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 a plurality of image forming portions; a rotatable endless belt; a plurality of stretching rollers including an inner roller and a steering roller; an outer roller; a steering mechanism; a position changing mechanism; and a controller. In a case that a changing operation for changing a position of the inner roller is performed by the position changing mechanism during execution of a job for forming the toner images on a plurality of recording materials, the controller controls the steering mechanism so that a tilting operation for tilting the steering roller in a predetermined amount in interrelation with the changing operation is executed.

An electrophotographic printing system for printing with a set of toners including a white toner. A plurality of printing modules are configured to print respective toner patterns, each including a toner image printed onto a receiver medium being transported on a transparent transport web and a corresponding registration mark positioned outside a border of the receiver medium. A registration mark sensing system is positioned to detect the printed registration marks. The registration mark sensing system includes a light detector positioned to detect light that is emitted by a light source, transmitted through the transport web and reflected off a non-white colored reflector plate positioned behind the transport web. The colored reflector plate has a color that provides detection signals for the registration marks having a magnitude that is greater than or equal to a predefined threshold.

An electrophotographic printing system for printing with a set of toners including a white toner. A plurality of printing modules are configured to print respective toner patterns, each including a toner image printed onto a receiver medium being transported on a transparent transport web and a corresponding registration mark positioned outside a border of the receiver medium. A first registration mark sensing system is positioned to detect the registration marks printed with a first subset of the toners that doesn't include the white toner. A second registration mark sensing system is positioned to detect the registration marks printed with a second subset of the toners that includes the white toner. The registration mark sensing systems each include a reflector plate positioned behind the transport web. The reflector plate for the first registration mark sensing system is white, and the reflector plate for the second registration mark sensing system is black.

An image forming apparatus includes a first sensor configured to measure measurement images on a first photoreceptor, a second sensor configured to measure measurement images on an intermediate transfer member, and a controller. The controller controls a first image forming unit to form first measurement images, wherein the first measurement images are formed along a rotation direction of the first photoreceptor, and controls the first sensor to measure the first measurement images on the first photoreceptor. The controller further controls the first image forming unit and a second image forming unit to form a plurality of measurement images while a rotation speed of the first photoreceptor is being controlled based on a measurement result of the first sensor, wherein the plurality of measurement images are formed along the predetermined direction of the intermediate transfer member.

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.

A printing apparatus includes a printing device to print, on a sheet, a detection mark for acquiring an amount of deviation of an image, a detection device to read a position of the detection mark and acquire the amount of deviation of the position of the detection mark, and control circuitry to perform correction according to the amount of deviation. The circuitry prints the detection marks on both faces of the sheet in duplex printing, reads the detection marks on both faces with the detection device, calculates a first correction value from the position of the detection mark on a first face on which printing is performed first, calculates a second correction value from the position of the detection mark on a second face on which printing is performed later, and calculates a third correction value from the positions of the detection marks on the first and second faces.

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 with respect to 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 is provided. The image forming apparatus includes an image forming part to form a pattern including at least one white dot line and at least one black dot line on an image forming medium using a photoconductive drum. A registration sensor is to sense an amount of light reflected from the image forming medium. A processor is to determine a state of the photoconductive drum based on the amount of sensed light in the pattern.

An image forming device which forms an image for color correction in the margin of a continuous recording medium such as continuous paper as appropriate without causing erroneous detection by a mark sensor at a post-processing stage. In the image forming device, a printing data generator (control section) performs: acquiring a detection criterion to detect a post-processing image for use at the post-processing stage; creating a color correction image to be used for color correction of an original image according to the detection criterion; and arranging the color correction image as an outer area image in an area other than an original image formation area in printing data.