Dot-matrix printers use a set of pins on a print head to create an image on a page. The print head moves back and forth across the page while the pins strike the paper in different combinations, through an inked ribbon. The quality of the image improves with a greater number of pins. Earlier dot-matrix printers had nine pins resulting in a vertical resolution of only nine dots. Newer models have 24 pins resulting in a greater overlap of dots and less white space, or higher resolution.
Laser printers use a separate small computer, as well as a laser and toner, to produce an image.
The printer's computer interprets the data from the microcomputer, and controls the laser. The laser charges a drum which then picks up particles of ink having an opposite electronic charge, called toner . The toner is transferred from the drum to paper using heat and pressure, much like a photocopier. Unlike dot- matrix printers, laser printers are quiet and produce higher quality output. Resolution on a laser printer is measured in dots per inch or DPI .