In recent years, flexographic printing has experienced tremendous leaps in technology with the availability of faster presses.This allows printers to vastly improve the quality of their finished products while managing to keep printing costs in line for a wide variety of products, including both tissue and non-woven substrates.
Think, for example, of the beautiful and highly detailed, seasonal paper towels produced by your favorite brands. Some of them have become to function as counter-top works of art!
This goes to show that with the appropriate selection and control of the press, print speed, flexo components, artwork, and inks, a high-quality print job can be achieved.
However, as with other substrates, some print problems can be encountered with tissue and non-woven products. If you're experiencing issues with flexo printing on tissue and non-woven fabric, consider the following troubleshooting tips.
Troubleshooting Problems with Flexo Printing on Tissue and Non-Woven Fabric
In general, there are a few primary problems when it comes to printing on tissue and non-woven fabric, due to the very nature of the substrate:
- WEB SHIFT: Here the substrate does not maintain a true course as it moves through the printing process. This results in images that are blurry, misaligned or uneven. The press or rollers could be out of alignment, which will require a time-wasting reregistration.
- DIRTY PRINT: More so than with other substrates, the fibrous nature of non-woven and tissue materials can cause dust and other contaminants to transfer to the printing materials, resulting in a dirty print or fill-in. Additionally, these particulates can clog the anilox rolls, causing them to fill in and prohibit proper ink transfer.
- SUBSTRATE WRINKLES: Tissue and non-woven fabric can become easily wrinkled during the printing process, causing the images to print unevenly. Make sure the pressure and tension are adjusted properly to assure the material remains taut. The rollers must be evenly impressed, while still allowing the material to flow freely.
- INK PROBLEMS: Tissue and non-woven fabric are very absorbent, so special care must be taken to choose water-based inks that are capable of performing exceptionally well. A paper towel, for example, is meant to absorb liquids, so the ink cannot be too thin or too thick. If the ink viscosity is too thin, it will absorb through the paper towel, causing strikethrough, bleeding onto the back up roll, and causing undue wear and tear on your image carrier. If the ink is too thick, it will not permeate the surface of the paper towel. Keep in mind that these products also need to be free of harsh solvents or printing agents as they may come in contact with food or flesh.
How to Improve Common Tissue and Non-Woven Flexo Print Problems
Challenges in tissue and non-woven printing can include poor print quality, improper ink dry time, clean-up problems, and other mishaps. Tips to improve the process include:
- Press Maintenance: Always maintain and align presses and rollers properly prior to the print run.
- Tension: Adjust the tension to keep the substrate sufficiently taut.
- Eliminate Potential Sources of Contamination: Keep image carriers in top condition and look for dried ink on the print materials. Avoid using harsh solvents or cleaning agents.
- Anilox: Choose an anilox with cells that hold and support your ink transfer at the appropriate rate. Additionally, ensure proper cleaning of your anilox.
Flexo Problem Still Not Solved?
Luminite works with numerous printers of paper towel and tissue products. Our sleeves enable these companies to produce print widths of up to 110.000” with repeats up to 60.000”. Sleeves allow for greater flexibility in printing across multiple lanes with no distortion, increasing productivity on each press run.
For more information about troubleshooting tissue and non-woven printing problems to minimize dot gain, reduce bounce, maximize ink coverage and produce vibrant colors, contact a flexographic printing expert at Luminite.