Printing JAC Synthetic Sheets

JAC Synthetic sheets can be printed using either conventional or UV offset inks. Here’s a few tried and tested tips for the best results.

1. Contact your ink supplier for the oxidation drying inks you need. If you’re conventional offset printing only use inks manufactured for printing on synthetics and which dry by oxidation.

2. For a high degree of printability run your fountain with the least amount of water needed whilst carrying a full body of ink ie enough so as not to allow the plate to ketch and scum.

3. Isopropanol (alcohol) improves the wetting properties of water. This can be used at the rate of 8-10% of the normal fountain. Check if your fountain solution is compatible with alcohol additives and remember alcohol only lasts two hours in the fountain.

4. With alcohol dampening systems you won’t need extra alcohol. However, to help with drying on synthetic stocks, add a fountain drier to the fountain solution.

5. To assist with water displacement on the plate, a 3mm to 5mm solid band can be exposed on the grip edge of the plate. This prevents excess water on the non-image areas from creeping back and building up on the print area. Whilst the solid band will ink up, this should not cause any print problems. It will not matter if this band does not completely print on the stock, provided it creates a water balance on the press to inhibit the water flowing back.

6. To help achieve ink key onto the face stock when running synthetic stock, add approximately 2% cobalt or equivalent to the ink and mix thoroughly. Too much drier can also slow down the oxidation drying process.

7. Some printers carry too much water on normal jobs. With the oxidation principle (ink drying on the top of the sheet), it is essential to carry the least amount of fountain on the plate to avoid “water trap”. Excess water between the ink and the synthetic film will slow the process of drying considerably. This procedure can be used on all types of printing machines with all styles of dampening including alcohol, Molleton-type and integrated systems.

8. When printing synthetic stock on offset machines, it is essential that the printed stock be taken out in small stacks (200-300 sheets). After a few hours when the ink has settled, carefully aerate or loosen the printed stack to avoid set off.

9. Offset powder should be used sparingly so it does not slow down the normal oxidation drying process. If a spray powder is used, a coarse grain type is best. Too much powder will also lead to loss of gloss and make the finished product feel gritty.

10. Check with the manufacturer for more information about the use and suitability of your particular ink.