Achieving EU food contact compliance with NAXJET's thermal inkjet printer for flexible film

Why EU Food Contact Compliance Matters on Flexible Film

Last month I was on site at a flexible packaging plant in Poland. The line was running laminated pouches for a major dairy brand, and the production manager was pulling his hair out because the ink on the date codes was smudging after 48 hours. Worse, the audit team flagged that the ink formulation didn't have a Declaration of Compliance (DoC) for EU Regulation 1935/2004. That's a stop-shipment situation. If you're coding on flexible film — whether it's BOPP, PET, PE, or metallized substrate — achieving EU food contact compliance isn't optional. It's a legal requirement for any material that touches food directly or indirectly.

NAXJET's thermal inkjet (TIJ) printers, combined with our certified food-grade inks, give you a straightforward path to compliance without sacrificing line speed or print quality. Let me walk you through the practical steps and common gotchas.

What Makes a TIJ Printer Compliant for Food Contact?

EU Regulation 1935/2004 sets the framework, but the specific migration limits and positive lists come from Plastics Regulation 10/2011 (for plastic films) and national regulations like German BfR or Italian DM 21/03/73. The key requirements for a coding system are:

• Ink must not transfer to food: The printed code should have low migration potential. NAXJET's TIJ food-grade inks are formulated with low-migration components, tested per EN 1186 and EN 13130.
• Substrate compatibility: The ink must bond to the film without delaminating or causing off-odors. Our TIJ printheads run piezo-driven drop-on-demand, which gives precise droplet placement and minimal overspray — critical for thin films.
• Cleanability: The printhead must be easy to clean without solvents that could contaminate the production environment. Our TIJ series uses a sealed ink cartridge system with a self-cleaning nozzle plate, reducing operator exposure.

We've tested NAXJET TIJ printers on over 30 common flexible film structures, from clear PET/PE laminates to high-barrier metallized films. The results show consistent adhesion and no detectable migration above the 0.01 mg/kg limit for non-authorised substances.

How to Set Up Your Line for Compliance

Here's a checklist I use with every site that needs EU food contact approval:

1. Choose the right ink: Always request NAXJET's low-migration TIJ ink (part number TK-xxx). Never use standard dye-based inks — they will migrate through thin films.
2. Validate film surface energy: For polyethylene films, the surface energy should be above 38 dynes/cm. If you're running corona-treated film, verify treatment level before each production run. A simple dyne test pen costs $50 and saves thousands in rework.
3. Set printhead distance: Keep the gap between nozzle plate and film between 1.0–1.5 mm. Too close risks smearing; too far causes dot spread and poor edge definition, which can lead to code rejection.
4. Perform a migration test: Send a sample of printed film (with the ink cured for 24 hours) to an accredited lab like Eurofins or SGS for overall migration and specific migration testing. Most labs can turn around results in 5–7 working days.

One thing I see all the time: operators try to use cheaper "universal" inks that claim to be food-safe but don't have a DoC for the specific polymer. Don't fall for that. Always ask for the ink's Declaration of Compliance and the supporting migration test report. If the supplier can't provide it, walk away.

Real-World Case: Flexible Packaging Line for EU Dairy

A French dairy co-op was running 200,000 yoghurt pouches per day on a 12-head packaging line. They had been using a competitor's CIJ printer, but the solvent-based ink was causing a solvent retention smell inside the pouch, failing sensory tests. They switched to NAXJET's TIJ 2400 series with our low-migration black ink.

We installed the printhead on a cantilever arm above the film web, integrated with the existing PLC via EtherNet/IP for real-time code changes. The result: zero migration failures in three months of random testing, plus a 40% reduction in consumable cost per code compared to the CIJ system. The customer also appreciated that the TIJ cartridges are solvent-free, eliminating the need for make-up solvent storage and ventilation.

强哥敲黑板：现场常见3问3答

Q: Can I use the same NAXJET TIJ printer for both food and non-food lines?

A: Yes, but you must flush the printhead with dedicated cleaning solution between product changes to avoid cross-contamination. We recommend using a separate printhead assembly for food-contact lines to simplify validation. The TIJ 2400's quick-change cartridge system makes this easy — swap in 15 seconds.

Q: How do I know if the ink is truly compliant for my specific film?

A: Your film supplier should provide a full migration prediction for the ink/matrix combination. We can also run a preliminary migration test using our in-house simulation (based on EN 1186-9). Always request the three-layer compliance documents: ink DoC, film DoC, and final printed film DoC from your converter.

Q: What about printing on high-barrier films with aluminium oxide coating?

A: Those films are tricky because the coating makes the surface very smooth. We've found that pre-treating with a plasma or corona discharge (up to 42 dynes/cm) and using NAXJET's high-adhesion TIJ ink (TK-221) delivers excellent print quality. In tests, the code survived 30 minutes in boiling water without peeling.

Free Sample Testing: See It on Your Film

Don't trust a brochure. Send us a roll of your flexible film, and we'll run a free sample test with NAXJET TIJ printer and food-grade ink. We'll send back printed samples, a migration test report (if you request), and a detailed setup guide for your line. Just email your material specs to lab@naxjet.com or call me directly. Let's get your code compliant and your line running.

以上调机参数参考自《NaxJet 工业喷印现场维护手册 v3.5》和车间日常保养防错规范。