The three most popular types of machines for copying are a dedicated copier, an all-in-one (also called multifunctional) printer, and a fax machine that is able to copy images. Scanning, on the other hand, usually requires a computer or a memory device in addition to the scanner. A scanner is most effective when partnered with a computer to allow images to be edited, emailed, printed, and saved to disk. A computer is not required if the scanner saves to a memory card or USB device. Some scanners also scan to email or transmit scanned images wirelessly to portable devices. All-in-one printers add the option of scanning documents and then faxing them.