A printing apparatus corrects image data for printing on the basis of a color measurement result obtained by a sensor, prints a set of first color tone correction patches on a first sheet with a predetermined size and prints a set of a second color tone correction patches on a second sheet with the predetermined size. When the first sheet and the second sheet are printed one after another, a color measurement result of the tone correction patches printed on the first sheet and the second sheet is used in correcting the image data for printing. When the first sheet and the second sheet with the predetermined size are not printed one after another, a color measurement result of the tone correction patches printed on the first sheet and the second sheet for correcting the image data for printing is not used in correcting the image data for printing.

To make it possible for a user to easily grasp, at the time of selection of a measuring device and a chart, which are necessary for color verification of a printer, whether or not it is possible to use them. Based on a chart configuration information indicating the configuration of a chart on which a color patch is arranged and specification information indicating specifications of a measuring device that is used for colorimetry of the color patch, determination processing to check whether it is possible to perform colorimetry is performed. Then, results of the determination processing are output to be presented to a user.

A method is described in which a first color is detected at a user-selected arbitrary position of a first print; a second color is detected at a user-selected arbitrary position of a second print printed by a printer; a color difference between the first color and the second color is determined; and settings of the printer are changed to reduce the color difference in further prints printed by the printer.

Certain examples described herein relate to the control of colorants and treatments for printing. In certain examples image data, a colorant color mapping and one or more treatment color mappings is obtained. The colorant color mapping may be used to map the image data to colorant application values. The one or more treatment color mappings may be used to map the image data to treatment application values. The colorant application values and treatment application values may be used to generate discrete print control instructions to apply the set of colorants and set of treatments to a printing substrate.

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.

An image forming apparatus including a plurality of sheet feeding cassettes includes a control unit. The control unit performs control. In a case where a predetermined condition is satisfied during execution of a print job to print image data, the control unit performs control to execute interruption processing of a correction job to print a correction patch. The control unit performs control to determine, from the plurality of sheet feeding cassettes, a sheet feeding cassette to be used for the correction job based on information on the sheet feeding cassette used for the print job.

An image reading apparatus includes a first roller including a first rotation shaft and a first roller portion, an image reading unit, a first guide portion, a second guide portion arranged downstream of the first roller in a sheet conveyance direction, the second guide portion being curved with respect to a direction orthogonal to an axial direction of a first rotation shaft and the sheet conveyance direction, and a second roller. A reading position is located in a region between a first straight line and a second straight line, the first straight line passing through a first end, in the axial direction, of the first roller portion and extending in the sheet conveyance direction, the second straight line passing through a second end, in the axial direction, of the first roller portion and extending in the sheet conveyance direction.

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.

A spectral property acquisition apparatus includes: a first conveying device to convey an object in predetermined conveying direction; a color data acquisition device including a plurality of spectroscopic sensors in the conveying direction, the plurality of spectroscopic sensors receive light emitted and reflected by the object to acquire color data on the object; a second conveying device to convey the color data acquisition device in a direction orthogonal to the conveying direction; and circuitry to estimate a spectral property of the object based on the color data. The circuitry controls the first conveying device so as to generate predetermined tension for the object in a color data acquisition area in which the color data on the object is acquired.

An image forming system may comprises an image forming unit, a sensor, and a controller. The controller 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.