Date Coding & Marking: Inkjet, Laser, and TTO
The small print that carries big compliance and traceability weight.
By PPI Technologies Group · · 6 min read
Key Takeaways
- Coding carries date, lot, and traceability data that compliance and recalls depend on
- Continuous inkjet (CIJ) is versatile and fast for non-contact coding on many substrates
- Laser coding is permanent and consumable-free but substrate-dependent
- Thermal transfer overprinting (TTO) gives crisp, high-resolution codes on flexible film
- Code verification (vision/scan) prevents missing or wrong codes from shipping
Small mark, big consequences
The date and lot code is among the smallest things you print, yet it underpins shelf-life claims, recall traceability, and increasingly formal traceability rules. A missing, illegible, or wrong code can mean held shipments, failed audits, and broken recall chains — so the technology and its verification matter.
The three workhorses
How they compare:
- Continuous inkjet (CIJ) — non-contact, high-speed, works on curved and varied surfaces; needs ink/solvent and maintenance
- Laser — permanent, consumable-free, very low running cost; mark quality depends on the substrate and may need film design support
- Thermal transfer overprinting (TTO) — crisp high-resolution codes and barcodes on flexible film; uses ribbon, ideal for flow-wrap and pouches
Substrate decides a lot
The best coder for a glass jar isn't the best for a flexible film bag. Match the technology to the surface: TTO for film webs, CIJ for mixed and curved surfaces, laser where permanence and low consumable cost win and the substrate marks cleanly.
Don't skip verification
Printing a code isn't the same as confirming it. Inline vision or scanning to verify the code is present, correct, and readable is what keeps a coding error from becoming a shipped traceability gap — especially under modern traceability and serialization rules.
Bottom line
Choose your coder around substrate, speed, and permanence — then back it with code verification. Reliable, verified coding is the quiet foundation of traceability, compliance, and recall readiness.
Equipment for this topic
Machines and brands we supply that apply to what you just read.
- PSG SUNG ESPM-100P Band Sealer (with Printer) — PSG SUNG · Band Sealing: Horizontal band sealer with integrated date/lot printer.
- PSG SUNG ESPM-200P Vertical Band Sealer (with Printer) — PSG SUNG · Band Sealing: Vertical continuous band sealer with integrated date/lot printer.
- PSG Automatic Pouch Labeler — PSG Labelers · Labeling: Fully automatic premade pouch labeling machine with dual-lane feeding — applies pressure-sensitive labels to filled or empty pouches at up to 100 pouches per minute, two pouches per cycle.
- PSG Top & Bottom Labeler — PSG Labelers · Labeling: Automatic top and bottom labeling machine — applies labels to both sides of pouches, trays, tubs, and cartons in one pass at speeds up to 75 products per minute.
Browse the full line-up
- PSG Labelers — Pouch & Package Labeling
- PSG SUNG — Tray / Flow Wrap / Band Seal
Buyer's guide: Packaging Machines
Frequently Asked Questions
What is date coding and marking?
Printing lot codes, expiration or best-by dates, and other variable data onto packaging for compliance and traceability.
What coding technologies are available?
Continuous inkjet (CIJ), thermal inkjet (TIJ), thermal transfer overprinting (TTO), and laser coding.
How do I choose a coding method?
Based on substrate, line speed, code content, and durability requirements. We can match the right coder to your line.
Keep reading
- FSMA 204: What the Food Traceability Rule Means for Packaging — Why your coding, labeling, and records need to talk to each other.
- DSCSA Serialization: Track-and-Trace for Pharma — Unit-level serialization, aggregation, and the road to full interoperability.