An image forming apparatus includes a developing device, a first container, a second container, and a toner supplying device. The toner supplying device includes first and second conveyance members that convey the toner in the first and second containers, and first and second sensing shafts that are used to sense the remaining quantities of toner there. The first and second sensing shafts have a first or second light-shielding plate that moves into and out of the optical path of an optical sensor. Of the first and second light-shielding plates, one rotates together with the first or second conveying member selectively driven and makes contact with the other, and thereby makes it move out of the optical path of the optical sensor.

An image forming apparatus includes: a detection unit configured to detect an amount of developer stored in a developing container and to output remaining amount information; and a control unit configured to perform control, during a replenishment of the developer to the developing container using a replenishment container, to cause a display unit to display a message related to the replenishment. When the replenishment is instructed, the control unit is further configured to perform a first control during the replenishment in a case where the remaining amount information indicates a first remaining amount, and configured to perform a second control different from the first control during the replenishment in a case where the remaining amount information indicates a second remaining amount greater than the first remaining amount.

An image forming apparatus includes an image forming device and circuitry. The image forming device forms an image with colorants of different colors. The circuitry determines whether there is a possibility that a shortage of a colorant adhesion amount occurs in primary-color image formation using a colorant of a primary color and cause the image forming device to perform two-color image formation in which only secondary-color image formation using a colorant of a secondary color different from the colorant of the primary color is added to the primary-color image formation using the colorant of the primary color to form an image to be formed with the colorant of the primary color, when the circuitry determines that there is a possibility that the shortage of the colorant adhesion amount occurs in the primary-color image formation using the colorant of the primary color.

A waste toner storage container includes a container body, a toner storage chamber, and a paddle. The toner storage chamber includes an introduction port, a first space, and a second space. The introduction port receives waste toner. The first space stores the introduced waste toner, and extends in a first direction. The second space is disposed in an end portion of the first space in a second direction orthogonal to the first direction. The paddle includes a shaft, a first plate, and a second plate. The shaft is disposed in the first space, extends along the first direction, and is elongated. The first plate is formed on an outer peripheral surface around a central axis of the shaft, and conveys the waste toner in the first direction. The second plate is formed on the outer peripheral surface of the shaft, and conveys the waste toner toward the second space.

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 rotatable image bearing member to bear an electrostatic latent image, a developing container to accommodate developer including toner and to allow new developer to be replenished by a developer replenishing container, and a developer bearing member to develop the electrostatic latent image into a toner image by using the developer in the developing container. A transfer roller transfers the toner image born on the image bearing member onto the recording material, and a controller notifies replenishment information for prompting replenishing the developing container with the new developer by the developer replenishing container. The controller notifies the replenishment information in a state in which an index correlated with a ratio of an amount of paper dust mixed in the developer in the developing container to an amount of the developer in the developing container has not exceeded a preset threshold value of the index.

An image forming apparatus includes a toner container, a first conveyance unit, and an apparatus main body. The apparatus main body includes a photosensitive drum, a development roller, a second conveyance unit, a toner conveyance passage, light sensor, an acquisition unit, and a control unit configured to execute an abnormality detection mode. In an abnormality detection mode, the acquisition unit acquires a first acquired value after the driving of the second conveyance unit with the driving of the first conveyance unit stopped. When the first acquired value satisfies a first condition, the acquisition unit further acquires a second acquired value after the driving of the second conveyance unit with the driving of the first conveyance unit stopped. The apparatus main body further includes a notification unit to make notification of the abnormality when the second acquired value satisfies a second condition.

A waste toner storage container includes a container body, a toner storage chamber, and a paddle. The toner storage chamber includes an introduction port, a first space, and a second space. The introduction port receives waste toner. The first space stores the introduced waste toner, and extends in a first direction. The second space is disposed in an end portion of the first space in a second direction orthogonal to the first direction. The paddle includes a shaft, a first plate, and a second plate. The shaft is disposed in the first space, extends along the first direction, and is elongated. The first plate is formed on an outer peripheral surface around a central axis of the shaft, and conveys the waste toner in the first direction. The second plate is formed on the outer peripheral surface of the shaft, and conveys the waste toner toward the second space.

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 in the developer container.

An attachment is attached to a holding shaft and includes a first hollow axial portion including a first slit that receives the holding shaft. A supplemental member includes a second hollow axial portion including a second slit that receives the holding shaft. The supplemental member rotates in a forward direction and a backward direction. A restrictor restricts rotation of the supplemental member in the forward direction and the backward direction in a state in which the first slit and the second slit receive the holding shaft.