I’m a big fan of the inkjet printer. What’s there not to like? These printers are efficient little machines and printing can be achieved for a nominal amount of money. Okay, inkjet ink cartridges can be expensive so why not try out the wonderful world of inkjet compatibles? I say ‘thumbs-up for the inkjet printer’ and all who sail in her! 
But I had realised until I delved a little deeper that there was much more to these printers than first meet the eye. First off the bat, I didn’t realise they run of two different types of technology, those of Drop On Demand (or DOD) and Continuous (otherwise known as CIJ). In fact DOD printing can be subdivided into either thermal Drop On Demand as well as Piezo-Electric Drop On Demand.
Patented in the first place by Lord Kelvin (1867) the process known as continuous inkjet printing came to be used for commercial package marking when Siemens invented the device known as a medical strip chart recorder in 1951.
In a nutshell, this continuous inkjet method produces numerous droplets of ink through the Plateau-Rayleigh instability. This happens thanks to the high pressurized pumping of liquid ink direct from its reservoir via a gun body through a tiny nozzle. Who would have known?
An acoustic wave is created from the Piezo-electric crystal within the gun body causing essentially a stream of ink through droplets at a rate of 64,000 to 165,000 drops a second.
What of the other inkjet technology, thermal inkjet printing otherwise known as Drop On Demand? This particular DOD inkjet process was unveiled in 1977 by Inchiro Endo. Favoured by commercial printer entities the world over, the thermal inkjet method was much cheaper to manufacture than other inkjet printing technologies.
With thermal inkjet printing a droplet of ink is released from each chamber. Next a current pulse passes through a heating element to effectively vaporize the ink. A bubble is formed and pressure is increased as a result, which results in an expulsion of an ink droplet onto the paper. The surface tension together with the condensation produces a certain amount of contraction and more ink gets pulled into the chamber.
That of the Piezoelectric inkjet (DOD) costs more to manufacture on account of the material required. The good news is that it allows a broader range of inks to be used (than the thermal method). This is a popular technology found in the majority of our printers including industrial and home computer printers.
Thinking of buying a new printer? I know what I prefer…