Practical tip: The underestimated influence of fountain solution additives on print quality
High availability in offset printing due to suitable dampening solution additives
Dampening solution additives play a decisive role in the variables of the influencing parameters in industrial offset printing. Very often we observe that unthought changes of the additives used to other, usually slightly cheaper products have an enormous impact on the print quality and performance of the printing presses.
In the case of installing new printing presses, the properties of the dampening solution additive required for the intended use of the press are determined by an experienced and knowledgeable process engineer during the setup. Substrates, roller materials, and ink requirements are taken into account. Subsequently, either a product offered by the printing press manufacturer is used or a suitable additive from the pool of existing suppliers of the printing press operator is used.
A suitable dampening solution additive makes an essential contribution to stabilizing the printing process, keeping the pressroom clean, minimizing service costs and maintaining a high level of press availability throughout its service life. The positive influence on maintaining the value of the press should also be mentioned here.
Attention Framing. Warning signal: high dampening solution feed at the print edges
If an unsuitable dampening solution additive is used (even temporarily), this can cause lasting damage to the press. An important indication of an unsuitable additive is the so-called framing.
Framing leads to an unwanted transfer of ink particles in image-free areas of the printing plate due to a disturbed printing process. Framing does not interfere with the printed image, as the barely perceptible small ink particles are removed via the substrate. Outside the printing format, however, the ink cannot be removed or transported back into the inking unit via back-trapping, as moisture on the blanket cylinders prevents this. This means that ink, especially on the impression cylinders, builds up over the entire print run. It is often only when changing plates that it becomes apparent that the printing plates, which have just been cleaned, are inked outside the printing format. This happens because many printing presses get into pressure when the plates are extended. The blanket cylinders, which are dry at this point, adopt the ink from the impression cylinder and transfer it to the printing plate. This results in high and incalculable expenditure of time due to additional cleaning. Framing can cause considerable damage to the press over a long period of time. If the problem is not solved, in the worst case the grippers, guide plates, and other sheet guiding elements can become dirty or even fail. Doubling, register issues, and early wear on blankets are all serious early-indicators. Press-downtime and high fixing-costs may follow up.
Possible issues caused by improper dampening additives
Framing on ejected printing plates
Framing on back cylinders caused by unsuitable dampening-additive
Different fountain solutions impact printing results
Unsuitable dampening additive causes dirty printing units
Disturbed printing process due to wrong fountain solution
Ghosting caused by unsuitable dampening additive
Streaking in printed images
UV-Ink-Piling as effect of improper dampening solution
Destroyed printing plates by unsuitable fountain additive
Influence on print quality, ink control, and drying
As mentioned at the beginning, a fount solution additive adapted to the printing process contributes to consistent, quality-assured print production. Only when the printing process is stable does color control work quickly and accurately. Process calibrations retain their validity. Fast inking up, minimal waste and ecologically sustainable printing require this.
A fountain solution additive that harmonizes well with the ink also has an advantageous effect on drying behavior. An optimized ink-water balance enables the printing plates to run free quickly and the dampening solution flow to be reduced overall. Printing sheets printed with conventional, oxidative-stroking printing inks dry much faster and the products can be processed more quickly. Less powder is needed to treat the printed sheets. The delivery and the pressroom remain clean. Printing with UV inks benefits from lower process fluctuations and stable dot gain.
This article is intended to help raise sensitivity to the significance and influence of the dampening solution additive in offset printing.
If you have any questions in relation to achieving high-performance printing processes and constant print quality in offset printing, please do not hesitate to contact us. We will also be pleased to take over the communication between your suppliers in order to find the optimum dampening solution additive for you.