Printer, printing method, and non-transitory computer-readable storage medium storing printing program

A printing method by a printer, the printer being configured to perform printing on a thermosensitive medium, the thermosensitive medium comprising a base material and a plurality of color developing layers that are layers stacked on the base material in a stacking direction and that develop colors in accordance with energy applied,

• the plurality of color developing layers comprising:
• a first layer disposed at a position farthest from the base material among the plurality of color developing layers in the stacking direction and configured to develop a first color based on a first energy being applied to the thermosensitive medium;
• and
• a second layer disposed between the base material and the first layer in the stacking direction and configured to develop a second color based on a second energy being applied to the thermosensitive medium, the second color being different from the first color, the second energy being different from the first energy,
• the printer comprising:
• a conveyance device configured to convey the thermosensitive medium in a conveyance direction;
• and
• a thermal head having a plurality of heat generation elements aligned in an arrangement direction perpendicular to the conveyance direction and configured to perform printing on the thermosensitive medium conveyed by the conveyance device by heat generation of the plurality of heat generation elements from the first layer side in the stacking direction,
• the printing method comprising:
• obtaining pre-conversion image data;
• converting the pre-conversion image data obtained in the obtainment process to post-conversion image data;
• and
• performing a printing control comprising outputting, to each of the plurality of heat generation elements, a signal pattern for applying energy to the thermosensitive medium based on the converted post-conversion image data to cause the plurality of heat generation elements to selectively generate heat while controlling conveyance of the thermosensitive medium by the conveyance device,
• wherein the pre-conversion image data and the post-conversion image data respectively indicate a plurality of dots and colors corresponding to the plurality of dots, the plurality of dots being aligned in a sub-scanning direction corresponding to the conveyance direction and a main-scanning direction corresponding to the arrangement direction, respectively, and
• wherein in the converting, in a case target dots that are dots of a color containing the second color is included in the plurality of dots in the pre-conversion image data, the method comprises converting a color of conversion dots to a conversion color containing a color developed by any one of the plurality of color developing layers, the conversion dots being at least one of dots among a pair of first dots adjacent to the target dots in the sub-scanning direction, a pair of second dots adjacent to the target dots in the main-scanning direction, and four third dots adjacent to each of the pair of second dots in the sub-scanning direction.

A non-transitory computer-readable storage medium storing a printing program readable by a computer of a printer, the printer being configured to perform printing on a thermosensitive medium, the thermosensitive medium comprising a base material and a plurality of color developing layers that are layers stacked on the base material in a stacking direction and that develop colors in accordance with energy applied,

• the plurality of color developing layers comprising:
• a first layer disposed at a position farthest from the base material among the plurality of color developing layers in the stacking direction and configured to develop a first color based on a first energy being applied to the thermosensitive medium;
• and
• a second layer disposed between the base material and the first layer in the stacking direction and configured to develop a second color based on a second energy being applied to the thermosensitive medium, the second color being different from the first color, the second energy being different from the first energy,
• the printer comprising:
• a conveyance device configured to convey the thermosensitive medium in a conveyance direction;
• and
• a thermal head having a plurality of heat generation elements aligned in an arrangement direction perpendicular to the conveyance direction and configured to perform printing on the thermosensitive medium conveyed by the conveyance device by heat generation of the plurality of heat generation elements from the first layer side in the stacking direction,
• the printing program, when executed by the computer, causing the printer to perform operations comprising:
• receiving pre-conversion image data;
• converting the received pre-conversion image data to post-conversion image data;
• and
• performing a printing control comprising outputting, to each of the plurality of heat generation elements, a signal pattern for applying energy to the thermosensitive medium based on the converted post-conversion image data to cause the plurality of heat generation elements to selectively generate heat while controlling conveyance of the thermosensitive medium by the conveyance device,
• wherein the pre-conversion image data and the post-conversion image data respectively indicate a plurality of dots and colors corresponding to the plurality of dots, the plurality of dots being aligned in a sub-scanning direction corresponding to the conveyance direction and a main-scanning direction corresponding to the arrangement direction, respectively, and
• wherein in the converting, in a case target dots that are dots of a color containing the second color is included in the plurality of dots in the pre-conversion image data, the printing program, when executed by the computer, further cause the computer to perform converting a color of conversion dots to a conversion color containing a color developed by any one of the plurality of color developing layers, the conversion dots being at least one of the dots among a pair of first dots adjacent to the target dots in the sub-scanning direction, a pair of second dots adjacent to the target dots in the main-scanning direction, and four third dots adjacent to each of the pair of second dots in the sub-scanning direction.