With the rapid development of the printing industry in China, offset printing machines of various brands at home and abroad and fountain solutions of various brands continue to emerge, making users at a loss. Here is an analysis of the design of dampening fluid for lithographic printing and its relevance to various factors. For user reference.
Design of fountain solution for lithographic printing
The composition of the general fountain solution consists mainly of the following:
Wettability enhancers, ink over-emulsification inhibitors, tension modifiers, surface conditioners, buffers, defoamers, preservatives, rust inhibitors, dyes, and water.
In use, the user uses concentrate and water = 1:50 to 1:100. At present, a large number of low-cost fountain solution in China is mainly based on pH buffer and surface conditioner. In high-grade printing, there are problems such as poor dampening effect, poor ink-water balance, and corrosion equipment. Therefore, when designing the fountain solution mother liquor, it is necessary to fully consider the appropriate compositional proportions of the above-mentioned various components and the mutual influence relationship thereof so as to obtain the optimal ratio and obtain a mother liquor of the fountain solution having a satisfactory effect.
Fountain solution, ink, printing plate interaction
1. Lithographic printing mechanism
The adhesion of the graphic ink is greater than the cohesive energy, and the attachment of the graphic part to the water is less than the cohesive energy. On the other hand, the non-graphical part has a greater attachment energy to water than agglomeration energy, while the ink and water have less attachment energy than agglomerating energy, so that only non-graphical Parts can adhere to water.
Because the actual printing process is complicated, there are ink emulsification problems, weakening of the effective substance components in the fountain solution, etc., so it is difficult to quantify the mechanism.
2. The interaction between fountain solution and ink
An important interaction between the fountain solution and the ink during the printing process is ink emulsification. The emulsification of ink has two states of W/O and O/W: the emulsified state of oil-in-water or water-in-oil. The reason for emulsification is that the surface tension between the fountain solution and the ink is small, and emulsification easily occurs.
Source: Shun Jingyuan
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