An image forming apparatus includes: an image forming unit configured to form an image on a sheet based on original image data; a selection unit configured to determine a non-image region of the sheet to which toner does not attach in a formation of the image by the image forming unit based on the original image data, and select, from the non-image region, a determination region depending on an image defect to be detected; a reading unit configured to read a surface of the sheet; and a control unit configured to obtain read image data by causing the reading unit to read the determination region after the image forming unit has formed the image, and perform detection processing for detecting whether the image defect has occurred based on the read image data.

An image forming apparatus includes an image carrier, an exposure device, a developer image forming unit, a memory, and a processor. The image carrier carries a developer image. The exposure device exposes the image carrier. The developer image forming unit forms the developer image by transporting a developer to a latent image formed on the image carrier. The processor generates correction data for correcting density unevenness in a main scanning direction detected based on an image generated by the developer image, corrects the density unevenness in the main scanning direction occurring in the developer image by changing an exposure amount when the image carrier is exposed by the exposure device, using the generated correction data, and when a position change of the developer image forming unit in the main scanning direction is detected, adjusts the correction data by a detected position change amount.

An image forming apparatus includes an image bearing member, an image forming unit, a detection unit, and a control portion. The detection unit includes a casing, an optical sensor, a shutter portion, a moving member, a groove portion, and a project portion. The optical sensor is disposed within the casing facing the image bearing member to detect the toner image and comprises a light emitting portion emitting light to the image bearing member through the opening portion and a light receiving portion receiving the light reflected from the image bearing member. The shutter is configured to open/close the opening portion as the project portion moves in a direction intersecting with the predetermined direction as the moving member moves in the predetermined direction. The groove portion is disposed perpendicularly above an extension line of an optical axis of the light irradiated from the light emitting portion to the image bearing member.

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 includes a density sensing portion, a cleaning portion, and a control portion. The density sensing portion includes a substrate and a sensor package and outputs a sensing value related to a toner density of a toner image formed on an outer circumferential surface of an image carrier. The control portion performs control so that, when the cleaning portion performs cleaning of a sensing surface, a brush is moved to a cleaning position where the brush contacts the sensing surface. The control portion also performs control so that, when the cleaning portion does not perform the cleaning of the sensing surface, the brush is moved to a retracted position where the brush does not contact the sensor package and the substrate.

An image forming apparatus, configured to operate in first and second modes of which color gamut is different from each other, includes an exposure unit configured to expose a photosensitive drum; a developing roller configured to form a toner image; a detection unit configured to detect density of the toner image transferred to an intermediate transfer member; and a controller configured to adjust the density based on a value of input image data. A dithering process for the controller's controlling of the exposure unit is different depending on whether the operation is in the first mode or the second mode, and in at least a part of the input image data, the density of the toner image formed by the dithering process in the first mode is higher than the density of the toner image formed by the dithering process in the second mode.

An optical sensor comprises a first light-emitting element, a second light-emitting element, a light-receiving element, a first amplifier circuit and a second amplifier circuit. The light-receiving element receives reflected light from an object to be measured, and outputs an output value on the basis of a light receiving result of the light-receiving element. The amplifier circuits amplifies the output value output from the light-receiving element.

An image forming apparatus includes a fixing portion and an optical sensor having first and second positioning holes and a connector. The fixing portion includes first and second screw holes, a through-hole, and an extension portion. If the optical sensor is placed on the fixing portion in a first orientation where the first positioning hole is aligned with the first screw hole and the second positioning hole is aligned with the second screw hole, the connector is inserted into the through-hole without interfering with the extension portion so that screws fix the optical sensor. If the optical sensor is placed on the fixing portion in a second orientation where the first positioning hole is aligned with the second screw hole and the second positioning hole is aligned with the first screw hole, the connector interferes with the extension portion so that the connector is not inserted into the through-hole.

An image forming apparatus includes a paper transport unit, an image forming unit, a reading unit, a foreign matter detection signal generation circuit, and a foreign matter detection control circuit. The foreign matter detection signal generation circuit generates a first foreign matter detection signal, based on an analog image signal to be output from a line sensor. In foreign matter detection processing, when a pixel that reads foreign matter continues by a specific first consecutive number or more in a signal based on the analog image signal of each pixel to be output from the line sensor, the foreign matter detection signal generation circuit sets a level of the first foreign matter detection signal to a level indicating the presence of foreign matter.

Disclosed is an image forming apparatus including: a fixation unit configured to heat a toner image formed corresponding to image data and fix the heated toner image onto a recording material; and a control unit configured to determine a fixation target temperature used by the fixation unit to heat the toner image on the basis of the image data, wherein the control unit performs a first determination to calculate a first target temperature on the basis of image density information in each of a plurality of regions in which the image data is divided in a main-scanning direction and a sub-scanning direction and a second determination to determine whether the image data is a text image, and determines the fixation target temperature on the basis of results of the first determination and the second determination.