h2. What is a printer? A printer is an output device that produces text and graphics on paper.
h2. Major types of printer Printers can be divided into two main groups, impact printer and *non-impact printer*. Impact printer produces text and images when tiny wire pins on print head strike the ink ribbon by physically contacting the paper. Non-impact printer produces text and graphics on paper without actually striking the paper.
Printers can also be categorized based on the print method or print technology. The most popular ones are inkjet printer*, *laser printer*, *dot-matrix printer and *thermal printer*. Among these, only dot-matrix printer is impact printer and the others are non-impact printers.
Some printers are named because they are designed for specific functions, such as photo printers*, *portable printers and all-in-one / *multifunction printers*. Photo printers and portable printers usually use inkjet print method whereas multifunction printers may use inkjet or laser print method.
Inkjet printers and laser printers are the most popular printer types for home and business use. Dot matrix printer was popular in 70's and 80's but has been gradually replaced by inkjet printers for home use. However, they are still being used to print multi-part forms and carbon copies for some businesses. The use of thermal printers is limited to ATM, cash registers and point-of-sales terminals. Some label printers and portable printers also use thermal printing.
Due to the popularity of digital camera, laptop and SoHo office (small office / home office), the demand for photo printers, portable printers and multifunction printers has also increased substantially in recent years.
h1. Inkjet Printers 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 of inkjet printers:
1) Low cost
2) High quality of output, capable of printing fine and smooth details
3) Capable of printing in vivid color, good for printing pictures
4) Easy to use
5) Reasonably fast
6) Quieter than dot matrix printer
7) No warm up time
Disadvantages of inkjet printers:
1) Print head is less durable, prone to clogging and damage
2) Expensive replacement ink cartridges
3) Not good for high volume printing
4) Printing speed is not as fast as laser printers
5) Ink bleeding, ink carried sideways causing blurred effects on some papers
6) Aqueous ink is sensitive to water, even a small drop of water can cause blurring
7) Cannot use highlighter marker on inkjet printouts
Many consumer inkjet printers are selling at very low price (under $100) these days. It is the printer manufacturer's marketing strategy to reduce the price of the printers but dramatically mark up the price of replacement cartridges. However, consumers still have the options to buy cheap compatible and remanufactured inkjet cartridges or ink refill kits to cut down printing cost.
h1. Laser Printers Laser printers are non-impact printers which can print text and images in high speed and high quality resolution, ranging from 600 to 1200 dpi.
Unlike inkjet printers, laser printer use toner (black or colored powder) instead of liquid inks. A laser printer consists of these major components: drum cartridge, rotating mirror, toner cartridge and roller. The drum cartridge rotates as the paper is fed through. The mirror deflects laser beam across the surface of the drum. Laser beam creates charge that causes the toner to stick to the drum. As the drum rotates and presses on paper, toner is transferred from the drum to paper, creating images. Rollers then use heat and pressure to fuse toner to paper. Colored laser printers add colored toner in three additional passes.
Advantages of laser printers:
1) High resolution
2) High print speed
3) No smearing
4) Low cost per page (compared to inkjet printers)
5) Printout is not sensitive to water
6) Good for high volume printing
Disadvantages of laser printers:
1) More expensive than inkjet printers
2) Except for high end machines, laser printers are less capable of printing vivid colors and high quality images such as photos.
3) The cost of toner replacement and drum replacement is high
4) Bulkier than inkjet printers
5) Warm up time needed
h2. Dot-matrix printer Dot-matrix printer is an impact printer that produces text and graphics when tiny wire pins on the print head strike the ink ribbon. The print head runs back and forth on the paper like a typewriter. When the ink ribbon presses on the paper, it creates dots that form text and images. Higher number of pins means that the printer prints more dots per character, thus resulting in higher print quality.
Dot-matrix printers were very popular and the most common type of printer for personal computer in 70's to 80's. However, their use was gradually replaced by inkjet printers in 90's. As of today, dot matrix printers are only used in some point-of-sales terminals, or businesses where printing of carbon copy multi-part forms or data logging are needed.
Advantages of dot matrix printer:
1) Can print on multi-part forms or carbon copies
2) Low printing cost per page
3) Can be used on continuous form paper, useful for data logging
4) Reliable, durable
Disadvantages of dot matrix printer:
2) Limited print quality
3) Low printing speed
4) Limited color printing
h2. Thermal printers Thermal printers use two types of printing technologies: direct thermal and thermal transfer printing.
Traditional thermal printers use direct thermal method by pushing electrically heated pins against heat-sensitive paper (thermal paper). The coating on the thermal paper turns black in the areas where it is heated, producing characters or images. Direct thermal printers have no ink, toner or ribbon. These printers are durable, easy to use and cost less to print than other printers. However, the thermal paper is sensitive to heat, light, water, and abrasion and the text and images may fade over time.
In thermal transfer printing, a thermal print head applies heat to a heat-sensitive ribbon, which melts ink onto paper and a wide range of materials to form text and images. The printouts can be extremely durable and can be stored over long period of time.
Thermal printers are often used in cash registers, ATM and point-of-sales terminals. Direct thermal printing was used in some older fax machines before the 21^st^ century. However, these old models are now replaced by new machines which use laser and inkjet printing. Thermal printing is still considered as the best technology for bar code printing because it produces accurate, high quality images with exact bar widths. Some portable printers and most label printers still use thermal printing method.
Thermal printer is not the same as thermal inkjet printer. The latter uses inkjet print technology by heating liquid ink to form vapor bubble, which forces the ink droplet onto the paper from the nozzle.
h1. Specialty Printers h2. Photo printer Photo printers are color printers that produce photo lab quality pictures on photo paper. They can also be used to print documents. These printers have a very high number of nozzles and can print very fine droplets for improved image quality.
Some photo printers also have media card readers. They can print 4" x 6" photos directly from the media card of digital cameras without a computer in between.
Theoretically, most inkjet printers and high end laser printers are capable of printing high quality pictures. Sometimes, these printers are marketed as "photo printers". However, a dedicated photo printer is designed to print photos effectively and economically. Apart from a higher number of nozzles and very fine droplets, these printers also use additional cartridges, such as photo cyan, light magenta and light black. These additional color cartridges allow the printing of more vivid and realistic photos and the result is better than ordinary inkjet and laser printers.
h2. Portable printer Portable printers are small, lightweight inkjet or thermal printers that allow computer users to print from laptop computers when traveling. They are easy to carry, convenient to use but generally more expensive than normal inkjet printers due to the compact design. Their printing speed is also lower than normal printers. Some portable printers are designed to print photos immediately from digital cameras and are known as portable photo printers.
h2. MultiFunction / All-in-One Printers Multifunction printer (MFP) is also known as all-in-one printer or multifunction device (MFD). It is a machine that includes several functionalities including printer, scanner, copier and fax.
Multifunction printer is very popular in SoHo (small office / home office) offices. It can use either inkjet or laser print method. Some multifunction printers also have media card readers, allowing printing of pictures directly from digital cameras without using a computer.
Advantages of multifunction printers:
1) Low cost - it is often cheaper to buy a multifunction printer than individual components (fax machine, scanner, printer, copier) separately
2) Take up less room
Disadvantages of multifunction printers:
1) If one component is broken, the entire machine has to be replaced
2) Failure in any component will affect other functions
3) The print quality and speed may be lower than some stand alone components