A printer puts digital text or images onto paper. A scanner does the opposite: it turns a paper document into a digital file. A photocopier makes paper copies of a paper original without needing a computer, though most modern copiers also have scanning and printing functions. A fax machine sends a scanned image through a phone line to another fax machine, which then prints it. A multifunction device (or all-in-one) combines printing, scanning, copying, and sometimes faxing in one machine. For example: 'I scanned the contract with the office scanner and then printed a copy for each team member.' vs. 'She sent the signed form by fax machine because the client did not have email.' The printer is the most common of these in homes; the others are more typical in offices.
The word 'printer' comes from 'print' (to press words or images onto a surface) plus the suffix '-er' meaning 'a person or thing that does something.' The verb 'print' entered English through Old French 'preinte,' which came from Latin 'premere' (to press). In the 1500s a printer was always a person who pressed inked type onto paper by hand. By the late 1900s, when computer-connected machines took over most of this work, the same word was naturally used for the device as well.