How Does Thermal Inkjet Printing Work?

One of the most popular categories of industrial inkjet printers available today, thermal inkjet (TIJ) printers are compact, cost-effective machines that are built to create high-resolution codes on a variety of substrates. Coming in a host of makes and models that emphasize different advantages (e.g., mobility, substrate specialization, print height, etc.), TIJ printers can meet the needs of the modern production line without compromising quality. However, depending on the unique needs of your enterprise, there is a possibility that an alternative machine, such as a continuous inkjet (CIJ) printer or high-resolution case coding printer, may be better suited. 

To provide clarification on the subject, this article will detail the basics of the question, “How does thermal inkjet printing work?” as well as profile what benefits arise from the “drop ejection” printing process used by these machines. With this information, you should be able to determine which of these devices is right for you. 

How Does Thermal Inkjet Printing Work?

As opposed to the replenishable tanks used by CIJ machines, TIJ printers use a system of replaceable cartridges for ink delivery. Through a process called “drop ejection,”  TIJ models propel the ink from these cartridges and onto the desired substrate via these 4 steps:

  1. Heat the ink: To start the process, the ink is delivered by the cartridge to a firing chamber where electronic resistors heat it at a rate of 1,800,032°F / 1,000,000°C per second.
  2. Generate a bubble: Once the heat from the resistors causes the ink to reach a temperature of 644°F / 340°C, the ink is vaporized and generates a bubble.
  3. Propel the ink: As the bubble expands, the ink droplet is propelled from the chamber and out of the nozzle.
  4. Collapse the bubble: Once the droplet breaks away from the nozzle and onto the substrate, the bubble it was propelled by collapses. This creates a vacuum effect that pulls more ink into the chamber, causing the entire process to repeat.

Benefits of the Thermal Inkjet Printing Process

As a result of the drop ejection process outlined above, TIJ printers provide the following benefits:

Low Maintenance/High Dependability

With the ink cartridge system utilized by TIJ printers, printhead services (which are a significant maintenance focus for other machines) are unnecessary. If there is a problem, simply switching out the ink cartridge for another often fixes the issue easily and within seconds. 

The four-step thermal inkjet printing process is far simpler than that of a continuous inkjet printer, which operates using ink-filled tanks, pressurizers, and piezoelectric print heads. Accordingly, TIJ machines can create high print quality for years without maintenance, while CIJ printers require regular expert care for optimal performance. 

Along with the convenience of foregoing maintenance with TIJ printers is a lower overall cost of ownership as well.


In addition to reducing upkeep costs, the simplicity of the drop ejection process allows for TIJ machines to be far more compact than other printer types. For instance, following installation and a full ink load, many CIJ machines can weigh close to 100 lbs. This requires them to be fixed in a stationary position along production lines. 

For operations that require more mobility from their printers, TIJs will be a better fit, as even when fully equipped, these devices only weigh one to two pounds. To capitalize on this light-weight construction, TIJ printers come in both easily-adjusted, mounted models, as well as handheld varieties

Versatility in Substrate Specialization

While TIJ models of the past were often limited to printing on only certain substrates (generally paper and cardboard), the list of encodable surfaces has grown substantially as printing technology has advanced. Now, depending on the model in question, TIJ printers can be used to print on:

  • Porous substrates: including paper, cardboard, sponge, untreated woods, etc.
  • Semi-porous substrates: including waxed surfaces, plaster, concrete, coated paper, etc.
  • Non-porous substrates: including plastics, metals, varnished woods, glass, etc.

The disposable ink cartridge system of TIJ printers allows the user to find the best possible ink solution to fit their unique products. Consulting with an expert about your specific encoding needs and product details can help you find both the optimal ink for your enterprise as well as the right model to use it with. 

For example, looking at the InkJet, Inc. Anser line of TIJ products, options are available for all substrate types, with two notable examples being:

  • The Anser U2 Smart, which is designed for both porous and semi-porous substrates.
  • The Anser U2 SmartOne, which is the same as the U2 Smart but supports 1” printing.
  • The Anser U2 Pro-S, which is designed for both porous and semi-porous substrates, as well as non-porous substrates, thanks to its ability to use solvent-based inks. 

Could Your Production Line Benefit from a TIJ Printer?

Based on the information we have discussed here, the right question to ask is no longer, “How does thermal inkjet printing work?” Instead, you should be asking yourself, “Is a thermal inkjet printer right for me?” If you look at your production facility and see a need for reliably scannable codes but not the requirement of a high-speed, industrial printer like a CIJ printer, then a TIJ printer is likely right for you. However, if you aren’t sure that this product type will best suit your operation, our printing experts are happy to help point you towards the right printer and ink for your unique operation. 

To learn more about how thermal inkjet printing works or to find out which inkjet printer model is right for you, contact InkJet, Inc. today by dialing (800) 280-3245.