| 摘要 |
PURPOSE:To attain stable high speed copying and increase number of sheets of copy per unit time by providing plural start position of an exposure lamp of an optical system and selecting the start position according to the condition of copying. CONSTITUTION:An original 2 placed on a platen glass 1 is exposed and scanned by an exposure lamp 3 that moves in the direction of the arrow mark A, and light reflected by the original 2 is projected on a photosensitive body 8 of rotary drum type through an optical system consisting of a mirror 4 which is in a body with the exposure lamp 3, a V mirror 5, a lens 6 and a fixed mirror 7. The start position of the exposure lamp 3 is made to two positions, a point (1) and a point (2), and the point (1) is made start position at the time of reduction of long approach distance, and the point (2) is made start position in case of natural size where the distance of approach is short. As the start position of the optical system is made changeable, necessary minimum time until the exposure lamp 3 gets to stable speed can be selected, and the number of sheets of copying can be increased by operation devoid of futility.
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