| 摘要 |
PURPOSE:To prevent the resolution from decreasing owing to the conveyance of a slit while removing the influence of a flicker component that the illumination light from an exposure lamp or the like contains. CONSTITUTION:When the exposure lamp 2 uses an AC power source of frequency fdd, its light contains the flicker component of 2fdd. The cutoff frequency fc of a low-pass circuit 22 is so set that fc<2fdd (LS: conveying speed of slit 20, DS: slit width of slit 20), and consequently the flicker component and higher-frequency components are removed. Further. components on the lower-range side than a spatial frequency F=LS/DS generated owing to the conveyance of the slit 20 are passed, so line drawings which are wider than at least the slid width DS can be discriminated. Consequently, various images can be transferred with optimum density without deteriorating the resolution. |
