| 摘要 |
A thermal printer for printing a continuous tone image includes an image signal source (201), a thermal printhead for printing one line of image pixels at a time, and an image signal converter that transforms each line of image signals into print pixels that are applied to the heat elements of the printhead. The image signal converter includes an image memory (207) that stores the set of successive lines of image pixel signals for the entire image obtained from an image source and a memory for storing a subset of the successive lines. A control processor (205) transfers the set of successive image signal lines to the image memory and then sequentially transfers one successive line at a time to the subset memory. The stored subset comprises the line of image pixel signals being converted, a plurality of lines of image pixel signals preceding the line of image pixel signals being converted and a plurality of lines of image pixel signals succeeding the line of image signals being converted. An image signal processor cooperates with the subset memory to modify the image pixel signals of the image signal line being converted in response to the image signals of the line of image signals being converted, the image signals of the plurality of image signal lines preceding the image signal line being converted and the plurality of image signal lines succeeding the line of image signals being converted. |
