A developing apparatus includes: a developer tank that contains a developer; and conveyance members that convey the developer while agitating the developer. The conveyance members include a first screw and a second screw. The developer tank includes: a first storage chamber in which the first screw is provided; a second storage chamber in which the second screw is provided; a partition that separates the first storage chamber from the second storage chamber; and a flow area that opens the partition to flow the developer between the first storage chamber and the second storage chamber; a developer detection sensor that detects an amount of the developer thereof; a discharge port that discharges the developer; and a discharge guide that guides the developer to the discharge port. The developer detection sensor detects that the developer tank is full according to the amount of the developer.

Provided are a counting assembly and a developing box. The counting assembly comprises a counting member for attaching to and detaching from an external counted member; the counting member comprises a rotating member and a toggling member, the rotating member receives driving force from outside to rotate and the toggling member is driven to rotate; the counting assembly further comprises a holding member in contact with the rotating and toggling members. During counting, the rotating member applies a discontinuous acting force to the toggling member through the holding member; when applied with the acting force, the toggling member is kept by the holding member at a static position where the counted member is continuously pressed; when not applied with the acting force, the toggling member rotates under the action of the counter force of the counted member along a direction opposite to the rotating direction of the rotating member.

A developing apparatus includes: a developer tank that contains a developer; and conveyance members that convey the developer while agitating the developer. The conveyance members include a first screw and a second screw. The developer tank includes: a first storage chamber in which the first screw is provided; a second storage chamber in which the second screw is provided; a partition that separates the first storage chamber from the second storage chamber; and a flow area that opens the partition to flow the developer between the first storage chamber and the second storage chamber; a developer detection sensor that detects an amount of the developer thereof; a discharge port that discharges the developer; and a discharge guide that guides the developer to the discharge port. The developer detection sensor detects that the developer tank is full according to the amount of the developer.

Provided is an image forming unit including a photosensitive unit including an image bearing member, a developing unit including a developer bearing member and a container capable of containing a developer, a rotation shaft, the developing unit being rotated around the rotation shaft and positioned at one of a development position where the developer bearing member supplies the developer to the image bearing member and a separation position where the developer bearing member separates from the image bearing member, and a sensing portion sensing a variation or an amount corresponding to an amount of the developer contained in the developing unit. The rotation shaft is located below a developing portion, which is formed of the image bearing member and the developer bearing member, in a gravity direction.

Provided is an image forming unit including a photosensitive unit including an image bearing member, a developing unit including a developer bearing member and a container capable of containing a developer, a rotation shaft, the developing unit being rotated around the rotation shaft and positioned at one of a development position where the developer bearing member supplies the developer to the image bearing member and a separation position where the developer bearing member separates from the image bearing member, and a sensing portion sensing a variation or an amount corresponding to an amount of the developer contained in the developing unit. When the developing unit is at the separation position, the sensing portion restricts the rotation of the developing unit thereby receiving a force from the developing unit.

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 system for sensing material within a container includes a container having a reservoir for storing material and an impact member configured to selectively impart an impulse force on the container to cause vibration of the container. A sensor is configured to sense the vibration of the container upon the impact member imparting the impulse force on the container. Processing circuitry in communication with the sensor is configured to determine an estimate of an amount of the material in the container based on the sensed vibration of the container.

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.

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.