Research On Flexographic Printing Ink Transfer Characteristic

Flexographic printing is green environmental protection, simple, quick, cheap,can print almost any type of substrates and conforms to the requirement of sustainable development, that make the flexographic printing become the world’s fastest growing printing way. While the development prospect of the flexographic printing is broad and flexographic has already been used in the printing electronics, medical and biotechnology fields. This paper introduce the flexographic printing process, and study the impact on the flexographic printing quality of several important parts of the flexographic—plate, ink, and roller. Anilox roller as the most important part of flexographic printing, it’s various parameters has a great influence on the printing.Firstly, in this paper, we establish a geometrical model of flexographic printing ink transfer, analyze the anilox roll movement, and theoretically analyze the contact angle effect the ink transfer. Secondly, due to the use of low viscosity flexographic printing inks, we generally consider it to be Newtonian fluid, so here we use laminar two-phase flow model. Using the multiple physical fields based on the finite element simulation software for a numerical simulation in the printing ink transfer of the flexographic printing.Throughout the flexographic printing ink transfer process, we analyze the impact of contact angle, surface tension, aspect ratio, angular velocity on the transfer rate. The conclusion as following: The contact angle between two plate changing will affect the ink transfer, showing that the down plate’s contact angle is constant, ink transfer decreasing while the up plate’s contact angle increasing; When the up plate’s contact angle is constant, ink transfer increasing while the down plate’s contact angle increasing. In the case that printing ink transfer of the anilox roll towards to the plate, take the anilox roll as axisymmetric trapezoidal groove, the trapezoidal groove fixed contact angle is 70 °, ink transfer rate decreases with the rising contact angle; And the up plate’s contact angle is 70 °, ink transfer rate increases with the rising contact angle. The ink transfer rate between plates also affected by the surface tension of ink, characterized by increasing with the increase of surface tension. At the same time we discuss the trapezoidal groove aspect ratio and the influence of the angular velocity on ink transfer rate.