Failure caused by ink printing process and its treatment

The prints left on the prints are formed by ink. The ink is the colorant used for printing and is the main raw material for printing. The ink is crucial for the quality of the print. When the ink properties are not suitable for printing, it will cause a series of processes. Failures severely affect the progress of production and the quality of products. The printing operator must change some of the properties of the ink to suit the needs of the printing, but some malfunctions are caused not only by the ink, but also related to other factors, so the printing operator must carefully analyze the correct treatment. This article discusses the failures caused by the ink printing process and the treatment methods, hoping to be helpful.

First, the slow drying phenomenon and reasons: imprint from the plate after the blanket is transferred to the paper, the general requirements of drying in about 10 hours, to facilitate the post-color printing or finished product inspection factory, once the imprint slow drying, this Not only can the next color not be overprinted, but also it can easily make the back of the print dirty. The dryness of the blot has three factors: oxidized conjunctiva, paper absorption, and moisture evaporation. We must master the operation and prevent it in advance. The reasons for the slow drying of common imprints are as follows: (1) The pH value of the paper is below 6. (2) The PH value of the bucket is 3 or less. (3) The layout of the water is large and the ink is too large to cause serious ink emulsification. (4) The workshop temperature is low. Relative humidity is higher than 75%. (5) Absorption of paper is poor. (6) There are too many auxiliary materials such as ink varnish and detackifier in the ink. (7) The amount of dry oil is too small. Treatment methods: (1) In order to prevent the printed matter from appearing slow-drying, the height of the printed matter should be reduced, fluffing loose paper piles, and the air permeability of the semi-finished product can allow air to infiltrate the stacked paper, shortening the time for oxidation and conjunctiva. (2) If the printing is urgently needed, use the original printing plate for dry oil overprinting. The formula is 70% for VERI oil and 30% for dry oil. (3) In order to prevent unfavorable drying, add appropriate amounts of dry oil, dry oil consumption: winter more than summer, after the color than the previous one more place, dilute the ink more than did not dilute the ink more.

Second, chromatography is not printed on the occurrence and cause: the ink is added an excess drying oil or semi-finished products stacked too long, resulting in rapid surface drying blots generated vitrification blotting too smooth surface, loss of adsorption capacity, after printing one color Do not go. This failure is common in full version of the field, especially yellow (ink) or line prints. Treatment methods: (1) Prevention is the most important method. Prior to adding vitriol, Kangbang, magnesium carbonate powder, etc. to the viscous yellow ink, appropriate auxiliary materials are used to make the surface of the film rough or extend the drying time. (2) If the vitrification phenomenon has already occurred and the latter color is not printed, if the number of products is small, a soft cloth and magnesium carbonate powder can be wiped gently on each surface of the ink film, and then a color is set. Larger quantities can be printed while cauterizing alkali water.

Third, the back surface offset phenomenon and causes: the back surface offset refers to the semi-finished or finished products into the delivery pile, the ink on the back surface of the next sheet offset. The cause of back sticking is. (1) The surface of the paper is too smooth. (2) The ink is too thin. (3) Layout surface water and ink. (4) The color quality of the ink is too light. (5) The printing pressure is too light. Processing methods: (1) In the printing process, there should be no water and large ink phenomenon. Control the layout water, darken the ink, and reduce the ink fountain ink volume. If the water content is reduced to produce a greasy or mushy plate, clean the water roller or replace the new water roller, or properly strengthen the acidity of the water bucket solution and put some gum arabic. (2) The ink is adjusted too thin and easy to stick on the back of the dirty print. New ink or some new ink should be transferred to increase the viscosity of the ink. (3) The use of pale complex ink is commonly used in the deployment of light red, light blue, light tea, light gray ink, and should be deep-tuned to improve its color quality, to avoid printers from feeling too light, in order to achieve the hue of the sample. The requirement to artificially increase the amount of ink to be delivered causes the ink layer to be printed too thick to produce a dirty backside of the printed product. (4) During the printing process, the rubber roller must ensure sufficient printing pressure when transferring the paper to the paper, so that the ink is completely transferred on the surface of the blanket, and the back of the printed material is prevented from getting dirty. [NextPage]

Fourth, chalking and Reason: refers to powdered ink after drying semi-finished or finished products, not a good combination of ink and paper, a slight friction, a pigment particle surface as amyloid off. This pulverization phenomenon is related to the properties of paper and ink, in addition to the high acidity of the water bucket medicine and the presence of too much surface active material. Common ink powdering has the following causes: (1) The ink's adhesive force is too small and the surface of the paper is relatively smooth, so that the ink layer and the paper surface cannot be well combined, resulting in the ink layer being wiped off from the paper surface. (2) The ink is too thin, the linking material is easily absorbed by the paper, a large amount of the linking material penetrates into the paper, which promotes the separation of the linking material and the pigment in the ink, causing the pigment particles to float on the paper, and the pigment loses the linking material. Adhesion, the degree of its connection is reduced, and it does not adhere well to the paper surface, resulting in falling off. (3) The used ink is emulsified seriously, which not only reduces the viscosity, drying speed, and increases the penetration. More importantly, the emulsified ink conjunctiva does not combine well with the paper surface, the adhesion is poor, and the film is firm. Very poor, slight rubbing will cause the film to break and fall off. (4) Coated paper is made by coating the base paper. The paint and base paper have strong absorption, and the paper is thicker, can absorb a large amount of linking material, and the coating surface is smooth and the pores are very fine. It is possible to inhale the pigment together and act as a filter layer, causing the pigment particles to float on the paper and fall out of the package due to lack of binder. Treatment methods: (1) No strong absorptive coated paper (absorption less than 30 seconds) is used to print products, otherwise it must be printed with strong adhesion resin ink. (2) Add appropriate amount of No. 0 varnish or adhesive to enhance the adhesion of the ink to the paper surface. (3) Control the emulsification of the ink, and the water consumption of the layout should be small. The PH value of the water bucket solution is often measured and adjusted to the required value. The dry oil is added with the use, and the ink emulsification is reduced so that the drying time can be grasped. (4) Fine products that have been pulverized can be treated by glazing or filming.

Fifth, the ink pan-color phenomenon and reason: Pan Seji ink ink hue change, color change, the print lost its artistic value, a common pan-black gold red, sky blue pan-blue, peacock blue and light blue yellowing . The yellow ink and transparent yellow color disappear, and the pan-color caused by the heating of semi-finished products or finished products. The causes of the above drawbacks are: (1) The ink pigment itself is not stable. (2) Acid dyes flooded after infiltrating the ink. (3) Oxidation fever reaction. Treatment methods: (1) When oily red and gold inks are used, the pigment powders react with iron to produce chemical reactions, and the hue is very easy to blacken. Resin inks are used instead, so as to avoid pan-color phenomenon. (2) Tianlan ink will be reddish on the paper a few days later, and the ink color will look deeper than the original. This phenomenon should be noted that when encountering batch printing of bulk products, the formula of ink color must be consistent. Do not arbitrarily change, so as not to cause product inconsistencies. (3) Malachite blue, pale blue ink met chromic acid water bucket liquid, the ink is easy to yellow, can use white potion. (4) Daylight illumination can fade the finished product, which can be solved on printed paper surface or film. (5) During semi-finished or finished products, during stacking process, it is easy to generate a great amount of heat, and there is a lack of oxygen in it. The time is longer and the product will become hot and dark. It should be mainly prevention, and the product should not be stacked too high, and it should be guaranteed 4 - Ventilate once in 6 hours to speed up the flow of air between the sheets, helping them spread heat and shorten the time for oxidizing the conjunctiva. (6) Reduce the use of Cobalt Drying Oil (ie, 402 Red Dry Oil) because the red dry oil tends to darken the hue of the ink when heated. [NextPage]

Sixth, the ink offset phenomenon and causes: the printing portion of the ink penetration to the back sheet member, there are obvious marks or patterns in the paper rear surface grease, especially for double-sided printing product requires harmfulness. Affect the quality of the product, resulting in product prints through the printing, in addition to the paper itself is too thin or transparent, the common causes of ink penetration are as follows: (1) ink is too thin, containing too much material, a large number of materials are absorbed by the paper And penetrate the back of the paper. (2) There are too many non-dried binders in the ink. Too many non-drying binders will slow the oxidative conjunctiva on the surface of the paper, and the penetration drying will accelerate. A lot of the binder will seep into the paper and print through to the back. . (3) The ink is printed too thick and is too slow to dry. It also causes a large amount of the binder to penetrate into the paper and print through to the back. (4) The oily pigments contained in the ink are dissolved in the binder. During the printing process, the pigments are printed in the paper along with the binder and printed on the back of the printed product. Treatment method: If there has been a printout on the printed product, there is no way to remedy the situation. Only precautions should be taken in advance to prevent the phenomenon of print-through. (1) Ink is properly added to No. 0 varnish to increase its viscosity. (2) Do not use non-dry oil as the linking material, and reduce the proportion of non-dried or highly permeable excipients. (3) Increase the color value of the ink, make the ink layer thinner, and accelerate drying. (4) If the pigment is oil-soluble, it is better to use resin ink to print.

Seven, print gloss and the reasons for the phenomenon: the print is a reproduction of the art of copying, color should be bright, distinct, there is a strong sense of texture, space and material sense, on the contrary, the print will lose its proper value. The common reasons for affecting the gloss of printed products are as follows: (1) Printing uses low-grade ink, and the gloss of the product is poor after being finely colored (except for low-grade products). (2) The surface of the paper is rough, and the larger the fiber gap is, the stronger the absorption ability of the linking material is. After the ink is transferred to the paper, the linking material is absorbed by the paper fibers in the unconjuncted condition, and most of the ink remains. The particles attach to the surface of the paper, thus making the product dull. Processing method: How to make the printed product have better luster, actual operation experience tells us that the obtainment of the gloss of the printed product can be started from the following aspects: (1) The luster of the ink itself is the most basic element in the high-grade fine product When printing, the ink should choose high-grade quick-drying light ink printing to get the best luster. (2) Add dry oil to the ink properly during printing to help the surface of the ink to form a good film, so that the product obtains a proper gloss. To properly understand the performance and dosage of red and white dry oil, the type and amount of dry oil used have a certain influence on the gloss. No. 402 Red Dry Oil is mainly composed of cobalt citrate, and the stimulating function is mainly surface oxidized conjunctiva. The dry speed is fast, about 23 times that of dry white oil, generally added in red ink and black ink, medium blue and deep blue can also be used. In particular, the latter color of the same type of printing product, if it can maximize the release of red and dry oil, this will have a good effect on increasing the gloss of printed products. When the yellow plate is used as the first color sequence, it is not appropriate to add red dry oil, because the color of red dry oil will change the hue of yellow ink, followed by the largest amount of yellow ink, and it is extremely dry and prone to vitrification. White dry oil is a mixture of metal salts of cobalt, manganese, and lead. It has a full-drying effect, but it is not as strong as red dry oil. The amount of white dry oil added correctly has an effect on increasing gloss of prints. (3) Apply a polish or film to the finished surface of the finished product. Ink is a complex colloid that is obtained by mixing and grinding pigments, binders and additives. Its properties are mainly determined by the properties of pigments and binders. It uses the three forms of volatilization, infiltration and oxidized conjunctiva to complete the drying of print imprints. As the main material for printing, knowing the ink composition, familiarizing with the properties of the ink, and correctly mastering the use of the ink are the necessary conditions for ensuring the printing quality.