The earliest development of Ink-jet Printing was in 1878. In 1951, Siemens applied for a patent for the technology of converting liquid ink into ink droplets. In 1964, it used a special machine to , which can control the size and ejection rate of ink droplets. This is the prototype of the inkjet machine. It was not until 1967 that Hertz developed a continuous inkjet printer, which is the Continuous Ink-jet Printing used in industry. In 1972, Siemens launched Piezoelectric (piezoelectric) Drop-on-Demand Ink-jet Printing. In 1979, Canon launched Thermal Drop-on-Demand Ink-jet Printing, but it was called Bubble Ink-jet Printing. In 1984, HP also Thermal's Drop-on-Demand Ink-jet Printing was launched. The above is the development history of Ink-jet Printing.