In CIJ technology, a high-pressure pump directs liquid ink from a reservoir through a gunbody and a microscopic nozzle (usually .003 inch diameter), creating a continuous stream of ink droplets via the Plateau-Rayleigh instability. A piezoelectric crystal may be used to create an acoustic wave as it vibrates within the gunbody and causes the stream of liquid to break into droplets at regular intervals: 64,000 to 165,000 irregular-sized ink droplets per second may be achieved. The ink droplets are subjected to an electrostatic field created by a charging electrode or by a magnetic flux field as they form; the field varies according to the degree of drop deflection desired. This results in a controlled deflection by electrostatic charge on each droplet. Charged droplets may be separated by one or more uncharged "guard droplets" to minimize electrostatic repulsion between neighboring droplets.