A test color sheet of color strips of color patches is used in calibration operations for a printing device. Control color patches are used to identify each color strip and the scanning direction of any measured data captured by a color measurement tool. The control color patches have a unique pattern for each row. The patterns are changed according to an updating process that associates each unique pattern with its respective color strip. Scanning operations may be done in any sequence or direction without having to update the data being captured. The control color patches include a specified control color that differs from the color patches used for calibration operations.

A test color sheet of color strips of color patches is used in calibration operations for a printing device. Control color patches are used to identify each color strip and the scanning direction of any measured data captured by a color measurement tool. The control color patches have a unique pattern for each row. The patterns are changed according to an updating process that associates each unique pattern with its respective color strip. Scanning operations may be done in any sequence or direction without having to update the data being captured. The control color patches include a specified control color that differs from the color patches used for calibration operations.

Provided is a measurement device including a spectroscope, a movement mechanism configured to relatively move the spectroscope along a first direction with respect to the measurement target, and one or more processors configured to execute detecting a measurement error indicating that spectroscopic measurement processing by the spectroscope is not executed normally, and controlling the spectroscope and the movement mechanism, in which the one or more processors, when the measurement target is a plurality of color patches arranged along the first direction, cause the spectroscope to execute first measurement processing of measuring light with a specific wavelength set in advance while relatively moving the spectroscope in the first direction to acquire a measured value with respect to the specific wavelength obtained by the first measurement processing and a position of the spectroscope, and when the measurement error is detected, move the spectroscope to a position where an amount of variation of the measured value is greater than or equal to a threshold value in a second direction opposite to the first direction and then move the spectroscope in the first direction.

Aspects of the disclosure provide for a method. In some examples, the method includes printing a target plot comprising a color ramp, scanning the target plot via a first image scanner to determine first scan results indicating a relationship between a scanned measurement determined by the first image scanner and lightness of a scanned portion of the target plot, scanning the target plot via a second image scanner to determine second scan results indicating a relationship between a scanned measurement determined by the second image scanner and lightness of the scanned portion of the target plot, and determining a lookup table indicating a difference determined based on the first scan results and the second scan results.

Apparatus is described that comprises a printer carriage (100), comprising a printhead (105), at least one sensor (101, 102) for scanning an image deposited on a print media by the printhead (105) and a spectrophotometer (104) connected to the at least one sensor (101, 102) for generating data based on a reference image (120) on a test print media (110). The sensor (101, 102) is calibrated based on the generated data to detect a specific ICC profile, and wherein, in use, the sensor (101, 102) scans and digitizes an image of a final print media as the image is being printed on the final print media; and wherein the sensor (101, 102) is connected to a controller (106) that performs image quality analysis of the digitized image to determine whether colour deviation has occurred.

An image reading apparatus includes: a reader that reads an image formed on a print medium; and a backing part that is disposed at a position facing the reader and is capable of switching a color of a portion to be a background of the print medium upon reading by the reader to a plurality of colors according to a type of the print medium and/or a color read from the print medium.

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 color measurement apparatus comprising: a color measurement unit configured to perform color measurement of an image on a sheet, the color measurement unit including a light source; a reference member used for calibration of the color measurement unit; a moving unit configured to move the color measurement unit to a first position at which the light source irradiates a region other than the reference member with light and a second position at which the light source irradiates the reference member with light; and a control unit configured to, after causing the light source to emit light when the color measurement unit is positioned at the first position, and then moving the color measurement unit to the second position, execute the calibration based on data obtained by causing the light source to irradiate the reference member with light.

A diagnostic system may comprise an image forming apparatus that forms a diagnostic image on a sheet and an image capturing apparatus that captures an image of the sheet on which the diagnostic image is formed and which has been discharged from the image forming apparatus, and outputs the image captured as a sheet image. The image capturing apparatus may make a diagnosis for a component of the image forming apparatus based on a position of an image deficiency in the sheet image, and output a diagnosis result for the component of the image forming apparatus.

Methods of measuring colours, methods of calibrating printers and printing systems for implementing the methods are disclosed. Calibration maps are printed on print media. The calibration maps have intertwined contiguous printed and non-printed areas. One or more colour signals are measured on contiguous printed areas. One or more noise signals are measured on non-printed areas that are adjacent to the contiguous printed areas. Clear colour signals are generated by removing the one or more measured noise signals from the one or more measured colour signals.