| 摘要 |
PURPOSE:To prevent scattering, photographic fog, or the like of an image without reducing the life of a lamp by controlling the copy density with density control means partially or overall different from each other correspondingly to originals of negative and positive pictures. CONSTITUTION:The picture density signal obtained by a photodetector 12 passes a multiplexer 21, an output amplifier 22, and an A/D converter 23 and is inputted to a CPU 20 and is stored in a RAM 35. The CPU 20 performs the operation processing of the picture signal and switches current values of a primary charger 29, a transfer charger 30, etc., and a developing bias voltage value and switches positive and negative developing devices 31 and 32 by clutches 33 and 34 on the basis of the processing result. The developing bias voltage or the like is controlled through a D/A converter 25 and a high voltage unit 27 by the signal sent from the CPU 20. A lamp 2 is similarly controlled through a D/A converter 24 and a lamp control circuit 26 by the signal sent from the CPU 20. |
