1. The color change of ink after high temperature baking
Heat curing ink printing ink, belonging to the technical requirement, one of which is the same color after high temperature baking. But in practice, some color ink through the baking after more or less in some color, such as white ink, ink and dilute with plenty of white ink, dilute ink mixing ink, the ink will occur after repeated baking yellowing, especially with a large number of the deployment of a dilute ink agent, baking after the color change will be great. For example, with a large amount of diluent adding blue ink mix into blue, light blue after baking may become blue specially designed. The craft planner should take full consideration when making the printing process, and try to put the inks which are bake many times in the final printing.
2 color changes before and after the glazing
The last process of printing is the polish oil. The purpose of the polish is to protect the pattern and prevent the damage; two is to improve the gloss and increase the beauty. In general, the printing of light oil by high temperature after curing are yellowing, and the light oil to light reflectivity increases, so after glazing ink color will generally be brighter than before polishing. However, some gloss oils contain brighteners, which are blue in the light. Therefore, after using the varnish, the ink color will be more blue than the original. The overall hue is the superposition of the color of the ink itself and the gloss of the gloss.
3. Color change of metal color special ink after oxidation
Printing gold and silver ink is made of gold, aluminum and other metal powder to color. The printing gold ink is printing ink by copper powder grinding and modulation; tin silver ink is composed of aluminum powder after grinding and modulation of ink. The chemical properties of gold and silver powder printing gold and silver ink in general is not stable enough, when the acid and alkali, water vapor, gas and sulfide carbonate gas, will produce a chemical reaction, the lack of metal color printing inks. The law of discoloration of metals is from gold to brown and then to black. Because copper can be generated in the early red cuprous oxide oxidation, after further oxidation into black copper oxide; in addition, gold powder in carbonated thick and high moisture conditions, easy to become a basic copper carbonate, and gold ink printing on the times gradually darken. After the color of the silver and ink, it becomes gray and lacks the silver metal texture.
4. The thickness of the printing ink layer is different
We know that the same ink printing thickness is different, and the color is different. In actual printing, the thickness of the ink layer is controlled by the printing pressure and the amount of ink. Generally speaking, after adjusting the printing pressure reasonably, it will not change. Therefore, the thickness and uniformity of the ink layer is achieved by controlling the amount of ink. Most of the domestic printing machine or by hand to adjust the amount of ink to the inking screw to control, because artificial adjustment is influenced by many factors, so that the printing ink layer may have uneven thickness, ink color will be shades of color and color difference standard draft.
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