THE DATA FRONT

Labels&Labeling |109
changes and low operational costs,’ comments Jim Hammer,
president of Hammer Packaging. ‘The Variable Sleeve Offset
Printing technology helps us to both lower costs and increase
the quality of our products. Our customers, companies
like Coca Cola and Pepsi, are able to decrease their costs
when they run rolls of labels and shrink sleeves on their own
equipment. And the more we do in-line, the more freedom the
designers get to create an attractive product.’ John Swain,
principal of design company Packaging Arts, agrees: 'Hammer
was able to assist us in migrating our labels seamlessly from
cut & stack to roll-fed by using their Drent Goebel press. We
also benefited by changing our printing process to hex or
expanded gamut. It is nice to have a partner who stays ahead
of the technology curve.'
A high speed UV/WB flexo printing group was introduced
for the VSOP at drupa. The web can be directed into a hot-air
dryer and over the chill roller or directly over the chill roller with
optional integrated UV lamps for curing.
Another example of a wet-glue printer shifting to offset roll
production is German converter Offsetdruckteam Witten GmbH
(ODT). Two years ago, when the company was taken over by
the Ellerhold Group, half its annual 20m euros sales came from
wet-glue labels, mainly for the beverage industry. Responding
to the beverage sector’s move to filmic roll labels and shrink
sleeves, group managing director Frank Ellerhold invested in a
Muller Martini Alprinta 74V variable-size web offset press. The
740mm-wide press has eight offset press units, a flexo unit and
UV curing. It was originally specified with a Muller Martini offline
sheeter, but this was later integrated into the press, along with
in-line lamination and a hot air dryer.
Frank Ellerhold maintains that variable-size web offset offers a
cost-effective alternative to conventional flexo and rotogravure
printing on small-to mid-size labels runs. ‘Here, the quality and
the pre-press costs tipped the scale in favor of offset printing
and the Muller Martini machine.’
ODT also uses the Alprinta 74V to produce wet-glue labels,
as Ellerhold explains: ‘it can print 365 linear meters per minute,
which equates to 20,000 sheets with a 3B machine.’ The size
can be changed in just a few minutes. It is also possible to print
and coat wet-on-wet using conventional printing inks.
Offset mix and match
An option for converters with platform flexo presses is to use
interchangeable offset cassettes in the flexo press line. One converter
which has adopted this approach is Skanem Introl in Poland, which last
year installed a 10-color Gallus RCS 430 press specified with six flexo
stations but equipped to accept offset as well as flexo units (along with
two moveable cold foil stations). The offset printing unit can be deployed
anywhere in the press and can be combined freely not only with flexo,
but with screen printing, hot foil embossing and UV rotogravure.
The RCS offset printing units incorporate individually driven inking
and damping units. During the startup sequence the unit rotates at a
makeready speed of just 1m/min to minimize waste. Ink and water
profiles can be recalled for repeat jobs.
Interchangeable offset units are also now available for the RCS330,
along with UV rotogravure.
Sticking to cassettes
Not all offset press manufacturers have adopted sleeves for
format changes. ‘To achieve a perfect match and drive of
blanket and plate roller we believe that a cassette solution is
still the best solution,’ says Eric Hoendervangers, MD of MPS,
which – interestingly – developed its offset unit jointly with
Drent-Goebel.
‘Cassettes allow us to “open up” all print towers to insert
no-nonsense solid drop-in technologies for flexo, gravure,
hotfoil and screen. These drop-in technologies last forever and
perform also at high speed.’
MPS has retained its ‘solid lock’ technology for the offset
change cassettes as well as its other drop-in technologies.
‘This prevents play in gear positioning and gear marking,’ says
Hoendervangers. ‘No mechanical or software re-adjustment is
required to get the modules up and running.’
Other technologies MPS has carried across to its offset
units include the ‘Crisp Dot’ free running impression cylinder,
claimed to eliminate changes in web tension between
print units caused when the web is pulled through a driven
impression cylinder. Omet is another manufacturer which
has gone down the insert route, choosing interchangeable
Nilpeter MO-4
may 2009 | L&L