High Speed Inline Coating

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High Speed Inline Coating
for Sheet Fed Printing Presses
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High Speed Inline Coating for Sheet Fed Printing
Presses

• Preconditions

- up to 12,000 prints/h the usual processing
instructions are to be observed
- for High Speed Inline Coating with a printing
speed of up to 18,000 sheets/h the processing
range must be adapted regarding
- substrate- ink layer thickness- coating
viscosity- coating selection- performance of
the dryer- distance under the dryer
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High Speed Inline Coating for Sheet Fed Printing
Presses

• Substrate - Ink

- the combination of substrate and ink should be
selected in a way to assure a good bond between
ink and substrate
- poor ink drying cannot be improved by coating
- the result is bad rub resistance and
insufficient scotch tape resistance
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High Speed Inline Coating for Sheet Fed Printing
Presses

• Adhesion Substrate - Ink

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High Speed Inline Coating for Sheet Fed Printing
Presses

• Ink Layer Thickness

- Overinking of the ink layer thickness with
parallel inline coating will reduce the
performance of the printing press
- as by reducing the printing speed the drying
time is adjusted
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High Speed Inline Coating for Sheet Fed Printing
Presses

• Ink Layer Thickness

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High Speed Inline Coating for Sheet Fed Printing
Presses

• Cell Volume of the Screen Rollers

- the cell volume of a screen roller is indicated
with the scoop amount of water in ml/m²
- the coating application amount corresponds to
about 1/3 of the indicated cell volume of the
screen roller
Example A cell volume of the screen roller
of 15 g/m² corresponds to
approx 5 g/m² coating application
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High Speed Inline Coating for Sheet Fed Printing
Presses

• Gloss Diagram after 24h Drying

Wet-on- Wet Printing
3 g/m² 2 g/m² 1 g/m²
Gloss in
Drying Time in h
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High Speed Inline Coating for Sheet Fed Printing
Presses

• Coating Viscosity

• the coating viscosity depends on the
  temperature and is determined with a 4 mm DIN cup
  at 20C

• when the temperature in the coating rises the
  viscosity will decrease

• in case of a viscosity decrease, e.g. below 25
  sec., an even coating application cannot be
  assured any more

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High Speed Inline Coating for Sheet Fed Printing
Presses

• Viscosity depending on the Temperature

Viscosity in s
Temperature in C
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High Speed Inline Coating for Sheet Fed Printing
Presses

• Variable Coating Viscosities

Cooling Units for Coatings by EASYLAC keep the
coating stable in viscosity
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High Speed Inline Coating for Sheet Fed Printing
Presses

• Too high Coating Viscosity

- a too high coating viscosity, e.g. above 65
sec. can be adjusted by dilution with water to
the required viscosity
- a too high coating viscosity in connection with
High Speed Inline Coating will lead to splashing
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High Speed Inline Coating for Sheet Fed Printing
Presses

• Dilution of the Coatings with Water

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High Speed Inline Coating for Sheet Fed Printing
Presses

• Coating Selection

• the drying behaviour of coatings depend on the
  coating type
• if for example the following coating types are
  used

• matt- semi matt- protection- gloss- high
  gloss- UV coatings

their drying behaviour will be considerably
different
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High Speed Inline Coating for Sheet Fed Printing
Presses

• Coating Selection

Rule of thumb
For dispersion coatings The higher the gloss,
the slower the thorough drying
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High Speed Inline Coating for Sheet Fed Printing
Presses

• Gloss Diagram different coatings on the same
  substrate

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High Speed Inline Coating for Sheet Fed Printing
Presses

• Influence of the Surface Structure of the
  Substrate

Carton 1 Carton 2
Gloss in
Application Amount g/m² wet
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High Speed Inline Coating for Sheet Fed Printing
Presses

• UV Coatings

- UV coatings dry immediately by
photo-polymerisation using short wave light
- the acetone test shows whether the coatings
have dried thoroughly
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High Speed Inline Coating for Sheet Fed Printing
Presses

• Performance of the Dryers

- the drying behaviour of the coatings is
determined by the performance of the dryer
- the thorough drying of dispersion coatings is
primarily determined by the available amount of
air ? The more air, the better for the

thorough drying
- beginning at a pile temperature of approx. 35
C problems may occur in the pile
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High Speed Inline Coating for Sheet Fed Printing
Presses

• Drying of UV Coatings

• for UV coating processes the condition of the
  UV lamps and a sufficient performance are
  responsible for a good coating result

• the temperature in the pile is also decisive for
  UV coatings and may be responsible for subsequent
  problems in print finishing

• too high temperatures may result in breaking of
  the printed matter during the grooving and
  folding process

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High Speed Inline Coating for Sheet Fed Printing
Presses

• Drying Distance

An extended delivery between coating tower and
delivery is advantageous for the printing speed.
A short delivery is a disadvantage for High Speed
Inline Coating.
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High Speed Inline Coating for Sheet Fed Printing
Presses

• Printing Press with Double Extended Delivery

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High Speed Inline Coating for Sheet Fed Printing
Presses

• Special Coating Applications

- for special coating applications, as e.g.
application of blister coating, a coating amount
of 6 8 g/m² has to be applied in order to
assure good bonding with the plastic foil
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High Speed Inline Coating for Sheet Fed Printing
Presses

• Result

High Speed Inline Coating with 18.000 prints/h
will not present any problems if the appropriate
coatings are used and the printing press is well
adjusted.