The image forming apparatus includes a developing device, a toner container, a first mechanism, a toner sensor, and a controller. The developing device adheres toner to an electrostatic latent image on a photoconductor to form a toner image. The toner container supplies toner to the developing device. The first mechanism causes a toner interface to undulate in the toner container. The toner sensor detects a capacitance between a first electrode and a second electrode arranged apart from the first electrode. The controller determines a remaining amount of toner in the toner container based on detection information from the toner sensor.

There are demands for stable connections of contact points between a process cartridge, including a development device, and an image forming device. A development contact point, a first contact point, and a second contact point are disposed in this order on the inside in a perpendicular direction with respect to an insertion direction in which a development device is inserted into an image forming apparatus.

An example toner refill cartridge includes a body to accommodate toner, a plunger inserted into the body and movably coupled to the body in a longitudinal direction of the body, and capable of pushing the toner out of the body, a toner injection amount detector to detect each of a plurality of movement positions of the plunger in accordance with the movement of the plunger, and a connection interface to connect to an image forming apparatus to transmit a signal corresponding to each of the detected movement position to the image forming apparatus.

According to an embodiment, an image forming apparatus includes an image bearing body, a developing unit, a supplying unit, a detecting unit, and a control unit. The supplying unit supplies a recording agent from a recording agent cartridge to the developing unit. The detecting unit detects a residual amount of the recording agent. The control unit controls, if the recording agent cartridge is not replaced, the supplying unit to supply the recording agent to the developing unit if the detected residual amount decreases to a first residual amount or less and controls, if the recording agent cartridge is replaced, the supplying unit to supply the recording agent in the recording agent cartridge after the replacement to the developing unit if the detected residual amount of the recording agent in the recording agent cartridge before the replacement decreases to a second residual amount or less.

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 example image forming apparatus includes a printing engine to perform a printing work by using toner filled in a toner cartridge, a communication device to communicate with a circuit board attached to a toner refill apparatus that refills toner in the toner cartridge by using a plurality of terminals, and a processor to identify a connection state of the toner refill apparatus based on a voltage value of at least one of the plurality of terminals.

An image forming apparatus including: a printing unit; a bottle which is rotationally driven in a predetermined rotation direction, whereby a waste developer conveyed from the printing unit to an opening is accommodated inside and the waste developer inside is conveyed to a second end side in a longitudinal direction; and a capacitive sensor having a first detection electrode and a first ground electrode arranged in parallel, where a first detection surface of an electrostatic capacitance formed by the first detection electrode and the first ground electrode is arranged to directly face a portion of an outer peripheral surface of the bottle which is positioned obliquely upward with respect to a center line of rotation of the bottle in a region which moves from a bottom to a top when the bottle rotates in the predetermined rotation direction.

A print agent vessel is disclosed that comprises a circuit, the circuit comprising a first electrically conductive portion to couple to a first terminal of a printing device, a second electrically conductive portion to couple to a second terminal of the printing device, and an electrically conductive component capacitively coupled to the first electrically conductive portion. The circuit has a variable capacitance that is indicative of a parameter of the component.

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 cassette attachment part and a collection side attachment part. To the cassette attachment part, a sheet feeding cassette storing a sheet is detachably attached. The collection side attachment part is disposed adjacent to the cassette attachment part. To the collection side attachment part, a collection container storing a waste toner discharged without transferred on the sheet is detachably attached. The cassette attachment part includes a cassette rail which supports the sheet feeding cassette slidably and a rail holding member which holds the cassette rail. The collection side attachment part includes a displacement sensor which is disposed so as to face the collection container and detects an electrostatic capacity varying in response to an accumulation amount of the waste toner stored in the collection container. The rail holding member is disposed so as to face at least a part of the displacement sensor.