US 4,728,986 AGranted

Optical scanning

AssigneeThe Imtec Group plc

InventorArthur C. E. Ravenshear

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Abstract

An optical scanning system for projecting an image onto a moving surface comprises four reflecting surfaces, a first or scan reflecting surface to deflect an incident light ray into a first direction, second and third reflecting surfaces mutually at right angles which together reflect the ray from the first reflecting surface in a direction opposite to the first direction and displaced laterally therefrom, and a fourth or exit reflecting surface to receive the ray reflected from the third reflecting surface and to deflect it parallel to the incident ray onto the moving surface. The scan and exit reflecting surfaces are maintained at right angles to each other as they are translated in opposite directions during a full scan of the image. The second and third reflecting surfaces are translated together in the same direction as the scan reflecting surface, and the translations of the scan and exit reflecting surfaces are effected at respective uniform rates each of which has a fixed ratio to the rate of movement of the moving surface. Rocking or tipping of the scan and exit reflecting surfaces during translation is effected automatically by a cam and cam follower for each.

Claims9

Dependent claims

An optical scanning system for projecting an image onto a moving surface, comprising a scan reflecting surface (A) to deflect an incident light ray into a first direction, second and third reflecting surfaces (B) mutually at right angles which together reflect the ray from the scan reflecting surface in a direction opposite to the first direction and displaced laterally therefrom and an exit reflecting surface (C) to receive the ray reflected from the third reflecting surface and to deflect it parallel to the incident ray onto the moving surface (5), means for translating said scan and exit reflecting surfaces (A, C) in opposite directions during a full scan of said image while maintaining said scan and exit reflecting surfaces at right angles to each other, means for rocking or tipping each of the scan and exit reflecting surfaces (A, C) during their respective translations while maintaining their right angle relationship throughout, means for translating the second and third reflecting surfaces (B) together in the same direction as the scan reflecting surface (A), and the translations of the scan and exit reflecting surfaces (A, C) being effected at respective uniform rates each of which has a fixed ratio to the rate of movement of the moving surface (5).

Dependencies are inferred from the claim text.