Relief Printing Plate Production Modern relief printing plates are made from rubber, photopolymer or occasionally metal, depending on the application Plates are modest in cost and can be made quickly. Nearly all are made by photographically imposing the image recorded on a photonegative onto a light-sensitive material. In the case of photopolymers, the polymer hardens where exposed to ultraviolet (UV) light and remains fluid where unexposed The unexposed part is then dissolved away. (See Figure 11.1)
Relief Printing ⚫ Plate Production. Modern relief printing plates are made from rubber, photopolymer or occasionally metal, depending on the application. Plates are modest in cost and can be made quickly. Nearly all are made by photographically imposing the image recorded on a photonegative onto a light-sensitive material. In the case of photopolymers, the polymer hardens where exposed to ultraviolet (UV) light and remains fluid where unexposed. The unexposed part is then dissolved away. (See Figure 11.1)
Relief Printing 000000000004-0 Image photonegative Cured photopolymer Uncured photopolymer Support material Figure 11.1 UVlight projected through the image photonegative will cure photopolymer Uncured polymer can be washed away, leaving the raised image areas
Relief Printing Figure 11.1 UV light projected through the image photonegative will cure photopolymer. Uncured polymer can be washed away, leaving the raised image areas
Relief Printing ● Flexography In a typical flexographic printing station (see Figure 11.2) excess ink is applied to an engraved transfer, or anilox roll. The engravings on the anilox roll meter the correct amount of ink, depending on the engraving geometry and depth. The ink is transferred to the raised surfaces of the printing plate attached to the plate cylinder. Line art printing plates have a solid, smooth surface. Halftone and process printing plate surfaces are composed of small dots standing out in relief. The substrate is passed between the plate cylinder and the impression cylinder to achieve ink transfer
Relief Printing ⚫ Flexography In a typical flexographic printing station (see Figure 11.2) excess ink is applied to an engraved transfer, or anilox roll. The engravings on the anilox roll meter the correct amount of ink, depending on the engraving geometry and depth. The ink is transferred to the raised surfaces of the printing plate attached to the plate cylinder. Line art printing plates have a solid, smooth surface. Halftone and process printing plate surfaces are composed of small dots standing out in relief. The substrate is passed between the plate cylinder and the impression cylinder to achieve ink transfer
Relief Printing To drying station Ink fountain Substrate Anilox Plate Impression roll cylinder cylinder Figure 11. 2 A typical flexographic print deck. A chambered doctor blade ink fountain applies ink to the anilox roll. In other systems, ink is applied with rolls rotating in the ink fountain
Relief Printing Figure 11.2 A typical flexographic print deck. A chambered doctor blade ink fountain applies ink to the anilox roll. In other systems, ink is applied with rolls rotating in the ink fountain