| 摘要 |
PURPOSE:To make suitable adjusting of exposure and to eliminate in vain copying, by scanning a film during carriage in high speed with a pair of light source and photosensor and forming a signal corresponding to the background density out of the output of the photosensor during scanning. CONSTITUTION:The light source 7 and the photosensor 8 are fitted to the location in which the picture region 9 of the microfilm stored at the opening of the aperture card 2 can be scanning, and the aperture card 2 can pass through between the light source 7 and the photosensor 8 surely with a pair of guide plates 10. Further, when optimum exposure for the film background density is given to the exposure lamp 25 with the exposure lamp control circuit 24, the carrier 11 is slided on the axis 26 to start the slit exposure to the photosensitive body 30. Thus, at printing, suitable exposure is given, it is not required to rely upon the experience of the operator, no in vain copying is produced. |
