Comparison of ink viscosity and consistency properties

The viscosity and consistency of the ink are related to the flow and transfer properties of the ink, and the two affect each other. The viscosity and consistency of the ink are different concepts. There is a certain difference between the two. The “sticky” ink is not necessarily “thick”, and the ink with a large consistency does not mean the ink with the same viscosity and the same viscosity. The thicker the ink is, the larger the consistency is. The worse the liquidity.

(a) conceptually different

The viscosity of the ink, also known as friction or cohesion, is the ink ink layer being stretched and disconnected during the ink transfer process. In order to resist tension, the ink exhibits a tensile strength that resists tension and breakage. Its size is mainly determined by the composition of the ink itself, such as the viscosity of the binder, the proportion, shape and size of the pigment and its dispersion in the binder, and the like.

The ink has a certain consistency, because the ink is a fluid substance and has a flowing property, that is, when the ink is subjected to external forces and gravity, it will flow like any other liquid in all directions. This kind of flow due to the force Known as the fluidity of the ink, its fluidity is the consistency of the ink, the better the fluidity, the smaller the consistency, the worse the fluidity, and the greater the consistency. The consistency of ink is affected by the multiple effects of viscosity, yield value and thixotropy. For example, when the ink viscosity is fixed, the greater the yield value and thixotropy, the greater the ink consistency and the worse the fluidity; otherwise, the smaller the yield value and thixotropy, The smaller the ink consistency and the thinner the ink, the better the fluidity of the ink.

(B) The role of differences

The ink must have a certain viscosity to meet the requirements of the printing process. It determines the transfer properties of the ink, the degree of imprinting, the amount of penetration, and the glossiness. Ink viscosity is too large or too small, all are detrimental to production: ink viscosity is too large, will cause uneven ink transfer, make the paper off hair powder, the paper from the rubber roller peeling difficulties, destroy the ink layer fracture, make the layout Insufficient ink layer in the text, under the action of fountain solution and pressure friction force, easy to print version, out of version; and if the ink viscosity is too small, easy to make the ink emulsification, floating dirty, paste version, dot network expansion serious, ink layer split Bad, affect product quality.

The consistency of the ink has an important effect on the transfer of dots and inks to achieve color reproduction. The ink with the appropriate consistency has good ductility and can be properly transferred between the ink rollers. Finally, a uniform ink film is obtained on the printing plate. After the imprinting is uniform and printed on the paper, the ink layer is leveled before drying, which promotes smoothness and smoothness of the ink film surface, thereby obtaining a good printing effect. If the consistency of the ink is too large, the fluidity of the ink will be too poor, which will result in the ink not spreading smoothly and unevenly, causing the front and back of the printing surface to be shallow and shallow, or the depth of front and back, and other abnormal ink supply. The drawbacks are that the ink film is also rough. In severe cases, orange peel surface appears, which affects the luster of the ink film. However, if the ink is not thick enough and the fluidity is too large, the print may not be well transferred, which will make the graphic. The level is not clear, the ink is not full, the color is not clear, the ink is also easy to spread, its geometric size is enlarged, and the printing quality is reduced.