Whether the ink supply system of DTF printer can work normally and stably on the machine directly determines the product quality. If the continuity is not good, it will lead to insufficient ink supply, resulting in ink interruption in the printing process, which will affect the printing quality to a great extent. So what are the factors that affect the fluency of DTF printing ink?
1.Particle size of ink
The particle size of printing ink has a great influence on the stability of ink system. Because the average diameter of the nozzle is only about 50um, it is easy to block the nozzle when the particle size is too large; The average particle size of ink should be negligible compared with the duct and nozzle hole, so as to ensure good flow properties. Therefore, the ink shall be filtered by 1um and 0.5um (the pore diameter of the filter membrane shall be adjusted according to the type of ink) in order to control the particle size.
2.Moisture retention of ink
The moisture retention and stability of water in digital direct jet printing machine make its viscosity and surface tension not easy to change with the change of temperature, and promote the formation of thin and brittle film at the nozzle, which is easy to dissolve without blocking when inkjet printing again. Ink is mainly water-based system. Most of the solvents used are water-soluble organic mixtures. The commonly used water-soluble solvents are alcohols, polyols and so on. These organic mixtures can improve the stability of ink.
3.Wettability of ink
The wettability of ink is related to the surface tension. The surface tension and dynamic surface tension of ink will affect the wetting of ink on pipeline and nozzle, as well as the final wetting and spreading on printing medium. If the surface tension is too high, it may lead to insufficient wetting and insufficient ink supply; If the surface tension is too low, that is, the wetting is too strong, it may cause the ink droplets to gather in the nozzle, resulting in the ink point breaking. Appropriate surface tension is the key factor. Generally, the surface tension is controlled about 30-50mn / m.
4.Digital printing equipment and printing environment
The pipeline tightness of the ink supply system of T-shirt printer is not good. Some water and low boiling solvent will volatilize during printing and placement, resulting in changes in physical and chemical parameters such as ink viscosity and surface tension, which will eventually affect the printing stability of ink on digital equipment. Therefore, it is necessary to maintain the digital printing equipment regularly.