Apparatus for correcting scanning speed in a polygon used for laser scanning
US4310757A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 14, 1980 |
| Grant date | Jan 12, 1982 |
| Priority date | — |
| Expiry date | Mar 14, 2000 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N2201/04794
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An electro-optical light scanning system using a modulated laser illumination source directed upon a multifaceted rotating polygonal mirror or polygon. The mirrored facets reflect the impinging light toward a moving photoreceptor and forms a raster of scan lines as the photoreceptor moves. The system incorporates sensing optics and closed loop electronics for correcting inaccuracies in the position of the reflected light resulting from defects in the angular relationship between the plane of the facets and that of the rotating axis of the polygon as well as those errors due to inherent angular misalignment between each of the facets of the rotating polygon. The invention also encompasses speed control as well as amplitude modulation for varying the intensity of the laser illumination in conjunction with the acousto-optical modulation for maintaining a constant level illumination and/or for varying the spot size.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.