Printing with Reduced Alcohol |
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Alcohol was introduced as an aid to overcome the problems that were experienced on older equipment when using conventional fountain solutions, these problems were exacerbated on presses that were not properly maintained, had settings that were not accurate or were run by inexperienced operators, adding alcohol made the printing process more forgiving allowing more tolerance when pursuing optimum Ink/Water Balance.
IPA (alcohol) reduces the surface tension of the fountain solution making it spread more quickly and increases its viscosity allowing a thicker film of solution to interact with the Ink and non-image areas of the plate. IPA evaporates quickly from the Inking rollers, therefore less dampening solution is transferred to the paper.
Whilst adding IPA to dampening solution has made the job of the operator an easier one, there are many drawbacks to using IPA, not the least being the environmental factor.
But it is not a simple matter just to eliminate or reduce alcohol from dampening solutions without experiencing problems, the metering roller can become more easily sensitised, banding can occur, filling in of halftones, and the stripping of rollers -the list goes on.
An alcohol substitute or alcohol free solution is required to make the change easier, however even then when printing with reduced alcohol everything needs to be in your favour, from the shore hardness of rollers and dampeners, to the hardness of the water, correct pH and conductivity and a well maintained press. Essentially the print window (tolerance) is narrower.
It is dependent upon the alcohol free fount that is used as to how the changeover progresses, the fount must be compatible with all other chemistries being used on the press, some substitutes work better with the metering roller having a crown, whilst others may work more efficiently with a parallel metering roller. There is no magic formula.
All in all it can be a difficult task to reduce alcohol and achieve the desired results, but for those that persist and succeed will find they can carry less water and ink attaining a stronger and glossier result, save on consumables and benefit to the workplace and the environment.
With Eco responsibility the topic on everyone’s lips the IPA reduced or IPA free effort may also enable your print shop to differentiate itself as a greener printer than the next shop.
Heidelberg recommends Saphira RIPA Fount for reduction/elimination of IPA and can help you plan for a “dry” spell.
Further Information:
Kevin Lampard
Account Manager - Consumables
Tel: +61 3 9263 3388
Email: Kevin.Lampard@heidelberg.com
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Consumables
Welcome to Heidelberg Consumables, where you will find a wide range of high quality, value-added Heidelberg consumable products.
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