Even today’s budget-priced home printers churn out quality photos that a few years ago you could have gotten only from a professional printing house. Key to the high quality are steady improvements in print heads, which can eject smaller and smaller droplets of ink with ever-greater precision.
A decade ago, eight-picoliter drops (that’s eight trillionths of a liter) were considered small. These days, inkjet printers deliver drops as tiny as one picoliter through thousands of nozzles—some less than half the width of a human hair.
To make prints that look like photos instead of finger paintings, the printer must precisely control how much ink comes out of every nozzle, every time, at a rate of up to 22,000 drops per second.
Two types of technology can squeeze ink through the nozzles.