| 摘要 |
PURPOSE:To stably form information peculiar to an image-forming device on an image by controlling the modulation amount of a prescribed pattern signal which is generated based on the density signal of image density and overlapping the pattern signal with the density signal. CONSTITUTION:The luminance signal of the image is obtained in CCD 105, is digital-converted by an A/D converter 106, is corrected by a shading circuit 12 and is converted into the density signal by a LOG conversion circuit 13. On the other hand, a machine number pattern generation circuit 15 generates the peculiar pattern specifying the device and a modulation amount control circuit 16 can change the modulation amount of the pattern signal in accordance with the size of the density signal. A comparison circuit 17 overlaps the modulated pattern signal with the inputted density signal and they are synthesized. Then, the overlapped image signal is modulated to lazer emitting time proportional to the density signal by a pulse width modulation circuit 18, is transmitted to a laser driver circuit 19 and a gradation image is formed. |
