Ink jet recording device and density unevenness correction method therefor

A density unevenness correction method for an image of an ink jet recording device, the ink jet recording device including

• a transporting unit having a medium supporting part configured such that a first support having a plurality of first supporting pieces arranged in the shape of comb teeth thereon and a second support having a plurality of second supporting pieces arranged in the shape of comb teeth thereon are engaged with each other and are extendable and retractable, and bringing a medium into close contact with the medium supporting part to transport the medium, and
• a line-type ink jet head that draws an image with a single pass on the medium transported by the transporting unit, the density unevenness correction method comprising:
• a test chart output step of outputting a test chart including a plurality of grayscales;
• a test chart read step of reading an image of the output test chart;
• a first density unevenness correction value derivation step of deriving a first density unevenness correction value, which is a correction value of density unevenness in a first region, from a reading result of the test chart, in a case where a region where the medium is supported by only the first support is defined as the first region;
• a second density unevenness correction value derivation step of deriving a second density unevenness correction value, which is a correction value of density unevenness in a second region, from the reading result of the test chart, in a case where a region where the medium is supported by only the second support is defined as the second region;
• a third density unevenness correction value derivation step of deriving a third density unevenness correction value, which is a correction value of density unevenness in a third region, from the reading result of the test chart, in a case where a region where the medium is supported by the first support and the second support is defined as the third region;
• and
• a density unevenness correction step of correcting data of an image to be drawn on the medium for each region on the basis of the correction value of the density unevenness for each region.