Dot Transfer Law of Flexographic Printing

1. Reasons for network expansion

       Dot expansion in printing is inevitable. There are two main reasons for dot expansion: one is physical or mechanical. At the moment of embossing, the ink on the printing plate dot will deform due to extrusion, resulting in dot expansion;Dot Transfer Law of Flexographic Printing

      Another reason is optical, that is, dot enlargement is caused by the reflection of light. Light is scattered at the edge of dot ink film, resulting in considerable dot enlargement in vision. Optical dot expansion depends on the transparency of ink and the smoothness and absorption of paper.Dot Transfer Law of Flexographic Printing

2. Flexo dot transfer law

      In flexographic printing, due to the large elasticity of the photosensitive resin plate used and the need to apply a certain printing pressure in the printing process, although light pressure printing is used in flexographic printing.Dot Transfer Law of Flexographic Printing

      It will still lead to the expansion of image dots on the printed matter, the elongation of the image, and the change of color and level reproduction.Dot Transfer Law of Flexographic Printing

       In practice, by measuring and drawing the corresponding flexographic printing characteristic curve, it can be seen that the dot expansion in the flexographic printing process is very serious, and the dot below 10% is difficult to control.Dot Transfer Law of Flexographic Printing

       Therefore, special treatment should be made for the high light area, and the screen should be flattened as much as possible. Dot Transfer Law of Flexographic Printing

       The compensation for dot expansion can be completed at the scanner end or on the Phototypesetter, preferably on the Phototypesetter. The edge shape of the small dot generated after exposure is relatively neat and of good quality.Dot Transfer Law of Flexographic Printing

3. Influencing factors

(1) The higher the number of screening lines, the more serious the dot expansion.Dot Transfer Law of Flexographic Printing

(2) The larger the printing pressure is, the more serious the dot expansion is. On the contrary, the smaller the dot expansion is. Therefore, we should try to maintain “zero pressure” in flexographic printing.Dot Transfer Law of Flexographic Printing

(3) Dot shape. Circular dot, square dot, chain dot and elliptical dot have different dot expansion under different tones. Chain dot is commonly used in flexographic printing; for small dot in high light area, FM dot is the best.Dot Transfer Law of Flexographic Printing