Preparation of a printing plate/cylinder, uses at least one point electrode to give an electrical field at the plate/cylinder with an effect on the base layer giving thermal distortion at the covering layer for the ink points of the image

摘要

To prepare a printing plate, at least one point electrode (5) gives a selective action with a high frequency electrical field to give the points where ink is to be taken to print the required image. The printing plate blank (1) has a base layer (3) and a polymer and polar covering layer (4). To prepare a printing plate, at least one point electrode (5) gives a selective action with a high frequency electrical field to give the points where ink is to be taken to print the required image. The printing plate blank (1) has a base layer (3) and a polymer and polar covering layer (4). The covering layer has differing adhesions for the ink or with a wetting agent during printing. The effect of the electrical field on the base layer causes thermal distortions in the covering layer to give the printing image. To prepare a printing plate for wet offset printing, the base layer is hydrophilic and the covering layer is hydrophobic. The base layer is of anodized aluminum. The covering layer is a polar polymer, polyethylene terephthalate (PET), polyvinyl chloride (PVC), or polyvinylidene fluoride (PVDF).