We sell thermal inkjet and we do not sell a continuous inkjet printer. You should know that before you read the comparison, because a comparison written by somebody who sells one of the two is worth exactly as much as its willingness to say when the other one wins.
So here is the short version, up front.
Continuous inkjet is still the right answer when you need to print from a distance, onto something that is moving very fast, or onto a surface a close range printer cannot get near: a bottle on a high speed beverage line, a cable, a pipe, a hot or curved or awkward surface, or anywhere the printhead physically cannot be put a few millimeters from the substrate.
Thermal inkjet is the right answer for most of what a food, produce or general packaging plant actually codes: dates, lots, batches and shift codes onto cases, cartons, trays, bags and film, at line speeds a packhouse actually runs, where the pack can be presented consistently and where nobody wants to own a solvent system.
In the plants we walk into, continuous inkjet on case coding is often there because that is what was available when the line was built, not because the application needs it. That is the honest headline, and the rest of this page is the reasoning.
Not sure which one your line needs? Book an equipment audit and we will look at the pack, the line and the room with you, and say so when the answer is a technology we do not sell.
What is a continuous inkjet printer?
A continuous inkjet printer pumps solvent based ink through a nozzle as an unbroken stream of droplets, charges the ones it needs, and steers them onto the product with deflection plates while the rest are caught and recirculated. Because the droplets are steered across a gap, it can code from a distance, fast, onto moving or awkward surfaces.
A pump pushes ink through a nozzle under pressure, and a vibrating crystal breaks the stream into a continuous train of uniform droplets. Each droplet is given an electrical charge as it forms. The charged droplets pass between deflection plates, which steer the ones needed for the image onto the substrate. The ones not needed are not charged, fly straight, and are caught in a gutter, returned to the system and reused.
Two consequences fall out of that immediately. First, because the droplets are steered electrostatically across a gap, the printhead can sit some distance from the product, which is why continuous inkjet prints from a distance and onto surfaces that are moving or irregular. Second, the ink is a solvent based fluid that is continuously circulating and continuously evaporating, which is why the system needs make up solvent, filters, a pump, and scheduled maintenance to stay clean.
How does a thermal inkjet printer work?
A thermal inkjet printer fires ink from a cartridge whose printhead is a row of tiny heated chambers: a heating element flashes, a bubble forms, and a droplet is ejected straight onto the pack. Nothing is charged, deflected or recirculated, and the printhead is replaced every time the cartridge is, so there is no printhead to maintain.
A cartridge holds ink behind a printhead made of a row of tiny chambers. Each chamber has a heating element. To print a dot, the element heats for a fraction of a millisecond, a bubble forms, and the expansion ejects a droplet straight out of the nozzle onto the substrate. The droplet carries no electrical charge, and there is no deflection and no recirculation.
The consequences here are equally direct. The droplet travels a short distance in a straight line, so the pack has to be presented close and consistently. And because the printhead is part of the cartridge, changing the cartridge replaces the printhead, which removes the entire category of printhead maintenance from the machine.
How do TIJ and CIJ compare, dimension by dimension?
TIJ versus CIJ comes down to one difference: in thermal inkjet the printhead is a consumable inside the cartridge, and in continuous inkjet it is a permanent component on a circulating solvent system. That single fact sets the throw distance, the maintenance, the consumables, the solvent handling, the speed ceiling, the resolution and the shape of the running cost.
| Thermal inkjet (TIJ) | Continuous inkjet (CIJ) | |
|---|---|---|
| Printhead | Integral to the cartridge. Replaced every time the ink is replaced | Permanent. Cleaned, serviced and eventually replaced as a component |
| Throw distance | Short. The pack has to pass close to the head | Long. This is the technology's defining advantage |
| Consumables | One item: the cartridge | Ink, make up solvent, and service parts including filters |
| Routine maintenance | Effectively none beyond keeping the head clean and the pack presented | Scheduled service, solvent top up, filter changes, and start up and shut down procedures |
| Solvent handling | Solvent based inks exist for non porous surfaces, in a sealed cartridge. There is no open solvent system | Solvent handling, storage and ventilation are part of owning the machine |
| Line speed | Suits the speeds a packhouse case or carton line actually runs | Higher ceiling. This is the other defining advantage |
| Print resolution | High. Small text, logos and barcodes print cleanly | Lower, and character based. Fine for a date and lot code |
| Print height | Set by printhead width, and increased by stitching multiple heads to print as one taller image | Set by the deflection range, typically a small number of character lines |
| Substrate range | Porous and non porous, decided by ink chemistry | Very wide, including surfaces a close range head cannot approach |
| Cost shape | Machine cost lower, consumable cost per code higher | Machine cost higher, consumable cost per code lower at volume, plus service |
| Failure mode when neglected | A dirty head or a badly presented pack. Fix the presentation | A blocked nozzle or a contaminated system. Fix it properly and on schedule |
| Downtime to change consumable | Change a cartridge | Top up ink and solvent, and observe start up and shut down procedure |
The line that matters most is the first one. Everything else about the ownership experience of these two technologies follows from whether the printhead is a consumable or a component.
When is a continuous inkjet printer the right choice?
A continuous inkjet printer is the right choice when the head cannot get close to the product, when the line runs faster than close range coding can follow, when the surface is hot, wet, oily or heavily curved, when the product is continuous like cable or pipe, or when a maintained CIJ fleet already works well.
We would rather tell you this than sell you the wrong machine.
- The printhead cannot get close to the product. Guarding, geometry, product movement, a wide variation in product position, or an inaccessible face. If a close range head physically will not fit or will not stay clean, that is the end of the argument.
- The line runs faster than close range coding can keep up with. High speed beverage, high speed bottling, and continuous product rather than discrete packs.
- The substrate is genuinely hostile. Hot, wet, oily, heavily curved, or a surface where close range contact risk is unacceptable.
- Continuous product rather than packs. Cable, pipe, extrusion, wire, tube.
- You already run a fleet of it, it works, and it is maintained. A working, maintained system with trained operators and a spares position is not a problem that needs solving. Replacing technology that works is a project, not an improvement.
In any of those cases, the honest answer is that we are not the supplier for that machine, and we will say so on the visit rather than after the quote.
When does thermal inkjet replace continuous inkjet?
Thermal inkjet replaces continuous inkjet on discrete case, carton, tray and bag coding in food and produce plants: a date and a lot code at moderate speed on a pack that can be presented close. Plants switch when the maintenance burden, a seasonal shutdown, print quality, solvent handling or cost visibility starts to matter more than throw distance.
- Case and carton coding in a food or produce plant. Discrete packs, presentable position, moderate speed, a date and a lot code. This is the everyday coding job in the plants we work in.
- When the maintenance burden stopped being acceptable. A solvent system is fine when somebody owns it. In a plant that lost its maintenance depth, or that runs hard for eight weeks and sits for forty, a technology with no scheduled service is worth real money.
- When the plant is seasonal. This is the specific Pacific Northwest case and it is underrated. A system that needs correct shut down, storage and restart is exposed in a plant that idles for most of the year. A cartridge based printer with no circulating fluid simply starts.
- When print quality became the constraint. Higher resolution, small text, logos, and barcodes that have to survive a scan rather than merely be present.
- When solvent handling became a compliance question. Storage, ventilation, and what an auditor thinks of an open solvent system near food.
- When cost visibility mattered more than cost per code. One consumable, one price, no service contract, no surprise. Total cost over a year is application specific, but the shape of it is far easier to predict.
The thermal inkjet printers and inks we supply are built to our own specification and carry our own part numbers; the platforms and ink chemistries are set out on our coding and marking equipment hub.
What are the other options besides TIJ and CIJ?
Besides TIJ and CIJ, a plant has two more answers: thermal transfer overprinting, which prints through a ribbon onto flexible film inside the packaging machine, and a printed label applied by a print and apply system instead of a direct code. Hot foil coding is a third, simpler option for small amounts of data on film and card.
The comparison is usually framed as a choice between two inkjet technologies, and in a real plant there are four answers, not two.
Thermal transfer overprinting. A thermal printhead prints through a ribbon directly onto flexible film, inside the packaging machine. Very high resolution, no ink system at all, and nothing circulating. For flow wrapped, thermoformed and sealed film packs it is frequently a better answer than either inkjet technology. The Altech range carries thermal transfer intermittent coders that integrate with the labeler machines and packaging equipment we supply.
A printed label instead of a code. If the variable data includes a barcode that has to be graded and scanned by somebody else's system, a print and apply label is usually the safer answer than any direct code, because the label surface is controlled and the code is printed at high resolution onto a known face. That is the job label printer applicators are built for.
There is also hot foil coding, which is a simple and robust way to date code onto film and card where the amount of information is small.
The correct question is not "TIJ or CIJ". It is "direct code or applied label, and if direct, which of the three direct technologies suits this substrate".
What should you check before switching from CIJ to TIJ?
Check six things before anybody quotes a switch: what you are actually printing, whether the substrate is porous or non porous, whether the pack can be presented close and consistently, the real line speed at the print height you need, where the data comes from, and whether the room makes packs sweat. Then test on your own pack.
1. What are you actually printing? A date and a lot code is a different problem from a two dimensional barcode. Write down the worst case content, not the typical case.
2. What is the substrate, and is it porous or non porous? Uncoated corrugate and kraft absorb ink and take water based chemistry. Coated cartons, plastics, films and foils need solvent based chemistry and will smear indefinitely with the wrong ink. This decision, more than the printer, determines whether a coding installation works.
3. Can the pack be presented close and consistently? If the pack wanders, a close range head fades on one side. A guide rail is cheaper than a technology change, and that fix is available far more often than people expect.
4. What is the real line speed, at the print height you need? Not the line's rated speed. The speed it runs at, with the image size you actually need.
5. Where does the data come from? A date typed in at shift start is a different system from a date pulled from a line controller or an ERP. That is a process decision before it is an equipment one.
6. What is the room like? Cold packs entering a warm room grow condensation in seconds, and no ink dries on water. That defeats both technologies equally and it is worth finding out before you blame either.
Then ask whoever quotes you for a print on your actual pack, at your actual speed, in your actual room, checked again an hour later to see whether it smeared. That hour answers more than a specification comparison does.
Frequently asked questions
What does CIJ stand for? Continuous inkjet. TIJ is thermal inkjet. Both are non contact coding technologies and they work in fundamentally different ways.
Are continuous inkjet printers good? Yes, at the jobs they were built for: coding from a distance, at high speed, onto moving, curved or awkward surfaces and continuous product. They are a poorer fit where the pack can be presented close, the line runs at packhouse speeds and nobody wants to own a solvent system, which is where thermal inkjet usually wins.
Is thermal inkjet faster than continuous inkjet? No. Continuous inkjet has the higher speed ceiling. What thermal inkjet has is enough speed for most discrete pack coding, at higher resolution and with no maintenance system.
Can thermal inkjet print on plastic and film? Yes, with a solvent based ink. Water based ink on a non porous surface will not dry. This is a common cause of a coding installation that smears, and it is an ink specification issue rather than a technology limit.
Do we have to handle solvent with thermal inkjet? Solvent based inks exist for non porous surfaces, and they arrive in a sealed cartridge. There is no open solvent system, no make up fluid to top up and no solvent circulating through a pump.
Is continuous inkjet cheaper to run? Cost per code is usually lower at volume. Total cost of ownership has to include service, solvent, filters, downtime and the labor of maintaining it. Which one wins depends on your volume and on whether you have the maintenance depth to own the system properly. We will not pretend the answer is always ours.
We are running continuous inkjet now. Is switching a big project? Less than people expect for case and carton coding: it is a printer, a mounting bracket and a trigger. It is more involved where the existing system prints onto something a close range head cannot reach, which is exactly the case where you should not switch.
Will thermal inkjet print a barcode that holds up? It prints at a resolution capable of it. Whether a given barcode holds up depends on substrate, print height, speed and ink, and it should be tested on your actual pack. Where your customer requires a barcode to meet a stated print quality grade, a printed label is often the safer answer.
Do you sell continuous inkjet? No, and we would rather say so than pretend otherwise. We supply thermal inkjet under our own label, thermal transfer overprinting and hot foil coding through the Altech range, and print and apply labeling where a label beats a code.
Do you service continuous inkjet equipment? Field service, commissioning and preventive maintenance on labeling and coding lines is the core of the business, and what we can and cannot do on a specific system is a question worth asking rather than assuming.
Test on your own pack before you decide
The most useful hour in a coding decision is the one where somebody prints on your actual substrate, at your actual speed, in your actual room, and checks an hour later whether it smeared. Whoever you buy from, ask for that before you commit. We will walk the line with you, tell you what the application needs, and tell you when the answer is a technology we do not sell. Request an equipment audit, or call 253-709-5566.