The deinking failure of the offset printing press often causes the ink fountain roller not to ink, or the ink transfer system does not transfer ink normally. The printing plate cannot obtain uniform ink surface printing plate, which causes great trouble for production and causes the deinking failure of the offset printing machine. There are the following types: 1) The viscosity of the ink is small, the ink is short, the oil is poor, the water on the layout is too large; 2) the dampening solution is too acidic; 3) the content of the glue in the dampening solution is too large; 4) the workshop temperature is too low .
1. Ink viscosity Small ink viscosity Small ink filaments are mainly due to inks formulated with other auxiliary materials in the desorption agent. After a period of use, the performance of the fountain solution deteriorates, after high speed extrusion of the ink roller, and the ink. Emulsification occurs. The ink that has been over-emulsified in turn contaminates the acid in the ink roller to the surface of the ink roller, causing the surface of the ink roller to be eroded, creating a new water layer, thereby discharging oil and discharging ink. In the same way, inks with poor oil properties are deinking in the main form, but the source of the warp is the poor manufacturing of the ink or the process is defective. When the water on the plate is too large, it will cause the ink to be de-inked. The possibility of a deinking failure caused by a simple layout of water is still relatively small.
Treatment: For the ink with low viscosity, ink ink caused by a short deinking failure, you can add ink to know the amount of concentrated varnish; for ink due to poor ink deinking failure, you can add known amount of thin ink. In either case, the layout moisture should be minimized to avoid over-emulsification of the ink.
In fact, the proper amount of ink-ink emulsification is beneficial to offset printing, and absolute oil-water separation is impossible under the high-speed rolling pressure of the ink roller and the interaction between the ink and the fountain solution. The degree of emulsification of the offset ink is about 20%, which is the most commonly known as the water-in-oil state, so that the dampening ink and ink are basically in balance. Therefore, the real ink emulsion failure should be excessive emulsification.
2. There are two main aspects of the deinking failure caused by the excessively acidic dampening solution of the dampening solution. The first is that the acidity is too strong, the surface tension of the fountain solution is very small, and a large amount of moisture is dispersed in the ink, which greatly exceeds 20 % of the optimum moisture content, so that the balance of the liquid and ink is destroyed, the final layer of this degree of milk and the resulting deinking failure; the second is too acidic, the fountain solution on the ink pigments and paper coatings to accelerate the dissolution, resulting in Too much calcium salts make it difficult to deliver ink and cause deinking due to emulsification imbalance.
Treatment: Control the pH of the fountain solution to about 5.
3. Adding too much gum arabic in the fountain solution adds too much gum arabic to improve the wetting properties of the fountain solution, but if too much is added, the degree of emulsification of the ink will increase, eventually leading to excessive ink. Emulsification creates a deinking failure because gum arabic itself is also an emulsifier.
Disposal: Reconstitute the fountain solution as required.
4. The workshop temperature is too low. The de-inking failure caused by the gradual decrease of the shop floor is usually hidden and difficult to find. However, this failure has two characteristics: 1) It mostly occurs in the winter, especially when the temperature is lower than 3 degrees Celsius; 2) The region is very strong, and the occurrence area is mostly south, and the north is in the intersection zone.
1. Ink viscosity Small ink viscosity Small ink filaments are mainly due to inks formulated with other auxiliary materials in the desorption agent. After a period of use, the performance of the fountain solution deteriorates, after high speed extrusion of the ink roller, and the ink. Emulsification occurs. The ink that has been over-emulsified in turn contaminates the acid in the ink roller to the surface of the ink roller, causing the surface of the ink roller to be eroded, creating a new water layer, thereby discharging oil and discharging ink. In the same way, inks with poor oil properties are deinking in the main form, but the source of the warp is the poor manufacturing of the ink or the process is defective. When the water on the plate is too large, it will cause the ink to be de-inked. The possibility of a deinking failure caused by a simple layout of water is still relatively small.
Treatment: For the ink with low viscosity, ink ink caused by a short deinking failure, you can add ink to know the amount of concentrated varnish; for ink due to poor ink deinking failure, you can add known amount of thin ink. In either case, the layout moisture should be minimized to avoid over-emulsification of the ink.
In fact, the proper amount of ink-ink emulsification is beneficial to offset printing, and absolute oil-water separation is impossible under the high-speed rolling pressure of the ink roller and the interaction between the ink and the fountain solution. The degree of emulsification of the offset ink is about 20%, which is the most commonly known as the water-in-oil state, so that the dampening ink and ink are basically in balance. Therefore, the real ink emulsion failure should be excessive emulsification.
2. There are two main aspects of the deinking failure caused by the excessively acidic dampening solution of the dampening solution. The first is that the acidity is too strong, the surface tension of the fountain solution is very small, and a large amount of moisture is dispersed in the ink, which greatly exceeds 20 % of the optimum moisture content, so that the balance of the liquid and ink is destroyed, the final layer of this degree of milk and the resulting deinking failure; the second is too acidic, the fountain solution on the ink pigments and paper coatings to accelerate the dissolution, resulting in Too much calcium salts make it difficult to deliver ink and cause deinking due to emulsification imbalance.
Treatment: Control the pH of the fountain solution to about 5.
3. Adding too much gum arabic in the fountain solution adds too much gum arabic to improve the wetting properties of the fountain solution, but if too much is added, the degree of emulsification of the ink will increase, eventually leading to excessive ink. Emulsification creates a deinking failure because gum arabic itself is also an emulsifier.
Disposal: Reconstitute the fountain solution as required.
4. The workshop temperature is too low. The de-inking failure caused by the gradual decrease of the shop floor is usually hidden and difficult to find. However, this failure has two characteristics: 1) It mostly occurs in the winter, especially when the temperature is lower than 3 degrees Celsius; 2) The region is very strong, and the occurrence area is mostly south, and the north is in the intersection zone.
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