| 摘要 |
PURPOSE:To perform uniform recording without not being influenced by the smoothness of a recording medium by detecting a reflective light energy from a recording medium, seeking an average value, adding an absolute value of a difference between the average value and the detected value to obtain a cumulative sum and controlling a recording head. CONSTITUTION:A light emitting device 1 outputs a beam obtained by reflection of a main beam directed to a printing paper 6, after being converted to a voltage value by a light receiving device 2. An A/D converter 10 supplies a digital value corresponding to an output analogic value from the light receiving device 2 to a sampling control circuit 11. If a sampling device 12 completes storage of data in a sample register, an arithmetic and logic operating device 17 starts the operation. A total sample value is added by a process 18 and an average value Av is output by a process 19. A process 20 substracts the average value Av and each sample value and sums up an absolute value, then output it as NT. A digital comparator 21 compares a cumulative addition value NT with a specified value K. In the meantime, a process 22 outputs an appropriate offset value for NT to a D/A converter 23, referring to a conversion table 22a. |
