| 摘要 |
PURPOSE:To adjust automatically an exposure and a developing bias voltage so that copied images having a proper quality are obtained for originals from an original having a low density to an original having a high density. CONSTITUTION:A photodetector 10 detects the light from a film 2 while a moving table 6 is moved from the home position indicated by a solid line to the exposure start position indicated by a dotted line, and the density of an original is measured on a basis of the difference of the quantity of light between a picture part (having the lowest density) and a nonpicture part (having the highest density). This measured result is inputted to a CPU in a control circuit 17. The control circuit 17 controls voltage supply circuits 18 and 19 on a basis of the measured result and determines a supply voltage to a lamp 3 and a developing bias voltage to a developing device 14. The quantity of illuminating light for the original, namely, the exposure and the developing bias voltage are controlled on a basis of the density of the original in this manner to obtain a copied having a proper density without photographic fog even from an original having an improper density. |
