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With all the high speeds and productivity needed
in today's sheetfed market, How does the printer
keep it all together? 20 or 30 years ago most
of the process was hand driven in other words
all press operations were completed by hand. If
you needed to adjust ink, you did it by "tweaking"
the "ink keys" at the ink fountain which meant
climbing up to the ink system on the press. Most
of the rollers also needed to be engaged by hand.
Ink levels and print quality was left to the eye
of the press operator which of course varied over
the course of the day. When a new job came to
press, the press operators had to "eyeball" the
plate and make a guesstimate as to where the ink
keys and fountain should be set - a trial and
error method. Today, however, is much different
as automation and computerization has set in.
Today's modern sheeted-presses are fully automated
with internal computers do assist the press operator.
Presses can come equipped with a "plate scanner"
and computer consoles to do many of the tasks
the press operator did by hand years ago.
Today when the offset plate comes to the press,
the press operator can scan the plate on a "plate
scanner" (if equipped). The image densities are
read across the individual plate and the fed into
the press console which can then preset the ink
keys and the ink fountain (total ink flow). The
operator can scan the black offset plate, for
example, via the press computer the black ink
unit would be preadjusted based on the readings
taken from the plate scanner. The same would be
done for all the additional plate colors such
as cyan, magenta, yellow and any other special
colors.
Plates
today can be automatically "hung" or mounted as
well as be removed without operator interaction.
Cleaning of the blankets today also is fully automatic.
Once the plates are mounted make-ready begins.
While the plate scanner will be close in color
and density, the operator usually has to make
some small adjustments on color and registration.
Unlike in years past, however, the operator can
do this electronically through the press console.
With a image scanner attached to the press (closed
loop) the press sheet can be scanned using color
bars. This device measures ink density and relates
it to ink film thickness. The operator can read
the results via a computer screen. By electronically
activating the ink keys and fountain via the press
console adjustments are made quickly and easily
compared to years past.
Once the customer or press operator has approved
the color the press operator can "lock" the values
into the computer. During the press run the operator
will scan sheets every so often on the scanner
to measure color. If a color starts to shift out
of tolerence, the scanner will display that information
and the operator can "send" the data over to the
press computer which will automaticity adjust
the proper ink unit to bring the density levels
back in customer tolerance. Some modern presses
today even have the color system "closed looped"
fully so small adjustments are being made continuously.
You can do the same with an off-line scanner or
hand held scanner, however, the press operator
will make a judgement call based on their experience
on changing the ink level (via the press console).
What has this done? Well, it has speeded up make-ready
time by as much as 85% which in turn reduced cost
and increases productivity.

With any manufacturing process, and printing
is a manufacturing process, productivity is a
must!
This
unit is programmable from the press console. A
cloth material is installed in the unit. As it
washes, with press solvent also being applied,
the cloth material will "wipe" the debris and
solvent away. At the conclusion of each wash the
cloth will advance. After a while the cloth unit
needs to be replaced with a new cloth unit.
Important
Properties
- Paper
Consistency
- flat
and dimensionally stable
- Good
surface strength
- Surface
cleanliness
- Good
slitting/cutting - clean edges
- Accurate
and square cut
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