These Factors Affect The Absorption Of Offset Ink By Paper
Jan 04, 2023
The ink absorption of paper is the degree of absorption of the binder in the ink. It is the surface properties of paper fibers, and is a comprehensive reflection of factors such as fiber interweaving, filler and rubber properties and content. Its essence is the capillary adsorption effect of the fiber itself and the space between the fibers on the ink binder.
Therefore, the greater the ink absorption of paper, the better the ink absorption, and vice versa. The ink absorption of different papers is very different. Offset paper generally cannot absorb ink well, especially the ink absorbency of high-end paper such as coated paper, card paper, and cloth paper is strictly limited. The ink absorption of newsprint, writing paper, and letterpress paper is relatively strong.
①Fiber surface smoothness. The smoother the paper fiber surface, the weaker the ink absorption. If the smoothness of coated paper is high, the ink absorption is poor.
②The quality of paper filler. The white clay filler has strong ink absorption, while the ink absorption of kaolin (pottery clay), talc, and barium sulfate used in high-grade art paper is poor.
③The amount of paper filler and rubber applied. Paper with more glue and filler has poor ink absorption, and vice versa. Commonly used sizing materials are rosin gum, aluminum sulfate, starch, casein, paraffin and so on. Sizing has the effect of blocking the gaps between fibers and reducing capillary tubes. The rubber material also has certain water resistance properties, which can hinder the penetration of water, improve the gloss, strength, and sound of the paper and prevent the paper surface from fluffing. Adding certain fillers, sizing materials, and pigments can improve the smoothness of the paper surface, reduce paper transparency and ink absorption. Increase the whiteness and weight of the paper.
④I think that paper with more lignin has strong ink absorption. If newsprint has more lignin, ink absorption is strong.
⑤The absorption of offset printing ink by paper is also related to the pressure of the printing press, the length of printing time and ink viscosity.
In short, the ink absorption of paper is a two-way effect of paper and ink, and is related to the printing process.
