Inkjet printers. Piezoelectric or thermal technology?
Nowadays there are two kinds of inkjet printers:
Thermal head
The thermal technology is used by HP(Hewlett-Packard) printers and other brands like Canon. This is an easy system because the heat is used to print. The head has a little chamber with a heater. The head is always full of ink and when the heater is working, the ink inside the head expands and the head eject microdrops.
The volume of the drop is important, however, with a tiny drop we get better results. The resolution will be better and the quality as well. With a tiny drop we can get more DPI (dots per inch), and more DPI implies better quality.
The black drops are bigger than color drops because printing in black and white requires less precision.
Another important parameter is the printing speed. As the dots are so tiny, the mechanism of heating and ejecting drops of ink has to be very quick.
At first, the thermal in jet printers had lack of quality because the head was in the cartridge, the piezoelectric printers offered better quality. Later on, the technology has improved and both systems have the same quality.
Another problem with this system is that if you print without ink inside the cartridge, you can ruin it because the ink acts like a refrigeration system. Nevertheless, if you are going to recycle your cartridges, don’t wait till the cartridge is empty.
Piezoelectric head
The piezoelectric technology is quite different than the thermal technology but uses a system to eject the ink of the chamber as well. This is the technology used by Epson printers. It uses piezoelectric materials that can move if you apply an electric charge on them.
When a piezoelectric material receives an electric charge, it pushes the chamber and the ink ejects.
With this system you can use inks based on pigments in order to resist the humidity and to print with better quality. The thermal inkjet printers can not use inks based on pigments because the cartridge can get stuck easily.