A remaining toner amount detecting apparatus detects a remaining toner amount in a toner bottle. The remaining toner amount detecting apparatus includes at least one pair of electrodes that are configured to face each other with the toner bottle interposed between the electrodes; a first estimator configured to estimate the remaining toner amount based on a capacitance between the electrodes of the at least one pair of electrodes; a second estimator configured to estimate the remaining toner amount by counting a number of pixels in a printed image; and an estimation selector configured to use either one of the first estimator or the second estimator to output the remaining toner amount, based on a temperature or a humidity inside an apparatus in which the toner bottle is mounted.

An image forming apparatus includes a sensor configured to detect a remaining amount of a recording agent in a cartridge mounted in the image forming apparatus, an output device configured to output at least one of visual and audio information, and a controller. The controller is configured to, upon a first cartridge being dismounted, store, as a previous remaining amount, a remaining amount of a recording agent in the first cartridge detected by the sensor. The controller is also configured to, upon a remaining amount of a recording agent in a second cartridge that has been mounted in the image forming apparatus after the first cartridge is dismounted decreasing to or below a first threshold value as detected by the sensor, control the output device to output information that varies based on a value of the previous remaining amount.

An image forming apparatus includes a developing device, a toner tank configured to receive toner supplied from a toner cartridge mounted in the image forming apparatus and to supply the toner to the developing device, a first toner sensor configured to detect a first toner residual level in the toner tank, a second toner sensor configured to detect a second toner residual level lower than the first toner residual level in the toner tank, and a processor. The processor is configured to count a number of times the first toner sensor switches from a non-detection state to a detection state subsequent to the second toner sensor switching from a detection state to a non-detection state, and then output a notification indicating a residual amount of toner in the toner cartridge based on the counted number.

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 bearing member unit and a developing unit are respectively configured to be attachable to and detachable from an apparatus main body of an image forming apparatus, the image bearing member unit has a first memory that stores information related to a toner amount during a toner supply in accordance with a use amount of the image bearing member unit, the developing unit has a second memory that stores information related to a toner amount during the toner supply in accordance with a use amount of the developing unit, and a control device controls, during the toner supply, the toner supply with a toner amount based on the information stored in the first memory and the information stored in the second memory.

A sensor holder includes a holder body that accommodates a sensor, a first snap fit that presses the sensor from a rear surface of the sensor, and two second snap fits that fix the holder body to the housing at at least two points.

A powder-amount detection device includes a first electrode, a second electrode, a third electrode and a voltage detector with the second electrode adjacent to the first electrode on the powder container and have a smaller surface area than a surface area of the first electrode. The third electrode is on a side opposite to the second electrode with the powder container interposed between the third electrode and each of the first electrode and the second electrode. The voltage detector detects voltages of the first electrode and the second electrode by detecting charging and discharging behaviors of the first electrode and the second electrode when a voltage is applied between the third electrode and each of the first electrode and the second electrode for a short time, and detects the amount of powder in the powder container based on the voltages of the first electrode and the second electrode.

An image-forming apparatus includes: a main casing; a drawer movable in a first direction between a first position inside the main casing and a second position outside the main casing; process cartridges attachable to and detachable from the drawer; a controller; and a device-side terminal connected to the controller. The process cartridges are arranged in the first direction in an attached state to the drawer. Each process cartridge includes a photosensitive drum, a magnetic roller, a developing container for storing carrier, a conveying member, a toner sensor, a process memory, and a process-side terminal. The toner sensor is configured to output a detection signal corresponding to a concentration of toner in the developing container. The process-side terminal is for both outputting the detection signal of the toner sensor and outputting information about the process cartridge stored in the process memory. The device-side terminal is configured to contact the process-side terminal.

An image forming apparatus includes an attachment section, an intermediate hopper, second storage, an image forming section, a first calculation section, and a second calculation section. The image forming section forms an image on a sheet using the toner contained in the intermediate hopper. The first calculation section, in a case where an image is to be formed on a first predetermined number of the sheets, calculates a consumed toner amount that is the amount of toner consumed during formation of the image on a second predetermined number of the sheets, the second predetermined number being smaller than the first predetermined number. The second calculation section calculates the maximum number of the sheets on which the image can be formed, on the basis of the consumed toner amount, the first toner amount, and the second toner amount.

An image forming apparatus includes a first controller having an image processor that performs image processing on image data, the first controller configured to determine a first statistic value based on the image data, and output the first statistic value; an obtaining unit configured to obtain the image data; an image forming unit configured to form, based on the image data, an image by using toner; a supply unit configured to supply toner to the image forming unit; and a second controller configured to control the supply unit based on the first statistic value. In a case where the first statistic value is not outputted by the first controller in a predetermined period, the second controller controls the supply unit based on a second statistic value, the second statistic value being determined based on the image data.