Paste version is also called dirty version, which is a problem often encountered in gravure printing. Simply put, ink is stuck to a film that should not be printed. Its causes and solutions are as follows:
First, the blade due to blade wear is not sharp enough, thus failing to clean the ink; due to the blade angle is too small or installed into a soft blade, blade pressure is too small can cause paste phenomenon. At this time, the blade angle or pressure should be adjusted and even the blade replaced.
Second, rough layout This situation is usually produced when the amount of printing is too much, the new version generally does not appear this phenomenon. At this point, the surface of the plate should be polished with metallographic sandpaper or the ink in the fast-drying solvent should be allowed to rotate for 1 to 2 hours. If this problem cannot be solved, the plate factory can only be re-chrome plated.
Third, the affinity of the ink for chromium is stronger This situation can also cause paste phenomenon. At this time, you can change the ink of different manufacturers to try, or add no more than 2% of isopropyl alcohol (when the ambient air is relatively dry).
Slow-drying solvents When slow-drying solvents are used and the squeegee is close to the copper version, the area where the printing plate is in contact with air is small, and the layout is still wet due to slow-drying solvents. This makes it easy to form stencils. phenomenon. At this time, the quick-drying solvent should be changed or the scraper should be kept away from the copper plate. If it can not be solved, the plate can be dried by the wind. When these measures are taken, attention should be paid to the speed. When the speed is too slow, ink may be caused. The consequences of not being able to transfer the film.
Fifth, the ink mixed with impurities or ink viscosity is too large When the ink contains impurities, sometimes firmly stuck to the blade, so that the blade can not be in a sharp state to scrape the ink, resulting in paste version, then Use 80 to 120 mesh filter to filter the ink. When the viscosity of the ink is too large, some additional solvents may be appropriately added to effectively solve the problem of stencil.
In practice, the most difficult reason for stencil printing is that when a single solvent is used and the quality of the ink is not very good, printing is usually done at the beginning. However, it will not be long before the stencil printing occurs. . At this time, it can be seen that the surface of the plate is covered with a layer of colored material and is hard to be wiped off with a solvent. This is because the resin in the ink is firmly adhered to the plate after deposition, and only the ester solvent can wipe it off. It is best to use a special cleaning agent. After cleaning the plate with a mixed solvent such as ethyl ester:toluene (8:2), ethyl ester:toluene:butanone (7:2:1), the problem can be effectively solved, but one issue to note here is: If you can solve with ethyl ester, toluene, it is best not to butanone, because the residual odor of butanone is relatively strong, may have an impact on the quality of prints. In addition, when using this mixed solvent, it is also necessary to pay attention to the speed of the vehicle. When the vehicle speed is too slow, it is easy to produce a dry plate phenomenon.
To solve the problem of stencil in practice, it is sometimes necessary to use the above methods in a comprehensive manner. For example, use a quick-drying solvent and a sharp blade to keep the scraper as far away as possible from the copper plate, and use a duct to blow the air toward the plate.
The above has made a comprehensive analysis of the cause of the paste and its solution. Here we will discuss in detail how to improve the ink transfer effect.
In gravure printing, the transfer of ink is the sticking of the ink in the plate texture to the film. In general, the transfer rate (that is, the ratio of the ink adhered to the film to the ink in the texture) is unlikely to reach 100%, and the size of this transfer rate directly affects the quality of the printed matter. On the surface, the prints appear as snowflakes. In some shallowly textured editions, this problem is often encountered and is a more difficult problem. The following analysis of the cause of this problem and its solutions are provided for your reference.
1. Use chronic solvents. For example, toluene mixed with xylene or xylene alone, especially when the humidity is high, care must be taken not to use fast-drying solvents. If necessary, install a central air conditioner to control the humidity of the printing environment, or put some desiccant near the printing plate. .
2. Adjust the blade. Including the small blade pressure, the blade installed as a soft blade, the knife's angle is properly reduced, so as not to scrape the ink scraped off most of the film and can not be transferred. Or make the scraper as close to the plate as possible, so that the contact area between the plate and the air is minimized.
3. Adjust the ink tray so that the plate area is immersed in the ink as much as possible to keep the plate wet.
4. Clean the plate. Carefully clean the texture with a copper wire brush and wash away the ink that is clogged inside. Use a special cleaning agent or decontamination powder when cleaning.
5. Adjust the speed so that the speed is as fast as possible.
6. Adjust the pressure of the embossing roller so that the pressure of the roller is properly reduced.
7. Adjust the ink viscosity, because too large or too small viscosity will affect the ink transfer effect.
From the aspect of plate making, we should deepen the texture system as much as possible. This is a key issue, and we must ensure the quality. If not, how long will it take to print a lot of textures? Ink transfer effect.
From the ink point of view, to have a good stickiness, it is also very critical. If the characteristics of the ink is poor, it is difficult to achieve a good printing effect. In addition, new inks should be used as much as possible, because some old inks will cause resin to separate out after repeated use for a long time, so that they can hardly be adhered to the web, or they can be re-adhered just after cleaning. This is easy to overlook for many people. The problem.
First, the blade due to blade wear is not sharp enough, thus failing to clean the ink; due to the blade angle is too small or installed into a soft blade, blade pressure is too small can cause paste phenomenon. At this time, the blade angle or pressure should be adjusted and even the blade replaced.
Second, rough layout This situation is usually produced when the amount of printing is too much, the new version generally does not appear this phenomenon. At this point, the surface of the plate should be polished with metallographic sandpaper or the ink in the fast-drying solvent should be allowed to rotate for 1 to 2 hours. If this problem cannot be solved, the plate factory can only be re-chrome plated.
Third, the affinity of the ink for chromium is stronger This situation can also cause paste phenomenon. At this time, you can change the ink of different manufacturers to try, or add no more than 2% of isopropyl alcohol (when the ambient air is relatively dry).
Slow-drying solvents When slow-drying solvents are used and the squeegee is close to the copper version, the area where the printing plate is in contact with air is small, and the layout is still wet due to slow-drying solvents. This makes it easy to form stencils. phenomenon. At this time, the quick-drying solvent should be changed or the scraper should be kept away from the copper plate. If it can not be solved, the plate can be dried by the wind. When these measures are taken, attention should be paid to the speed. When the speed is too slow, ink may be caused. The consequences of not being able to transfer the film.
Fifth, the ink mixed with impurities or ink viscosity is too large When the ink contains impurities, sometimes firmly stuck to the blade, so that the blade can not be in a sharp state to scrape the ink, resulting in paste version, then Use 80 to 120 mesh filter to filter the ink. When the viscosity of the ink is too large, some additional solvents may be appropriately added to effectively solve the problem of stencil.
In practice, the most difficult reason for stencil printing is that when a single solvent is used and the quality of the ink is not very good, printing is usually done at the beginning. However, it will not be long before the stencil printing occurs. . At this time, it can be seen that the surface of the plate is covered with a layer of colored material and is hard to be wiped off with a solvent. This is because the resin in the ink is firmly adhered to the plate after deposition, and only the ester solvent can wipe it off. It is best to use a special cleaning agent. After cleaning the plate with a mixed solvent such as ethyl ester:toluene (8:2), ethyl ester:toluene:butanone (7:2:1), the problem can be effectively solved, but one issue to note here is: If you can solve with ethyl ester, toluene, it is best not to butanone, because the residual odor of butanone is relatively strong, may have an impact on the quality of prints. In addition, when using this mixed solvent, it is also necessary to pay attention to the speed of the vehicle. When the vehicle speed is too slow, it is easy to produce a dry plate phenomenon.
To solve the problem of stencil in practice, it is sometimes necessary to use the above methods in a comprehensive manner. For example, use a quick-drying solvent and a sharp blade to keep the scraper as far away as possible from the copper plate, and use a duct to blow the air toward the plate.
The above has made a comprehensive analysis of the cause of the paste and its solution. Here we will discuss in detail how to improve the ink transfer effect.
In gravure printing, the transfer of ink is the sticking of the ink in the plate texture to the film. In general, the transfer rate (that is, the ratio of the ink adhered to the film to the ink in the texture) is unlikely to reach 100%, and the size of this transfer rate directly affects the quality of the printed matter. On the surface, the prints appear as snowflakes. In some shallowly textured editions, this problem is often encountered and is a more difficult problem. The following analysis of the cause of this problem and its solutions are provided for your reference.
1. Use chronic solvents. For example, toluene mixed with xylene or xylene alone, especially when the humidity is high, care must be taken not to use fast-drying solvents. If necessary, install a central air conditioner to control the humidity of the printing environment, or put some desiccant near the printing plate. .
2. Adjust the blade. Including the small blade pressure, the blade installed as a soft blade, the knife's angle is properly reduced, so as not to scrape the ink scraped off most of the film and can not be transferred. Or make the scraper as close to the plate as possible, so that the contact area between the plate and the air is minimized.
3. Adjust the ink tray so that the plate area is immersed in the ink as much as possible to keep the plate wet.
4. Clean the plate. Carefully clean the texture with a copper wire brush and wash away the ink that is clogged inside. Use a special cleaning agent or decontamination powder when cleaning.
5. Adjust the speed so that the speed is as fast as possible.
6. Adjust the pressure of the embossing roller so that the pressure of the roller is properly reduced.
7. Adjust the ink viscosity, because too large or too small viscosity will affect the ink transfer effect.
From the aspect of plate making, we should deepen the texture system as much as possible. This is a key issue, and we must ensure the quality. If not, how long will it take to print a lot of textures? Ink transfer effect.
From the ink point of view, to have a good stickiness, it is also very critical. If the characteristics of the ink is poor, it is difficult to achieve a good printing effect. In addition, new inks should be used as much as possible, because some old inks will cause resin to separate out after repeated use for a long time, so that they can hardly be adhered to the web, or they can be re-adhered just after cleaning. This is easy to overlook for many people. The problem.
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