Thermal inkjet printer vs continuous inkjet printer – what’s the difference?

Both thermal inkjet printers (TIJ) and continuous inkjet printers (CIJ) are used to print batch codes, expiry dates, barcodes, and other information onto packaging. But they work in very different ways – and each is better suited to particular types of jobs.

Let’s start with thermal inkjet (TIJ). This type of printer uses small cartridges filled with ink. Inside each cartridge are tiny heating elements. When the printer sends a signal, the ink is rapidly heated to form a bubble. This bubble forces a tiny droplet of ink out of a nozzle and onto the surface you’re printing on. Because of this controlled burst, thermal inkjet printing is very accurate and clean.

TIJ is great for printing high-resolution codes and text very quickly – especially on flat, smooth surfaces like cardboard sleeves, cartons, paper labels, or plastic pouches. It’s a popular choice for use with offline carton feeders, such as the udaFORMAXX range from Koenig & Bauer Coding, where flat packs are fed through the printer before going to the packing line.

CIJ, on the other hand, works a bit differently. Instead of using a cartridge, it uses a continuous stream of ink droplets that are controlled by electric charges. Some droplets are guided to the product to form the code; the rest are recycled. CIJ is fast, can run for long periods without stopping, and works well even when the surface is curved, uneven, or moving quickly.

Continuous inkjet printers – like the alphaJET models from Koenig & Bauer Coding – are usually fitted directly to production lines. They’re ideal for high-speed environments where products like bottles, jars, cans or flow-wraps are whizzing past. CIJ can print on just about anything: plastic, metal, glass, film, foil, you name it!

Another key difference between these two printers is in how they handle inks. TIJ printers use ink cartridges, which makes them clean and easy to swap, but each cartridge has a limited life. CIJ systems use bulk ink and solvent tanks that last a long time and keep running without much hands-on work. CIJ inks also come in a wider range, including water-resistant, heat-resistant, and food-grade inks for tough environments.

So, which is better? It depends on what you’re printing and how. If you need sharp, high-quality codes on boxes or cartons at moderate speed, Thermal Inkjet printing could be perfect. But if you’re running a fast production line with bottles or pouches and need reliable, long-lasting prints, Continuous Inkjet printing is usually the way to go.

Many companies actually use both technologies – TIJ for offline coding and CIJ for inline coding – depending on the stage of the packaging process.