The Difference Between a Thermal Inkjet & an Inkjet

By Dave Maddox

Most inkjet printing looks similar, but inkjet technologies vary significantly.
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Inkjet technologies print everything from photos and memos to T-shirts and banners. Each type of inkjet technology delivers ink through a different process depending on image durability, pixel resolution, printing surface, cost and the specific application. The cost to manufacture supplies for thermal, piezo, or other inkjet systems along with the characteristics of the inks on the materials affects which ones are used in low-cost consumer printers versus printers used by professionals.

Inkjet Printing Methods

Inkjet printing techniques for home, office and industrial use include thermal and piezo printhead technology. Thermal technology is found on most consumer inkjet printers, although Epson and a few other companies use piezo. Other technologies, such as hot melt wax, fill niche markets. Both thermal and piezo inkjet printers deliver a droplet of ink from a chamber on the printhead -- one by heating and the other by squeezing.

Thermal Inkjet Printing

Thermal inkjet printing induces the ejection of the ink droplet by superheating a small portion of a solvent-based ink. The heating, performed by a small resistor or other heating element, causes a bubble to form and eject the ink droplet. Advantages of thermal inkjet printing over piezo include better performance, lower cost and ink versatility. Advanced thermal ink research has led to a variety of photo printing applications with results competitive to traditional photo printing techniques.

Piezoelectric Printing

The piezo printing method contracts the ink chamber by applying electricity to a piezoelectric substance which moves when energized. A droplet of ink is ejected onto the print media. Piezo printing has not been adopted by as many mainstream photo printer manufacturers. However, it has found more uses in industrial printing and specialized large-scale printers, including special surface printing where a greater variety of ink bases can be used.

Advanced Inkjet Technologies

Printing by inkjet has moved into most traditional printing areas. A few printing styles such as giclee also use inkjet in new ways. Companies can print on canvas, metal, glass and even fabric using a variety of inkjet printhead technologies and inks. Droplet size control has made highly detailed inkjet photographic prints a reality. Special metallic inks have enabled the printing of electronic circuits and sensor material. Three-dimensional printing, derived from inkjet printing, is opening new horizons in material production using printheads with non-ink substances.