Method and apparatus for ultrasonic etching of printing plates
OwnerJohn C. Urbanikinventor
Life of this patent
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Abstract
Method and apparatus for etching light-sensitive photopolymerizable surfaces of printing plates. The apparatus includes a bath of etching fluid (32), a conveyor (38,40,42,52) for conveying printing plates (10) in a prescribed path (54), and transducers (46) mounted above the plates as they are conveyed within the bath and capable of forming longitudinal waves in the etching fluid at generally right angles to the surface of the printing plates. The invention is characterized by directing cleaning fluid between the acoustical radiating surface of the transducers (46) and the surface of the plates (10) in such a manner that the surface to be etched is swept with cleaning fluid of a sufficient velocity and volume as to prevent substantial cavitational erosion of the surface to be etched.
Claims13
In a process for etching a light-sensitive photopolymerisable surface of a printing plate after exposure including the following steps:
- providing a bath of etching fluid;
- conveying a printing plate in a prescribed path with at least a surface to be etched being in contact with the bath of etching fluid;
- forming longitudinal waves in the etching fluid at generally right angles to the surface of the printing plate, the waves being of a suitable wave length and amplitude to normally cause substantial cavitation adjacent the surface of the printing plate to be etched;
- the improvement being characterized by
- sweeping the surface to be etched with a flow of etching fluid at a substantial angle to the longitudinal waves and of a sufficient velocity and volume to prevent substantial cavitational erosion of the surface to be etched.
In an apparatus for etching a light-sensitive photopolymerisable surface of a printing plate after exposure;
- said apparatus including a tank capable of containing a bath of cleaning fluid, conveying means mounted within said tank for conveying printing plates in a prescribed path with at least said surface being in contact with the bath of cleaning fluid, and transducer means mounted at least partially within said tank above said prescribed path and capable of forming longitudinal waves in the cleaning fluid at generally right angles to the path of the printing plates, the waves being of a suitable wave length and amplitude to normally cause substantial cavitation adjacent the surface of the printing plate to be etched;
- the improvement being characterized by
- sweeping means for sweeping the surface to be etched with a flow of cleaning fluid at a substantial angle to said longitudinal waves and of a sufficient velocity and volume to prevent substantial cavitational erosion of the surface to be etched.
Dependencies are inferred from the claim text.