Patent ID: 7542168
Filing Date: 2009-06-02
Classification: G03B,H04N

Abstract:
1. A gradation conversion calibration method of determining a correction amount to be used when converting an image data gradation to a print data gradation in an image forming device that outputs color images by forming them on recording media, said method comprising the steps of: outputting a color chart made of a test image for each basic color of three basic colors for creating a color image, and a grayscale chart made of a test image that combines each basic color of said three basic colors; and repeating a calibration task of calculating a correction amount based on the grayscale chart by comparing a measured density value that has been obtained by measuring a density of said grayscale chart with a target density value that has been found in advance, until said correction amount based on the grayscale chart is equal to or less than a first tolerance value; wherein as long as said correction amount based on the grayscale chart is equal to or greater than a second tolerance value that is larger than said first tolerance value, a correction amount based on said color chart is additionally calculated by comparing a measured density value that has been obtained by measuring a density of said color chart and a target density value that has been found in advance, and this correction amount is used in place of said correction amount based on the grayscale chart.