A toner amount detector detects an amount of toner in a toner bottle. The toner amount detector includes at least one pair of electrodes disposed opposite each other via the toner bottle, grounding members disposed outboard of the at least one pair of electrodes and electrically grounded, circuitry to switch a first detection processing and a second detection processing, and an indicator to indicate that a positional deviation of the at least one pair of electrodes has occurred. The grounding members face the at least one pair of electrodes. The first detection processing detects the amount of toner based on a first capacitance between the at least one pair of electrodes, and the second detection processing detects a positional deviation based on a second capacitance between each of the grounding members and a corresponding one of the at least one pair of electrodes.

A method of manufacturing a developer container including a frame configured to define a developer containing portion, a first electrode, and a second electrode arranged on a surface of the frame and having a surface opposed to the first electrode, a developer amount in the developer containing portion being detected based on a capacitance between the first electrode and the second electrode, the method including: holding a conductive resin member constituting the second electrode on a mold configured to mold the frame, a surface of the conductive resin member being in contact with a surface of the mold configured to mold a surface of the frame on a side of the developer containing portion; injecting a resin to be formed into the frame, into the mold on which the conductive resin member is held; and curing the resin to form the frame to which the second electrode is fixed.

A replaceable unit for an electrophotographic image forming device according to one example embodiment includes a housing having a reservoir for storing toner. A rotatable shaft is positioned within the reservoir and has an axis of rotation. A first magnet and a second magnet are connected to the shaft and rotatable around the axis of rotation in response to rotation of the shaft. The first magnet and the second magnet pass near at least a portion of an inner wall of the housing forming the reservoir during rotation of the first and second magnets. An amount of angular offset between the first magnet and the second magnet varies depending on an amount of toner in the reservoir.

According to one embodiment, there is provided a toner cartridge used in an image forming apparatus including a processor which forms a toner pattern image on a photoconductive member, transfers the toner pattern image on a medium, and changes an image forming condition based on a detection result obtained by optically detecting the toner pattern transferred onto the medium, the toner cartridge including: a toner accommodating container accommodating a toner, and a memory. The memory stores a plurality of reference data which are determined according to toner characteristics in the toner accommodating container and a value indicating an image forming execution amount, and are used for applying reference values for an optical detection result of a toner pattern formed by the toner on the medium.

A replaceable unit for an electrophotographic image forming device includes a housing having a reservoir for holding toner. An electrical connector is positioned on a first side of the housing. The electrical connector includes an electrical contact for contacting a corresponding electrical contact in the image forming device and a magnetic sensor electrically connected to the electrical contact. The electrical connector is movable between a first position and a second position. When the electrical connector moves from the first position to the second position, the electrical contact of the replaceable unit moves from a retracted position to an operative position. When the electrical connector moves from the first position to the second position, the magnetic sensor moves from a misaligned position to an aligned position with a point in a path of movement of a magnet for sensing a magnetic field of the magnet.

A developer container includes: an accommodating portion which has a first frame and a second frame and is configured to accommodate a developer; and a conductive sheet. The second frame has a joining surface for joining the second frame to the conductive sheet, the first frame and the second frame share an uneven fitting portion where the first frame and the second frame fit with each other in a direction of intersecting the joining surface, the uneven fitting portion has a contact face where the first frame and the second frame are being in contact with each other, a gap is formed by the first frame, the second frame and the conductive sheet, and the contact face is a face facing the gap and being disposed in a direction along the joining surface.

A replaceable unit for an electrophotographic image forming device according to one example embodiment includes a housing having a reservoir for storing toner. A rotatable shaft is positioned within the reservoir and has an axis of rotation. A first magnet and a second magnet are connected to the shaft and rotatable around the axis of rotation in response to rotation of the shaft. The first magnet and the second magnet pass near at least a portion of an inner wall of the housing forming the reservoir during rotation of the first and second magnets. An amount of angular offset between the first magnet and the second magnet varies depending on an amount of toner in the reservoir.

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.

A remaining toner amount detecting apparatus includes two electrodes; a remaining toner amount detector configured to detect a remaining toner amount in a toner container based on a capacitance between the two electrodes; a storage configured to store a first capacitance value between the two electrodes preliminarily detected in a non-disposed state in which the toner container is not disposed between the two electrodes; and an abnormality detector configured to detect an abnormality of the remaining toner amount detecting apparatus based on the first capacitance value stored in the storage and a second capacitance value between the two electrodes that is detected in the non-disposed state.

A resonance circuit (2) includes a capacitor (C1) and an inductor (L1, L2) of which an inductance is changed depending on developer including toner, and generates an output voltage corresponding to the inductance. A detecting circuit (3) detects the toner on the basis of the output voltage. An adjustment-purpose closed circuit (4) includes a semi-fixed resistor (VR1) and an adjustment inductor (L3) that forms magnetic coupling with the inductor (L1, L2), and causes an inductance of the inductor (L1, L2), a resonance frequency of the resonance circuit (2), an amplitude of the output voltage and a detected toner amount to be adjustable with a variable resistance value of the semi-fixed resistor (VR1).