All kinds of different scanners are being used in professional and business environments. Any kind of digital reading device is basically called a scanner. It doesn't matter whether it is a photo scanner, a document scanner or a product scanner for reading barcodes. The differences in form factor, application and technical functioning are often pretty big, so different types of scanners often have not much in common.
Basically there are two main device groups that should be distinguished. Devices for reading documents, photos and slides and barcode scanners.
The former illuminates the document that is to be scanned with a light source and reads the reflecting light (or, in case of slides, the light shining through) pixel by pixel and row by row with an optical sensor and converts it into digital data. Often these devices are shaped as flat bed scanners. The document that is to be scanned lies on a glass surface while it is digitally swept by a moving sensor element. However, indent scanners are also very common. Here the document is inducted by the scanner and goes past a fixed sensor element. Slide scanners can read single slides or, depending on the device, digitalize complete stacks of slides with a large amount of pictures at once.
Product scanners work by a deviating function principle. They are made for scanning an recognizing barcodes, therefore they are made especially for reading the black and white contrasts of a typical barcode. They are designed as mobile handscanners or as stationary scanner that illuminates the barcodes usually with a laser light. The reflection is used for identifying the barcode. While document scanners are optimized for high resolutions and vast amounts of data, product scanners are made for reading barcodes from a greater distance quickly and reliably. They are designed for optimal results, also under difficult lighting conditions. They can also be used by laymen as well, due to their easy handling.