What Factors Will Affect The PH Value Of The Fountain Solution?

(A) The amount of fountain solution added As the original solution PH value of acidic is very low, if too much is added, the ph value will be too low, if too little is added, the ph value will be too high.

(B) The impact of water quality on the fountain solution, for example: the total hardness of water and bicarbonate composition PH value have a negative impact. In order to understand the impact of external factors, to analyze the water. Through the analysis in order to adjust the water bucket drug water according to water quality. If the hardness of tap water is too high, the hydrogen carbonate content is too high or contains other harmful substances, it is necessary to purify the water before use. The hydrogen carbonate content in the water at about 50 mg / l is more suitable for offset printing fountain plate.

(C) Paper and fountain solution interaction Paper is not a homogeneous material, but by the composition of many layers. Raw materials used for paper is not neutral, usually non-coated paper is acidic, coated paper is alkaline. On those water delivery devices where the fountain solution is in direct contact with the paper (e.g., Daguerreotype water delivery devices), it is used to create direct interactions that can have an effect on the fountain solution pH. On water delivery devices that are not in contact, this effect is not present or is only slight. Since the amount of plate moisture transferred to the paper through the rubber blanket is not too small, there is a rather pronounced interaction depending on the quality of the paper. When the paper fibers absorb water, they begin to swell. If the absorption of too much water, the result on the one hand, resulting in paper size changes, on the other hand, water can play a role in the role of a closed layer, hindering the rapid penetration of printing ink.

(D) The interrelationship between printing inks and fountain solution Some printing inks also contain substances that affect the PH value. This is also like the above-mentioned paper situation, and fountain solution contact and no contact between the water delivery device there is a similar relationship. Offset printing ink is based on mineral oil, it is not comparable with the fountain solution. However, it is this difference that allows offset printing to exist. I am afraid it is not appropriate to say that water and ink are mutually exclusive. In fact, offset printing ink must absorb a certain amount of fountain solution. Without this ability, Dahlgren water delivery device (through the first inking roller wetting) is unimaginable application. The important thing is that the water should be absorbed as quickly as possible, and this can form a stable water-in-oil emulsion.