Offset letterpress

Most metals receive a base coat of enamel (or occasionally paint), which is baked on. Printing then takes place on the enamel coating by offset lithography, dry offset letterpress, and occasionally other processes. 

Security printing does not denote a particular printing method but an application sector in which one or several well-known printing methods are used, such as offset, letterpress and gravure printing. 

Letterpress and Offset Letterpress (Dry Offset) Lithography Rotogravure Printing Rapid Prototyping UV Powder Coatings... 

Impression cylinder FIGURE 7.6 Offset letterpress (dry offset). 

Over the years letterpress printing has declined into niche markets, two of which are the printing of plastic self-adhesive labels on narrow-web rotary-offset letterpress machines that are fitted with UV drying and the common-impression rotary-offset letterpress and UV-curing on mandrel of plastic containers such as yoghurt tubs and toothpaste tubes. In uses such as these the most common self-adhesive plastic is PVC and the most usual for tubs and tubes are polystyrene, PVC, ABS, and polypropylene. 

In the context of printing plastics, the Nyloprint photo-polymer plate appears to be the most popular in the areas of narrow-web rotary-letterpress label printing and rotary-offset letterpress printing of plastic tubs and tubes. 

Metal containers produced by impact extrusion must be decorated as the last stage rather than the first stage. The process normally used is rotary dry offset letterpress. Drawn containers may be decorated either before fabrication (by offset lithography) or after fabrication (by dry offset letterpress). The choice depends on the depth of draw and the amount of distortion which can be tolerated. Deep drawn components are invariably decorated after forming. 

The decorative effects which can be achieved by offset letterpress printing are much more limited than those available by offset lithography on sheet materials. The design is limited to a maximum of six colours and a second pass is not possible. 

Relief—print area is raised above the non-print area—letterpress, flexography, dry offset letterpress, hot die stamping. 

Process Flexo and Gravure Litho Offset, Letterpress Screen and Pad Laminating Coating ... 

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