An image forming apparatus includes an image forming device and circuitry. The image forming device forms an image on a recording medium, based on an image forming condition. The circuitry determines a position of the image formed on the recording medium by the image forming device, based on a detection signal of a pattern formed on the recording medium by the image forming device and reference position information of the pattern on the recording medium. The circuitry determines a reference position of the pattern differently depending on the image forming condition.

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.

Prediction accuracy of a color misregistration amount in an image formation executed in an image forming apparatus is improved. The image forming apparatus comprises an optical box storing an optical system for irradiating a laser beam from a laser source to a photosensitive drum, a scanner temperature sensor provided near the optical box, and an environmental temperature sensor for detecting a surrounding temperature of the image forming apparatus, and a control section. When image formation is executed, the control section obtains a temperature Tscn detected by the scanner temperature sensor and a temperature Tenv detected by the environmental temperature sensor and calculates a prediction value of a position misregistration amount to the photoreceptor of the laser beam using difference between Tscn and Tenv and Tscn.

An image formation apparatus that includes: first to third image formation units provided in this order in a traveling direction of a transfer target medium; a detector configured to detect first to third correction pattern formed on the transfer target medium by the first to third image formation units, respectively; and a control unit programed to control image misregistration correction based on a result of detection by the detector. The control unit causes the first and third image formation units to form the first and third correction patterns on the transfer target medium, respectively. When an amount of image misregistration between the first correction pattern and the third correction pattern is less than a predetermined value, the control unit neither causes the second image formation unit to form the second correction pattern, nor executes the image misregistration correction.

An image forming apparatus includes: a controller configured to compare a threshold value and an output value corresponding an intensity of the light reflected from the detection image, and to detect the color misregistration amount based on a comparison result; an update unit configured to update the threshold value based on a previous output value corresponding to the intensity of the light reflected from the detection image; and an adjustment unit configured to adjust an emission intensity of the light emitting element. The update unit updates, in a case when the emission intensity is adjusted, the threshold value based on the previous output value, a previous emission intensity, and the emission intensity adjusted by the adjustment unit.

An image forming apparatus includes: a first image forming unit for forming toner images on a first photosensitive body; a second image forming unit for forming toner images on a second photosensitive body; a first exposure unit for exposing the first photosensitive body; a second exposure unit for exposing the second photosensitive body; a transfer unit for transferring, onto an intermediate transfer belt, toner images for correction formed from the first image forming unit and the second image forming unit; a detection unit for detecting the toner images for correction; and a control unit for controlling an exposure cycle of the first exposure unit, wherein the control unit corrects the exposure cycle of the first exposure unit based on a detected consequence of the detection unit.

An image forming apparatus comprises a plurality of image forming units, an intermediate transfer member, a detection unit, and a controller. The controller is configured to control the plurality of image forming units to form, on the intermediate transfer member, a pattern image including a first detection image having a reference color among the plurality of detection images and a second detection image having another color among the plurality of detection images. The first detection image and the second detection image are superimposed on a predetermined detection image. The controller is configured to control the detection unit to detect the amount of color misregistration which is related to a relative position of the first detection image and the second detection image, and to determine an adjustment value for adjusting an image write start timing of the other color different from the reference color.

An image forming apparatus performs misregistration correction based on a detection result of a detection pattern. The detection pattern includes basic patterns arranged at a first interval in a sub-scanning direction. Each basic pattern includes N image groups arranged at a second interval. In the N image groups, a first group including an image at a first angle and a second group including an image at a second angle are arranged alternately in the sub-scanning direction. The first interval corresponds to a distance that a surface of an image carrier moves in a period of M times a first period corresponding to a rotation period of a rotational member, and the second interval corresponds to a distance that a surface of the image carrier moves in a period of 1/(N−1) of the first period.

An image forming apparatus includes a first sensor configured to measure a measurement image on a first photoreceptor, a second sensor configured to measure a measurement image on an intermediate transfer member, and a controller. The controller controls the 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 the 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 is formed along the predetermined direction of the intermediate transfer member.