| 摘要 |
PURPOSE:To brighten a color tone in a low gradation area and besides, to smooth variation in a color tone according to a gradation level by a method wherein for the number of striking of black dots, an increase of the number of dots corresponding to a gradation level signal is restrained in the low gradation area, and the increase of the number of dots corresponding to the gradation level signal is enlarged in a high gradation area. CONSTITUTION:For a threshold matrix for black 1, a unit area corresponding to one pixel is divided into 4X4 matrixes, and a threthold Tij is established to each of then. Then, power is applied thereto, and a gradation level signal Vij is inputted to a comparator 2. The comparator 2 compares the gradation level signal Vij with the threshold Tij of a threshold matrix 3 and only when it is larger than the threshold Tij corresponding to the threshold matrix 1, a recording signal is generated. Herein, since it is so set that as the threshold Tij grows higher, an increment becomes less, the number of increased dots per one gradation level grows larger as the gradation level signal Vij becomes higher. Thereby, a color lightens in a low gradation area, and a recording image of smooth variation in the color toner can be obtained in the all gradation area. |
