PATCH CHART, CALIBRATION METHOD, AND CHART DATA CREATION DEVICE

摘要

PROBLEM TO BE SOLVED: To enable appropriate correction of the fluctuation of density due to in-plane unevenness while increasing the number of measurement color patches in a patch chart, and thereby improving the accuracy of calibration of an image forming apparatus.SOLUTION: This patch chart includes a plurality of blocks arranged in a two-dimensional manner. Each of the blocks has N (N>1) patches arranged without gaps respectively in the main scanning direction and sub scanning direction. All the plurality of blocks have only one reference patch for correcting measurements by the measurement color patches at the same position; the reference patch is any one of the patches located on the four corners of the block, and other patches than the reference patch in the block are measurement color patches.