| 摘要 |
PURPOSE:To reproduce an original image with excellent gradations even when the image has abundant half tones, by changing development AC bias voltage frequencies in accordance with original image quality. CONSTITUTION:When a switch 16a is changed over, a sine wave oscillator 9b with a 200-600Hz low frequency is selected for an image with many half tones like a photograph, and the other sine wave oscillator 9a with a 800-1,500Hz high frequency is selected for an original with less half tones. Consequently, development AC bias voltage frequencies are changed through an amplifying circuit 10, a transformer 11, etc., in accordance with original image quality to reproduce with excellent gradations even when the original image has abundant half tones. |
