Proper control of the fountain solution is key to printing quality, as it influences ink transfer, accuracy, drying, and glossiness. The amount of fountain solution should be determined based on specific printing conditions and adjusted as needed during the printing process. Currently, operators often use visual inspection to monitor changes in the amount of fountain solution, but this has limitations. Too much fountain solution can cause issues like light ink color, increased ink on rollers, moisture on the ink film, and paper curling. Solutions include adding glycerin, polyethylene glycol, ethanol, gum arabic or CMC to the fountain solution to help control its properties. When choosing additives, considerations include cost, toxicity, compatibility, and effects on surface

1. How to control the fountain solution in printing
Offset printing quality is largely related to the fountain solution, so proper use of the fountain solution and the
nature of the fountain solution is the key to printing.
Fountain solution dosage control
The size of offset printing surface water has a great influence on ink transfer, overprint accuracy, ink emulsification
and drying, printing plate resistance to printing force, and glossiness of printing, etc. In the printing process, the
printing plate should be determined according to the specific printing conditions. The amount of water supply, but
due to too many variable factors, it should be in the printing process, pay close attention to the layout of the
amount of water changes, timely adjustment of the printing plate water supply.
Judgment method
At present, operators often use visual inspection to control the change of layout water volume. It is easier to
identify whether the water content is too small, mainly to observe whether the blank part of the printing plate is
dirty. To identify whether the layout water is too large is more complicated, a common method is to identify the
strength of the reflected light on the screen, because a certain thickness of the water film can fill the grain of the
plate, and the gloss of the plate will increase. However, this method has certain limitations and is affected by
many factors, such as the proportion of the area of the layout graphic, the type of printing plate, the intensity of
the light, and the angle of observation, resulting in the same water film thickness and cannot have the same
glossiness. Therefore, in the actual printing operation, it is often judged from the following phenomena whether
the water is too large.
(1) The ink on the printed matter is light, and even if the ink volume is increased, the ink color cannot be
deepened in time.
(2) The amount of ink accumulated on the ink roller increases, and the ink particles are coarser.
(3) Too much moisture remains on the surface of the ink film. There are drops of water when the ink blade scrapes
the ink, and the ink added to the ink fountain is not easy to stir evenly, and the ink transfer roller is slippery.
(4) There is a sticky flow of water in the dragging part of the blanket roller, and drops of water drop at both ends
of the roller.
(5) The layout often appears dirty or shut down.
(6) The outlets of the printed materials are empty, and the mouth marks are wavy and pale, and the ink is dull and
dull.
(7) When the paper absorbs excess water, the water content on both sides is inconsistent when it is printed on
one side, resulting in curling of the paper.

2. (8) Before and after the printing was interrupted, there was a large gap between the shades of the printed ink.
Solutions
(1) Glycerin is added to the fountain solution. Three hydroxyl groups in the molecule can be adsorbed on the
surface of the colloid to help absorb the solution, which is equivalent to the surfactant.
(2) Adding polyethylene glycol, which is a moisturizer, can absorb moisture to protect the printing plate after
shutdown. It is a good lubricant.
(3) Ethanol alcohol is added, which can not only reduce the surface tension of the solution, but also utilize the
volatility to make the paper absorb the minimum moisture.
(4) Add gum arabic and macromolecular surfactant CMC to the fountain solution.
Reasonable choice of fountain solution additives
Please pay attention to the following points when choosing the fountain solution.
(1) The price is low and the cost is low.
(2) The additive used in the fountain solution is a non-toxic, low-toxic chemical material that can reduce the
damage to the operator, and is the best without pollution.
(3) Adapt to other chemical materials and cannot interfere with each other and cannot produce precipitates.
(4) Choosing a reasonable fountain solution additive, to master the basis of analytical chemistry, to comprehensive
analysis, a comprehensive measure. For example, reducing the surface tension of the fountain solution can cause
severe ink emulsification.