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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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