Ultra-Sonics and the Inkjet..
Ultra sonic cleaning involves the use of high frequency sound waves (above the range of human hearing about 18kHz) to remove a variety of contaminants from parts (or in our case, a printer cartridge print head) immersed in aqueous media. These contaminants might be dirt, oil, grease, buffing/polishing compounds and mould release agents and probably many others. Materials that can be cleaned include metals, glass, ceramics etc.
In the printer cartridge recycling industry we use the ultrasonic cleaner to remove these contaminants from the print head itself. Cartridges that have dried out or have been out of the printer for some time can, on many occasions be brought back to life using this method of cleaning.
Ultrasonic cleaning is powerful enough to remove tough contaminants, yet gentle enough not to damage the substrate. It provides excellent penetration and cleaning into the smallest crevices and between tightly spaced parts in a cleaning tank and therefore lending itself as ideal for cleaning the inkjet cartridge print head.
The use of ultrasonics in cleaning has become increasingly popular with the worldwide restrictions being imposed against the use of clorofluorocarbons.
How does it work?
Temperatures inside a cavitating bubble can be extremely high, with pressures up to 500atm. The implosion event, when it occurs near a hard surface, (such as the print head face), changes the bubble into a jet about 1/10 the bubble size, which travels at up to 400kph toward the hard surface. With the combination of pressure, temperature and velocity, the jet will free contaminants from their bonds with the substrate. Because of the inherently small size of the jet and the relatively large energy, ultrasonic cleaning has the ability to reach into the smallest of crevices and remove trapped soils very effectively. Hence an ideal application for the inkjet printer cartridge.
In a process called "cavitation", micron sized bubbles form and grow due to alternating positive and negative pressure waves in a solution. The bubbles subjected to these alternating pressure waves continue to grow until they reach resonant size. Just prior to the bubble "imploding", there is a tremendous amount of energy stored inside the bubble itself.