Group 4 Scanners
Device and History
Scanners owe their existence to the concept of telephotography, a technology based on telegraphs, only instead of simple text, entire images can be transmitted. Belin began working on the technology circa 1905. Modern scanners entered the market in the 1980's, although resolutions (measured in dots per inch, or DPI) remained low until the late 1990's. A scanner is an input device that scans documents such as photographs and pages of text.
Different Types of Scanners
Sheet-fed scanners which can only accept paper documents. While sheet-fed scanners cannot scan books, some models include an automatic document feeder, or ADF, which allows multiple pages to be scanned in sequence. Flatbed devices, which means they have a flat scanning surface. This is ideal for photographs, magazines, and various documents.
- For a flatbed scanner the price range is all the way from $19.99 to $6,500.00.
- For the Sheet-fed scanner the price range is from $34.99 all the way to $ 400.00
Device Parameters Impacting Performance
Scanners for Business Use:
- Flatbed: high resolution settings, that result in large file sizes. Unfortunately, this causes the hard drive to fill up quickly. To avoid this with everyday scanning, reduce the DPI to 200. Can scan full books, magazines, etc.
- Sheet-fed: (home office or business) moves paper across a stationary scan head. Restricted to scanning only paper documents. Has speeds around 40 PPM, 80 IPM, and adjustable DPI
- Pen scanner: Has 8MB of memory and can hold 100 pages of black-and-white text or two full-page color scans. If you need more storage, upgrade with a MicroSD memory card.
Scanners for Home Use or Small Business:
- Multifunction: good investments; include printer, scanner, copier, and fax. Higher DPI’s negatively affect the speed of the PPM (ex. 5760 x 1440 DPI only has 9 PPM, while 4800 x 1200 DPI has 28 PPM)