Flatbed scanner
A desktop scanner where the document lies still on a glass platen while a sensor bar sweeps beneath it.
Under the glass a carriage carrying a light source and a row of light-sensitive elements — either a mirror-fed CCD or a contact sensor (CIS) pressed close to the glass — reads the image one line at a time. Resolution is given in DPI: more dots per inch means a sharper scan but a bigger file. Unlike sheet-fed and handheld scanners, it makes no difference whether the source is a loose slip, an open book, or a fragile photo.
Consumer models turned cheap in the 1990s and made the paper archive searchable, often paired with OCR that reads the scanned pixels back into text. All-in-one machines later folded the same scanner unit into the printer.