A printer is one of the output devices of a computer, used to print computer processing results on relevant media. There are three indicators to measure the quality of a printer: print resolution, print speed, and noise. There are many types of printers, and they can be divided into impact printers and non impact printers based on whether the printing components have a striking action on the paper. According to the structure of printed characters, there are two types of printers: full form character printers and dot matrix character printers. Divide a string printer and a line printer by forming a line of words on paper. According to the technology used, printers can be classified into cylindrical, spherical, inkjet, thermosensitive, laser, electrostatic, magnetic, LED, and other types.