The problem of printing napkins with flexographic water-based ink？
Date: Jul 31 2024 From: Star Color
When printing napkins with
flexographic water-based ink, a series of problems may be encountered, mainly involving ink performance, paper characteristics, printing equipment, and operating environment. Here are some possible problems and their brief analysis:
1、 Ink performance issues
Improper ink viscosity:
Problem manifestation: Excessive ink viscosity may cause paper to become rough, lose powder, and even break during the printing process; If the viscosity is too low, it may cause problems such as light color, large dot expansion, and uneven ink transfer.
Solution strategy: Strictly control the viscosity of the ink and adjust it according to the printing speed and paper characteristics. Usually, the viscosity of water-based ink is more suitable to be controlled within the range of 30-60 seconds/25 ℃, and it should be adjusted according to the actual situation.
Inappropriate ink drying speed:
Problem manifestation: Excessive drying speed may cause dirty plates and unclear patterns around them; If the drying speed is too slow, it may affect color overlay printing and even cause adhesion.
Solution strategy: Adjust the drying speed of ink reasonably according to the needs of printed materials and the ink absorption of paper. The dryness of ink can be adjusted by adding fast or slow drying agents.
Unstable pH value:
Problem manifestation: Both excessively high and low pH values can affect the viscosity and dryness of ink, thereby affecting printing quality.
Solution strategy: Regularly check the pH value of the ink and adjust it using stabilizers to ensure that the pH value remains within the appropriate range (such as 8.5-9.5).
2、 Paper characteristic issues
Low surface strength of paper:
Problem manifestation: The surface strength of napkins is low, which can easily cause the paper surface to become rough and lose powder during the printing process.
Solution strategy: Choose napkins with relatively high surface strength, while reducing printing pressure and adjusting ink viscosity to improve printing results.
Paper has strong ink absorption:
Problem manifestation: Napkins have a strong ability to absorb ink. If the ink absorption is too strong, it can cause the ink film on the paper surface to pulverize, resulting in weak imprints and dull luster.
Solution strategy: Reasonably allocate suitable printing ink, such as increasing ink viscosity appropriately, and paying attention to controlling printing pressure and embossing time.
Unstable moisture content of paper:
Problem manifestation: Napkins have strong water absorption, and high or low moisture content can affect the printing effect.
Solution: During the storage and printing process of napkins, pay attention to controlling the appropriate moisture content to ensure the stability of the paper.
3、 Printing equipment issues
Printing plate issue:
Problem manifestations: Damaged printing plates, damaged scrapers, or improper angles can all lead to printing quality issues such as creasing and ghosting.
Solution strategy: Regularly check the status of the printing plate and scraper, replace damaged parts in a timely manner, and adjust the angle of the scraper and the pressure of the printing plate.
Insufficient equipment accuracy:
Problem manifestation: Insufficient equipment accuracy may lead to issues such as blurriness and ghosting in printed materials.
Solution strategy: Improve the accuracy and stability of the equipment to ensure the smooth progress of the printing process.
4、 Operating environment issues
Improper temperature and humidity control:
Problem manifestation: Changes in temperature and humidity can affect the viscosity and drying speed of ink, thereby affecting printing quality.
Solution strategy: Maintain stable temperature and humidity in the printing workshop to avoid drastic changes in temperature and humidity that may affect ink performance.
In summary, the problems that may be encountered when printing napkins with flexographic water-based ink involve multiple aspects such as ink performance, paper characteristics, printing equipment, and operating environment. In order to obtain high-quality printed materials, it is necessary to comprehensively consider these factors and take corresponding solutions.
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