Output devices (Inkjet Printer)

 

Inkjet printers are non-impact printers which print text and images by spraying tiny droplets of liquid ink onto paper.  They are the most popular printers for home use.

Currently, most inkjet printers use either thermal inkjet or piezoelectric inkjet technology.  Thermal inkjet printer uses heating element to heat liquid ink to form vapor bubble, which forces the ink droplets onto the paper through the nozzle.  Most inkjet manufacturers use this technology in consumer inkjet printers.

Piezoelectric inkjet technology is used on all Epson printers and industrial inkjet printers.  Instead of using heating element, these printers use a piezoelectric crystal in each nozzle.  The piezoelectric crystal changes shape and size based on the electric current received, and forces tiny droplets of ink onto the paper from the nozzle.

Thermal inkjet printers use aqueous ink which is a mixture of water, glycol and dyes. These inks are inexpensive but they can only be used on paper or specially coated materials.  Piezoelectric inkjet printers allow the use of a wider range of inks, such as solvent inks, UV-curable inks, dye sublimation inks, and can print text and graphics on different uncoated materials.

The inkjet head design is also divided into two main groups: fixed-head and disposable head.  Fixed-head is built into the printer and should last for the whole life of the printer.  It produces more accurate output than cheap disposable head.  The ink cartridges for fixed head printers are also cheaper as the print head does not need to be replaced.  However, if the head is damaged, the entire printer has to be replaced. 

Disposable head is included in replacement ink cartridge.  It is replaced each time an ink cartridge runs out of ink.  This increases the cost of ink cartridges and also limits the use of high quality print head in these cartridges.  However, a damaged print head is not a problem as one can easily replace it with a new ink cartridge.

Some printer manufacturers use disposable ink and disposable print head separately.  The print head can last much longer than cheap disposable head and is suitable for high volume printing.  However, it can also be replaced easily if the head is clogged or damaged.

Although inkjet printers are generally used in home and small businesses, some manufacturers, such as Hewlett Packard, have produced high end inkjet printers for industrial use.  These professional inkjet printers are usually used to print advertising graphics or technical drawings.

ADVANTAGES	DISADVANTAGES
Low cost	Print head is less durable, prone to clogging and damage
High quality of output, capable of printing fine and smooth details	Expensive replacement ink cartridges
Capable of printing in vivid color, good for printing pictures	Not good for high volume printing
Easy to use	Printing speed is not as fast as laser printers
Reasonably fast	Ink bleeding, ink carried sideways causing blurred effects on some papers
Quieter than dot matrix printer	Aqueous ink is sensitive to water, even a small drop of water can cause blurring
No warm up time	Cannot use highlighter marker on inkjet printouts