Inkjet printing is a print method that can recreate photographic-quality images and text using microscopic drops of ink. The ink is dispensed from tiny nozzles by applying heat or electrical charge as well as pressure. The concept of inkjet printing dates back as far as the 1800s, but the technology was not sufficiently advanced until the 1950s. Inkjet printing has since been improved and developed for consumer and commercial printing purposes.
If inkjet printing is a user's method of choice, one must use discs with a surface compatible to the ink, otherwise smearing and smudging may result. CD, DVD and Blu-ray discss with printable surfaces will benefit from the high resolution and photo-like quality of inkjet printing. Additionally, professional printing services may coat inkjet-printed discs with a lacquer to preserve the integrity of the artwork.
Inkjet CD, DVD or Blu-ray printing is intended for both consumer and commercial purposes. Professional inkjet disc printers are priced at several thousand dollars and an at-home consumer will pay a few hundred dollars for an inkjet printer that is meant for short-run disc purposes.
Inkjet printers also have a shorter warm-up time than other printing technologies. Printing one inkjet disc may take up to four to five minutes, so this method is preferable for smaller orders of printed discs. If time or approaching deadlines are a factor, other printing methods may be better suited. Moreover, color matching can be a challenge with inkjet because of its lack of support for the Pantone color palette.
There are two types of inkjet technologies: continuous inkjet (CIJ) and drop-on-demand (DOD). Drop-on-demand also employs two different methods. Both types of DOD methods are more widely used than CIJ technology.
For continuous inkjet (CIJ), a continuous stream of ink is supplied to the print head by a pump and piezoelectric nozzle cycle. A gutter near the medium's surface catches extra ink droplets and returns the unused ink to a waste ink tank.
Like its name suggests, drop-on-demand uses less ink than its CIJ counterpart by spraying only the necessary amount onto the disc at hand. Fewer parts are also required to force the ink through the printer system and on to the disc's surface.
The two methods of drop-on-demand include thermal and piezoelectric processes. Thermal drop-on-demand heats a conductive part of the printer called a resistor. The increase of heat causes an air bubble to form, which in turn, pushes the ink forward and out of the nozzle opening. Canon, HP and Lexmark are a few companies whose inkjet printers employ this method.
The piezoelectric method of drop-on-demand uses expanding crystals and electrical currents to propel the ink toward the nozzle's opening to release it drop by drop. The composition of crystals produces an electrical field when they are charged. This accounts for the crystal enlargement. Epson is known for using the piezoelectric method in their disc printers.