| 摘要 |
PROBLEM TO BE SOLVED: To provide a thermal printer capable of printing in a desired density even when gradation values of input image data to be printed are greatly deviated in a line in the main scanning direction. SOLUTION: Line image data S40 in a frame memory 40 is fetched into a line memory 51 and line image data S51 is outputted. The line image data S51 is converted to line pulse width data S52 by a gradation value/pulse width conversion section 52a. The line pulse width data S52 is divided by a block making section 53, then block pulse width data S53 is outputted. The block pulse width data S53 is inputted to an average pulse width data calculating section 54, then average pulse width data S54 is calculated. The average pulse width data S54 is stored in a memory 55 and target block pulse width data S56 is outputted from a weighing section 56. The target block pulse width data S56 is inputted to an LUT 57 and a correction value S57 is outputted. The line pulse width data S52 is corrected based on the correction value S57.
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