THE DATA FRONT

106 | l&l
Offset opportunities
The latest developments in web offset technology is making the process more attractive for
shorter runs and increasing in-line options available to converters. Andy Thomas reports
The new generation of web offset presses are designed to
open up new, shorter run markets previously closed to offset
by high levels of makeready waste and inflexible repeats.
The new Nilpeter MO-4 offset press, successor to the
MO-3300, typifies these trends. The key development on the
MO-4 is the use of sleeves for plate and blanket cylinders.
‘The cost of the aluminum-based sleeve system is around a
fifth of the price of an offset cassette,’ notes Jakob Landberg,
global sales and marketing director at Nilpeter. The sleeves are
mounted on hydraulic expansion shafts, allowing fast changes
between jobs.
Nilpeter’s Easy Load sleeve system is already in place for
plate and anilox cylinders and screen units on the FA-4 press,
and this standardized system allows print and converting
technologies to be switched quickly on the offset platform.
To facilitate the change from offset to hot foil printing, Nilpeter
has designed the impression roller as an interchangeable
sleeve, with a rubber or steel surface depending on the printing
method. This means there is no need to break the web when
switching between processes or impression rolls, greatly
reducing set-up times and waste.
The MO-4 has a more comprehensive servo drive
implementation than its predecessor. Each print unit has
independent drives for the plate sleeves, blanket sleeves
and impression rolls. Similarly with the length and lateral
registers. When any corrections to lateral register are made,
the complete unit –inking unit, plate and blanket cylinder – is
moved, avoiding color profile modifications.
A print cylinder insert with sleeve
technology for a 520mm print width
The MO-4’s inking train has been redesigned for additional
stability. Two inking rollers have been added to each inking
unit along with stronger sidewalls, while a total of three rollers
can now be temperature controlled. Individually programmable
dampening curves maintain constant ratios of moistening and
ink delivery across all machine speeds.
Rotatek is another narrow web manufacturer moving down the
offset sleeve route, with its new Universal press, a 500mm-wide
machine operating at speeds up to 350 m/min and featuring
the company’s recently patented lightweight offset sleeves with
steel bearers. The press runs both UV and EB inks. Its modular
design supports various in-line options including hot stamping or
cold foil, rotary screen and rotogravure units, and it will convert a
wide range of materials, including unsupported film, from 30-400
microns.
A flexo unit was introduced at Labelexpo mounting lightweight
sleeves on servo-driven plate and anilox cylinders. A chambered
doctor blade is optional for high speed reel-to-reel applications.
From sheets to rolls
Web offset has proven particularly popular with converters
making the transition from sheetfed into roll-fed labels. One such
company is Hammer Packaging in the US, which installed its
first Drent Goebel Variable Sleeve Offset Printing (VSOP) press
in 2006, a 33.5in wide VSOP 850 machine. Early this year the
company finished installation of a second, similarly specified
press.
‘Both machines offer short make ready times, quick repeat size
The ghost of Giebeler
SDF will be a new name to many in the labels industry, but this young
company has just filed a patent on a sleeve offset print station design.
The core of SDF is former engineers, service technicians and mechanics
from Giebeler – one of the ‘big three’ business forms press manufacturers,
along with Goebel and Grapha in the 1970s and ‘80s.
According to Karl Hallwas, SDF technical manager, the Giebeler
successor company filed a patent for sleeve printing cylinder inserts back
in November 1999, before its competitors – including Drent and Grapha
(now part of Muller Martini). Development of the sleeve system came to a
standstill after the company’s insolvency in the same year.
SDF’s wet-offset printing unit mounts the printing cylinder insert
with plate, rubber blanket and counter impression cylinder. Standard
circumference is from 20-28”, but larger formats of 28-36” and 36-44” are
available. Printing widths can range from 520-920 mm.
The plate and counter impression cylinder are in a fixed position, with
the rubber blanket cylinder brought into printing position according to the
printing format.
The sleeve is changed through the frame wall and the support cylinder
remains in the insert frame. The mounting of the sleeve body on the
support cylinder is hydraulic, and the plate cylinder is equipped with
diagonal adjustment to allow limited register correction. Only the plate
and rubber blanket cylinder are separately driven, reducing electronic and
mechanical complexity.
As well as offset print cylinders, rotogravure, flexo and screen print
inserts can be installed into the same frame opening.
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