HP inkjet technology is really pretty amazing.  If you take a close look at how HP (also known as Hewlett Packard) inkjet cartridges work, you will see how innovative this company really is.  Ink droplets are jetted out of tiny holes in the bottom of the cartridge (called print-heads), at a speed of around 30 mph.  And the frequency that they are jetted? According to HP, more than 25,000 times per second! These print heads get electrical signals from the printer about how much ink droplets to jet, and at what specific part of the page.