Patent ID: 7573613

Claim:
A picture color tone controlling method for a printing press, comprising: a step of setting, when a printing picture is divided with an ink supplying unit width of an ink supplying apparatus, a target mixed color halftone density for each ink supplying unit width; a step of measuring an actual mixed color halftone density for each ink supplying unit width of a regular printing sheet obtained by printing using an IRGB densitometer; a step of determining, based on a corresponding relationship between the tone value and the mixed color halftone density set in advance, a target tone value of each ink color corresponding to the target mixed color halftone density; a step of determining, based on the corresponding relationship between the tone value and the mixed color halftone density, an actual tone value of each ink color corresponding to the actual mixed color density; a step of determining, based on a corresponding relationship between the tone value and the single color halftone density set in advance, a target single color halftone density corresponding to the target tone value; a step of determining, based on a corresponding relationship among the tone value, the single color halftone density and the solid density set in advance, a solid density deviation corresponding to a deviation between the target single color halftone density and the actual single color halftone density under the target tone value; and a step of adjusting the ink supplying amount for each ink supplying unit width so that the actual mixed color halftone density may approach the target mixed color halftone density, wherein at the step of adjusting the ink supplying amount, the ink supplying amount is adjusted for each ink supplying unit width based on the solid density deviation to make the actual mixed color halftone density approach the target mixed color halftone density.