The term gluing is often interpreted as dirty, blocking or dyeing, and different printing forms will result in different gluing. In recent years, paste printing has appeared frequently in transparent ink printing and composite ink printing. For example, offset printing paste is often caused by the imbalance of ink and water (the difference between the pH value of the ink and the ink). The gravure paste is mostly caused by the scraping of the scraper, and it mostly occurs in the summer with high temperature. It is not difficult to find when we discuss around this fault: the ink quality of the printing ink determines the occurrence of this phenomenon. It is impractical to determine what is the cause and what is the general situation, which prevents us from remediating and eliminating it in a very short time in the actual printing operation. First, the paste version of the letterpress The most obvious printing phenomena such as "products", "days", "mouths", etc. are filled with ink into a solid shape, and even dots are connected together, so it is often called blocking. The main reasons are: (1) The dryness of the ink is too large, which causes the ink to dry early or become too sticky, resulting in small dots of ink layer on the paper or plastic, or paper, plastic debris concentrated on the plate or dot part; (2) The ink dries too fast, and the ink in the ink fountain is skinned or has dry hard particles; (3) The ink is too thin, the ink is squeezed out under the printing pressure; (4) Too much paper or plastic absorption linking material leads to too much pigment content in the ink; (5) The roller is defective or unconscionable; (6) The printed relief is not flat or too high; (7) Too thick ink is used on rubber paper or smooth plastic (especially plastic woven bags); (8) Too much ink or too slow drying. The method of elimination is: (1) Adopt reasonable dryness and thick ink; (2) High-profile parts or dots to reduce printing pressure; (3) Re-filter the ink 15 ～ 25μm); (4) Separate or replace the substrate with base paper or plastic on the upper side of the printing; (5) Add additives to dilute ink in thick ink to increase the flow rate of ink; (6) Make up for drying ink or solvent; (7) Dye type ink should reduce the content of resin; (8) Reduce the amount of ink supply or add a slower ink inhibitor; (9) Do not blow the wind from the drying device onto the plate; (10) Add TM3 or silicone oil to the ink. [next] Second, the lithographic (printed) paste version 1. Lithography (printing) is greasy (greasy) and its manifestation is: the graphic lines are spread out and not clear and complete. In the blank area, there are dirty stains of different ink weights, especially on the blanket Pieces of ink. The reason is: (1) The water-absorbing portion on the printing plate forms an ink-absorbing center, causing the surfactant in the paper or plastic ink layer to migrate to the water-absorbing area. (2) The pH difference between the ink and the water is too large (that is, the water-ink imbalance is often said), which causes the metal of the printing plate to be dissolved by the acid in the medicine and the printing plate is not clean. (3) When using a paste-like dry oil containing lead, especially when the amount is too much, the dry oil is destroyed by a highly acidic potion, which is covered by a thin ink layer (which often leads to yellowing of the entire plate) ). Because the ink layer hinders the control of wetting, it becomes oily. (4) The ink is too oily and too thick to cause insufficient water on the plate surface. (5) Due to lack of induction treatment and high pressure of the inking roller in the non-printing area, improperly adding desiccant, and poor quality or poor installation of the water roller. The usual processing method is: (1) The pH of the ink should be adjusted down, close to the pH of the potion; (2) Add wax or sodium silicate to the ink; (3) Check the quality of printing plate and water roller; (4) Control the printing speed; (5) The ink should be as thin as possible; (6) Choose thick and thick ink. 2. The form of lithographic (printing) floating dirt is that the printing plate is full of slight ink, and it is very easy to transfer to the blanket, and then transfer to print on paper or plastic. Sometimes it is easy to wipe off, but it quickly reappears, staining in the potion. According to the phenomenon of floating dirt, people often think that it is caused by ink floating on water or dissolving in water. Therefore, some people call the disaster water or ink bleeding. Because: (1) The surface active substance in the paper is leached to form an emulsion of ink in water, and then covered with the moisture absorption part of the printing plate surface. (2) The pigment in the ink has poor lipophilicity and is not fully wetted by the binder (such as ink made by Zhongluo yellow pigment can easily run into water). (3) When synthetic resin uses low temperature to dissolve binder and the content of ink oil is relatively high, it is very easy to cause emulsification of ink. The usual processing methods are: (1) After the ink is produced, it should be stored for a period of time; (2) The resin in the ink should have good wetting of the pigment; (3) Reduce the acid value of the potion as much as possible, and reduce the amount of water supply ink; (4) Add viscous resin solution; (5) Pigments with large oil absorption or surface treated with hydrophobic additives are used. 3. The dirty form of lithography (printing) is the appearance of large dots of ink in the non-printing area. The reason is: (1) The printing pressure and the operation of the printer destroy the isolation membrane on the printing plate to expose the metal, and then it will be immediately affected by a small amount of surface activity, polarity, free fatty acid and other substances, causing these places to absorb ink create pollution. (2) The excessive residual ink layer left on the plate during the development of the printing plate is a dirty plate generated on the plate. (3) The ink is too thin and oily, soft, and insufficient viscosity, easy to cause the ink roller to slip and then make the water roller dirty. (4) In addition to improper induction treatment or poor glue application. (5) The insufficient water on the printing plate and the acidity of the potion are too low, which causes the water roller to absorb the ink. There are also inherent stains caused by the PS version and so on. The usual processing method is: (1) Add ink oil (resin liquid) to the ink; (2) The content of fat and oil in the ink should be reduced as much as possible; (3) Increase the amount of water supply, especially the acid value of the potion; (4) Use thick ink to make the print as thin as possible; (5) Choose a potion with higher surface tension; (6) Adjust the pressing force between the printing plate and the rubber roller; (7) Reduce desiccant; (8) Replace the faster drying resin ink. [next] Third, the gravure (gravure) paste version In the printing of plastics, especially in the manufacture of composite inks, small prints or hierarchical patterns cannot be printed, and even ink shades of varying shades are formed on the surface of the substrate. Some people think that it is due to poor adhesion (adhesion). If we do not scientifically add adhesion-promoting (resin) agents to promote adhesion, although it can overcome the disadvantages of pull-off, excessive addition will often lead to softening of the ink film. There is no way to control paste (dyeing). Because: (1) The affinity of its surface with metal intaglio and scraper due to floating color; (2) The acid value of the composite resin is too low; (3) The ink has a strong wettability to the chrome-plated surface on the intaglio plate, causing the scraper to scrape the ink; (4) The scraper is slow or the angle is wrong; (5) The surface of the plate cylinder is rough; (6) The initial drying (period) of the ink is too slow (such as the introduction of ethyl acetate (quick-drying solvent) in the printing ink system, preferably within 1 to 3S on the film. (7) In an environment with high humidity, the charged ink has an affinity for chromium (increasing the proportion of antistatic agent). (8) Paste plate caused by too slow printing speed or bad printing plate. The method to eliminate the fault: (1) If the chrome-plated surface of the new version of the cylinder is rough, add a quick-drying solvent to the ink to form a thin layer of ink between the blade and the impression cylinder. After two or even hours, polish the chrome surface, and then Change to a normal mixed solvent (such as 7 parts ethyl acetate, 2 parts toluene, 1 part butyl acetate, or 8 parts ethyl acetate, 2 parts toluene). (2) If there are impurities in the ink such as pigment particles and paper and plastic chips, the solvent should be increased. The best treatment method is to use 250 mesh screen to filter the ink. (3) Replace with a new scraper blade and adjust its angle. (4) If it is caused by a slow-drying ink, add a quick-drying solvent to dilute the ink, otherwise if it is caused by a quick-drying ink, you can add a slow-drying solvent or silicone oil to slow down the drying. (5) If the ink dries in the plate cavity due to air blowing, the angle of air blowing should be adjusted, generally to increase the speed of the printing press or remake the plate. (6) Add solvent to reduce ink viscosity or add anti-sticking anti-soiling agent (such as wax, etc.) and so on. (7) Add gold oil or resin liquid, or change to non-particle ink. Counter Display,Counter Display Stand,Display Counter For Shop,Countertop Display Rack Apache Industry Ltd. , http://www.apachedisplay.com
Causes and elimination of paste phenomenon in different printing processes
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