Details:
Summary:
The ink transfer and tone gain in flexographic printing are functions of the interaction of the features on the plates with process parameters such as speed and impression pressure. As well as tone gain in the plate making process, the plates can also have different physical characteristics, such as elasticity, that effect their behaviour during the printing process. In order to get an understanding of the extent of the potential effects of these parameters in normal production, a study was undertaken of plates produced by 3 different companies. Each company produced an image containing 100%, 75%, 50% and 25% tonal patches. The companies produced 5 plates under nominally the same conditions but at different times. The physical dot areas were measured on each plate using white light inteferometry and physical properties of the plates, i.e. roughness, Young's Modulus and surface energy, were measured.
Significant differences were found both in tone gain and dot depth both between plates made by the same manufacturer, as well as between plate makers. There was a wide spread of physical properties between the plates made by the different companies. This can be attributed to the use of different photopolymers. On the basis of