Possible Problems and Countermeasures in Alcohol-Free Printing

There are several important factors that need to be considered when completely replacing the use of alcohol in the printing process. It is indeed difficult to completely eliminate alcohol printing. First of all, printing operators need to abandon the dependence of traditional printing on alcohol, the concept and habits have milestone significance; Second, the hardness and pressure of the alcohol-free printing on the water roller; the structure of the ink system (with temperature control is the most Ideally); the amount of fountain solution added and water level adjustment, there are some differences with the traditional alcohol printing.

Free (reduction) expression of alcohol fountain solution

In the traditional printing, alcohol is a very common additive. As a single additive ingredient, it really plays a big role when alcohol and fountain solution are mixed together. However, alcohol is defined as a volatile organic compound (VOC), which, besides flammable dangerous goods, also contaminates the printing shop environment and endangers human health. Many countries’ governments and environmental protection agencies have begun to restrict the use of alcohol and its substitutes in the printing process. It is only a matter of time before the strict restrictions or legislative elimination of their use.

Problems that may occur with alcohol-free printing

1 dampening water "too high"

Due to the higher viscosity of alcohol-containing systems than non-alcoholic systems, the amount of water delivered to the printing plate by the alcohol-containing system is greater than the non-alcoholic system at the same time and at the water roller speed. To avoid dirty plates, the water must be raised. The speed of the roller gives a feeling that the amount of water is increased. If you reduce the pressure of the water roller, so that the water roller speed setting is comparable to when printing with alcohol, the worker will not feel the water is too high.

2. Excessive emulsification, cross-coloring, scumming

1) In the non-alcoholic printing system, the ink roller system will accelerate the emulsification and reach the ink-water balance, which may result in over-emulsification of the ink, especially when printing large field patches and large dot color areas. When this problem occurs, on the one hand, it is necessary to cut off the connection between the ink paths of the waterway in a timely manner, so that the fountain solution can be transferred to the printing plate before being emulsified. It is better to prevent the integrated ink roller from running on the water roller; on the other hand, In the system without alcohol, the ink will not be diluted, and at the same ink setting, the density of the color will be higher than that of the alcohol-containing system; thus reducing the setting of the amount of ink, while reducing the amount of fountain solution, It will be able to return to the minimum normal operating condition of the ink.

2) The hardness of the ink roller is checked, and the softer rubber has a more excellent effect in alcohol-free printing. The efficiency of any ink roller system depends on the performance of the ink roller at the maximum tension setting, which requires a certain adjustment when using a new dampening fluid. It is worth noting that the non-alcoholic system is completely different from the alcohol system. To successfully operate the alcohol-free system, new technologies need to be re-learned.

Influence of water quality on dampening effect

Excessively soft or hard water can cause many ink problems and increase the difficulty of maintaining ink-water balance. To maintain a more effective dampening process, the best way is to treat the water with a reverse osmosis system, especially without alcohol or The proportion of alcohol reduction is as follows. Because the fountain solution contains nearly 97% water, it is necessary to analyze the water quality. Excessively soft or hard water will cause and increase the difficulty of maintaining the ink balance. To maintain a more effective dampening process, the most effective way is to use a reverse osmosis system to treat the water quality to meet the standards of use.

Monitor the amount of fountain solution

When reducing or canceling the printing of alcohol, the amount of fountain solution added is very important. The San Lunji version has a strong buffer system. When the diluted solution is between 2% and 5%, the pH value does not change significantly. Controlling the pH to control the amount of fountain solution added is not completely accurate. The only way to measure the conductivity is to increase the concentration of the concentrate in the solution. This gives a reliable indication of the dampening system with buffered and unbuffered systems.

Non-alcoholic printing must be prepared

1. Thoroughly clean all the water roller rollers of the printing machine, and use a special cleaning agent to clean the dampening fluid circulation system;

2. With the addition of about 4% of the mixing ratio (SR-530) alcohol free high fountain solution;

3. Thoroughly cycle the dampening fluid and keep the temperature in the tank between 10°C and 12°C.

Practical experience has proved that whether it is used with trace amounts of alcohol or non-alcoholic printing, regular maintenance of the printing press is critical to the quality of the printing. The San Ling dealers and our service staff will be happy to give you the time you need. Suggestions and technical support.