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Many color printing plants sometimes because of ink quality problems, cost, stability and other reasons and need to replace ink manufacturers, but this kind of problem and more cautious, afraid of replacement ink and affect production, resulting in product quality fluctuation, causing economic losses to the factory. Different manufacturers of ink properties will be different, will have different impact on printing.
Color printing industry is currently used in the ink, many varieties of classification, according to the location of printing is divided into table printing ink and printing ink. Printing ink in accordance with the printing materials are divided into polyester nylon ink, OPP special ink, aluminum foil special ink; According to the use of different temperature is divided into ordinary ink, boiling ink, cooking ink.
Replace ink may encounter common problems
1. Ink hue
Ink is divided into primary color ink and spot color ink. Ink manufacturers production of primary color ink are the same, respectively for the original red, yellow, blue, black, white and so on. Special color ink has a group of green, red, light yellow, etc., in addition to the ink manufacturers will also according to the special requirements of customers, deployment of some special color ink (generally for printing volume is relatively large, the pattern is more special printing sheet).
2 ink viscosity
The ink viscosity produced by different ink manufacturers will be slightly different, color printing factory will be diluted with mixed solvent, so that the viscosity of ink printing is generally controlled between 16-26 seconds (no. 3 Charanthracene cup). Because the printing color sequence and the nature of the ink itself is different, the viscosity of each ink will be different, the viscosity of white ink is the lowest, about 17 seconds; Black ink has the highest viscosity, about 25 seconds, with other colors in between.
3. Fineness of ink
Different ink manufacturers, the same type of ink fineness is generally roughly the same, but the difference between different ink manufacturers is the normal distribution of ink particles, of course, there are other differences, for example:The ink produced by A factory and the ink produced by B factory, particle size, are between 20-28 microns, but the ink particle size distribution of A factory is more concentrated in about 24 microns, and THE INK of B factory is distributed between 20-28 microns, so the ink of A factory is better than the ink of B factory.
4. In addition to the performance of these ink also note that for plastic color printing industry, there is a performance requirements, the release of residual organic solvents in the ink, because the color of product is generally to direct contact with food, although materials such as ink, glue is not direct contact with food, but the small molecules will be migrated to the surface of the film, It affects the hygiene of food. Therefore, residual solvent countries have corresponding national standards, and color printing plants should also buy the corresponding detection equipment
But the current situation is that most small factories do not have such equipment, in addition, many domestic color printing factories with complete detection equipment are not strictly controlled on this index, resulting in unsatisfactory product health indicators.
5 production process is also a factor to consider, but at present each color printing factory process level has been basically mature, there is not much difference. Need special attention is that the printer speed difference, between different color printing speed probably from 80-250 m/min, if the color changing ink, want to consider the viscosity of ink features, especially the high-speed printing (above 200 m/min) ink viscosity is very low, want to mark, color concentration of printing ink factory has a high requirement.
Ink color printing manufacturers often encountered hue problems
1. There is A color difference between the same hue of ink produced by different ink manufacturers. There is A certain difference between the hue of ink from A and B factories.
This requires ink factory ink formula to do moderate adjustment, in order to minimize the difference. This increases the cost to the color printing factory, so in the replacement of ink manufacturers should also take this into account.
2 - general products because of the mesh between different color ink overlay, in the case of no revision and the same process conditions, will produce a slight difference in hue. At the same time, due to the characteristics of color printing, printing colors are mostly more than 5 colors, as many as a dozen colors, in addition to the original color ink, and special color ink, in addition to the special process requirements to add other auxiliary printing materials, such as light oil.
Designed the color is usually specially tuned by color technology personnel, under the condition of the plate, and other conditions unchanged, after the replacement of ink can generally be close to the original ink color sample proofing products, but if the printing pattern is complicated, special technology, a lot of time also can not meet the requirements of the color sample, if so will ink factory adjust the ink formula, or revision, if the latter, Will increase the cost of color printing factory, so in the replacement of ink manufacturers should also take this into account.
General process of ink replacement (from factory A to Factory B)
1. First of all, provide the color samples of the original color ink and special color ink of the ink of factory A to Factory B. If it is printed matter, it is required that the color blocks on the spot are not superimposed.
2. Color printing factory has many sets of plates, first of all to provide a set or several sets of plates to the ink factory, B factory proofing. Generally, the selection of the version provided to B factory is generally in the original color ink block, commonly used special color ink more.
3. In the experimental stage, ink factory technicians (proficient in printing process and ink performance) will go to the site for debugging.
4. In this process, mainly several original color ink, commonly used special color ink basically meet the requirements of A factory ink hue, so the color printing factory can basically replace the ink of B factory.
5. In this process, the difficulty is that when making such products, the color difference between the printed sample and the standard sample is produced. In the case of the basic consistency of the original color ink, the color difference is generally caused by the special color ink. Specific analysis is as follows:
A. In the printing pattern, the special color ink without mesh, no overlapping color, special color ink color difference, generally by the ink factory to readjust the ink formula.
B. In the case of mesh addition of printing patterns and the superposition of different ink colors, it should be analyzed first whether it is caused by original color ink or special color ink, and it should be adjusted according to E1. If it is caused by original color ink, ink factory should be required to adjust the original color ink formula, if it is caused by special color ink, it should be adjusted in accordance with E1.
C. There is a more special, more complex situation, is in a product pattern there are multiple color overlay, that is, there are several patterns of the same block of overlap mouth, if the first proofing, proofing results are inconsistent with the standard sample, the printing sample part is consistent, the other part is inconsistent, then pay attention to the analysis:
1. The original color ink different ink manufacturers between the hue difference.
2. There are differences in chroma depth between the same color ink (sometimes can be solved by revision).
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