MAJOR DEVELOPMENTS IN PRINTING Printing the “cover” of corrugated cardboard, before lamination, enables achieving superior quality packaging, with a fast and economical process. For this type of application, Uteco has designed a central drum long repeat flexographic printer, which proves appealing for many reasons.

The term “pre-print” denotes directly printing on paper before it is laminated onto corrugated cardboard. It represents a recent alternative to in line printing, which is generally performed with flexographic machines for sheets, with 4 colors and considerable limits in terms of speed (approximately 70 sheets/min, more or less corresponding to 110m/min). The solution’s field of application is constantly growing, stimulated by the demand for more visually appealing packaging on the part of major users in many consumer sectors: beverage, for example, and home electric appliances.
In order to respond to this kind of necessity, Uteco (Colognola ai Colli, VR) proposes a Long Repeat flexographic printer with the right characteristics for combining high print quality with high speed operation and the economy required by this application type.

The variables at play
Flexo-graphic pre-printing presents a series of features suitable for creating boxes with high definition images: an outcome achieved simply and economically using central drum, reel-to-reel machinery capable of printing with superior quality at a speed of up to 500-600 m/min.
The paper normally used in this type of application is between 50 and 80% recycled, with a base weight that varies between 50 and 180 g/m2; it can be printed in up to 8 colors, often with a final lacquering to enhance brilliance. In this type of process, the advantages of flexo pre-print derive from various factors:
– the total absence of dust during the print process improves quality;
– the corrugate’s greater resistance, since it is not compressed during printing;
– improved print register precision;
– the possibility of also printing on glossy paper with smooth varnish.

Ad hoc performance
The gearless central drum flexo printer developed by Uteco for pre-printing is a Diamond HP with web starting from 1,800 mm and an average print repeat of approximately 1,800 mm. It is supplied in a standard configuration with central drum, 8 colors and downstream flexo unit for final varnish.
This line of machines features a robust design and guarantees ease of operation, a significant reduction in waste, and very fast changeover. The performance of this range is owed to a series of innovations introduced both during the design phase and in that of construction.
They are numerous and conspicuous, involving nearly all elements of the machine: FEM Analysis software for resolving problems with structure and elasticity, a central drum cleaning system, Kiss&Go® for automatic printing press setup, lifting platforms, the SprintWash® automatic washing system and the WindSystems automatic drying system.