| 摘要 |
PURPOSE:To eliminate failure of duplication and to elevate economy and operation easiness by measuring an amt. of light reflected from an original exposed to the light having a set amt. of light, and setting a density-setting dial to the position of the pointer of a display device for displaying this measured result to set image density. CONSTITUTION:When a switch is selected in accordance with magnification, film transmission density, contrast, etc., and this switch for power supply is turned on, a lamp 1 is lighted, and an amt. of light transmitted through a film F is detected with a photodetector 30. A density-setting dial 33 is moved to be set to the position of this pointer. A signal provided from the dial 33 is fed to a comparator 34, the signal of an oscillator 35 is amplified with a variable amplification type amplifier 36, boosted with a booster 37, and rectified with a rectifier 38 to obtain a developing bias voltage. As a result, a proper developing bias voltage can be obtained by setting the dial 35 to the input from the photodetector 30. |
