Ink Jet Computer Printers

Ink jet computer printers

Well, I'm going to talk about ink jet computer printers, that I believe everybody knows, because we use them almost every day. I will present you what types of ink jet printers we know and how works each of them.

After my presentation or at home you should do the exercises, I (mr. somebody) gave you.

We know different types of ink jet printers like thermal ink jets, piezoelectric ink jets and continuous ink jets. Each of them works in a different way. Most of ink jet printers that we have at home or at work are thermal ink jets.

Thermal ink jets works by having a print cartridge with a series of tiny electrically-heated chambers constructed by photolithography. Photolithography is a process used in semiconductor device fabrication to transfer a pattern from a photomask to the surface of a substrate. To produce an image, the printer runs a pulse of current through the heating elements. A steam explosion in the chamber forms a bubble, which propels a droplet of ink onto the paper. Canon's trade name for this kind of inkjets is Bubblejet. The ink's surface tension pulls another charge of ink into the chamber through a narrow channel attached to an ink reservoir.

The ink used is usually water-based, pigment-based or dye-based but the print head is produced usually at less cost than other ink jet technologies.

Second type of ink jet printers are piezoelectric ink jets, which uses a piezoelectric crystal in each nozzle instead of a heating element. Piezoelectricity is the ability of crystals to generate a voltage in response to applied mechanical stress. When current is applied, the crystal changes shape or size, forcing a droplet of ink from the nozzle. Piezoelectric ink jet allows a wider variety of inks than thermal or continuous ink jet but is more expensive.

The oldest ink jet printers were and are continuous ink jets. In continuous ink jet technology, a high-pressure pump directs liquid ink from a reservoir through a microscopic nozzle, creating a continuous stream of ink droplets. A piezoelectric crystal causes the stream of liquid to break into droplets at regular intervals. The ink droplets are subjected to an electrostatic field created by a charging electrode as they form. The field is varied according to the degree of drop deflection desired. This results in a controlled, variable electrostatic charge on each droplet. Charged droplets are separated by one or more uncharged "guard droplets" to minimize electrostatic repulsion between neighboring droplets.

The charged droplets are then