Analysis of common faults in gold ink printing
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In the printing process, gold ink is often used, and gold can play a finishing touch, but the adsorption and transferability of gold ink is worse than that of ordinary ink. Therefore, many problems are encountered in the printing process, resulting in various factors of quality instability. When using gold ink, we must first adjust the printing suitability of gold ink. Pay close attention to the transfer effect of gold ink during the printing process. The running speed of the printing machine should not be too fast, and the transfer roller should always be in the best state. Conducive to the ink is transferred to the surface of the printing plate and the substrate evenly and evenly. Get better results.
There are many quality failures encountered in the printing process of gold ink, mainly in the dull imprinting, the imprinting is enlarged, the paste is imprinted, and the imprinting is exposed to the bottom.
Imprinted matt
1 Chemically unstable. When the gold ink is wet, heated, exposed to acid or alkali, or exposed to the air, it is prone to chemical reaction, which causes the gloss to become dark and lacks brightness. Therefore, the gold ink should be protected from heat, moisture and exposure during storage, and avoid contact with acid and alkali substances.
2 printing machinery is not clean. In the printing process, due to the high speed operation of the ink roller, the friction is heated for a long time, which accelerates the oxidation speed of the gold ink, and causes the ink to deteriorate. Under normal circumstances, for every 4 hours of continuous operation of the printing press, the rubber roller (offset printing including water roller) must be thoroughly cleaned once, and then replaced with new ink to keep the ink fresh and shiny.
3 The dispensing ink is stored for too long. When the gold ink is blended, it should be adjusted as little as possible. Generally, the dosage is kept for 3 to 4 hours. The time of the gold ink used is too long to be oxidized and deteriorated, and the color is dark, which affects the gloss of the product.
4 The substrate has poor smoothness. The smoothness of the printing material is poor, the surface is rough, and the gold ink is infiltrated into the middle of the fiber immediately after being transferred to the surface, so that the surface of the ink layer is tarnished.
5 The speed of the machine is too fast. The machine runs too fast, the heat generated by friction is too high, which accelerates the oxidation of the gold ink and loses its luster. Therefore, when printing gold ink, the machine speed is slower than printing other color inks.
Blot enlargement, paste
1 The amount of ink infused is too large. The ink output of the ink fountain is excessive, resulting in an excessive thickness of the ink layer on the surface of the ink roller. Transferred to the surface of the printing plate, the image part can not withstand the excess ink, under the effect of printing pressure, it will inevitably expand to the edge of the imprinting, or the phenomenon of ink drawing and paste printing will occur. If the ink volume is too large or the ink is too sticky, it should be timely. To control the amount of ink to be conveyed, the excess ink layer on the surface of the ink roller is removed, and then the ink is printed.
2 printing pressure is too heavy. Improper adjustment of the machine pressure or due to incorrect stencil method will cause the mechanical pressure to be too heavy, and the pressure will be too heavy. The ink mark on the graphic will expand to the edge and even paste. The pressure must be re-adjusted.
3 The drying is too slow or the finished product is too thick. Due to the excessively dry ink, the imprinting is enlarged, the paste is even sticky, and the paste is even sticky. In operation, an appropriate amount of desiccant should be added to the ink, and the stack should not be piled too thick.
Blots faint, exposed
1 The substrate has poor smoothness. The smoothness of the printing material is poor, and the surface is rough and uneven, which makes it easy to expose the ink layer and the print is not smooth. The ink color is uneven. Appropriate background color treatment, increase printing pressure and ink delivery, can improve the quality of gold ink blotting.
2 printing pressure is not ideal. The printing pressure is too light or uneven, causing the graphic ink layer to be uneven: the ink layer floats on the surface of the printing material. The particles of gold ink are relatively thick, so that it can be smoothly and evenly transferred to the surface of the substrate. It must be compacted and flattened, and the pressure should be properly increased to make it even and firm. It can avoid the occurrence of defects such as embossing and exposure. In the case of a thick line, it is usually solved by overprinting or two-time printing.
3 ink roller is less suitable. The roundness of the ink roller is not uniform, and the flexibility, viscosity and elasticity are poor, so that the gold ink cannot be transferred to the surface of the printing plate and the substrate during the transfer process. The ink layer of the graphic is not full, which affects the printing quality. Before the printing, all the ink rollers should be properly maintained, and maintain good printing adaptability, so as to create conditions for improving the printing quality of gold ink.
4 The ink layer is uneven. The gold ink is too thin, the consistency is poor, the transfer effect is poor, the ink supply is uneven, and the ink layer is too thin, which affects the quality. In the printing process, the thickness of the gold ink should be compatible with the printability. Keep the ink layer in a uniform state to prevent the print from being imaginary and exposed.