The inkjet printer is probably the least expensive printer from which the consumer has to choose. The quality of printing is high and the color is extremely good. The development of the inkjet printer is attributed to several of the top known manufacturers of today.
The inkjet printer works by thrusting drops of liquid onto the page being printed. There are three main methods of printing mechanisms used in inkjet printers - thermal, piezoelectric, and continuous.
The thermal inkjet printer uses a cartridge with very small electrically heated chambers. The printer runs current through heating elements in the chamber causing a steam explosion to form a bubble. This bubble is what thrusts the drop of ink onto the paper.
Certain factors, including condensation, help to pull another charge of ink into the chamber through a small passage which is linked to an area where ink is stored. The ink used in this process is a water based ink and the print head is cheaper to produce than other methods.
Piezoelectric basically means the electricity generated from crystals which are put under stress, such as mechanical pressure. Using the piezoelectric inkjet method, instead of a heating element method has chambers behind each nozzle which are filled with ink. When electrical current is applied the piezoelectric material changes. This causes a pressure pulse in the fluid which causes a drop of ink to be pushed from the nozzle. Similar to the
thermal method, the piezoelectric just uses a different principle to generate the pressure. This method has a more extensive selection of inks but replacing the print heads is more expensive than other methods.
Another method, the continuous ink jet method is the one used in commercial coding of products. This technology uses a high pressure pump which creates a stream of ink which comes from a reservoir via a gun body and a nozzle only visible using a microscope. The crystals make an acoustic wave which vibrates inside the gun body and the stream of ink breaks up into thousands of droplets - 64,000 to 165,000 drops per second. While forming they are charged by an electrostatic field which varies. The droplets that have been charged are separated by droplets that have not and the charged droplets print or are collected for using again. Most of the ink is recycled because it only takes a very small portion of a droplet to print.
Continuous ink printers are used for placing barcodes on item which can be read by scanners for information about the product as well as the price. These types of printers were first commercially used in 1951, when they were used for medical strip recording.