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 replaceable print component is disclosed that comprises first and second electrodes, and a circuit electrically connected between the first and second electrodes to vary an electrical property of the circuit with a frequency component within a selected frequency range to indicate a parameter of a part of the circuit in response to a stimulus.

A powder storage height detection device includes: a main body that includes a transport path along which powder is transported; a powder transport unit that is disposed to rotate in the transport path and includes a transporter provided spirally around a rotational shaft; a swinging unit that comes into contact with a surface of the powder transported in the transport path, and swings by following at least a storage height of the surface; a detection unit that detects a state of swinging of the swinging unit; and a determination unit that determines presence or absence of the powder based on a detection signal outputted from the detection unit. The transport unit includes a non-transport portion in which the transporter is not present, and which is formed as an eccentric shaft having a shaft center displaced from the rotational shaft, the swinging unit is located and disposed to swing in the non-transport portion, and the determination unit samples the detection signal at an interval, and when a proportion of the detection signal lower than or equal to an output level becomes greater than or equal to a threshold value, outputs a signal indicating determination of absence of the powder, the interval being obtained by dividing a required time for one rotation of the transport unit by a predetermined number, the output level defining that the storage height is relatively low.

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.

A powder storage height detection device includes: a main body that includes a transport path along which powder is transported; a powder transport unit that is disposed to rotate in the transport path and includes a transporter provided spirally around a rotational shaft; a swinging unit that comes into contact with a surface of the powder transported in the transport path, and swings by following at least a storage height of the surface; a detection unit that detects a state of swinging of the swinging unit; and a determination unit that determines presence or absence of the powder based on a detection signal outputted from the detection unit. The transport unit includes a non-transport portion in which the transporter is not present, and which is formed as an eccentric shaft having a shaft center displaced from the rotational shaft, the swinging unit is located and disposed to swing in the non-transport portion, and the determination unit samples the detection signal at an interval, and when a proportion of the detection signal lower than or equal to an output level becomes greater than or equal to a threshold value, outputs a signal indicating determination of absence of the powder, the interval being obtained by dividing a required time for one rotation of the transport unit by a predetermined number, the output level defining that the storage height is relatively low.

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 powder storage height detection device includes: a main body that has a transport path along which powder is transported; a powder transport unit that is disposed to rotate in the transport path and includes a transporter provided spirally around a rotational shaft; a swinging unit that comes into contact with a surface of the powder transported in the transport path, and swings by following at least a storage height of the surface; and a detection unit that detects a state of swinging of the swinging unit. The transport unit includes a non-transport portion in which the transporter is not present, and the swinging unit is located and disposed to swing in the non-transport portion, and an upper portion located above a contact portion to be in contact with the powder is configurated by an upward convex curved surface.

An example printing system for printing liquid ink has a developer device to transfer ink to an image plate of the printing system. The developer device has an ink inlet to receive ink from an ink reservoir of the printing system; a developer roller to transfer ink to the image plate, a motor to rotate the developer roller, and an ink sensor to detect arrival of ink at the developer device. The printing system is configured to start the motor in response to the ink sensor detecting arrival of ink at the developer device.

A developer storage level detecting device includes: a main body having a transporting path through which a developer is transported; a developer transporting unit that is disposed to rotate in the transporting path and has a transporting section provided spirally around a rotating shaft; a swingable member that comes in contact with a surface of the developer being transported in the transporting path and swings while following at least a level of the surface of the developer stored; and a detecting unit that detects a swing state of the swingable member, wherein the transporting unit has a non-transporting section without the transporting section, and the swingable member is disposed to swing in the non-transporting section.