In lithographic printing process, the so-called'dry'means that the blank part of the plate does not have enough average water film, that is, the lack of local water on the plate. Once the offset printing plate is dry, it will cause the blank part of the plate to hang dirty, thus affecting the quality of printing output, that is to say, the ink balance is out of control in Shenzhen packaging and printing process.
In offset printing process, the control of ink balance is related to many factors, including the proportion of ink volume to water volume, the quality of the embossing solution itself, the concentration of embossing solution, the amount and temperature of alcohol, the nature of the ink itself, the pressure of the ink roller, environmental temperature and humidity, etc.
If the amount of embossing solution and alcohol is correct in the printing process, the reason for the water drying of the printing plate may be the improper setting of the pressure of the ink-feeding roll and the water-supplying roll in the printing process, and may also be related to the quality of the embossing solution used in the printing process.
In offset printing process, water is the polar molecule and oil is the non-polar molecule. Because water is used to wet the plate, the phenomenon of ink emulsification will appear. The emulsification of ink will be controlled within 10-30%. The speed of water accumulation and evaporation is closely related to the dullness of printing. Because water molecule is very polar material, the existence of water can hinder the oxidation and polymerization of oil molecule to form film, which will affect the drying rate of imprinting. The environmental humidity will play a certain role in the evaporation rate of water. With the increase of ambient humidity, the activity of oxygen in the air will be weakened, which reduces the oxygen absorption of ink. At the same time, the emulsified water in the inner layer of ink film also softens the ink film, thus slowing down the drying speed of the ink. So in offset printing process to control ink balance, in the premise of dirty version, the use of as little water as possible, thus reducing the emulsification of ink, ink water content a few, the dull relationship of imprinting is very close.
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