Printing quality problems caused by poor character

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Printing quality problems caused by poor ink characteristics

Abstract: ink is one of the important raw materials in printing production. Its performance has a great impact on printing production efficiency and product quality. In the pre printing process of cartons, there are many examples of quality problems caused by poor ink characteristics. Therefore, a correct understanding of several quality problems related to ink and the adoption of corresponding process and technical measures for prevention and control are important to improve the printing quality of products. It is of great significance

key words: ink characteristics quality problems printing production product quality process technology production efficiency effects printing quality raw materials

I. product smudging caused by poor ink characteristics

when the ink printed on the paperboard is not fixed for enough time or the stacking pressure is too high, the ink layer is not dry, and the phenomenon of ink retransfer is called smudging. When the drying speed of ink fixation is too slow, the ink is too thin, and the ink output is too large, there is a greater chance of rubbing on the back of the printed product. In addition. When too much dry oil is used in the ink, it is easy to oxidize and heat the printing ink layer in the stack, making the imprint stick to the back of the product and cause hesitation. In this regard, the solution is: under the condition of meeting the requirements of printing hue, try to adopt the "deep ink printing" process, that is, darken the hue of the printing ink, and then print the stripped ink layer and print it thinner; Adjust the printing pressure evenly and enough to make the ink coating amount of the layout appropriate; Printing with quick drying ink; Properly adjust the concentration and dryness of the ink; Reduce the height of printed matter stacking; Add a human volume of anti adhesion agent to the ink to adjust and improve the characteristics of the ink

second, poor gloss of printing ink caused by poor ink characteristics

high gloss of printing ink is the main performance of good quality of color printing products. The brightness of printing ink depends on the good characteristics of the ink itself. Due to different types of inks, their use characteristics are also different. Like ordinary inks, they have medium viscosity, which is characterized by high lubricity, fast penetration, and no oxidation, odor, and only by penetration can the ink be absorbed by the paper before drying. Therefore, if this kind of ink is 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 and fast drying offset ink has high viscosity, good coloring power and transparency, and the ink layer after printing is easy to dry and make the printed matter have high gloss. Therefore, for color products with large ink absorption on the printing plate, this kind of ink can be selected for printing

III. flying ink phenomenon caused by poor ink characteristics

the so-called flying ink is a kind of malady that very fine ink particles fly out and splash on other parts of the machine during the printing process, which is easy to pollute the printing products. When the viscosity of the ink is too large or the specific gravity is too small, it is easy to cause the ink to be drawn too long during the rolling process, and the particles of the ink will splash out. The elimination method is to add some de sticking agent or high boiling oil to the ink to appropriately reduce its viscosity. For the flying ink caused by too small proportion of ink, it can be adjusted by adding some ink with a large proportion under the condition of meeting the printing color requirements

IV. imprinting chalking caused by poor ink characteristics

in the process of color printing, sometimes we encounter such a situation, that is, after the ink is printed on the paper, the imprint immediately falls off when it is slightly rubbed, which is the phenomenon of imprinting chalking. When the binder in the ink lacks the ability to adhere to the pigment, and the binder is too thin, so that the ink just printed on the paper, the binder soon penetrates into the paper, and the ink pigment is suspended on the paper. In addition, if corn flour is added when printing the base color ink, it is also prone to imprinting and chalking. To eliminate the disadvantages of powdered imprinting, you can add No. 0 inking oil to the ink to reduce the permeability of the ink. You can also add some synthetic resin oil appropriately to improve the conjunctival performance of the ink. At the same time, you can also add some dry oil appropriately, so that the printing ink layer can quickly fix the conjunctiva. If necessary, you can also apply a layer of gloss oil or gloss paste to the printed matter, which can increase; The brightness of printed matter can better protect the printing ink layer and prevent the occurrence of color fading quality problems

v. paste phenomenon caused by poor ink characteristics

when the ink is too thin, too thick, the ink delivery volume is too large, and the amount of desiccant in the ink is too large or the amount of anti adhesion agent is too large, it is easy to cause paste problems in the printing process. The solution is: adjust the ink property with ink blending oil to increase the consistency or dilute the ink a little; Reduce the ink supply properly; When mixing ink, the dosage of desiccant and anti sticking agent should be controlled

VI. smudging of prints caused by poor ink characteristics

the ink film is not dry in a short time, so it is easy to be smudged. When the amount of tackifier and inking oil in the ink is too much; Insufficient amount of desiccant; The drying speed of the binder in the ink is relatively slow; The relative humidity of the printing workshop is too high; Cardboard is too acidic and humidity is too high; Too high acidity of fountain solution will lead to the problem of printing products being easy to wipe. For this, we can add desiccant into the ink appropriately; Reduce the acidity of fountain solution; Reduce water supply; Change to quick drying ink, adjust the relative humidity of the workshop to less than or equal to 60%, and maintain the air circulation in the workshop, so that the printed matter is easy to dry under the condition of good air circulation and prevent dirt

VII. Stencils caused by poor ink characteristics

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 and tear due to excessive friction of the facial mask layer during the printing process, resulting in the phenomenon of printing graphics and texts. In this regard, the solution is: add an appropriate amount of debonding agent to the ink; Adjust the ink with good fineness for printing. If the ink is mixed with gold and silver powder, choose the powder with high mesh number or use the original gold and silver ink. It is easy to cause low strength without scraping the pot, so as to avoid the occurrence of pattern problems

VIII. Galling caused by poor ink characteristics

when the ink is too sticky or too thick, its cohesion is large, and it is easy to appear in the printing process. Evonik has developed a polymer 3 Multi curve mode data tracking: various curve tracking experiments, such as torque torque angle, torque time, axial force time, are realized, and the phenomenon of amide (PA) 12 powder hairiness leads to other chain quality problems. In this regard, the solution is: to add an appropriate amount of ink blending oil or de adhesion agent to the ink; When mixing ink, the dosage of desiccant should be strictly controlled to prevent excessive dosage from making the ink sticky

IX. printing color difference caused by improper ink adjustment

if the printing ink layer is too thick, its viscosity will increase accordingly, which is easy to cause problems such as paper powder dropping and roughening in printing, and then affect the uniformity of printing ink color. However, if the printing ink layer is thin and the ink viscosity is too small, the ink color of the print will appear light. On the other hand, due to the thixotropic nature of the ink, with the increase of the running time of ef]b machine and the acceleration of the printing speed, the temperature of the ink will gradually increase and its viscosity will correspondingly decrease. In this way, the printing ink color will be shallower and shallower, so that the ink color before and after the batch of products is inconsistent and form a color difference. Therefore, when adjusting the ink, we should adjust the appropriate ink concentration according to the climate and temperature conditions and the characteristics of the printing machine to make the printing ink color relatively stable. However, in the actual eobu process, the decline of ink viscosity is inevitable, and the ink color of the printed matter that has just been printed is often thicker, and then gradually fades. In this way, the ink volume can be gradually increased by appropriately adjusting the rotation angle of the ink transfer iron roller, so that the ink color of the front and back printing is basically the same. When blending intermediate and multicolor inks, we should also try to avoid mixing inks with large specific gravity, Phenomenon causes printing color difference. In order to maintain the continuous and uniform transmission of ink, the ink in the ink bucket should be often stirred with an ink knife in production to ensure uniform ink transmission and prevent the occurrence of printing color difference

to sum up, printing quality problems caused by poor ink characteristics are common phenomena in printing process, and the reasons are various, including process reasons and operation factors; There are defects in raw materials; There are also uncomfortable conditions in the edbu environment. However, as long as we correctly understand and understand the quality problems caused by poor ink characteristics, by controlling the production operation technology and process technology, we can not only better realize normal printing, but also effectively prevent the occurrence of various quality problems and ensure the printing quality of products

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