A container attachment device includes a toner container, an attached part for the toner container and a displacement sensor. The displacement sensor faces to the toner container to detect electrostatic capacity according to the toner. The attached part includes a cover opening/closing an opening of the toner container. The cover closing or opening the opening faces to the displacement sensor, and the cover opening or closing the opening is away from the displacement sensor. The displacement sensor detects the electrostatic capacity varying among a first condition opening the cover and detaching the toner container, a second condition closing the cover and detaching the toner container, a third condition opening the cover and attaching the toner container, and a fourth condition closing the cover and attaching the toner container. In the third or fourth condition, the displacement sensor detects the electrostatic capacity according to a toner quantity in the toner container.

A powder collection device includes a collection container configured to store powder collected and a powder amount detector including a pair of electrodes. The powder amount detector detects an amount of powder in the collection container based on capacitance between the pair of electrodes.

A resin member includes a base material and a resin molded body disposed on the base material, the resin molded body containing a main component constituted by an ethylene-vinyl acetate copolymer resin and a carbon black. The resin molded body has two or more peaks within a range of 25 C. to 80 C. in an endothermic curve obtained through measurement performed by heating from 25 C. to 150 C. at 5 C./min with a differential scanning calorimetry (DSC) apparatus.

A powder amount detector detects an amount of powder in a powder container of a cylindrical shape arranged horizontally. The powder amount detector includes a pair of measuring electrodes configured to detect capacitance between the pair of measuring electrodes to detect the amount of powder. The pair of measuring electrodes is disposed around the powder container. One of the pair of measuring electrodes has a flat shape, and the other of the pair of measuring electrodes has an arc shape following a shape of the powder container.

A printer including: a powder housing chamber that houses powder including a color material and carrier; a supplying conveying unit that conveys the powder while supplying the powder to a powder holder that holds the powder, by forward rotation; a detection unit that detects the amount of powder within the powder housing chamber, upstream in a conveyance direction from a discharge unit that discharges surplus powder, downstream in the conveyance direction from the supplying conveying unit, and above a rotary shaft of the supplying conveying unit; and a control unit that controls at least one of the rotation direction and the rotation speed of the supplying conveying unit on the basis of a detection result of the detection unit.

A printer including a body, a developer cartridge, and a developer level sensor. The body includes a printing unit to print an image on a print medium based on electrophotography. The developer cartridge is attachable to the body and includes a developer container including a developer, and a developer outlet provided at a length-direction side of the developer container to supply the developer from the developer container to the printing unit. The developer level sensor is installed on the body near the developer outlet to generate an electrical detection signal based on a developer level of the developer container.

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.

An image forming apparatus includes a developing device to contain a developer, the developer including a toner; a developer cartridge to supply the developer to the developing device; a toner concentration sensor to sense a toner concentration of the toner included in the developer contained in the developing device; and a controller. The controller controls, during a non-printing operation a sensor control voltage to adjust an output level of the toner concentration sensor, to control an output of the toner concentration sensor to satisfy a controlling condition, and detects an shape of the output of the toner concentration sensor after the controller controls the sensor control voltage to adjust the output level. The controller adjusts, during a printing operation, the output of the toner concentration sensor, based on the detected shape of the output of the toner concentration sensor, and adjusts supplying the developer from the developer cartridge to the developing device, according to the adjusted output of the toner concentration sensor, to control the toner concentration.

An image forming apparatus includes a permeability sensor configured to detect information on magnetic permeability of developer contained in a developer container for detecting toner density of the developer, and a controller configured to control a control voltage applied to the permeability sensor so that (i) a value of the control voltage that is applied to the permeability sensor in a case where a predetermined condition including a condition that the toner density of the developer contained in the developer container is a predetermined density is satisfied and an amount of the developer contained in the developer container is a first amount is greater than (ii) a value of the control voltage applied to the permeability sensor in a case where the predetermined condition is satisfied and the amount of the developer contained in the developer container is a second amount greater than the first amount.

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.