Printer Ink Cartridges And The Piezo Inkjet Process

2010-06-28

Not long after its introduction to the world in the early part of the 1980s, the inkjet printer became the pre-eminent printer type used in both commercial and consumer applications. While laser printing has found a viable market in the commercial and large-volume printing industries, the light weight portability and interchangeability of inkjet printers and inks has made them the printing method of choice for almost all applications. With a myriad of color and black printer ink cartridges available, in addition to multiple methods of ink application, the inkjet has proven its value over time, and although most inkjet printers currently use the thermal or continuous methods of ink dispensing, there is a third method, known as the piezoelectric or piezo inkjet process which makes them even more versatile.

The piezoelectric effect occurs when a substance under mechanical stress begins to generate voltage. Crystals, ceramics, and even bone and DNA are examples of substances that exhibit this effect. If the circuit that is created by this stress is closed, the voltage will immediately discharge. Similarly, all substances that exhibit this effect are also subject to the reverse piezoelectric effect - when voltage is applied, stress and possible shape change will result. It is through this shape change that piezo inkjet printers operate. Rather than using a heating element to dispense ink or creating a stream of continuous dots, piezo inkjets instead use a piezoelectric material - typically lead zirconium titanate - which is located in an ink-filled reservoir behind the print nozzle. When it is time for the ink to be dispensed, an electric current is supplied and the lead zirconium titanate changes shape, forcing a drop of ink from the nozzle. When the current is gone, the material returns to its original shape.

These types of printers do not suffer from some of the same problems that plague thermal printers such as the need for a volatile element and issues with kogation - the speed, shape and size of the ink droplets produced. Instead, piezo inkjets are able to produce consistent drops of ink from their printer ink cartridges with a much lower failure rate.

The main issue with any piezo printer is the cost. The lead zirconium titanate material is not cheap, and for this reason the most common use of these printers is in commercial applications such as "best-before" date stamping. Several printer manufacturers do make consumer versions of the piezo inkjet printer, but they are expensive and often not worth the prohibitive cost. While piezo printers may never go mainstream in the consumer market, they remain one more excellent example of the diversity of the inkjet printer and help cement its usefulness and popularity.