Packaging Industry - Printing

Flexo Printing With technological advancements in plate making and press manufacturing the use of flexography has bridged the quality gap that once separated it from other printing processes. Developments in direct laser engraving have opened new possibilities for the flexographic printing industry. Direct laser engraving improves print quality and cost efficiency. Start-up, waste, registration, make-ready time and print speed are all improved in today’s press design. Various working widths can be realized using a single mandrel size with adaptors added for change of repeat length. Fewer cylinders are required for a given press, reducing investment costs. Low sleeve weight facilitates ease of handling. Only sleeves need to be transported leaving the sleeve mandrel in the press. Storage of rubber covered cylinders is no longer necessary. Rotogravure printing process Rotogravure printing allows printing onto a variety of substrates including fibre, wood-based, or laminated material including synthetics, paper and metal foils. Today’s rotogravure printing presses use engraved cylinders, which can retain ink finely enough to produce the required image, when applied with pressure to the substrate material. Gravure printing is used extensively in both food and other packaging applications including wallpaper and labels. Rotogravure presses are usually arranged in-line with printing units added as required. An engraved printing cylinder – a tube without seams, made from steel, aluminium of other engraveable material. The engraving represents the required finished image. A device or blade removes excess ink before a rubber roller presses the engraved surface against the substrate material creating the image. Inks may be solvent or water-based and accordingly driers are added to each print stage and the power of the driers is calculated in proportion to the print speed of the line. The substrate is then ready to receive the next colour or varnish. The rotating print cylinder collects ink so that engraved cells are primed with ink before excess ink is removed and the cylinder surface is pressed against the substrate material by pressure rollers. Capillary action assists the transfer of ink.