Process for obtaining image information of an illustrated printing form, device for this and printing press

Abstract

A process is provided for obtaining or refreshing the illustration of a printing form, preferably in wet-offset printing. Instead of clearing the illustration over the entire area, the printing form is acted on during the production. For this, a processing agent can act on the printing form in different areas for images. A processing agent preferably acts over the entire area of the printing form, in which case the layer of ink located on the printing form leads to a locally different intensity of the action, corresponding to the illustration of the printing form. Photocatalytic effects are preferably used. A hydrophilization of non-image areas is brought about by irradiation in the presence of water molecules. Since printing ink containing little water lies on the image areas, hydrophilization cannot occur on the image areas. Thus, in spite of the entire-area action on the printing form, an image-related refreshing or obtaining of the illustration is automatically achieved. A device is also provided for carrying out the process and a printing press with such a device, especially a wet-offset rotary printing press in the printing of newspaper print runs.