| 摘要 |
PURPOSE:To prevent the blur of ink on paper, by determining the ratio of the removal of an under color performed when black ink is used according to the total amount of applied inks. CONSTITUTION:A/D converter circuits 11-13 convert signals R, G, B to digital signals and log table ROMs 31-33 convert said digital signals to density values Dc, Dm, Dy on the basis of R, G, B stored in an R-memory, a G-memory and a B-memory respectively storing said digital signals. A black extraction table ROM 34 calculates the optimum density value Dk from the above-mentioned density values and UCR (under color removal) ink selection circuits 41-43 respectively calculate Dc'(=Dc-Dk), Dm'(=Dm-Dk) Dy'(=Dy-Dk). Voltage converting circuits 51-54 calculate voltage values applied to heads from the density values and have a head driver 61. The black extraction table ROM 34 determines the ratio of under color removal performed when black ink is used according to the total amount of applied inks. |
