Example implementations applying thermal energy to sub-lines. In some examples, a printing device can include a processing resource and a memory resource storing non-transitory machine-readable instructions to cause the processing resource to receive print data about a line to be formed on a thermally activated print medium, divide the line into a plurality of sub-lines, determine a threshold colorant density level of a first sub-line and a third sub-line of the plurality of sub-lines based on the received print data, and cause a print head of the printing device to apply thermal energy to the first sub-line and the third sub-line on the thermally activated print medium using the received print data.

In some examples, a system may include a thermal print head including a plurality of print head elements to heat a print medium. The system may include a controller to determine a tri-color tuple of a pixel of an image to be printed; determine an input temperature at a specific print head element, of the plurality of print head element s, printing the pixel on thermal print medium; and determine a voltage pulse pattern for printing the tri-color tuple at the input temperature based on a previously printed pixel.

Provided is a thermal printer achieving high repeatability of one dot even in an image having a large change in a density and capable of printing a printing material having high sharpness. A thermal printer includes: an image data extension processing unit generating extended image data having pixels in which the number of pixels in a feed direction of a paper sheet is extended; a printing data correction processing unit correcting a density of at least one extended pixel based on a change in a density of the extended pixels in the extended image data in the feed direction or a change in a density of pixels in the image data before extended in the feed direction; and a printing unit printing the image on the paper sheet based on the extended image data in which the density of the at least one extended pixel is corrected.

A thermal transfer printing apparatus includes a storage to store a plurality of density adjustment parameters that are each associated with a corresponding one of a plurality of first-page calibration patterns and a plurality of second-page calibration patterns, a density adjustment processing part to adjust data on a color gradation value of a first-page superimposing portion and data on a gradation value of a second-page superimposing portion using their respective associated density adjustment parameters, and a printing part to make a print on recording paper to form a plurality of printed calibration patterns that include a printed superimposing portion where the first-page superimposing portion and the second-page superimposing portion are superimposed on each other based on data on color densities adjusted by the density adjustment processing part. A color density of the printed superimposing portion printed on the recording paper varies for each of the printed calibration patterns.

A thermal transfer printing apparatus includes a storage to store a plurality of density adjustment parameters that are each associated with a corresponding one of a plurality of first-page calibration patterns and a plurality of second-page calibration patterns, a density adjustment processing part to adjust data on a color gradation value of a first-page superimposing portion and data on a gradation value of a second-page superimposing portion using their respective associated density adjustment parameters, and a printing part to make a print on recording paper to form a plurality of printed calibration patterns that include a printed superimposing portion where the first-page superimposing portion and the second-page superimposing portion are superimposed on each other based on data on color densities adjusted by the density adjustment processing part. A color density of the printed superimposing portion printed on the recording paper varies for each of the printed calibration patterns.

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.

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.

An image forming apparatus includes a controller circuitry configured to control the ink-jet module to form a density adjustive image pattern on one of the multiple sheets, detect a jam during continuous feeding, and then determine whether or not images, which are to be formed on one or more fed-and-unejected sheets, include the density adjustive image pattern, where the images include the density adjustive image pattern, determine whether or not the unejected sheet, on which the density adjustive image pattern is to be formed, has passed through a certain position of the sheet conveyer path, and control the ink-jet module, where the unejected sheet, on which the density adjustive image pattern is to be formed, has passed through the certain position, not to re-form the density adjustive image pattern and to re-form images on rest of the unejected sheets.

An image forming apparatus includes a controller circuitry configured to control the ink-jet module to form a density adjustive image pattern on one of the multiple sheets, detect a jam during continuous feeding, and then determine whether or not images, which are to be formed on one or more fed-and-unejected sheets, include the density adjustive image pattern, where the images include the density adjustive image pattern, determine whether or not the unejected sheet, on which the density adjustive image pattern is to be formed, has passed through a certain position of the sheet conveyer path, and control the ink-jet module, where the unejected sheet, on which the density adjustive image pattern is to be formed, has passed through the certain position, not to re-form the density adjustive image pattern and to re-form images on rest of the unejected sheets.

There are provided a thermal transfer printer and a method for producing a printed matter capable of suppressing deterioration in printing quality. A first energizing pulse is generated at the beginning of one line period. The first energizing pulse causes each heating element to perform offset heating. Second energizing pulses whose number corresponds to a tone level are generated in one line period. The second energizing pulses cause each heating element to perform heating. When the timings at which the first energizing pulse and the second energizing pulses are generated can be evenly distributed within one line period, the timings are evenly distributed within one line period. When the timings cannot be evenly distributed within one line period, the timings are distributed within one line period such that an unevenly distributed portion included in the timings is arranged in an initial period of one line period.