There are 5 main types of printers:-

Dot Matrix - These usually come in either 9 or 24 pin. Not used a great deal now except for invoicing systems etc. These now tend to be quite expensive. Not very good at graphics due to the low resolution and tend to quite slow. Popularly available in black and tri colour.

Golf Ball - So called because they use a golf ball print head which hold all the available characters. Very rarely seen now as they could only print set characters in a set font. Usually can only print single colour.

Inkjet - These are the most popular printers now because the better ones can print near photo quality photographs and print on all types of media such as cd's and dvd's.They are also for the majority very cheap. These can usually print the full spectrum of colour's.

Thermal - Most fax machines used to use thermal printing technology. These printers require special heat sensitive paper in order to produce a document which is quiet expensive. Tend to be used for specialist applications.

LED/Laser - These printers use toner (Plastic pellets) which are melted onto the paper using a heated roller. Usually quite expensive to buy but much cheaper than inkjet's to run. I.e. Cheaper per page. They are also usually quite fast so this is the type used in most offices. These are available in single colour (black) or full colour. These are similar to photocopiers apart from the image is burned onto a light sensitive drum by laser/LED rather than a light reflected from a document. Due to the low cost and wide availability of colour laser printers these are now the most popular for anything apart from home use.