| 摘要 |
PURPOSE:To change only the impression of gradation in accordance with selection of a gradation characteristic by correcting exposure data based on a gradation curve and performing the color masking correction in accordance with it. CONSTITUTION:The picture of an original surface irradiated by an exposure lamp 12 is photoelectrically converted by a CCD sensor 14. The obtained multibit electric signal is converted into gradation data of yellow Y, magenta M, cyan C, and black K by a read signal processing part 20, and this data is stored in a buffer memory 30 for synchronism. A V0 sensor 44 detects the potential of the surface of a photosensitive body, and an SID sensor 210 detects the quantity of toner on the photosensitive body to set the exposure to an optimum condition. A masking processing part converts reading density data DG, DR, and DB of red, green, and blue to cyan C, magenta M, and yellow Y to perform the color masking correction. Thus, a targetted gradation is selected, since correction is performed in accordance with the change of gradation; and therefore, only the impression of gradation can be varied without changing a tone of color. |
