An image forming apparatus, including: a photoconductor; a developing device; a developer storage; a supplier configured to supply developer; an optical sensor; and a controller configured to execute: a developing process of developing an electrostatic latent image on the photoconductor; a usage-amount obtaining process of obtaining a usage amount of the developer; a supplying process of supplying the developer to the developing device every time when the obtained usage amount becomes equal to or greater than a first threshold; and a detecting process of detecting, by the optical sensor, an amount of the developer in the developing device every time when the obtained usage amount becomes equal to or greater than a second threshold larger than the first threshold, and wherein the controller is configured to execute the detecting process in a period different from a period in which the developing process is being executed.

An image forming apparatus, including: a photoconductor; a developing device; a developer storage; a supplier configured to supply developer; an optical sensor; and a controller configured to execute: a developing process of developing an electrostatic latent image on the photoconductor; a usage-amount obtaining process of obtaining a usage amount of the developer; a supplying process of supplying the developer to the developing device every time when the obtained usage amount becomes equal to or greater than a first threshold; and a detecting process of detecting, by the optical sensor, an amount of the developer in the developing device every time when the obtained usage amount becomes equal to or greater than a second threshold larger than the first threshold, and wherein the controller is configured to execute the detecting process in a period different from a period in which the developing process is being executed.

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.

An image forming apparatus includes an apparatus body, an image bearing member, and a process unit attached to the apparatus body, the process unit including a frame including a storage portion configured to store developer, a developer bearing member configured to supply developer to the image bearing member to develop an electrostatic latent image; and a circuit board attached to the frame, wherein the circuit board includes a light emitting portion configured to emit light, and a light receiving portion configured to receive the light emitted from the light emitting portion and having passed through an interior of the storage portion.

An image forming apparatus, including: a photoconductor; a developing device; a developer storage; a supplier configured to supply developer; an optical sensor; and a controller configured to execute: a developing process of developing an electrostatic latent image on the photoconductor; a usage-amount obtaining process of obtaining a usage amount of the developer; a supplying process of supplying the developer to the developing device every time when the obtained usage amount becomes equal to or greater than a first threshold; and a detecting process of detecting, by the optical sensor, an amount of the developer in the developing device every time when the obtained usage amount becomes equal to or greater than a second threshold larger than the first threshold, and wherein the controller is configured to execute the detecting process in a period different from a period in which the developing process is being executed.

According to one embodiment, an image forming apparatus includes: an image forming unit configured to form a toner image using a first toner supplied to the image forming unit with a first process bias VR; a density sensor configured to detect a density of toner in the image forming unit; a toner cartridge containing a second toner and including a memory that stores data representing a process bias VA appropriate for the second toner; a mounting unit on which the toner cartridge is mounted; and a toner replenishing unit configured to replenish the image forming unit with the second toner from the toner cartridge mounted on the mounting unit based on the density, in which a density detected by the density sensor when the toner cartridge is mounted on the mounting unit is converted into an estimated amount, and the image forming unit is set to a process bias V until the image forming unit is replenished with the second toner by the estimated amount after the toner cartridge is mounted on the mounting unit, the process bias V being obtained from the following formula V=VA−((VA−VR)/the estimated amount)×(an amount of the second toner with which the image forming unit is replenished after the toner cartridge is mounted on the mounting unit).

An image forming apparatus, including: a photoconductor; a developing device; a developer storage; a supplier configured to supply developer; an optical sensor; and a controller configured to execute: a developing process of developing an electrostatic latent image on the photoconductor; a usage-amount obtaining process of obtaining a usage amount of the developer; a supplying process of supplying the developer to the developing device every time when the obtained usage amount becomes equal to or greater than a first threshold; and a detecting process of detecting, by the optical sensor, an amount of the developer in the developing device every time when the obtained usage amount becomes equal to or greater than a second threshold larger than the first threshold, and wherein the controller is configured to execute the detecting process in a period different from a period in which the developing process is being executed.

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.

According to one embodiment, an image forming apparatus includes: an image forming unit configured to form a toner image using a first toner supplied to the image forming unit with a first process bias VR; a density sensor configured to detect a density of toner in the image forming unit; a toner cartridge containing a second toner and including a memory that stores data representing a process bias VA appropriate for the second toner; a mounting unit on which the toner cartridge is mounted; and a toner replenishing unit configured to replenish the image forming unit with the second toner from the toner cartridge mounted on the mounting unit based on the density, in which a density detected by the density sensor when the toner cartridge is mounted on the mounting unit is converted into an estimated amount, and the image forming unit is set to a process bias V until the image forming unit is replenished with the second toner by the estimated amount after the toner cartridge is mounted on the mounting unit, the process bias V being obtained from the following formula V=VA−((VA−VR)/the estimated amount)×(an amount of the second toner with which the image forming unit is replenished after the toner cartridge is mounted on the mounting unit).

An optical sensor includes a first light emitting diode (LED), a second LED, a first photodiode (PD), and a second PD. The first LED and the second LED are configured to irradiate an optical-axis center point of an intermediate transfer belt. The first PD is arranged at a position at which specularly reflected light of light emitted from the first LED and diffused reflected light of light emitted from the second LED are received. The second PD is arranged at a position at which diffused reflected light of the light emitted from the first LED is received.