An image forming apparatus that prints an adjustment pattern on a sheet includes a generator and an image former. The adjustment pattern is for correcting a color value obtained by reading a second patch region on the sheet with a second reader based on a color value obtained by reading a first patch region on the sheet with a first reader. The generator generates image data of the adjustment pattern, and the image former performs printing based on the image data. The adjustment pattern includes a first patch printed in the first patch region and a second patch printed in a region other than the first patch region in the second patch region. The second patch includes a common color patch in a same color as a color of the first patch, and a size of the first patch is larger than a size of the second patch.

An information processing apparatus includes processing circuitry. The processing circuitry detects an abnormality in an image reading apparatus from a first spectral reflectance and a second spectral reflectance, the first spectral reflectance being generated based on data read from a reference white plate installed in the image reading apparatus, the second spectral reflectance being generated before generation of the first spectral reflectance, and identifies a cause of an abnormality in the image reading apparatus in a case where the processing circuitry detects the abnormality.

An image forming apparatus includes: an image forming unit configured to form an image onto a sheet; a conveyance roller configured to convey the sheet through a conveyance path, the conveyance path including a curved path being bent; a sensor configured to read the image formed on the sheet conveyed through the conveyance path by the conveyance roller, the sensor being configured to read the image formed on the sheet when a part of the sheet is conveyed through the curved path; and a controller configured to obtain information related to a type of the sheet, and to control, based on the information, a conveying speed of the sheet conveyed by the conveyance roller when the sensor reads the image.

An image forming apparatus comprises an image forming unit; a sensor that measures a measurement image; and a controller. The controller controls the image forming condition based on a measurement result of measuring a first measurement image; acquires information having a correlation to density variation of images to be formed by the image forming unit; controls the image forming condition based on the information; determines a first value regarding a density of an image to be formed, based on a measurement result of measuring a second measurement image; determines a second value regarding a density of the image to be formed by the image forming unit, based on the information; and controls a timing at which the image forming unit next forms the first measurement image, based on the first value and the second value.

A lighting device (23) irradiates a web under conveyance with light. The lighting device includes a light source (43), and an irradiation port (61) configured to open linearly in a widthwise direction of the web at an end portion facing the web. The irradiation port (61) is formed between first and second parallel portions (62b, 63b) where a first plate member (62) and a second plate member (63) parallelly face each other. The web under conveyance is irradiated with linear light. It is possible to provide a lighting device capable of irradiating only an inspection region of a sheet or a web with light.

An image forming system includes an image forming unit, a sensor, and a controller. The controller is configured to control the sensor based on measurement modes including a first measurement mode and a second measurement mode. A sampling number of an image by the sensor while the sensor moves in the direction orthogonal to the conveying direction in the first measurement mode is less than a sampling number of an image by the sensor while the sensor moves in the direction orthogonal to the conveying direction in the second measurement mode.

A printing apparatus causes a printer engine to print first tone correction patches of a first color on a first sheet and to print second tone correction patches of a second color being different from the first color on a second sheet, generate correction information based on a color measurement result of the first tone correction patches and the second tone correction patches printed on the first sheet and the second sheet, respectively, as measured by a sensor, and correct image data using the correction information. In the generation of the correction information, in a case where there are more than a predetermined number of sheets of a size being different from a predetermined size between the first sheet and the second sheet, the correction information using the color measurement result of the first tone correction patches and the second tone correction patches is not generated.

In a color management system including a server and an image forming apparatus, the server stores information of a colorimetric sensor and paper information corresponding to the colorimetric sensor, obtains information of a colorimetric sensor mounted in the image forming apparatus, designates paper to use when executing a color adjustment process of the image forming apparatus, and, based on the stored paper information, selects a colorimetric sensor of the image forming apparatus corresponding to the designated paper. The image forming apparatus comprises causes a printer engine to print a chart on the designated paper in accordance with a color adjustment job for executing the color adjustment process, and measures a colorimetric value of the printed chart using the selected colorimetric sensor.

An information processing device includes: an acquisition unit configured to acquire color information on a specific color included in an inspection image, and a determination condition for determining a color shift with respect to the specific color; and a controller configured to: determine, based on the color information and the determination condition acquired by the acquisition unit, test image data representing a plurality of test images to be formed by an image forming apparatus; output the determined test image data to the image forming apparatus in order to form the plurality of test images; acquire luminance data on the plurality of test images, the luminance data being output from a color sensor; acquire spectral data on the plurality of test images, the spectral data being output from a spectroscopic sensor.

In a printing apparatus, a colorimeter is provided for performing imaging calibration on an inline scanner for inspecting a printed image. During a printing operation, the inline scanner captures a test pattern image formed on paper and thereby obtains calibration imaging data, the colorimeter performs color measurement on the test pattern image and thereby obtains calibration colorimetric data, both data are used to update a correction factor LUT for imaging calibration, and the correction factor LUT is used to perform imaging calibration on the inline scanner.