| 摘要 |
PROBLEM TO BE SOLVED: To eliminate printing of a color patch and to continuously monitor a design color tone change by calculating chromaticity and a spectral density based on spectral reflectance corresponding to a desired design area, storing them as reference values, and setting an allowable range based on a measured value and a color difference. SOLUTION: A spectrum measuring unit 22 is provided on a plurality of conveying rollers 18 for guiding a printed product from a cooler 10e to a folding machine 10f, and to smooth measuring errors, an aperture area is measured while overlapping a plurality of aperture area at each printing unit period. Measured results corresponding to desired design areas of all measured number are integrated, averaged at each CH, calculated as a spectral reflecting intensity, its spectral reflectance is calculated, and supplied to a color tone judging processor 28. The processor 28 calculates an Lab chromaticity and a spectral density in a wavelength indicating maximum absorption of each ink from the reflectance. A color difference is calculated by using the Lab chromaticity, a deviation of the color tone of the printed product is detected, and a detected result is displayed together with a spectral density difference. |
