| 摘要 |
PURPOSE:To make undercolor removal possible in a high ratio without making the hue achromatic, by controlling the undercolor removal quantity on the basis of the ratio of the primary color signal of each color to a black ink quantity signal or the like. CONSTITUTION:Three primary color signals from an original picture 1 due to a reading part 10 and a masking correcting circuit 20 are inputted to a black color calculating part 40 of an undercolor removing part 30, and a black ink quantity signal is formed through the calculating part 40 and a masking circuit 41. A ratio of each primary color signal to the black ink quantity signal is determined in a ratio calculating part 60, and removal black ink quantity calculating parts 45Y, 45M, and 45C of respective colors are controlled through undercolor removal controlling parts 70Y, 70M, and 70C in accordance with his ratio. Consequently, the undercolor removal considering the hue is performed in accordance with the ratio of each primary color signal to the black ink quantity signal by operational amplifiers 48Y, 48M, and 48C, and thus, undercolor removal is performed in a high ratio without making the hue achromatic, and transfer of inks is improved to economize in quantities of primary color inks. The similar result is obtained when the control based on the ratio of the black color signal to an average value of respective primary color signals is performed. |
