engleski

Influence of Various Concentrates on Quality of Printing Plates' Wetting Process

One of many elements that influence reproduction quality in lithography is the wetting process of nonprinting areas of the printing plate. Results of investigation of physical-chemical properties of various fountain solutions and influence of various buffer solutions on the wetting process were presented in this paper. Fountain solutions used to conduct investigation were made from demineralised water in which surface active substance, agent for increasing electrical conductivity and buffer solution were added. Main point of this research was to determine optimal volume concentration of surface active substance in dependence of used buffer solution. The results showed that increase of the amount of surface active substances causes decrease of electrical conductivity, but this decrease is dependent on used buffer solution. On the other hand, increase of surface active substance’s volume concentration cause increase of solution’s pH value, but this increase is not significant. Results of the contact angle measurement showed similar behaviour of Samples 1 and 3, reaching low point at nearly 11 percent volume concentration of surface active substance. A bit surprising is the fact that further increase of surface active substance‘s volume concentration causes increase of the contact angle. In conclusion, results showed that used buffer solution don’t have high impact on wetting process of lithographic printing plates, but further investigations should be conducted to determine how investigated sampled influence on surface properties of nonprinting areas of printing plate.

Electrical conductivity; contact angle; fountain solution; lithographic printing plate; pH value; Surface Active Substances (SAS).

nije evidentirano