Method and apparatus for imaging printing plates by spark discharge
US5005479A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 27, 1989 |
| Grant date | Apr 9, 1991 |
| Priority date | — |
| Expiry date | Sep 27, 2009 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/24521
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
A method of imaging a lithographic plate having a printing surface comprising mounting a plate to the plate cylinders of a lithographic press having at least two plate cylinders, a corresponding number of blanket cylinders and an impression cylinder, exposing the printing surface to spark discharges between each plate and an electrode spaced close to the printing surface produced in response to picture signals, the spark discharges producing sufficient heat to change the affinity of each printing surface for printing liquid at the points thereof exposed to the spark discharges thereby producing image spots on each plate corresponding to the picture signals, moving the electrode relative to the plate to effect a scan of the printing surface, and controlling the spark discharges to the plate in accordance with picture signals so that they occur at selected points in the scan so as to form an image of the original document on the printing surface. Imaging apparatus is also disclosed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.