Influence of the microsurface offset printing plates on the machine printing process

The surface structure of the offset printing plates has the key factor in functioning of the conventional offset printing. Following characteristics are most important: physical-chemical surface properties of the printing plates and surface geometry of the printing plates. One of the greatest causes of physical-chemical changes on the surface is in most cases the processing of the printing plates, i.e. the development of the printing plates. Because of that physical-chemical as well as geometrical changes in the surface microstructure of the printing plates have been observed, caused by the processing conditions of the printing plates and the composition of the developing solution. The changes of the properties of the nonprinting areas by measuring the surface roughness and by SEM analysis have been exclusively observed. The investigations showed that determined physical chemical changes as well as the geometrical ones appeared. These changes can have considerable influence on the application of the dampening solution on the printing plate and on the correct water-ink balance during the printing process.