Printing quality problems caused by poor ink properties

Abstract: Ink is one of the important raw materials for printing production. Its performance is of great influence on printing production efficiency and product quality. In the preprinting process of the carton, quality problems caused by poor ink characteristics are numerous. Therefore, correct understanding of a number of quality problems related to the ink and taking corresponding technological measures for prevention and control will improve the quality of the product. It is of great significance.

Keywords: Ink characteristics Quality problems Printing production Product quality Process technology Production efficiency Effect Printing quality Raw materials

First, the phenomenon of product dirt caused by poor ink properties

When the fixing time of the ink printed on the cardboard is not enough or the pressure of the stacking paper is too large, the ink layer is not yet dry, and the occurrence of the ink retransfer phenomenon is called tamping. Insufficient ink fixation drying speed, ink is too thin, when the amount of ink is too large, there is a large chance for the back of the printed product to appear dirty. In addition. When the dry oil used in the ink is too much, it is easy to oxidize the ink layer in the stack. Immersion of the back of the imprinted adhesive product causes it. In this regard, the solution is: Under the conditions of meeting the printing hue requirements, try to use the "dark ink printing" process, that is, to adjust the hue of the printing ink darker, it will print a thin layer of ink peeling; the pressure of printing is adjusted uniformly , adjust some of them to make the layout of the ink coating amount appropriate è¹²; use fast-drying ink for printing; appropriate adjustment of the ink concentration and drying; reduce the height of the accumulation of printing products; to add ink to the amount of anti-adhesive agent, To adjust and improve the properties of the ink.

Second, poor ink properties caused by poor ink color gloss

The high gloss of printed ink is the main performance of color printing products. The good brightness of printing ink depends on the good characteristics of the ink itself. Due to the different types of inks, their use characteristics are also different, such as ordinary inks are medium-viscous, showing a large degree of lubricity, fast penetration, no oxidative odor characteristics, but only by infiltration so that the ink is absorbed by the paper surface before drying, therefore, This type of ink if used to print large-area color products. The gloss of the printing ink layer is not good, and the color effect is also poor. The bright fast-drying offset printing ink has a large viscosity, good coloring power and transparency, and the printed ink layer is easy to be dried and the printing product has a higher glossiness. Therefore, a color product with a large ink absorption amount on the printing plate surface can be selected. This ink is printed.

Third, ink ink caused by poor ink characteristics

The so-called flying ink is the printing process, there is a very fine ink particles fly out, splashed on other parts of the machine, easily lead to pollution of the printing products of a drawback. When the viscosity of the ink is too high or the specific gravity is too small, it is easy to cause the ink to take a long time in the rolling process, and the ink particles are spattered out. The elimination method is: Add some detackifier or high boiling point oil to the ink to reduce its viscosity. For the ink that is caused by the ink's small specific gravity, it may be appropriate to add some important inks to adjust it in accordance with the printing color requirements.

IV. The phenomenon of imprinting chalking caused by poor ink properties

In the color printing process, sometimes encountered such a situation, that is, after the ink is printed on the paper, a slight touch of the imprint immediately fell, which is the phenomenon of imprinting powder. When the binder in the ink lacks the property of sticking pigments, and the binder is too thin, so that the ink is just printed on the paper surface, the binder material quickly penetrates into the paper, and the ink pigments are suspended on the paper surface. In addition, if corn flour is added during the printing of the base ink, the phenomenon of imprinting powder tends to occur. Eliminating the disadvantages of imprinting powder can be used in the ink plus 0 varnish to reduce the ink permeability. It is also possible to improve the conjunctival performance of the ink by adding some synthetic resin oil as appropriate. At the same time, it can also add a little dry oil, so that the printing ink layer fast fixation film. If necessary, a layer of bright oil or bright paste can also be applied to the prints to increase the brightness of the prints and protect the printing ink layer to prevent color quality problems.

V. Paste phenomenon caused by poor ink properties

When the ink is too thin, too thick, the amount of ink is too large, and the amount of desiccant in the ink is too much or the amount of the anti-adhesive agent is too much, the problem of stencil problems is easily caused in the printing process. The solution is: use ink to adjust the ink, make the ink thicker or reduce the point; appropriate to reduce the amount of ink; adjust the amount of desiccant and anti-adhesion agent should be controlled.

Sixth, the ink characteristics caused by poor print graze

Ink film is not dry in a short time, it is easy to be dirty. When the amount of de-adhesive and varnish in the ink is too much; the amount of desiccant is insufficient; the drying speed of the linking material in the ink is slow; the relative humidity in the printing shop is too high; the acidity of the cardboard is too high and the humidity is too high; Too high acidity will cause the printing products to easily rub the dirty problem. In this regard, the desiccant may be properly added to the ink; the acidity of the fountain solution may be reduced; the amount of water may be reduced; the quick-drying ink may be used, the relative humidity of the plant may be adjusted to 60% or less, and the air circulation in the workshop may be maintained. In the condition of good air circulation, it is easy to dry and prevent scratching.

VII. Flower patterns caused by poor ink properties

When the ink viscosity is too large or the ink particles are too rough (such as printing gold, silver ink, etc.), it is easy to cause wear due to excessive friction of the printing plate layer during the printing process, which causes the printing product graphic to appear to be flowering. In this regard, the solution is: to add an appropriate amount of de-adhesive to the ink; adjust fine fine ink for printing, if the use of gold, silver powder deployment of ink, should use a high number of mesh powder or use the original gold, silver ink To avoid the issue of floral issues.

VIII. Bad hair caused by poor ink properties

When the ink is too sticky or too thick, the cohesion force thereof is large, and the pulling phenomenon is likely to occur during the printing process, thereby causing the occurrence of other interlocking quality problems. In this regard, the solution is: to add an appropriate amount of ink to adjust the ink or detackifier; adjust the ink, the amount of desiccant should be strictly controlled to prevent excessive use of the ink to make it sticky.

Nine, ink adjustment does not cause the printing color difference

If the printing ink layer is thicker, the viscosity of the printing ink layer will increase correspondingly, thereby easily causing problems such as paper powder falling and napping in the printing, thereby affecting the ink color uniformity of the printing product. However, if the printing ink layer is thin and the ink viscosity is too small, the ink color of the printing product will appear subdued. On the other hand, due to the thixotropic nature of the ink, as the operating time of the EF]B machine increases and the printing speed increases, the temperature of the ink will gradually increase and the viscosity of the ink will also decrease accordingly, so that the printing ink color will be reduced. The more India the more shallow, so that the batch of products before and after the ink is inconsistent and the formation of color. Therefore, when adjusting the ink, the appropriate ink concentration should be adjusted according to the climate temperature conditions and the characteristics of the printing machine, so that the printing ink color is relatively stable. However, in the actual EOBU process, ink viscosity reduction is unavoidable, often the ink of the newly printed ink is darker, and then gradually fades. In this way, the amount of ink can be gradually increased by appropriately adjusting the rotation angle of the ink transfer roller. , so that the ink before and after printing is basically the same. In the deployment of color and complex color inks, it should also try to avoid using a large proportion of ink with a large disparity, so as not to print due to the large difference in the proportion of the ink in the ink box to produce "delamination (ie, precipitation and suspension) phenomenon caused by printing Chromatic aberration: In order to maintain the ink's continuous and uniform transmission, ink knives should be used in the production process to stir the ink in the ink fountain to ensure uniform ink transfer and prevent the production of color differences.

In summary, the printing quality problems caused by poor ink properties are common in the printing process. The reasons are many, there are process reasons, there are operational factors; there are raw material defects; there is also EDBU environmental discomfort conditions of. However, as long as we correctly understand and recognize the quality problems caused by poor ink properties, we can not only achieve normal printing, but also effectively prevent the occurrence of various quality problems by ensuring good production and operation technologies and process technologies. Product print quality

Kang Qilai Fujian Putian Printing Factory Source: China Packaging Industry