According to an embodiment, an image forming apparatus includes: a motor that drives a fixing device; and a controller. The motor outputs a signal corresponding to a driving current value of the motor. The controller performs a first operation where a magnitude value of the signal has fallen out of a first range while driving the motor in a first operation mode. The controller performs a second operation where the magnitude value of the signal has fallen out of a second range while driving the motor in a second operation mode.

A fixing device includes: a fixing belt with no ends configured to stretch rotatably; a heating unit configured to heat the fixing belt; a fixing member disposed outside the fixing belt and configured to be in contact with the fixing belt by pressurizing; a pressing member disposed inside the fixing belt and configured to press the fixing member with the fixing belt involved; and a lubricant supply unit configured to supply a lubricant to the inner periphery of the fixing belt so as to supply the lubricant between the pressing member and the fixing belt, wherein the lubricant supply unit is disposed inside the fixing belt, configured to hold the lubricant, and includes a holding unit provided with a lubricant ejection port having a longitudinal shape and extending along a width direction of the fixing belt.

An image forming apparatus includes an ID sensor arranged to face an intermediate transfer belt, and a board provided with the ID sensor. The ID sensor is integrally formed with the board and while emitting light toward the intermediate transfer belt, the ID sensor includes a sensor body that individually receives light regularly reflected and light diffused and reflected by the intermediate transfer belt, a lens that is arranged between the sensor body and the intermediate transfer belt to control emitted light from the sensor body and incident light to the sensor body, and a holding member that holds the lens. The holding member is directly welded and fixed to the board.

An image forming apparatus includes an image bearer, an image former, a transferor, and circuitry. The image bearer bears an image and an identification pattern. The image former forms the image and the identification pattern on the image bearer. The transferor transfers the image and the identification pattern on the image bearer directly or indirectly to a recording medium. The circuitry determines whether the identification pattern is an image portion pattern arranged at a position superimposed on the image or a position adjacent to the image, or a non-image portion pattern arranged at neither a position superimposed on the image nor a position adjacent to the image. The circuitry further causes the image former to form the non-image portion pattern larger than the image portion pattern.

If a timing of outputting magnification correction data for first image data to form first electrostatic latent image for an (n+1)th print medium overlaps a timing of outputting magnification correction data for second image data to form an electrostatic latent image for an nth print medium having a size smaller than the (n+1)th print medium in a conveyance direction of the print medium, a CPU outputs the magnification correction data for the second image data to form the second electrostatic latent image for the nth print medium before the magnification correction data for the first image data to form the first electrostatic latent image for the (n+1)th print medium is output and outputs the magnification correction data for the (n+1)th print medium after a magnification correction process performed by a second data processing unit based on the magnification correction data for the nth print medium is completed.

An exposing unit forms a latent-image electric potential on each photosensitive drum. A detecting toner image of each color is transferred to an intermediate transfer belt using a first potential difference between a latent-image electric potential and the potential of an intermediate transfer belt at each primary transfer portion. When the polarity of voltage to be applied from a transfer power source to a secondary transfer roller is to be switched to an opposite polarity while the detecting toner image of each color is passing through each primary transfer portion, the absolute value of a second potential difference between the potential of the intermediate transfer belt and the background electrical potential of each photosensitive drum is made equal to or greater than the absolute value of the first potential difference by a control unit.

An image forming apparatus transfers toner images of respective colors, formed on photosensitive drums, onto an intermediate transfer belt conveyed in a predetermined direction to thereby form a color toner image. A steering roller tilts the intermediate transfer belt in a direction orthogonal to the conveying direction. A first sensor detects a position of a belt lateral end of the belt, and when controlling driving of the steering roller based on a detection result of the first sensor, a controller performs predetermined filtering on the detection result, to thereby control the driving of the steering roller according to the detection result subjected to the predetermined filtering.

A characteristic measuring portion measures current-voltage characteristics of a primary transfer member before a toner image for a first surface of a sheet is primarily transferred. A characteristic information storage portion stores characteristic information that indicates the current-voltage characteristics. A first transfer voltage determining portion determines a first transfer voltage based on a first target current value and the characteristic information. A second transfer voltage determining portion determines a second transfer voltage based on a second target current value and the characteristic information that was used when the first transfer voltage was determined, the second target current value being smaller than the first target current value. A voltage control portion applies the first and second transfer voltages to the primary transfer member by a constant-voltage method when the toner images for the first and second surfaces of the sheet are primarily transferred, respectively.

Disclosed herein is an image forming apparatus. The image forming apparatus includes a sensing unit having a window and a sensor which senses a developer through the window, and a shutter device which opens and closes the window, and thereby the sensing unit in a sensible state is maintained, and a lifetime thereof is extendable.

An image forming system for transferring foil onto an image to be foil-pressed formed by a toner to perform foil pressing print includes: an image forming unit that forms a normal image or the image to be foil-pressed on a recording material; an operation reception unit that receives an operation of selecting a foil pressing mode of causing the image forming unit to form the image to be foil-pressed or a normal mode for causing the image forming unit to form the normal image; an image data analysis unit that analyses the image data and acquiring the amount of each toner; and a determination unit that determines whether to interrupt the image forming operation. When the amount of toner not used for the image to be foil-pressed is a predetermined first threshold or more, the determination unit determines to interrupt the image forming operation.