A color calibration chart may be created including a plurality of colors that are variations of a print color established for printing a reference color by a printing system using multiple colors. The colors in the calibration chart may be measured. A color from the calibration chart may be selected for printing the reference color which has a measurement value indicative of a color consistency within a predefined distance from a reference value for the print color.

A print apparatus calibration method is disclosed. The method comprises printing, from each of a plurality of dies of a print head onto a printable substrate, an image in a first color according to a calibration pattern and an image in a second color according to the calibration pattern, the calibration pattern comprising a plurality of patches having a plurality of different densities. The method may comprise scanning, using a scanning unit, the images formed on the printable substrate to generate scanned image data, wherein the images in the first color are scanned by a first scanning module of the scanning unit and the images in the second color are scanned by a second scanning module of the scanning unit. The method may comprise analyzing, using processing apparatus, the scanned image data to identify any differences between printed densities of corresponding patches in different images of the same color. The method may comprise performing a calibration based on the analysis. A print apparatus and a machine-readable medium are also disclosed.

An image forming apparatus having a plurality of imaging units prints, in a case that a print job received from an information processing apparatus is a print job for printing a chart for adjustment, the chart based on the print job, and decides, based on the chart, which of the plurality of imaging units is to be used to perform colorimetry of a printed product on which the chart has been printed. The image forming apparatus changes a conveyance path of the printed product to use the decided imaging unit for the colorimetry of the printed product, and notifies the information processing apparatus of a result of the colorimetry by the decided imaging unit.

Multiple measurement images are formed in a test chart. Reflected light from the test patterns is received by light receiving elements of a color sensor for an accumulation time that is determined for the respective test patterns. The lengths of the test patterns in the conveyance direction of the test chart are determined according to the lengths of the accumulation times for the respective test patterns.

A printer includes: an inline scanner which acquires an RGB value of each patch of a color chart; an inline colorimeter which acquires a colorimetric value of each patch of the color chart; a profile creation unit which creates a profile for associating the RGB value with the colorimetric value of each patch; and a color conversion unit which estimates a colorimetric value corresponding to an RGB value of input data by extrapolation calculation using four points including three points forming a plane and one supporting point in data of the profile, wherein the color conversion unit estimates the colorimetric value corresponding to the RGB value based on a set of four points remained after deleting one or a plurality of sets of four points according to a predetermined rule from a plurality of sets of four points selected for an RGB value input.

A color image processing apparatus includes an image forming unit configured to form a color image using recording materials of plural colors, an image processing unit configured to implement plural image processing methods that achieve plural types of pseudo-halftone representations, a color measurement unit configured to perform color measurement of the color image formed by the image forming unit, and a control unit configured to control execution of multi-color calibration in which the color measurement unit performs color measurement of a pattern image including plural multi-color patch images formed using recording materials of plural colors by using a smaller number of image processing methods than plural image processing methods used in single-color calibration for correcting reproduction characteristics of single-color images formed by the image forming unit and in which reproduction characteristics of a multi-color image formed by the image forming unit are corrected using a result of the color measurement.

An image reading apparatus and an image forming system are provided which can reduce the influence of magnification error, detect patches in correct positions, and save the sheets required for adjusting an image. The image reading apparatus makes use of an image scanner which reads patches printed on a sheet P, a spectral colorimeter which colorimetrically measures the patches read by the image scanner, and is provided with a timing compensation unit which compensates the colorimetric measurement timing with which colorimetric operation of the spectral colorimeter is triggered based on the positional information of the patches read by the image scanner, and an image correction unit which corrects the color information of the patches read by the image scanner based on the colorimetric values of the patches colorimetrically measured by the spectral colorimeter.

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 information processing device performs processing of specifying a positional relationship between a first printing section and a second printing section based on image capturing data of a test image that is printed on a printing medium by the first printing section and the second printing section in each of which a plurality of printing elements are arranged. The test image includes a plurality of first lines which are printed by the first printing section so as to have printing positions different from each other in a line arrangement direction on the printing medium and a plurality of second lines which are printed by the second printing section so as to have printing positions different from each other in the line arrangement direction. The information processing device contains a printing coordinate acquisition section, a printing position acquisition section, and a positional shift amount calculation section.

A printer includes a spectroscope and a carriage moving unit. The spectroscope includes a wavelength-selective interference filter on which light from a measurement target is incident, and the carriage moving unit moves the spectroscope in an X direction with respect to the measurement target. If the measurement target is a color patch, the spectroscope performs spectrometry by changing a wavelength of light passing through the wavelength-selective interference filter in a first period during which the spectroscope is moved in the X direction, and passes light of an initial wavelength through the wavelength-selective interference filter at a start of measurement and at an end of measurement in the first period. A first output value that is a measured value from the spectrometry at the start of measurement is compared with a second output value that is a measured value from the spectrometry at the end of measurement.