| 摘要 |
<p>PURPOSE:To make it possible to obtain the constant quality of photoengraving by keeping a photoelectric conversion peak value invariably constant by enabling a photo-current control circuit to attain the individual or interlocking control of the power voltage of a light source. CONSTITUTION:The beams of light from light sources 4 and 4' are reflected by original 1 and led to photoelectric converting element 7, which generates an electric signal proportional to the light and shade of the picture element of original 1. For the purpose, element 7 is used whose photoelectric conversion rate depends upon the power voltage, and photo-current control circuit 15 is provided which compares the photoelectric conversion peak value where the reflection factor of the original is the highest to the reference voltage; this circuit 15 performs the individual or interlocking control of the power voltage of element 7 and power voltages of light sources 4 and 4', thereby keeping the photoelectric conversion peak value invariably constant. Consequently, the variation of the quantity of light from original 1 is suppressed to obtain the constant quality of photoengraving.</p> |
