Photographic copying machine with means for varying exposure across the surface of the original copied
US4239385A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 9, 1979 |
| Grant date | Dec 16, 1980 |
| Priority date | — |
| Expiry date | May 9, 1999 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B27/73
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A photographic copying machine of the type in which exposure radiation is transmitted through a transparent original onto a photosensitive medium. Arranged in the exposure radiation path is an array of multitudinous controllable-transmissivity elements, the individual transmissivity values of which are individually controllable. A control electronics, preferably incorporating a computer and multiplexer, controls the transmissivity values of the multitude of controllable-transmissivity elements of the array. The transmissivity values to which the multitude of elements are set can be equal, but in accordance with the present invention are not; instead, the array is employed to establish a two-dimensional controllably non-uniform distribution of exposure radiation onto the photosensitive medium. This is done to implement non-uniform density and/or color correction during printing, or to superimpose onto the image projected onto the photosensitive medium images of symbols, text, or the like, which are to be appear on the final copy, or to implement border effects, by way of example.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.