Drop-on-demand
The inkjet method that fires each droplet only at the instant it's needed — the opposite of a continuous stream.
The technology in virtually every desktop and photo inkjet. The nozzle sits idle until a dot is due, then a pulse ejects exactly one droplet. Two schools split the market: thermal DoD (Canon's Bubble Jet, HP) boils a microscopic vapour bubble that shoves the ink out, while piezoelectric DoD (Epson) flexes a crystal that squeezes the droplet free. Its advantage over continuous inkjet is that no ink is wasted or recycled — no droplets form needlessly. The drawback is that nozzles can dry and clog if the printer sits unused, which is why it burns through cleaning cycles.