| 摘要 |
PURPOSE:To improve resolution and granularity through the increasing of gradation by providing a plurality of threshold matrices when multivalued image data to be entered is developed into binary image data so that these may meet the sequence needs of overprinting. CONSTITUTION:A 4X4X4 threshold pattern matrix including its overprinting direction is provided in a pattern memory 10, and the 4X4X4 threshold pattern matrix and multivalued image data 1 are compared by a comparator 3. In the case of threshold pattern matrix, data for overprinting is prepared. Therefore, 4-dot overprinting requires a memory size four times as large as that of the conventional threshold. In addition, the number of times of comparison with the image data 1 is four-folded. Output data digitized to 0 and 1 by the comparator 3 according to overprinting pattern design is entered into a line memory 4 and this digital data is converted to a discharge signal S for ink jet. |
