JPS5567762A - Exposure device - Google Patents

Abstract

PURPOSE: To provide the construction suited for high speed copying by providing a stationary light source in such a manner that its light condenses on the same plane as the original plane and providing a scanning mirror which is perpendicualr to the original plane and moves along the optical path into its optical path.

CONSTITUTION: A stationary light source 3 is so constituted that its luminous flux is of a fixed angle to an original platen 1 and is condensed onto the same plane as the original plane 2. A scanning mirror 4 is placed perpendicular to the original plane 2 and reciprocates along the optical path in the perpendicular posture from nearly the cneter thereof up to the alternate-long-and-two-short-dashes-line position. Light out from the stationary light source 3 radiates the original plane 2 by way of the scanning mirror 4 and its reflected light forms the original image to the photoreceptor 6 by a lens 5. Since the lens 5 horizontally moves at the same speed as the horizontal component speed of the scanning mirror 4, the foregoing imaging becomes of the same position. Since the horizontal moving distance of the scanning mirror 4 is about half the original face length, the horizontal moving component speed of the mirror 4 becomes half the speed of the scanning light of the orignal plane 2. Hence, the moving mass of the scanning mirror 4 or the like becomes small and the construction suited for high speed copying is made possible.

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