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High Speed Inline Coating for Sheet Fed Printing Presses.

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Presentation on theme: "High Speed Inline Coating for Sheet Fed Printing Presses."— Presentation transcript:

1 High Speed Inline Coating for Sheet Fed Printing Presses

2 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

3 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

4 High Speed Inline Coating for Sheet Fed Printing Presses Adhesion Substrate - Ink

5 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

6 High Speed Inline Coating for Sheet Fed Printing Presses Ink Layer Thickness

7 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

8 High Speed Inline Coating for Sheet Fed Printing Presses Gloss Diagram after 24h Drying Gloss in % Drying Time in h 3 g/m² 2 g/m² 1 g/m² Wet-on- Wet Printing

9 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 20°C - 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

10 High Speed Inline Coating for Sheet Fed Printing Presses Viscosity depending on the Temperature Viscosity in s Temperature in °C

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

12 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

13 High Speed Inline Coating for Sheet Fed Printing Presses Dilution of the Coatings with Water Viscosity in sec. DIN 4 mm Cup at 20 °C approximate Water Amount in %

14 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

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

16 High Speed Inline Coating for Sheet Fed Printing Presses Gloss Diagram: different coatings on the same substrate

17 High Speed Inline Coating for Sheet Fed Printing Presses Influence of the Surface Structure of the Substrate Carton 1 Carton 2 Application Amount g/m² wet Gloss in %

18 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

19 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

20 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

21 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.

22 High Speed Inline Coating for Sheet Fed Printing Presses Printing Press with Double Extended Delivery

23 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

24 High Speed Inline Coating for Sheet Fed Printing Presses Result High Speed Inline Coating with prints/h will not present any problems if the appropriate coatings are used and the printing press is well adjusted.


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