An image forming apparatus superimposes a plurality of color images each formed of a single-color developer to form a superimposed color image. The image forming apparatus includes a transfer belt and processing circuitry. The processing circuitry forms, as a correction pattern, combination patterns arranged along a conveyance direction of the color images and including a first pattern, a second pattern, and a third pattern. A formation interval of the first pattern constituting one combination pattern is shorter than a formation interval between one horizontal line of the first pattern constituting the one combination pattern and another horizontal line of the first pattern constituting another combination pattern. The one horizontal line is opposite the other horizontal line.

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.

An image forming apparatus includes a plurality of image forming portions, an intermediate transfer belt, a plurality of primary transfer members, a belt cleaning device, a secondary transfer member, a voltage application device, an image density sensor, and a control section, and executes calibration based on a result of detection by the image density sensor. The control section is capable of executing a cleaning assist mode in which, at the time of executing the calibration, a part of patch images on the intermediate transfer belt is transferred to the secondary transfer member. In a case of forming a toner image on the intermediate transfer belt after one belt revolution, the control section executes the cleaning assist mode, and in a case of not forming the toner image after one belt revolution, the control section continuously applies a reverse transfer voltage to the secondary transfer member.

An image forming apparatus includes a plurality of image bearers, a plurality of rotation reference position detectors, and circuitry. Each of the plurality of rotation reference position detectors faces a corresponding image bearer of the plurality of image bearers to detect a rotation reference position of the corresponding image bearer. The circuitry performs, before an operation of rotating the plurality of image bearers, alignment control based on a result of detection performed by the plurality of rotation reference position detectors. The alignment control is control of driving of the plurality of image bearers to acquire a given relationship between the respective rotation reference positions of the plurality of image bearers. The circuitry determines whether to perform the alignment control based on whether the operation of rotating the plurality of image bearers is a function maintenance related operation.

An image forming apparatus comprises: an image processor to convert image data based on a conversion condition; an image forming unit to form an image based on the converted image data using a replaceable member; a memory to store the image data and the converted image data; a sensor to perform measurement of a test image; and a controller. If the replacement of the replaceable member is detected while forming images, the controller controls the image forming unit to form the test image and generates the conversion condition based on a result of the measurement of the test image. If the replacement of the replaceable member is detected while forming the images, the controller further controls the image processor to convert the image data stored in the memory based on the generated conversion condition.

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 imaging system includes a toner imaging device to form a toner image, a toner image conveying device to convey the toner image, a medium conveying device to convey a medium, and a toner image recording device to record the toner image conveyed by the toner image conveying device on the medium conveyed by the medium conveying device. Additionally, the imaging system includes a control device to determine a stop state including at least one of a state where a recording check toner image is recorded on the medium, a state where a conveyance check toner image is positioned on the toner image conveying device, and a state where a formation check toner image is positioned on the toner imaging device. During the stop state, the control device stops a formation of the toner image that is performed by the toner imaging device, stops a conveyance of the toner image that is performed by the toner image conveying device, and stops a conveyance of the medium that is performed by the medium conveying device.

An example image forming apparatus includes a printing engine including a plurality of photosensitive drums, a motor device to provide a driving force to each of the plurality of photosensitive drums, and a processor to control the printing engine such that printing data is printed on a printing paper and control the motor device such that at least one of the plurality of photosensitive drums operates at a different speed from the other photosensitive drums while the printing data is printed.

An image forming apparatus includes an image bearing member, an optical sensor configured to detect a pattern image formed on the image bearing member, and an attachment member to which the optical sensor is attached. The optical sensor includes a circuit board, a light emitting element and a light receiving element which are provided on a first side of the circuit board, and a connector provided on a second side opposite to the first side of the circuit board. The attachment member has a surface contacting the second side of the circuit board. In an insertion/removal direction of a cable to be connected to the connector, a first thickness, from the surface, of a part of a portion, contacting the second side, of the attachment member is smaller than a second thickness, from the surface, of a portion, not contacting the second side, of the attachment member.

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.