engleski

The influence of the printing plate's temperature on its wetting properties

Lithography is based on opposite surface properties of nonprinting and printing areas. The printing areas are oleophilic and hydrophobic which enables them to adsorb printing ink and in the same time repel water based fountain solution. The nonprinting areas are hydrophilic to attract the fountain solution which repels the printing ink. During the printing process the printing plate comes in contact with the rollers for fountain solution, printing ink and offset cylinder, which is covered by rubber blanket. In these contacts friction is present, which could result with change of the printing plate temperature, and in the long run the change of the printing plate’s surface properties. The aim of this paper was to detect the effect of the printing plate's temperature on the wetting properties of the nonprinting areas. For the purpose of this research, grained and anodized aluminium base (the nonprinting areas), liquids with defined surface tension and two fountain solutions were used. Results have shown the importance of temperature on the wetting properties of the solid surface, i.e. printing plate. They have shown that this parameter should be taken into account when performing determination of the surface free energy of a solid.

printing plate; contact angle; surface free energy; temperature change

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