When it comes to flexographic printing, maintaining consistent quality is paramount to the success of your operation — and profitability.
Yet riding that thin line of consistency is easier said than done, as any number of issues can crop up in your process.
However, every issue has a solution.
Here are four common problems that can occur with your ink, including known causes and how you can potentially correct each one.
#1 — Adhesion issues
When you have issues with adhesion, ink will flake off your substrate when crinkled — or it will be easily removed in the “tape test” — which can easily lead to customer rejections.
|
CAUSE |
SOLUTION |
|
Viscosity too high |
Reduce viscosity consistent |
|
Viscosity too low |
Add virgin ink to fountain |
|
Ink surface tension |
Consult your technical |
|
Incorrect ink system for |
Ensure that the correct ink for |
|
Poor film treatment |
Check surface of film for adequate treatment; if possible treat in line |
|
Ink drying too slow |
Check driers for heat and airflow; consult your ink manufacturer or reduce with faster solvent blends |
|
Substrate surface |
Apply primer before printing, |
|
Insufficient web |
Increase temperature settings of driers, check drier balance |
#2 — Bleeding or smearing issues
Bleeding or smearing occurs when the color spreads into your coating or adhesive. While some may not view this as the most dire of issues, it still affects your quality and can lead to waste and possibly rejections.
|
CAUSE |
SOLUTION |
|
Improper pigment use |
Reformulate ink, consult |
|
Coating or adhesive may be rewetting ink |
Reformulate ink, consult |
|
Ink viscosity too high |
Reduce viscosity or |
|
Incorrect solvent |
Use faster or slower |
#3 — Color strength issues
When your color is too strong, your printed colors will not match the expected target. This is a problem especially in today’s world where consumers expect perfection when it comes to branding images.
|
CAUSE |
SOLUTION |
|
Viscosity too high |
Reduce viscosity consistent |
|
pH too high |
Check & adjust pH, reduce |
|
Ink pigmentation |
Reduce colorant strength |
|
Anilox roll cell volume |
Replace with higher line count |
|
Pressure roller setting |
Adjust impression to |
|
Plate or ink metering |
Consult your plate or |
|
Inadequate doctor blade |
Adjust doctor blade to recommended pressure |
#4 —Ink consumption issues
When you’re using too much ink, you’re getting fewer impressions per ink volume. Ultimately, it will eat away at your bottom line and damage your profitability.
|
CAUSE |
SOLUTION |
|
Viscosity too high |
Reduce viscosity |
|
Ink color too strong |
Use extender to weaken color |
|
Weak/old ink |
Check ink to original standard, check date and usage; consult |
|
Excessive anilox volume |
Replace with appropriate anilox |
|
Metering roll too soft for job |
Check metering roll durometer, reduce ink |
|
Ink loss on startup |
Review ink handling setup & shutdown procedures |
Ink management…
Whatever issue you may be experiencing, it’s clear that consistent print quality requires effective ink management. However, ink management can be a difficult process. There are many different elements to be held in careful balance as can be seen in the issues discussed above, including pH, viscosity and evaporation (both of which are related to temperature), etc.
Fortunately, printers can simplify this delicate balancing act through ink control automation.
Norcross’ StablINK system is designed to improve ink performance by continuously monitoring and making adjustments in solvent-based or water-based printing applications. To learn more, download our brochure or contact Saint Clair Systems directly to discuss your application.
