| 摘要 |
PURPOSE:To prevent a printing plate from the reduction of image quality by dividing a large original document into normal original size at the photoengraving of the large original document larger than the normal one and executing the partial electrostatic exposure of respective divided originals. CONSTITUTION:When an original M is set up on a prescribed position of a movable original platen 10, four-divided original parts are arranged on an exposure system and the whole surface is electrostatically exposed, the reflected photographing light forms its image on a corresponding position P1 of a master P held in a photographing part through a reflection mirror 2 and a lens 3. Then, the exposure system is moved to a prescribed position in the Y direction and the whole electrostatic image of an original part M2 is formed on a part P2. Then the original platen 10 is moved in the X direction, the exposure system is arranged on an original part M3 and the master P is moved in the Z direction, so that the whole electrostatic image of the original part M3 is formed on a part P3. Then the exposure system is moved to the prescribed position (initial position) in the Y' direction to form the whole electrostatic image of an original part M4 on a part P4. Consequently, photoengraving having excellent image quality can be attained.
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