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 on 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 on 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 includes a converter configured to convert image data with use of a tone correction condition corresponding to a position in a main scanning direction of the image data, and an image forming unit, which includes a photosensitive member and an exposure portion configured to expose the photosensitive member to light based on the converted image data, and is configured to form an image on a recording medium. The image forming apparatus further includes a holding portion configured to hold a plurality of feedback conditions corresponding to a plurality of tones and a controller configured to control the image forming unit to form a plurality of test images, acquire measurement results for the plurality of test images, and generate the tone correction condition based on the measurement results and the plurality of feedback conditions.

An image forming apparatus is provided. The apparatus comprises an image forming unit to form an image based on an image forming condition; a sensor to measure a measurement image formed by the image forming unit; and a controller to obtain information correlated with a change in density of an image to be formed by the image forming unit, control the sensor to measure the measurement image, determine first data related to density of the image to be formed by the image forming unit, determine, based on a result of measuring the measurement image, second data related to density of the image to be formed by the image forming unit, and generate the image forming condition based on a weighted average of the first data and the second data.

An image forming apparatus includes a light scanning device, a developing portion, a control portion and a storage portion. An evaluation chart includes a first evaluation pattern and a second evaluation pattern. The first evaluation pattern includes a first patch row. The first patch row is formed by arranging a plurality of first evaluation patches. The first evaluation patch includes a first dot row and a second dot row. The second evaluation pattern includes a second patch row. The second patch row is formed by arranging a plurality of second evaluation patches.

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: an image forming unit configured to form an image on an image bearing member based on an image forming condition, an optical sensor including: a light emitter configured to irradiate the image bearing member with light based on a supplied current; and a light receiver configured to receive reflected light of the light emitted from the light emitter; a temperature detector configured to detect a temperature of the optical sensor; and a controller configured to: control the image forming unit to form a detection image on the image bearing member; control the optical sensor to detect reflected light from the detection image; and adjust the image forming condition based on a result of detecting the detection image by the optical sensor. The controller is configured to control the light emitter to emit light; and generate a correction condition.

An image forming apparatus includes an image forming unit includes a photosensitive member; a charging unit configured to uniformly charge the photosensitive member; an exposure unit configured to form an electrostatic latent image on the photosensitive member by scanning the charged photosensitive member with laser light; and a developing device configured to develop the electrostatic latent image to form an image on the photosensitive member, a reading unit configured to read a test image, which is formed by the image forming unit, for detecting image density of the image, and a controller configured to: control the image forming unit to form the test image; detect periodic fluctuation of the image density based on a detection result of the test image which is acquired by controlling the reading unit to read the test image; and correct an image forming condition to suppress the detected fluctuation.

A processor selects a target sheet from a plurality of predetermined sheet candidates in accordance with selection information that is input via an input device. Furthermore, the processor derives feature information regarding a noise point from a target image that is obtained through an image reading process performed on an output sheet output from an image forming device, the noise point being a dot-like noise image included in the target image. Furthermore, the processor determines whether or not the noise point is a dot-like sheet noise by applying the feature information to a determination algorithm that corresponds to the target sheet, the sheet noise being included in a sheet of the output sheet itself, the determination algorithm being one of a plurality of determination algorithms that respectively correspond to the plurality of sheet candidates.

An image forming apparatus includes: an image forming unit comprising: a photosensitive member configured to rotate; a charging unit configured to charge the photosensitive member based on a charging bias; an exposure unit configured to expose the photosensitive member charged by the charging unit with laser light to form an electrostatic latent image on the photosensitive member; and a developing device configured to develop the electrostatic latent image based on a development bias to form an image on the photosensitive member, a reading unit configured to read a test image formed by the image forming unit, and a controller configured to: control the image forming unit to form the test image; control the reading unit to read the test image.