| 摘要 |
PURPOSE:To improve dot area of each level and density reproduction, to simplify the device and to make simple data processing possible by driving heat generating elements of the same level simultaneously dividing them for each level. CONSTITUTION:Sent image data for one line are portioned out every level 1-3 by a data portioning and zero detecting section 10 and stored in corresponding level buffer 111-113. At the same time, levels 1-3 are detected as '1', and level '0' is detected as '0' by a dot presence/absence detecting section 12 and stored in a buffer 13 and transferred to a front line buffer 14. The contents of buffers 111-113 are inputted to a shift register 16 of a comparator section 15, and those of a buffer 14 are inputted to a register 17, and the comparator section 15 makes weighting for each level by an encoder 18. Then, an impression pulse of width corresponding to the weight is prepared by a pulse width converting section 19 for each level and impressed to each heat generating element of a thermal head in order of levels 1-3.
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