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 includes an image forming portion, an exposure device, an image density sensor, and a control portion. The control portion can, by adjusting the development voltage based on the image density of a reference image and the amount of exposure from the exposure device, perform image density correction to adjust the image density. The control portion predicts the toner charge amount based on a formation condition of the reference image and the image density of the reference image and determines the timing of performing the image density correction next time based on the rate of change of the toner charge amount calculated using a first toner charge amount predicted when the image density correction was performed last time, a second toner charge amount predicted when the image density correction is performed this time, and the interval between the image density correction performed last time and this time.

An image forming apparatus includes a forming unit, a transfer unit, a blowing unit, a temperature detection unit, and a control unit. The forming unit forms a toner image on a photosensitive member. The transfer unit transfers the formed toner image onto a recording material. The blowing unit takes outside air into the apparatus to generate an air flow for adjusting a temperature of the transfer unit. The temperature detection unit detects an ambient temperature outside the apparatus. The control unit controls driving of the blowing unit based on the detected ambient temperature. The control unit drives the blowing unit in a case where the detected ambient temperature is less than or equal to a first temperature threshold and a gradient value indicating a change in the detected ambient temperature is at least a first gradient threshold.

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 one embodiment, an estimation unit corrects ambient temperatures or ambient humidities measured by an environment measurement unit on the basis of calculating an estimated temperature or humidity from measured temperatures or humidities and temperature correction values or humidity correction values, so as to estimate ambient temperatures or ambient humidities of other photoconductors of which the ambient temperatures or the ambient humidities are not measured. A control unit determines image formation conditions for the image forming units forming images on the photoconductors of which the ambient temperatures or the ambient humidities are not measured, on the basis of the ambient temperatures or the ambient humidities estimated by the estimation unit.

An image forming apparatus includes an attachment portion to which any one of a first fixing apparatus and a second fixing apparatus is selectively attached, and a power supply circuit including a plurality of power supply paths. The first fixing apparatus includes a plurality of first heating elements grouped into a plurality of groups, and a number of the plurality of groups is equal to a number of the plurality of power supply paths. The second fixing apparatus includes at least one second heating element grouped into at least one group whose number is smaller than the number of the power supply paths. In a state where the second fixing apparatus is attached to the image forming apparatus, a power supply path of the plurality of power supply paths in which a power line has a largest allowable current value is electrically connected with the at least one second heating element.

A driving control apparatus includes a movable member that can be displaced between first and second positions, a solenoid that displaces the movable member at the first position to the second position, a control unit that controls supply of current to the solenoid, and a transmission mechanism that transitions between first and second states according to a position of the movable member. The transmission mechanism transmits a driving force to a driven member in one of the first and second states. When the solenoid displaces the movable member from the first position to the second position, the current is supplied to the solenoid at a first duty cycle in a first period and is supplied to the solenoid at a second duty cycle lower than the first duty cycle in a subsequent second period.

An image forming apparatus, temperature control method, and temperature control device are provided. The apparatus includes the device, which acquires a first temperature difference between a temperature estimation value of a fixer, which is obtained by simulating a member temperature of a temperature control target serving as a heat capacitor-resistor circuit at an initial stage of operation of the fixer, and a detected temperature detected by a temperature sensor, and acquires a second temperature difference between a temperature estimation value of the fixer, which is obtained during an operation after the first temperature difference is acquired, and a detected temperature. The device calculates a difference between the first temperature difference and the second temperature difference, determines that the detected temperature is abnormal in response to the difference being equal to or greater than a threshold value, and performs temperature control for correcting a target temperature of the member temperature.

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.