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Rubber stacking fault in offset printing production

     “Stacking rubber” is one of the common faults in offset printing production. When ink is just piled on the blanket, the print imprint is not clear and the dot is pasted; Rubber stacking fault in offset printing production

    When stacked to a certain extent, it will cause color deviation and dirty plate phenomenon, and aggravate the wear of printing plate. There are many factors causing “stacking rubber”, and the treatment methods are also different.Rubber stacking fault in offset printing production

Rubber stacking fault in offset printing production

      The coating on the paper surface is not firmly adhered and there is too much paper powder. The coating on the paper surface is uneven or the sizing is insufficient.Rubber stacking fault in offset printing production

      Under strong light, it can be seen that the paper surface is rough or there are many paddles. Rubber stacking fault in offset printing production

      For the “stacking rubber” fault caused by this situation, in addition to adding an appropriate amount of additives, it can also appropriately reduce the printing pressure without affecting the print quality, and slow down the speed during the printing process to reduce the peeling of paper.Rubber stacking fault in offset printing production

      If possible, first pass the white material through the empty drum to remove some paper wool and paper scraps on the paper surface. If the product allows, the effect will be better if you pass the bright paddle first.Rubber stacking fault in offset printing production

Rubber stacking fault in offset printing production

     One of the main reasons for stacking rubber is that due to the high viscosity of the ink, the fibers and paper powder on the paper surface are stuck off, so they accumulate on the blanket. Solution: Rubber stacking fault in offset printing production

     You can put an appropriate amount of additives or viscosity reducer into the ink to reduce the viscosity of the ink. The amount of additives should be controlled to avoid affecting the drying performance and gloss of the ink.

     The surface of blanket is crystallized and too smooth. Through experimental comparison, the adsorption force of smooth rubber cloth on paper wool impurities is much greater than that of rough rubber cloth. Solution:Rubber stacking fault in offset printing production

      Thoroughly clean the surface of the blanket to restore its fluffy state, or select the blanket with slightly rough surface, which will get better results.Rubber stacking fault in offset printing production

     Excessive emulsification of ink. After the ink is emulsified, the pigment will be separated from the floating state and retained on the blanket to cause “stacking rubber” or on the printing plate to cause “stacking plate”. Rubber stacking fault in offset printing production

     It can be seen that the ink on the ink roller is sticky and granular, and the ink is dull. It can be solved by cleaning the ink roller, appropriately reducing the ink viscosity, readjusting and controlling the ink balance.Rubber stacking fault in offset printing production 

       The drying speed of ink is too fast. When the ink layer on the ink roller of the unit is thin, after printing for a period of time, the ink roller will heat up, so that the drying speed of the ink is too fast. Because the viscosity of the ink is the strongest when it is dry, the transfer rate decreases, and the backward pulling phenomenon will occur, resulting in the phenomenon of “stacking rubber”. Rubber stacking fault in offset printing production

     It can be solved through the following ways: A. reduce the workshop temperature and keep the humidity at about 65%; b. Add an appropriate amount of viscosity reducer or anti drying agent to the ink.Rubber stacking fault in offset printing production

       Improper color sequence arrangement. The ink viscosity of the rear color group is greater than that of the front color group. Rubber stacking fault in offset printing production

     The rear color group pulls down the ink of the front color group, resulting in accumulation and serious color mixing.Rubber stacking fault in offset printing production

      It can be solved by adjusting the color sequence and adjusting the viscosity of the ink to make the viscosity of the rear color group ink slightly less than that of the front color group ink. Rubber stacking fault in offset printing production