Patent ID: 6918339

Claim:
A method of controlling a feed rate of dampening water in an offset press, comprising: a density measuring step for measuring densities of a plurality of detecting patches including a set of detecting patches having an equal number of lines and different area ratios between a printing area and a non-printing area, a set of detecting patches having an equal area ratio between a printing area and a non-printing area and different numbers of lines, and solid patches; a first calculating step for calculating area ratios S relating to quantities of dampening water by using density of the set of detecting patches having the equal number of lines and different area ratios between the printing area and non-printing area, and density of said solid patches; a second calculating step for calculating coefficients N relating to emulsification rates of ink by using density of the set of detecting patches having the equal area ratio between the printing area and non-printing area and different numbers of lines, and the density of said solid patches; and a dampening water adjusting step for adjusting the feed rate of dampening water by using said area ratios S and said coefficients N.