Use and protection of blanket
We are a big printing company in Shenzhen China . We offer all book publications, hardcover book printing, papercover book printing, hardcover notebook, sprial book printing, saddle stiching book printing, booklet printing,packaging box, calendars, all kinds of PVC, product brochures, notes, Children's book, stickers, all kinds of special paper color printing products, game cardand so on.
For more information please visit
http://www.joyful-printing.com. ENG only
http://www.joyful-printing.net
http://www.joyful-printing.org
email: info@joyful-printing.net
In offset printing, the blanket plays a vital role. If it is used improperly or not properly maintained, it will not only affect the service life of the leather cloth, but more importantly affect the quality of the printed product. Because the role of the cloth is to transfer the ink on the plate to the substrate. So, how to use and keep the cloth properly? The following seven points should be noted:
1. When a blanket is printed once, it should be removed in time, clean the ink and stain on the blanket with a special ink cleaning agent, and then dry it. After it is completely dry, wipe the blanket recovery agent and dry it in the seal. In a good dark room, return it to the pre-press appearance for future use.
2. Pay attention to the cleaning and cleaning work of the blanket. During the printing process, due to the influence of the printing environment, some dust, impurities and dry ink particles will inevitably fall into the ink. If it is not removed in time, it will block the ink transfer of the blanket and affect the effect of printing dots.
3. When the old blanket is damaged and needs to be replaced with another blanket, the work at this time is very important. First of all, we must ensure that the newly replaced blanket is exactly the same as the old blanket. The type, nature and telescopic parameters must be basically the same. Otherwise, the blanket lining must be replaced, resulting in a certain waste. Second, use a special leveling instrument - a micrometer to test the level of the new blanket. Because lithographic printing emphasizes that the blanket should be thick and uniform, the standard is that the flatness per square inch should not exceed 1% mm. Beyond this standard, the printed products will have ink transfer, uneven ink, and defective dot shape. Not complete.
4. The blanket should be evenly wrapped around the drum of the printing machine as it is, and it must be completely close to the drum. It must be rectangular when the blanket is cut, punched, and installed with the flow tube splint. This is stable and the blanket is not. A slip appears.
5. The blanket has strong shrinkage. Therefore, when changing the blanket, the first time can't be too tight or too loose, because the elasticity of the blanket is very strong. During the use, it is easy to squeeze when it is slightly affected by external force. The pressure deformation causes the two ends of the contact area to exhibit a convex hull, thereby affecting the smoothness of the dots. Generally, the new blanket is properly tightened first. After the fixing, a number of products can be tested and printed, so that the blanket is no longer deformed, and then the blanket is tightened for the second time for large-scale printing.
6. Replace the blanket in time to give it a chance to recover. Because the construction material of the blanket is synthetic rubber, the construction principle is that the surface layer of the blanket and the bottom of each layer are evenly covered with a layer of rubber, so the blanket has better elasticity. Because of its elasticity, after it has been used for a period of time, quickly find a spare blanket to replace it, clean it, and maintain it until it returns to its original shape. If it is not replaced in time, it will be used until it is scrapped, and its life will become shorter. We know that when the blanket is printed at high speed, it is deformed in an instant due to the compression of the layout and the substrate, but the pressure is slightly loose, and it can be recovered instantaneously. However, if it is fastened to the drum for a long time, it is always in a state of continuous imprinting and tensioning, and its internal stress gradually declines with time, thus accelerating its aging.
7. Different types of blankets have different oxidized protective films on the surface. Therefore, it is necessary to select appropriate inks to print according to different materials of the oxide film during printing, which is also a method for protecting the blanket. If some of the components of the ink react with certain components of the blanket oxide film, the protective effect of the oxide film is quickly destroyed, thereby damaging the blanket.
In addition to the reasonable use of blankets in accordance with normal procedures, in the daily printing, if there are some abnormal phenomena in the blanket, it should be eliminated in time. Here are a few examples:
1. The blanket has a scar. There are generally two types of indentations and cuts. This is the most common type of failure that a blanket encounters during use. The indentation is caused by the use of paper that does not match the blanket. For example, the paper is too hard and the surface is rough. However, these slight indentations can continue to be used as long as they are applied to the traces with benzene solvent. If the indentation is too deep and close to the cut, that is, it is cut by a sharp metal, it needs to be repaired with a blanket repair liquid to ensure its flatness.
2. There is mildew on the blanket. This is due to the high humidity in the printing room and the long time due to the rainy season. After the mildew is removed, remove the cleaning solution with a cleaning solution and apply a protective tape to the blanket to ensure it is not affected by printing.