Method for direct making of lithographic printing plates
US4774165A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 19, 1987 |
| Grant date | Sep 27, 1988 |
| Priority date | — |
| Expiry date | Oct 19, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F3/04
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Disclosed is a direct making of multicolor printing plates by the procedure of exposing a photosensitive material (P) of the lithographic type for making a black plate to an original bearing both the continuous tone image and the line images. The said procedure comprises (1) exposure to the continuous tone image which is performed by exposing the sensitive material (P) through a contact screen to the original in which the line images are covered with a mask (M-1) having an optical reflectance of 2% or less and the continuous tone image is covered with a mask (M-2) having a large optical reflectance, then again exposing, in the absence of contact screen, the sensitive material (P) to the original in which the line images are covered with said mask (M-1), and the mask (M-2) for the continuous tone image is removed, and (2) exposure to the line images which is performed by exposing the sensitive material (P) to the original in which the continuous tone image is covered with the mask (M-1).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.