| 摘要 |
PURPOSE:To enable printing with favorable image quality to once storing inputted image data into a memory, reading sequentially the image data from the memory, and subjecting the image data to a predetermined edge-emphasizing process to vary a density value of the image data. CONSTITUTION:An image memory 30 stores image data inputted under the control of a DMA controller 40. An image-processing circuit 50 for performing an edge-emphasizing process comprises a CPU, a ROM storing an operating program and a table therein, and a RAM for storing the image data, whereas a system-controlling circuit 60 controls operating timings of a gradation- controlling circuit 20, the DMA controller 40 and the image-processing circuit 60. In response to instructions from the system-controlling circuit 60, the image- processing circuit 50 performs the edge-emphasizing process for one line at a time, and transfers the data thus processed to a line buffer 21. The gradation- controlling circuit 20 converts a one-line amount of gradation data stored in the line buffer 21 into energizing operations for a thermal head part 10, thereby enabling an expression of a multiplicity of gradations. |
