This is Andrew from link testing instruments co.,ltd which is specialized in film and packaging testing instruments of 10 years.
Ink viscosity is an important condition for the transfer performance, ink layer fastness, penetration and gloss of printing ink. Therefore, too large or too small ink viscosity will have a negative impact on printing quality. If the ink viscosity is too high, it is easy to cause sticky sheet, ink transfer, uneven ink cloth, pull off paper powder, make the surface paste or flourish; if the ink viscosity is too small, it is easy to occur slippery glue caused by printing screw marks, as well as ink transfer, ink poor composition of the print light, ink emulsification, dirt floating and other undesirable phenomena.
Ink viscosity mainly depends on the composition characteristics and proportion of the ink, and is also related to temperature, printing machine speed and so on. When the temperature is low, the ink viscosity will be high; when the printing machine speed is low, the ink viscosity will be high; when the number of ink rollers used on the printing machine is small, the ink viscosity will be high. This is because the ink has thixotropy, when the heat is high, the ink becomes thinner, and its viscosity also decreases. Because the speed of the machine and the number of ink rollers determine the size of friction heat in the process of machine movement. When the friction coefficient of the printer is large, the ink is heated by the action of external force, so it is easy to dilute, and its viscosity also decreases. The viscosity of ink is adjustable.
The zahn cup is the main tool for test the viscosity of the paint. It's simple useful and workable. So I recommend it for you for testing. Attach the catalog of the zahn cup for your reference.
The price is 55USD one Piece FOB Qingdao China
If you have any question please feel free contact me any time