Optical element positioning apparatus for use in electrophotographic copying machine

Claim 1

An optical element positioning apparatus for use in a variable magnification copying machine which has movable optical members for scanning an original, a lens for projecting an image of the original and a mirror for directing the image of the original from the lens toward a photosensitive medium, the apparatus comprising; means for supporting the lens continuously shiftably along the optical path from the optical members, means for suporting the mirror continuously shiftably along the optical path from the lens to make the length of the optical path equal to the total conjugate distance corresponding to a selected magnification and pivotally movable relative to the optical path to make the image of the original incident on the photosensitive medium always at a definite position, said mirror supporting means having a shiftable member shiftable along the optical path from the lens, a holding member which holds the mirror and is supported pivotally on said shiftable member, an eccentric cam in contact with said shiftable member to shift the shiftable member, and a fixed position slanting cam in bearing contact with a portion of the holding member to move the mirror pivotally, a drive source, first means for transmitting a drive force of the drive source to the lens to locate the lens in a position corresponding to a selected magnification, and second means for transmitting the drive force of the drive source to said eccentric cam to give to the mirror supporting means a position and an angle corresponding to the selected magnification, whereby the position of the lens and the mirror can be changed substantially continuously to a position of newly selected magnification.