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.

An image recording apparatus includes: a plurality of recording heads driven on a basis of drive waveform data; a data storage that retains parameter sets corresponding to the respective recording heads; a simultaneously driven nozzle count detector that detects, for each of the recording heads, a simultaneously driven nozzle count that represents a count of nozzles to be driven at an identical drive timing based on image data to be recorded on a recording medium; a correction parameter selector that selects, for each of the recording heads, a correction parameter corresponding to the detected simultaneously driven nozzle count from among a plurality of correction parameters included in the parameter set corresponding to the recording head; and a drive waveform data generator that corrects reference waveform data using the correction parameter selected for each of the recording heads and generates the drive waveform data for each of the recording heads.

An image forming apparatus includes an image forming device, a reading device, and circuitry. The image forming device discharges ink droplets through nozzles to form an image on a recording medium conveyed in a first direction. The reading device reads the image formed on the recording medium. The circuitry generates a correction chart that includes patches, located in the first direction and representing different densities from each other, and two marks located at different positions from each other in a second direction perpendicular to the first direction. The circuitry locates opposed end portions of the patches in the second direction outside the two marks in the second direction. The circuitry derives correction data, based on read data of an area of the patches existing inside the two marks in the second direction included in read data provided by the reading device reading the correction chart formed on the recording medium.

An example is given of a non-transitory computer-readable medium to store machine-readable instructions to be executed by a controller. The controller controls a heating element to print pixels of an image. The controller calculates an estimated thermal energy accumulation based on control of the heating element. The controller controls the heating element to print subsequent pixels based on the estimated thermal energy accumulation.

An image forming apparatus includes an image forming device, a reading device, and circuitry. The image forming device discharges ink droplets through nozzles to form an image on a recording medium conveyed in a first direction. The reading device reads the image formed on the recording medium. The circuitry generates a correction chart that includes patches, located in the first direction and representing different densities from each other, and two marks located at different positions from each other in a second direction perpendicular to the first direction. The circuitry locates opposed end portions of the patches in the second direction outside the two marks in the second direction. The circuitry derives correction data, based on read data of an area of the patches existing inside the two marks in the second direction included in read data provided by the reading device reading the correction chart formed on the recording medium.

In an example, a printing device may include a cartridge including a print substance, a belt, and a controller including a processing resource and a memory resource. The processing resource may execute instructions to deposit a plurality of patches of the print substance from the cartridge onto the belt to determine a cartridge density based on a density of a sub-set of patches of the plurality of patches; and adjust a print substance output of the cartridge based on the determined density of the print substance in the cartridge.

A data processing apparatus includes a plurality of heat-generating elements configured to apply different heating energies to a print medium in which a plurality of color development layers which develop colors different from each other upon receipt of the different heating energies are laminated. In addition, a printing apparatus includes: an obtaining unit configured to obtain a heat-generating characteristic of each of the plurality of heat-generating elements; and a deriving unit configured to derive a correction value for correcting print data based on a color development heating characteristic of each of the plurality of color development layers and the heat-generating characteristic of each heat-generating element, the print data causing each heat-generating element to generate the heating energy based on image data corresponding to a pixel.

In an example, a printing device may include a cartridge including a print substance, a belt, and a controller including a processing resource and a memory resource. The processing resource may execute instructions to deposit a plurality of patches of the print substance from the cartridge onto the belt to determine a cartridge density based on a density of a sub-set of patches of the plurality of patches; and adjust a print substance output of the cartridge based on the determined density of the print substance in the cartridge.

A first image has a first superimposing portion being a rear end portion of the first image. A second image has a second superimposing portion being a front end portion of the second image. A filter processing unit performs filter processing on the first superimposing portion and the second superimposing portion. A panoramic image has a superimposing region. The filter processing is processing for reducing change in image quality of the superimposing region occurring in a situation where the second superimposing portion overlaps the first superimposing portion in a misaligned manner.

When printing is performed using a thermal head to convert power into heat and to heat an ink sheet laid on paper by the heat, a change in density in a paper carrying direction D1 of an image to be printed in an output region of the paper is calculated using printing data, printing-data-for-correction to indicate an image-for-correction to be printed in a margin printing region of the paper and to cause a change of power required by the thermal head while a combined image including the image and the image-for-correction is printed onto the paper to be smaller than a change of the power required by the thermal head while only the image is printed onto the paper is created, and the ink sheet is heated by the thermal head in accordance with the printing data and the printing-data-for-correction.