Recent trends in flexo press design and technology have been spurred by the need to reduce makeready
time, improve print quality and create presses that are more efficient and user friendly.
To achieve this target one of the viable way is undoubtedly the integration of different automation and
informatic control systems to incorporate into C.I. flexographic presses of new generation.
The deck movement can be controlled in various ways ranging from simple systems of motorised deck
positioning to the more sophisticated ones such as the computerised numerical control (CNC). The latter
provide the pre-register and the completely automatic meshing of the plate cylinder gears to the central
impression bull gear in register colour to colour.
Flexo impression adjustment is critical to controlling flexo image quality; the more precise control a
printer has and the finer adjustment he can achieve, the more closely and easily he will be able to
control printed image quality. On advanced deck positioning achieved by synchronised motors (stepping or
AC motors) shaftless deck advancing eliminates many of the mechanical components on the deck, by
increasing among other things operator accessibility to the print deck.
By controlling the movement of these individual stepping motors you can precisely adjust the fine
impression settings via remote keypads in the region of micron with an automatic and dynamic increase of
print pressure on ramping up in speed. The computer will store the last input print pressure adjustment
on each deck for that particular job assuring the repeatability of an unlimited number of jobs.
Therefore, each time you re-call that job the print unit will automatically return to the previous
impression setting with optimisation of production start-up and consistency of print quality.
Digitally controlled motors allow remote or automatic control of the press opening up the press for
computer interface whereas digitally controlled drives on the press certainly improve accuracy of
integrated systems.
The most advanced computerised systems such as the FNC 3000 include the possibility of connection with
'Management Information Systems' where all data can be transferred from the computer of the press to any
office computer at the converter's whilst offering a monitoring data sheet of press performance.
To safely and quickly handle the cylinders Flexotecnica has for long put on the market the roboted
Safelink ® system where each movement is managed in sequence by a dedicated PLC, on the other hand by
switching it into manual mode it also gives the advantage of carrying out the removal of cylinders from a
remote keypad under total operator's control. The Safelink ® system is equipped with its own trolleys for
stocking cylinders. To comply with such a system all caps of cylinder bearing supports have to be opened
and closed automatically.
In terms of dimensions the structure of machines for flexo printing can be very big in the 8 colour
versions for large print repeats and wide web widths.
Therefore regardless of the automated system the press may be equipped, changing inks from one print run
to the next on a C.I. flexo press and consequently cleaning anilox roller, doctor blade chamber and ink
pipe affects negatively the down time and the human resources applied for such operations.
Flexotecnica has studied and engineered since late 1997 their own fully automatic wash-out system named
"Speedy clean" which provides a fast automatic ink supply and cleaning of the whole inking group (doctor
blades, anilox rollers, ink pumps, ink hoses and viscosity controls) in enclosed loop suitable for both
solvent and water based inks.
The inside cleaning of the chamber doctor blade is achieved by pumping into the chamber solvent/water
with alternative cycles whilst using the whirlpool created inside the chamber by the higher rotation
speed of the anilox roller.
At the end of each job, operator may select one or more units to be washed up on a programmable sequence.
The expected time for a complete wash-up for one or all units is 4-5 minutes depending on the ink and
colour. The average consumption of solvent/water for a complete wash-up cycle is 8/10 litres per unit,
obviously in relation to the press width. All these operations are managed by a dedicated PLC.
The system includes special chamber doctor blades which move horizontally and linearly into position
achieving a very accurate setting with minimum friction. This doctor blade is specially designed to
provide depression when solvent or water is pumped violently into the doctor blade for wash-out with
increasingly control of ink supply and return.
To conclude the market growth of flexo printing process in the sectors of both flexible packaging as well
as folding carton with subsequent in-line operations of lacquering, old seal coating, laminating and
die-cutting will strongly put forward to take advantage of high technology Flexotecnica has consolidated
for long.
Design flexibility and product innovation are our driving forces which have made Flexotecnica leader on
the competitive edge of the flexo industry.
