Circuit for modulating a scanning beam in a text and graphics image setting apparatus
US4794405A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 22, 1986 |
| Grant date | Dec 27, 1988 |
| Priority date | — |
| Expiry date | Sep 22, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N2201/04798
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Image setting apparatus is disclosed for producing two-dimensional image on photosensitive material. The apparatus includes a device for transporting the photosensitive material past an imaging line to provide a first dimension of the two-dimensional image, a controllable source of electromagnetic radiation (EMR) for producing a modulated EMR beam, a scanning device for converting the EMR beam into a scanning beam, and a scan lens in the path of the scanning beam to focus the beam spot on the photosensitive surface. The beam spot thus moves repeatedly along the imaging line to provide the other dimension of the two-dimensional image. According to the invention, the EMR source is controlled to switch the EMR beam on and off at a frequency which is adjusted to compensate for variations in the scanning speed of the beam spot along the imaging line.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.