Erasable printing form
AssigneeMAN Roland Druckmaschinen AG
InventorsAlfred Hirt, Barbara N ussel, Robert Weiss
Life of this patent
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Abstract
A method for producing an erasable printing form by making the outer layer of the printing form from a material containing strong micro-dipoles, preferably a ferroelectric material, in particular a ferroelectric ceramic. In wet offset printing, the non-printing areas of the printing form are rendered hydrophilic by a hydrophilizing agent and they are maintained during the entire printing process. Plate cleaners can, for example, be used as the hydrophilizing agents. The printing form can be erased by a nonpolar solvent and can be reused again by rendering the non-printing areas hydrophilic again.
Claims9
A method for printing, comprising the steps of:
- providing an erasable printing form having an outer layer having a hydrophobic surface and micro-dipoles at least in the outer layer, the micro-dipoles having a strength sufficient for tightly bonding an agent having a hydrophilic effect to the surface, the printing form being produced by applying a masking material to the hydrophobic surface according to the image areas;
- and applying a hydrophilizing agent to the printing form during a production run to render non-image areas hydrophilic.
A method for erasing an ink-containing printing form having an outer layer having a hydrophobic surface and dipoles at least in the outer layer, the micro-dipoles having a strength sufficient for tightly bonding an agent having a hydrophilic effect to the surface, which printing form is produced by applying a masking material to the hydrophobic surface of the printing form according to image areas, and rendering non-image areas hydrophilic with a hydrophilizing agent, the erasing method comprising the steps of:
- cleaning the ink from the printing form with a solvent;
- and applying a nonpolar solvent to the printing form so as to render it hydrophobic again.
A method for producing an erasable printing form for dry offset printing, comprising the steps of:
- providing an outer layer and micro-dipoles at least in the outer layer, the micro-dipoles having a strength sufficient for tightly bonding an agent having an oil-repellent effect to the outer layer;
- applying a masking material to the outer layer corresponding to image areas;
- and rendering non-image areas oil-repellent with an oil-repelling agent.
Dependencies are inferred from the claim text.