Patent ID: 8132509
Filing Date: 2012-03-13
Classification: B41F

Abstract:
1. A printed product color misregister amount detection method comprising the steps of: printing, in a reference color on a printed product to be printed by a multi-color printing press, a reference register mark including first color area portion with a predetermined width and a blank portion in contact with the first color area portion; printing, in a color other than the reference color, a positional shift detection register mark including a second color area portion with a width smaller than that of the first color area portion of the reference register mark to have as a target position a position where the width of the second color area portion falls within the width of the first color area portion of the reference register mark; measuring density information representing a density of a color component which is of the same color as that of positional shift detection register mark within a target range including the first color area portion and the blank portion in contact with the first color area portion of the reference register mark where the positional shift detection register mark has been printed; and obtaining a positional shift amount between the reference color and the color other than the reference color as a color on misregister amount on the basis of the measured density information, wherein the step of printing the reference register mark comprises the step of determining a convey direction of the printed product in the multi-color printing press as a circumferential direction and the circumferential direction as a widthwise direction of the first color area portion, wherein the step of determining the circumferential direction as the widthwise direction comprises the step of printing as the reference register mark a first reference register mark and a second reference register mark, the step of printing the positional shift detection register mark comprises the steps of printing a first positional shift detection register mark and a second positional shift detection register mark, respectively, as the positional shift detection register mark, the step of printing the first positional shift detection register mark comprising printing the first positional shift detection register mark to have as a target position a position where an edge of a second color area portion of the first positional shift detection register mark overlaps an upward edge of a first color area portion of the first reference register mark at least partially, and the step of printing the second positional shift detection register mark comprising printing the second positional shift detection register mark to have as a target position a position where an edge of a second color area portion of the second positional shift detection register mark overlaps a downward edge of a first color area portion of he second reference register mark at least partially, the step of measuring comprises the step of measuring, as first density information, density information representing a density of a color component which is of the same color as that of the first positional shift detection register mark within a target range including the first color area portion and a blank portion in contact with the first color area portion of the first reference register mark where the first positional shift detection register mark has been printed and, as second density information, density information presenting a density of a color component which is of the same color as that of the second positional shift detection register mark within a target range including the first color area portion and a blank portion in contact with the first color area portion of the second reference register mark where the second positional shift detection register mark has been printed, and the step of obtaining comprises the step of obtaining an upward color misregister amount on the basis of the measured first density information and a downward color misregister amount on the basis of the measured second density information.