| 摘要 |
To remove hydrophobic particles from the surface of a hydrophilic printing plate, particularly when the printing plate is used in offset printing, an ionized reactive gas is conducted to the surface of the printing plate, and applied thereto, to cause the hydrophobic particles to form volatile reaction products, which are then removed by suction. The gas can be generated either in a burner, preferably supplied with an oxygen/hydrogen mixture, emitted from nozzles spaced between 10 to 50 mm from the printing plate, in which the printing plate and nozzle are relatively moved at a rate of about 20 mm/sec; or, alternatively, the ionized gas is generated in form of a plasma by a plasma generator, for example a magnetron, operating at 2.45 GHz, which plasma is conducted to the surface of the printing plate in a reaction chamber which is physically sealed with respect to the printing plate, so that the reaction with the hydrophobic particles can there occur. The reaction chamber is coupled to a high-vacuum pump, to maintain a vacuum in the order of about 0.5 mbar above the printing plate and within the reaction chamber.
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