Measures to improve the brightness of offset ink layer
the thickness of the ink layer in offset printing process is also thinner than that in embossing, and the brightness of the imprinted ink layer will be significantly different from that of other printing methods. In particular, the packaging and decoration printing based on "on-the-spot" printing requires bright and thick ink, which causes certain difficulties for offset printing. In order to solve this contradiction, appropriate measures must be taken to improve the printing process, and the following aspects should be paid attention to:
1 The ideal pressure is the primary condition to improve the brightness of the imprinted ink layer. Insufficient pressure will make the imprint empty, the ink float transferred to the substrate surface will be exposed, and the plates and rubbers will be stacked. Therefore, the relative density should be 2.07 to prevent the pressure from being too light. "Field" printing can appropriately increase the lining thickness
2. The water consumption of the layout should not be large. Due to the large water, the ink transmission is difficult, the imprinting is empty, the ink color is dark and uneven (the production capacity of synthetic fibers in the world is interrupted to print is expected to increase by about 2.6% every year), and the color is not fresh (the ink color is diluted due to the increase of emulsion value). If the "field" area is large or there are many color blocks, the pH value of the potion can be appropriately reduced to ensure that the minimum water content is used, there will be no dirt, and the ink volume in the ink bucket will not be reduced
3. If possible, adopt the ink stacking printing method, use light ink as the base color and dark ink as the complexion, and properly grasp the interval of ink stacking overprint to achieve good ink stacking effect
4. The light color "on the spot" can be diluted with transparent diluent to improve its brightness. High grade prints can also be diluted with bright paste. Except for the special requirements of products since 1988, white ink should be used as diluent to print as little as possible
5. The diluted ink should choose the ink with weak coloring power and low concentration to meet the needs of the color saturation of the imprinted ink. Because the ink with strong coloring power is used as the diluted multicolor "field" ink, the ink layer of the layout will be too thin, resulting in "stencil" and reducing the gloss height
6. Adding dry oil properly can improve the brightness of the "field" color block. For urgent items, add white dry oil and red dry oil, and add less red dry oil (generally in red ink and black ink, medium blue and dark blue can also be added), which can increase the brightness of the "field", If there is no stack "advanced automobile drive and transmission system will directly affect the fuel and energy efficiency printing, you can only add red drying oil to make the brightness stronger.
7. The printing surface is coated with bright oil or pasted with plastic film, which can enhance the brightness, but the cost is high.
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