How does drop on demand work? In contrast to CIJ printers drop on demand printers only print the ink that is actually used. Depending on the type of drop on demand a different technique ist used to get the ink out of the nozzle .When the product passes the print head, the drops create grid-like characters or graphics.
The industrial ink cartridges have a series of tiny electrically heated chambers, in which pulses produce a steam bubble. This pushes the ink droplets through the nozzle and places the droplets precisely onto the print material. The contraction of the bubble ensures that within a 100 millionth of a second re-ink from the connected ink reservoir is pulled into the chambers and shot out.
With this principle, an electric pulse is passed through piezoelectric crystals or ceramic chambers. The run voltage causes a change in the shape of the ink chambers, whereby the ink is forced through the nozzles. The resulting vacuum in the chamber draws more ink from the ink tank and fill it up again.