Apparatus and method for facsimile scanning
AssigneeTeletype Corporation
InventorJack S. Abrams
Life of this patent
Estimating the term…
Abstract
A selector disc defining a single revolution spiral aperture is concentrically rotated with a scanning disc defining four nested multiturn spiral apertures. An elongated fixed slit is positioned between the discs and as the discs rotate, an exposure aperture is defined by the slit and a selected scanning spiral, the aperture moving linearly across the slit. The drive ratio between the discs is such that their relative positions advance so that adjacent scan lines are defined by alternate scanning spirals. Further, each scanning spiral is composed of a series of contiguous, arcuate segments forming in the general path of an Archemedian spiral thus providing a scanning system having improved resolutional characteristics.
Claims16
An apparatus for scanning a document by optically dividing the document into a large number of small discrete areas comprising:
- means defining a fixed linear slit;
- a scanning disc defining a plurality of nested spirally shaped apertures said disc being positioned adjacent said slit defining means so that each of said spiral apertures intersect said slit;
- a selector disc defining at least one spiral aperture, the center of rotation of said selector disc being concentric with the center of rotation of said scanning disc;
- the plane of said selector disc being oriented parallel to the plane of said scanning disc so that the registration of said selector spiral and one of said scanning spirals with said slit defines an exposure aperture;
- and
- means for rotatably driving said discs whereby the exposure aperture is caused to move across the document along a predetermined path as determined by the orientation of said elongated slit with said scanning spirals being alternately selected by said selector spiral so that adjacent scan lines are defined by alternate scanning spirals.
An apparatus for scanning a document by optically dividing the document into a large number of small discrete areas comprising:
- means defining a fixed linear slit;
- a scanning disc defining a spirally-shaped aperture, said disc being positioned adjacent said slit, defining means so that the intersection of said scanning spiral and said slit defines an exposure aperture;
- means for rotatably driving said scanning disc so as to cause said scanning aperture to move across the document along a predetermined path as determined by the orientation of said elongated slit and said scanning spiral, said scanning spiral being formed by a continuous path of contiguous arcuate segments, each of said segments having a common center and forming a small portion of the total scanning spiral.
A method for scanning a document comprising the steps of:
- rotating a scanning disc defining a plurality of nested multiturn spirals in proximity with an elongated slit so as to define a number of apertures;
- rotating a selector disc defining a single selector spiral in proximity with said scanning disc;
- and
- varying the phase relationship between rotating scanning and selector discs so that said selector discs selects alternate scanning spirals for sequential scanning of lines of the document.
Dependencies are inferred from the claim text.