An image forming apparatus includes an image bearing member, a transfer member, a voltage source, a sensor configured to detect a current value or a voltage value, an image detecting portion, and a controller capable of executing an operation in a mode for setting a transfer voltage to be applied to the transfer member, on the basis of a result of detection of a test chart formed on a test recording material. The controller sets the transfer voltage on the basis of a first detection result acquired by the sensor under application of a voltage to the transfer member when the recording material is absent in the transfer portion and a second detection result acquired by the sensor under application of the test voltages to the transfer member when the test recording material is present in said transfer portion during the operation in the mode.

An image forming apparatus includes an image forming unit, a detector, and a controller. The image forming unit transfers an image from a photoconductor to a transfer body, and then transfers the image to a sheet. The detector detects a positional deviation of a conveying surface of the transfer body from a reference position. The controller executes a correction process including forming a test pattern and a correction control processing including forming the test pattern for the correction pattern based on a detection result from the detector.

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.

An image forming apparatus includes an image forming unit, a control unit, a reading unit, an analysis unit, a storage unit, and a computation unit. The image forming unit forms an image on a sheet. The control unit controls the image forming unit. The reading unit reads the sheet. The analysis unit analyzes a reading result acquired by the image formed on the sheet being read by the reading unit, and outputs an analysis result. The storage unit stores a printing condition used when the image was formed and the analysis result in association with each other. The computation unit computes a control parameter to be used by the control unit in order to control the image forming unit, with reference to the analysis result and the printing condition stored in the storage unit.

An image forming apparatus includes an image forming device and a control device. The image forming device forms an image on a recording medium. The control device controls an image forming process. The control device includes circuitry. The circuitry changes a plurality of partial images in a target image into a certain state. The target image is to be formed on the recording medium. The plurality of partial images are to be formed peripheral to a plurality of pattern images. Each of the plurality of pattern images is to be formed at a certain position on the recording medium. The circuitry further controls the image forming device to form the target image including the changed plurality of partial images and the plurality of pattern images on the recording medium, and corrects a position of the target image based on a detection result of the formed plurality of pattern images.

A method for correcting in-track position errors in a digital printing system having a linear printhead includes printing a test target including a plurality of alignment marks. A data processing system is used to automatically analyze a captured image of the printed test target to determine a measured in-track position for each of the alignment marks. The measured in-track positions for the alignment marks are compared to reference positions to determine measured in-track position errors. An in-track position correction function is determined responsive to the measured in-track position errors, wherein the in-track position correction function specifies in-track position corrections to be applied as a function of cross-track position. A corrected digital image is determined by resampling an input digital image responsive to the in-track position correction function.

An image forming apparatus includes an image forming device, a corrector, and a controller. The image forming device is configured to form an image on a sheet using a rotating body under a predetermined image forming condition. The corrector is configured to correct the image forming condition to adjust image density unevenness corresponding to a rotation cycle of the rotating body. The controller is configured to control the image forming device to form on at least one sheet (i) plural test images that are different in correction amount for the image forming condition and (ii) pointing portions indicating intervals corresponding to the rotation cycle of the rotating body, in a state where the rotating body is continuously rotated.

An exposure control device includes an exposure light amount calculator that obtains, for each of correction points that are associated with a respective one of primary correction values and are separated from each other, a correction factor for correcting the primary correction value of the correction point, based on a pixel value of the correction point, calculates, for each correction point, a secondary correction value based on the primary correction value and the correction factor of the correction point, and calculates a distribution of the secondary correction values on an image based on the secondary correction values of the correction points, and an exposure controller that causes an exposure unit to form a latent image by exposure to light having a corrected light amount obtained by correcting a light amount corresponding to a pixel value of each point based on the secondary correction value of the point.

An image forming apparatus includes: a detecting unit configured to detect a test image formed on an image carrier; and an obtaining unit configured to obtain a color misregistration amount using a detection result of the test image by the detecting unit. The test image includes one or more basic patterns; each one of the one or more basic patterns includes a first pattern group and a second pattern group disposed at different positions in a conveyance direction of the image carrier; the first pattern group and the second pattern group each include a plurality of V-shaped patterns; and the V-shaped patterns of the first pattern group and the second pattern group have an axisymmetrical shape about an axis corresponding to a width direction orthogonal to the conveyance direction.

An image forming apparatus includes an image forming device, a corrector, and a controller. The image forming device is configured to form an image on a sheet using a rotating body under a predetermined image forming condition. The corrector is configured to correct the image forming condition to adjust image density unevenness corresponding to a rotation cycle of the rotating body. The controller is configured to control the image forming device to form on at least one sheet (i) plural test images that are different in correction amount for the image forming condition and (ii) pointing portions indicating intervals corresponding to the rotation cycle of the rotating body, in a state where the rotating body is continuously rotated.