to or more than the first reference amount and less than a predetermined second reference amount. The second reference amount is larger than the first reference amount. The first release processing unit releases the regulation on the attachment/removal of the developer housing portion when the first state is detected. The second release processing unit releases the regulation when unit the second state is detected and a predetermined release condition is met.

A powder transport device includes: a rotation shaft rotatably supported in a container chamber that contains powder; and plural blade members detachably attached to the rotation shaft, the blade members including spiral blades configured to transport the powder in an axial direction of the rotation shaft in response to the rotation shaft rotating.

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.