The fountain solution has a great influence on the stability of the print quality of offset printing products. In order to make the printed images well-colored and clear ink, and the blank layout can not be dirty, it is necessary to rationally adjust the concentration of fountain solution according to the specific printing conditions to ensure the printing of high-quality prints.
1 paper performance and fountain solution concentration When the print paper texture is loose or paper contains sand and dust, due to the sticky printing ink, often in the imprint will make paper hair, paper powder pile up on the blanket, it is bound to increase the plate film The friction of the layer makes the printing plate easy to get dirty. In this case, the concentration of the fountain solution should be increased. When printing a tough and white paper, especially when printing coated paper and glass paper, it should be Appropriately reduce the fountain solution concentration.
2 ink performance and the concentration of the fountain solution due to the different nature of printing ink, its viscosity, fluidity and acid resistance and other properties are also different, the response to the concentration of the fountain solution will be a correspondingly different, it should adjust the fountain solution as appropriate concentration. In general, the principle of using the concentration of the fountain solution is: the concentration of the printed red ink is greater than the concentration of the printed black ink; the concentration when printing the black ink is greater than the concentration of the printed blue ink; and the concentration when printing the dark ink is greater than The density of printed light ink.
3 For desiccant use, when the size of the printed multi-color plate product, in order to make the ink drying faster, the ink should be placed dry oil, which also makes the ink particles thicker, increased viscosity, so the printing plate blank parts of the fat-sensitive Increased, it is easy to produce paste problems. Based on this situation, the amount of raw liquid should be appropriately increased.
4 Plates and dampeners Concentration printing products are available in a variety of layouts, including field layouts, and line and screen layouts. If the layout is dominated by lines and solid vignettes, the density of the fountain solution should be adjusted to a larger extent due to its smaller cloth area, so that the blank layout is not easy to get dirty; if the entire plate is a dot structure, it should be The use of a low concentration of fountain solution; and for the printing of the printing plate in the field and the dot, we should take the principle of taking into account all aspects to ensure the quality of the printed product.
5 Workshop temperature and fountain solution concentration When the printing environment temperature rises, the molecular movement of the material must accelerate, the ink fluidity increases, and at the same time, more free fatty acids can be decomposed, so that the printing plate surface is easy to produce dirt, so the temperature is high. When appropriate, increase the concentration of fountain solution.
6 Printing speed and fountain solution concentration Because the ink has thixotropy characteristics, when the printing speed is high, the ink roller of the printing machine has a large coefficient of friction, which tends to cause the ink to become thin due to heat generation, which causes the tinting strength to decline and the ink color to fade. Respectively increase the amount of ink to deepen the printing ink color, so that the printing plate is prone to dirt. Therefore, when the printing speed is high, the concentration of the fountain solution should be appropriately increased.
In addition to the above, if the printing pressure is large, and the blanket and liner texture is too stiff, it should be considered to appropriately increase the concentration of fountain solution in order to achieve a better anti-dirty effect. The above situation shows that the concentration of fountain solution should be comprehensively considered according to various specific conditions.