A date coder is the machine that prints the date, lot and expiry onto your product as it goes by. Whether you need one, or a printed label instead, depends on the pack in front of you, and we will tell you which.
For a food, produce or packaged goods plant, a date coder prints the variable information that makes a pack traceable: best before, use by, packed on, lot, batch, shift, plant. The mark goes directly on the case, carton, bag or film, in line, at the speed the line already runs. This page is about industrial machines mounted on a production line, not hand stamps, desktop printers or the apps that decode a bottle's batch code.
Marapack Services is the Pacific Northwest distributor for Altech labeling systems, and on the coding side we supply thermal inkjet date coders under our own label, with our own part numbers on the ink, to plants anywhere in the United States. We also supply thermal transfer and hot foil coders through the Altech price list, and we are straightforward about the jobs where a label is the better answer.
Not sure whether your pack wants a code or a label? Book an equipment audit and we look at the pack, the substrate and the line before anything is specified.
What is a date coder, and what does an industrial one print?
A date coder is an in-line printer that marks a date, lot or batch code directly onto a pack. An industrial date coder is mounted on the line, fired by a product sensor, and prints the code on each case, carton, bag or film as it passes, with no label and no liner.
What it prints is usually short: a date, a lot or batch number, sometimes a shift or plant code and a line of text. It can also print a barcode, with a caveat covered below. The same family of machines is called a date code printer, a date coding machine, a lot code printer, a batch code printer, or an expiry date printer. They are one category.
Four technologies do this job. Thermal inkjet, the one we lead with, fires ink from a sealed cartridge at close range. Thermal transfer overprinting prints through a ribbon onto flexible film inside the packaging machine. Hot foil coding presses a coded mark onto film and card. Continuous inkjet and laser marking are the other two; we do not sell either.
Should you code the pack or print a label?
Code the pack directly when the only variable data is a date, lot, batch or shift, and the surface is clean and printable. Use a printed label when the data includes a barcode that must scan to a stated grade, when the surface will not take a good mark, or when a customer specification calls for a label.
This is the first decision, and it comes before any choice of printer. A coder is the cheaper way to mark a pack, because there is no label, no liner and no label stock to buy. It is the wrong answer more often than a coder salesman will tell you.
A date coder is usually the right answer when:
- The variable data is a date, a lot and perhaps a shift or plant code
- The pack is a corrugated case, a carton, a bag or a film, and the surface is dry and reasonably clean
- Everything fixed (brand, product, barcode) is already on preprinted packaging or a preprinted label
- You want the lowest cost per unit marked
A printed label is usually the better answer when:
- The case or pallet needs a barcode that a customer's scanner has to read, such as a GS1-128 case label or a pallet SSCC
- The surface is dusty, wet, waxed, deeply textured or chilled, and a direct mark will not hold
- The information is long enough to need the real estate of a label
- A customer or retailer specification requires a label
If a label is the answer, the equipment is a print and apply labeling system, and where the line is not a heavy duty one, the ALcode LT print and apply head is the economical version. For the compliance side of case and pallet barcodes, see our guide to GS1-128 and SSCC labels.
Many plants run both: a coder on the retail pack and the case, a label on the pallet. That is a normal shape and not a sign that something was specified badly.
Which type of date coder fits your line?
The pack decides the technology. A corrugated case or paper carton usually wants a thermal inkjet coder. A flow wrapped film pack can suit a thermal transfer overprinter. A little data on film or card can suit hot foil. A fast beverage line or a hot, curved surface may need a technology we do not sell.
Thermal inkjet date coder (we sell this). The printhead sits in a sealed ink cartridge, so changing the cartridge changes the printhead and there is no ink system to clean. It prints at close range, so the pack has to pass the head consistently. Fixed mount printers cover case lines; handheld units cover off line marking. The range is on our coding and marking equipment page.
Thermal transfer overprinter (available through the Altech price list). A thermal printhead prints through a ribbon onto flexible film, inside the packaging machine. Right for flow wrapped, thermoformed and sealed film packs, and not applicable to a corrugated case.
Hot foil coder (available through the Altech price list). A simple, robust way to date code film and card where the amount of data is small.
Continuous inkjet and laser (we do not sell these). Continuous inkjet has the longer throw distance and the higher speed ceiling, and it is still the right technology on some lines. We set the two inkjet technologies side by side in our thermal inkjet versus continuous inkjet comparison, including when we are not the right supplier.
How do you date code cases and retail packs differently?
Cases are coded by a printer mounted beside the conveyor, usually on a side panel, and the ink follows the case material. Retail packs are coded on the film, the carton or an applied label, as the pack is made. One ink can serve both only if both surfaces share a porosity class.
Cases and cartons. The code goes on a panel that faces the printer as the case travels. The two things that decide success are consistent presentation (a guide rail keeps the case at a steady distance) and the ink. Uncoated corrugate and kraft absorb ink and take water based chemistry. Coated cartons, plastic and foil need solvent based chemistry, and the wrong ink will smear indefinitely. To code two faces of a case you need a printer on each face.
Retail packs. On film, the choice is between a thermal transfer overprinter inside the packaging machine and a thermal inkjet coder. On a carton, a coder on the line. A common, underused arrangement is to preprint everything fixed on the label, apply it, and code only the variable part onto the applied label in line. It costs less than printing the whole label and keeps the converter's print quality on the fixed content.
What does a date coder need to print well?
Six things decide whether a date coder installation works: the substrate, throw distance and pack presentation, line speed against print height, the trigger, where the data comes from, and the room. When a code smears or fades, check the substrate and the presentation before suspecting the printer.
1. Substrate. Porous or non porous, and how clean and dry it is at the moment of printing.
2. Throw distance and presentation. Thermal inkjet prints close to the pack. A pack that wanders fades the code on one side. A guide rail is cheaper than a technology change.
3. Line speed against print height. A taller image at speed needs more printhead width, which is why stitched multi head configurations exist, up to 4 inches of print height.
4. The trigger. The printer must know a pack arrived, at the right moment, every time. A poorly placed product sensor causes faults that look exactly like printer faults.
5. The data. A date typed in at shift start is a different system from a date or lot pulled from your ERP or line controller. That is a process decision before it is an equipment one.
6. The room. A chilled pack pulled into a warm room grows condensation in seconds, and no ink dries on water.
Then print on your actual pack, at your actual speed, and look at it an hour later. That hour tells you more than a specification sheet.
What does lot code printing add beyond the date?
A lot code ties a pack to the batch it came from, so a recall, a complaint or a quality hold can be scoped to a defined set of product instead of a whole season. The date says when the product expires; the lot says where it came from, which is what an investigator asks for.
Plants commonly combine the lot with a shift, a line or a plant code so that a problem can be narrowed to one run. Where a retailer or customer requires the lot and date inside a scannable barcode on the case, that is a label job, and the barcode has to be printed to a stated grade. A coder prints text well and will print a barcode, but whether the symbol holds up depends on substrate, print height, speed and ink, and it should be tested on your pack.
Where traceability is driven by a produce buyer, the case label is covered on our PTI labeling systems page.
How do you keep a date coder supplied through the season?
Order ink ahead of the season, not during it. We supply the ink under our own part numbers and set up standing pre-season orders, because private-label ink is made to order rather than pulled off a shelf. A coder is a machine you buy once and an ink account you keep.
Running out of ink stops a line as surely as a failed printer, and produce plants code hardest in the weeks when nothing can wait. Specify the chemistry once and hold it: changing ink mid season changes dry time and adhesion. We would rather build the order with you in spring than take the call in July. For the labeling equipment around the coder, our labeler repair and service work covers Altech, Label-Aire, PackLeader, CTM and Tach-It machines.
Frequently asked questions
What is the difference between a date coder and a label printer? A date coder prints directly on the pack, in line, with no label. A label printer prints a label that is then applied to the pack. The coder is cheaper per unit and suits dates and lots. The label suits barcodes that must scan to a grade and surfaces that will not take a direct mark.
Can a date coder print a lot code and an expiry date on the same pack? Yes. Date, lot, batch, shift and a line of text are normal content for a thermal inkjet coder. The height of the printhead sets how many lines fit in one pass, and stitched multi head configurations print a taller image.
Can a date coder print on plastic, film and foil? Yes, with a solvent based ink. Water based ink on a non porous surface will not dry and will smear. On flow wrapped film, a thermal transfer overprinter inside the packaging machine is also worth considering.
How much does a date coding machine cost? It depends on the printhead configuration, whether it is fixed or handheld, the ink the substrate needs and the mounting the line needs. We quote after we know the pack, the substrate and the line speed, because a price given before that is a price for a different machine.
Do you sell continuous inkjet or laser date coders? No. We supply thermal inkjet under our own label, plus thermal transfer and hot foil coders through the Altech price list. Where continuous inkjet or laser is the right technology for an application, we will say so.
Does a handheld date coder work for production? For low volume, mixed product and off line marking, yes. For a line that runs all day, a fixed mount printer triggered by a product sensor is the better fit, because it prints every pack in the same place.
Can you help with a date coder we already own? We support the printers we supply. For other coding equipment, bring us what is on the line and we will tell you honestly whether to keep it, retrofit it or replace it.
Ask before you buy the wrong coder
Tell us the pack, the surface, the line speed and what has to appear on it, and we will tell you whether the answer is a date coder, a thermal transfer overprinter, a label, or a mix, including when the answer is a technology we do not sell. Call 253-709-5566, or request a coding line assessment.