In the use of water-based ink, there will usually be inaccurate color, drying too fast or too slow, blurred outline, difficult to register, ink bubbling, paste plate sticky dirty, blot off and other problems, the main reasons are the following:
 
 
PH control
 
PH value is the key to determining the success or failure of water-based ink manufacturing and printability technology. When using water-based inks, it is necessary to precisely control their viscosity and PH value. Its PH value should be controlled between 8.0 and 9.5. If the PH value of the water-based ink is too high, the alkaline is too strong will affect the drying speed of the ink, and the back will be sticky and dirty, and the water resistance is poor. If the PH value is too low, the alkalinity is too weak, the viscosity of the ink will increase, the drying speed will become faster, and it is easy to cause defects such as dirty plate, paste plate and foaming.
 
 
The PH value of water-based ink is mainly maintained by amine compounds. In the printing process, due to the continuous volatilization of the amine in the binder, the PH value will decrease, affecting the printing quality. In the actual control, on the one hand, it is necessary to avoid the leakage of amines as much as possible, such as covering the upper cover of the ink tank; On the other hand, the stabilizer should be added to the ink tank regularly and quantitatively. When PH value is low, PH stabilizers or a small amount of alkaline substances can be added; When the PH value is high, solvents or diluents can be added for polar dilution. Control of temperature and humidity
 
The temperature and humidity of the printing workshop are closely related to the drying and color of water-based ink printing products. Compared with the relative humidity of 95% and 65%, the drying time is almost more than 2 times different. At the same time, the dry humidity of the substrate itself will also directly affect the drying time of the print.
 
Ventilation degree and printing stacking method
 
Because oxygen or blowing is a factor that promotes the oxidation polymerization of water-based ink and the formation of volatile solid ink film, the ventilation degree of the printing workshop and the way of stacking the printing parts will also affect the drying speed of the ink.
 
 
substrate
 
The PH value of the substrate also has an effect on the drying and gloss of the water-based ink. Water-based ink printing to the surface of the paper will be affected by the PH value of the substrate paper. When paper acidity is high, the coupling agent of water-based ink as a drier does not work, and the alkali in water-based ink is neutralized, so that the dryness is advanced. When the paper alkaline is high, the water-based ink dries slowly, and sometimes limits the water-based ink to achieve complete water resistance.

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