An image forming apparatus includes a developing device, an image bearing member, an image density detecting portion, a toner content detecting portion, a humidity sensor, a supplying portion, and a controller configured to control the supplying portion so that a toner content is between an upper limit and a lower limit thereof. The controller can execute setting control in which the target value of the toner content is set on the basis of an image density of a reference toner image. The controller sets the lower limit until execution of subsequent setting control, wherein the lower limit is higher when a humidity is a first humidity and an average image ratio is a first ratio than when the humidity is a second humidity higher than the first humidity and the average image ratio is a second ratio larger than the first ratio.

An image forming apparatus includes a high-voltage power supply that supplies high-voltage electric power, a charging device that is charged by the electric power supplied from the high-voltage power supply, a photoconductor that carries an image to be formed on a recording medium, with the electric power supplied from the charging device, a temperature sensor disposed at a distant from the photoconductor that detects temperature inside the image forming apparatus, a humidity sensor disposed at a distant from the photoconductor that detects inside the image forming apparatus, and circuitry that outputs a signal for commanding an electric power value to the high-voltage power supply to cause the high-voltage power supply to supply the electric power with the electric power value, and controls supply of the electric power based on an electric power value feedback signal from the high-voltage power supply.

An image forming apparatus including a controller, which starts rotation of a rotary polygon mirror when a predetermined condition is satisfied, rotates the rotary polygon mirror at a predetermined rotation speed based on a first pulse in a first state in which light beams are not emitted from a light source, thereafter starts emission of the light beams, switches a rotation control based on the first pulse to a rotation control based on the second pulse, and rotates the rotary polygon mirror at the predetermined rotation speed based on the second pulse in a second state in which the light beams are emitted from the light source, and thereafter detects a temperature of a drive circuit board by a temperature detector, and corrects color misregistration using a detected temperature of the temperature detector and the detection result of a pattern detector.

According to an embodiment, an image forming apparatus includes a developing device including a toner receiving portion configured to contain toner and a movable part moveable at a first speed and a second speed, the moveable part at least partially disposed within the toner receiving portion, a temperature sensor disposed adjacent to the developing device, and a control unit operatively coupled to the temperature sensor and the developing device, wherein the control unit controls the movable part to move at a first speed when the temperature sensor detects a temperature less than a first temperature and controls the movable part to move at a second speed lower than the first speed when the detected temperature is less than a second temperature that is greater than the first temperature.

An image forming apparatus includes: an image former having parts provided in a replaceable manner to be used for image formation; a sensing part that detects a characteristic value of the parts; and a controller that determines whether the characteristic value of the parts, which fluctuates immediately after manufacture, is in a stable state based on a comparison between information regarding the characteristic value of the parts based on a detection result of the sensing part and a threshold value and sets a process condition for the image former based on the detected characteristic value when determining that the characteristic value of the parts is not in the stable state.

An image forming apparatus includes an image bearing member, a developer bearing member, a fixing unit including a heating member, a rotary member which is heated by the heating member, and a nip area where the rotary member comes into contact with a sheet, and configured to perform fixing by heating a developer image transferred to the sheet and fixing the developer image to the sheet in the nip area, and a control unit configured to execute, while the fixing is not performed, a mode in which the image bearing member is rotated with the developer bearing member being in a separated position and the heating member is controlled such that a temperature of a portion of a surface of the rotary member, after the rotary member passes through the nip area, is maintained higher than the temperature of the portion during the fixing.

In an image forming apparatus, a calculation processing portion includes an input portion and an input-portion abnormality determining portion. The input portion is connected to a temperature detection portion. When an abnormality detection circuit has detected that a temperature detected by the temperature detection portion is an abnormally heated temperature, the input-portion abnormality determining portion determines whether or not a first temperature calculated as a temperature of a fixing member is lower than a predetermined second temperature, and upon determining that the first temperature is lower than the second temperature, determines that the input portion is abnormal.

A thermopile sensor that is a temperature measuring device of a fusing device is held on a substrate. The substrate is provided with a cylindrical member extending in front of the thermopile sensor and an aperture disposed at an end of the cylindrical member.

In accordance with an embodiment, an image forming apparatus comprises a housing, an image forming section, a temperature sensor, a determination section and a controller. The image forming section has a photoconductive drum and a charging roller for forming an image on a sheet which are arranged in the housing. The temperature sensor measures a temperature in the housing. The determination section determines whether or not the temperature meets a predetermined temperature. The controller carries out an image forming processing by controlling the image forming section if it is determined that a determination result by the determination section meets the predetermined temperature.

An image forming apparatus includes an image bearer, a developing device, a motor, and circuitry. The developing device includes a screw and a developing roller. The screw stirs and conveys a developer. The developing roller bears the developer stirred and conveyed by the screw, brings the developer into contact with the image bearer, and develops an electrostatic latent image on the image bearer. The motor drives the developing device at multiple process speeds. The circuitry is configured to cause the motor to drive the screw and the developing roller before the developing roller starts developing the electrostatic latent image on the image bearer and adjust a drive time of the motor based on a process speed in a previous printing and a process speed in a next printing.