| 摘要 |
PURPOSE:To obtain uniform recording density by preventing the generation of the variation in recording density on the same gradation level, by grouping a plurality of gradation level signals to allot a predetermined index showing heat effect at every group and referring to the combination of the indice based on the past and present recording patterns. CONSTITUTION:A gradation level signal 1 is successively inputted to a line memory 2, a judge means 4 and a pulse generating means 8. The first judge means 4 outputs the group number corresponding to the inputted gradation level signal 1 to input the same to a shift register 6 and the gradation level signal 1 before one line from the line memory 2 is inputted to the judge means 5 and set to the corresponding group number to be inputted to a shift register 7. The stage constitutions of the shift registers 6, 7 correspond to the arrangement of heat generating resistors and a pulse generating means 8 receives the gradation level signals 1 and the outputs from the shift registers 6, 7 to read the correction factor preliminarily stored on the basis of a heat effect index to perform the current supply/heat generation of a thermal head 9. |
