How to use fountain solution
We are a big printing company in Shenzhen China . We offer all book publications, hardcover book printing, papercover book printing, hardcover notebook, sprial book printing, saddle stiching book printing, booklet printing,packaging box, calendars, all kinds of PVC, product brochures, notes, Children's book, stickers, all kinds of special paper color printing products, game cardand so on.
For more information please visit
http://www.joyful-printing.com. ENG only
http://www.joyful-printing.net
http://www.joyful-printing.org
email: 860681365@qq.com
Reasonable control of the use of dampening solution in the printing production process can prevent and solve a variety of printing problems, often with a multiplier effect, you may wish to try.
The amount of dampening solution additive should be kept stable. Standard measuring tools should be equipped for manual addition. The automatic tank adding device should be regularly checked and maintained to ensure the normal operation of the extraction equipment. The test conductivity is used to control the amount of dampening solution additive added. Firstly, the conductivity of the clean water should be measured. In practice, the conductivity of the clean water should be deducted. Since the alcohol or alcohol substitute is non-conductive, the conductivity will decrease after the addition. The conductivity should be measured after adding the alcohol.
Water: The main component of the dampening solution is water. The water quality conditions vary from place to place. Generally, the soft water has a conductivity of about 0-225 μs, and the hard water usually has a temperature of 450 μs or more. When the water quality is hard (mainly when the Ca+ content is high), it usually causes the Ca+ to contact with the resin in the ink to form saponified calcium. When combined with the acid in the acidic fountain solution, it will produce calcium calcium or calcium phosphate. Salt like that. The saponified calcium has lipophilicity, which causes the ink to be deposited in unnecessary areas such as water rollers and inking rollers, causing the surface of the rubber roller to crystallize, resulting in poor water transfer and ink transfer; and the calcium salt is hydrophilic, which hinders the ink. The transfer and cause the ink roller to deink, so the dampening solution additive used when the water is hard water should contain the corresponding substances to eliminate the influence of excessive calcium ions.
The lithographic plate is based on the principle of incompatibility, wetting, adsorption and selective adsorption of oil and water. Ink balance is the most important principle of lithographic offset printing. Reasonable control and use of dampening solution is very important in lithographic offset printing operation. This article takes the alcohol-based fountain solution which is currently used more as an example. From the aspect of the composition and application method of the fountain solution, combined with the author's printing work practice experience, talk about how to properly control the use of dampening solution.
Alcohol or alcohol substitute: The main role of alcohol in dampening solution is to reduce the surface tension of the aqueous solution. The volatility of the alcohol can reduce the emulsification of the ink, keep the color of the printed product bright and accelerate the drying of the ink on the substrate. Since isopropanol has a slower volatilization rate, the ability to lower the surface tension of water is stronger, while general industrial alcohol has a higher volatility and a lower ability to lower the surface tension of water, and the production quality of isopropanol is generally stable. At present, the quality and price of alcohol products on the market are quite different. When using, products with high purity and good texture should be carefully selected. Use isopropyl alcohol as much as possible. Do not use industrial alcohol, which can reduce the dosage, improve the use effect and product quality, and reduce cost.
Generally, the surface tension of tap water is about 72 dynes, and the surface tension of offset ink is about 30 to 36 dynes. The surface tension of the fountain solution must be controlled to be the same as the surface tension of the ink, so that the two are balanced and stable. To control the degree of emulsification of the ink. Usually, the isopropyl alcohol content can be up to 8% to 12%, and the alcohol content should not be too high, otherwise the ink will be seriously emulsified.