Positive PS version as long as the national standard (HG/T2694-95) is qualified. Users only need to use properly, you can print a good print, so the standard PS version is very popular with the printing factory.
Apparent quality indicators
Apparent quality indicators are: flat layout, uniform coating, no scratches, creases, bubbles, dirt, de-coating, and obvious scratches, wind marks, drip marks, etc.
To make the apparent quality of the PS plate meet these standards, the flatness of the aluminum plate to be rolled is better, the surface of the plate is required to be fine and uniform in the production, the precision of the coating equipment is high, and the transmission mechanism can operate stably on the black market, and the interior of the coating system The environment should meet the technological requirements, try to make the coating process conditions in the best condition, and match the viscosity of the prepared photosensitive resin with the coating speed. When the surface of the plate base is chemically treated, the rubber roller must be completely removed. Can produce scratch all the sand, scaling, miscellaneous hold, etc.; after the filter, the photosensitive rubber should be allowed to stand for a long time (at least for 24 hours); the position of the air duct should be set properly. I should also use the chemical treatment stage for washing. The water is clean.
Surface roughness index
The control range of the surface roughness (Ra) is 0.4 to 0.9 μm, the deviation within the same plate is ≤ 0.15 μm, and the deviation within the same batch is ≤ 0.2 μm.
To achieve the above three standard indicators, the PS version must regulate the following process conditions.
1. Electrolyte and its concentration
When hydrochloric acid solution is used as the electrolytic solution for sand, a "edge effect" occurs. Usually, an appropriate amount of corrosion resistance agent such as chloride-containing salts, amines, aldehydes, etc. is added to the electrolyte. The amount of corrosion resisting agent generally increases as the concentration of the electrolytic solution increases.
The concentration of hydrochloric acid will vary with the speed of the vehicle and the area of ​​the aluminum plate to be electrolyzed. The faster the vehicle speed, the larger the area of ​​the aluminum plate that is electrolyzed and the higher the concentration of hydrochloric acid.
The sand formed by electrolysis using nitric acid solution is lighter than that formed by electrolysis using a hydrochloric acid solution, so the resistance to imprinting is low, but the grain of sand is concave and convex. It is a fine double-grain structure with high resolution. Beautifully printed artwork and commercial PS version. The concentration of nitric acid solution is generally controlled at 0.5% to 5.0%. It is also possible to add appropriate amount of cultural properties to improve the quality of sand.
The use of a mixed solution of nitric acid and hydrochloric acid as an electrolytic solution for electrolytically roughening the plate base allows printing plates having a high print resistance and a non-dirty portion to be printed. The weight ratio of nitric acid to hydrochloric acid in this electrolyte is 4:1. The obtained grain-mesh roughness (Ra) is 0.50 to 0.65 μm. Although the print resistance is low, it has a high resolution and is suitable for fine-printing.
2. The temperature of the electrolyte
The speed of the electrolysis reaction increases with the increase of temperature. When the temperature exceeds 22°C, the gray matter cannot be dissolved in time due to the high electrolysis rate, which hinders the normal electrolysis. Practice shows that the electrolyte temperature should be controlled at 16 ~ 22 °C. When the production line speed is 6m/min, the temperature can be controlled at 16~25°C. In this range, the higher the temperature, the better the quality of the electrolytic grit, and the finer the obtained sand.
3. Electrolyte current, voltage and power
These conditions must be matched with the composition and concentration of the electrolyte in order to obtain the electrolysis effect of the best sand state.
At present, the ideal method for sand treatment of the PS plate base is to carry out mechanical or liquid honing first, and then perform electrolysis by applying an asymmetrical waveform alternating current in a mixed electrolyte mainly composed of nitric acid. In this way, the comprehensive treatment of the aluminum plate by a variety of patrol techniques will form a multi-layer grit with coarse sand in the coarse sand head and fine sand in the middle sand head. The coarse sand in the multi-layered sand structure has good water retention and is not easy to get dirty; the medium sand spot can improve the developability, enhance the resistance to the printing force, and the fine sand can keep the ink balance, so that the printing plate has good printing Suitability, FDD, FND type PS plate produced by Japan Fuji Film Company is electrolytically roughened according to the above method, and the PS plate with this ideal roughness is not only high in resolution, but also has high resistance to printing force.
 (to be continued)
Apparent quality indicators
Apparent quality indicators are: flat layout, uniform coating, no scratches, creases, bubbles, dirt, de-coating, and obvious scratches, wind marks, drip marks, etc.
To make the apparent quality of the PS plate meet these standards, the flatness of the aluminum plate to be rolled is better, the surface of the plate is required to be fine and uniform in the production, the precision of the coating equipment is high, and the transmission mechanism can operate stably on the black market, and the interior of the coating system The environment should meet the technological requirements, try to make the coating process conditions in the best condition, and match the viscosity of the prepared photosensitive resin with the coating speed. When the surface of the plate base is chemically treated, the rubber roller must be completely removed. Can produce scratch all the sand, scaling, miscellaneous hold, etc.; after the filter, the photosensitive rubber should be allowed to stand for a long time (at least for 24 hours); the position of the air duct should be set properly. I should also use the chemical treatment stage for washing. The water is clean.
Surface roughness index
The control range of the surface roughness (Ra) is 0.4 to 0.9 μm, the deviation within the same plate is ≤ 0.15 μm, and the deviation within the same batch is ≤ 0.2 μm.
To achieve the above three standard indicators, the PS version must regulate the following process conditions.
1. Electrolyte and its concentration
When hydrochloric acid solution is used as the electrolytic solution for sand, a "edge effect" occurs. Usually, an appropriate amount of corrosion resistance agent such as chloride-containing salts, amines, aldehydes, etc. is added to the electrolyte. The amount of corrosion resisting agent generally increases as the concentration of the electrolytic solution increases.
The concentration of hydrochloric acid will vary with the speed of the vehicle and the area of ​​the aluminum plate to be electrolyzed. The faster the vehicle speed, the larger the area of ​​the aluminum plate that is electrolyzed and the higher the concentration of hydrochloric acid.
The sand formed by electrolysis using nitric acid solution is lighter than that formed by electrolysis using a hydrochloric acid solution, so the resistance to imprinting is low, but the grain of sand is concave and convex. It is a fine double-grain structure with high resolution. Beautifully printed artwork and commercial PS version. The concentration of nitric acid solution is generally controlled at 0.5% to 5.0%. It is also possible to add appropriate amount of cultural properties to improve the quality of sand.
The use of a mixed solution of nitric acid and hydrochloric acid as an electrolytic solution for electrolytically roughening the plate base allows printing plates having a high print resistance and a non-dirty portion to be printed. The weight ratio of nitric acid to hydrochloric acid in this electrolyte is 4:1. The obtained grain-mesh roughness (Ra) is 0.50 to 0.65 μm. Although the print resistance is low, it has a high resolution and is suitable for fine-printing.
2. The temperature of the electrolyte
The speed of the electrolysis reaction increases with the increase of temperature. When the temperature exceeds 22°C, the gray matter cannot be dissolved in time due to the high electrolysis rate, which hinders the normal electrolysis. Practice shows that the electrolyte temperature should be controlled at 16 ~ 22 °C. When the production line speed is 6m/min, the temperature can be controlled at 16~25°C. In this range, the higher the temperature, the better the quality of the electrolytic grit, and the finer the obtained sand.
3. Electrolyte current, voltage and power
These conditions must be matched with the composition and concentration of the electrolyte in order to obtain the electrolysis effect of the best sand state.
At present, the ideal method for sand treatment of the PS plate base is to carry out mechanical or liquid honing first, and then perform electrolysis by applying an asymmetrical waveform alternating current in a mixed electrolyte mainly composed of nitric acid. In this way, the comprehensive treatment of the aluminum plate by a variety of patrol techniques will form a multi-layer grit with coarse sand in the coarse sand head and fine sand in the middle sand head. The coarse sand in the multi-layered sand structure has good water retention and is not easy to get dirty; the medium sand spot can improve the developability, enhance the resistance to the printing force, and the fine sand can keep the ink balance, so that the printing plate has good printing Suitability, FDD, FND type PS plate produced by Japan Fuji Film Company is electrolytically roughened according to the above method, and the PS plate with this ideal roughness is not only high in resolution, but also has high resistance to printing force.
 (to be continued)