US 4,374,619 AGranted

Variable magnification copying apparatus

AssigneeXerox Corporation

InventorsRichard A. Spinelli, Edward C. Bock

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Abstract

An optical system is provided for a copying apparatus which includes a plurality of components whose displacements relative to each other can be made to yield differing magnification at an imaging plane. In particular, during a magnification mode a dual rate scanning mirror pair is displaced a fixed distance and a catadioptric lens is displaced an identical distance, from their normal 1x positions. A third mirror, located at the photoreceptor plane is displaced a second distance. The displacements are a function of the magnification, the lens focal length and the angular displacement of the lens. All displacements are parallel to the document plane, resulting in a compact scanning system.

Claims2

Dependent claims

An optical system for use in a document reproducing apparatus wherein enlarged or reduced images of an original document lying in an object plane are exposed onto a flat imaging plane, said system including:

a first mirror adapted to scan said document in a plane parallel to said object plane,
a second mirror adapted to maintain a constant object conjugate during 1x operation but a variable object conjugate by displacement of a distance K upon selection of a magnification mode,
a lens located at a fixed location during 1x operation but displaced a distance K in a plane parallel to said object plane during a magnification mode, and
a third mirror located in the optical path between said lens and said imaging plane, said mirror displaced a second distance N and adapted to reflect reduced or enlarged images onto the imaging plane while maintaining constant image conjugate.

1 more element

Dependencies are inferred from the claim text.