What Is Ink Migration and Why It Matters
Ink migration refers to the movement of ink components from the printed surface into the packaged product—either through direct contact or via diffusion through packaging materials. This phenomenon is especially concerning in food, pharmaceutical, and cosmetic packaging, where ink ingredients can compromise product safety. Understanding and preventing ink migration is critical in industrial inkjet printing.
How Ink Migration Happens
1. Direct Contact Migration
Occurs when printed surfaces touch the product itself (e.g. printing on the inner layer of packaging or wrap-around labels).
2. Set-Off Migration
When wet or semi-dried ink from one surface transfers to the product or inner packaging during stacking, rewinding, or folding.
3. Penetration/Permeation Migration
Ink solvents or additives diffuse through porous materials or plastic films over time, even without direct contact.
Industries Where Migration Control Is Critical
- Food packaging: Especially when inks are printed on films, sachets, or wrappers with direct or indirect product contact
- Pharmaceuticals: Blister packs, sachets, cartons requiring absolute chemical safety
- Cosmetics: Packaging for creams, liquids, or sensitive formulations
Risks of Ink Migration
- Health hazards from ink solvent, monomer, or pigment exposure
- Altered taste, odor, or contamination of packaged product
- Non-compliance with food safety regulations (e.g. EU Regulation 1935/2004, FDA indirect food additive rules)
- Loss of brand trust and potential legal liability
How to Prevent Ink Migration in Inkjet Printing
1. Use Low-Migration Inks
- Formulated with low-volatility solvents and compliant components
- Often UV-curable or highly crosslinked inks with minimal migration risk
- Check for certification to food packaging standards
2. Print on the Non-Contact Side
- Always print on the outside of a multilayer film (reverse printing may trap ink between layers)
- Avoid coding on direct food-contact surfaces unless using approved edible inks
3. Ensure Full Curing or Drying
- UV or solvent-based inks must fully dry or cure to lock in components
- Use IR dryers, fans, or UV lamps if line speed is high
4. Use Barrier Layers in Packaging
- Use laminates or coatings (e.g. PET/PE or BOPP/ALU) that prevent migration of ink molecules into the product
Inkjet Printer Recommendations
- CIJ: Use only certified low-migration solvent inks; excellent for outer surface marking
- TIJ: Use water-based food-grade formulations; suitable for cartons and labels
- UV DOD: Ideal for highest safety in pharmaceutical and flexible film coding
FAQs
- Is ink migration a problem if I print on the outside? It can still happen via set-off or permeation—barrier layers help mitigate risk.
- What if I only code on boxes? No direct migration risk, but still use safe ink if packaging touches inner food wrap or blister trays.
Conclusion
Ink migration is a serious concern in modern packaging, especially for regulated industries. Using certified low-migration inks, controlling drying, and choosing the right substrate design can minimize risks. Need help choosing safe, compliant inkjet solutions for food or pharma packaging? Contact Cheef Inkjet at sales@cheef.cn.
