Fundamentally speaking, the real difference between A3 scanners and A4 scanners is that the former are primarily designed for large businesses whereas the A4 types are used for personal as well as small businesses. In general, sheet fed scanners are more expensive than normal flatbed ones. This is because automated sheet fed models are time savers in the sense that one can scan a large pile of documents without much effort and in a short period of time without interruptions. Flatbed scanners, however, require the user to scan each and every individual page.

For large businesses that have to scan huge volumes of printed or hand written data, an automated A3 scanner is the best device possible. These gadgets normally have high optical resolution of about 1200 dpi and coupled with a Xenon lamp apparatus can deliver high quality results in a short period of time. The automated sheet feeder component normally has a capacity of 100 sheets or greater and one just has to place the sheaf of documents inside the feeder. Such devices can also be setup in a way that they automatically convert the softcopies into PDF format and can also be programmed to store files in a particular folder. Hence, the normal A3 scanner is primarily designed to satisfy the requirements of large businesses. The basic idea behind their functionality is the inclination towards as much automation as possible.

On the other hand, an A4 flatbed scanner is preferred for home use as well as small or personal businesses. Some individuals generally require scanning devices to have backups of their entire document and picture portfolios. For such people, the flatbed A4 scanner type is perfect because it is affordable and provides practical functionality. Such devices are also available in much smaller and portable forms. Similarly, small businesses require devices such as the Epson GT 1500 which provides a speed of 18 ppm in black and 14 ppm in color. This particular type is extremely efficient in terms of energy and requires significantly lesser power than other standard models.

Primarily, A4 scanners normally employ an LED device as the internal apparatus. However, recent devices with advanced capabilities and better quality come equipped with the cold cathode lamp for illumination. These types of scanners are also lightweight, portable and easy to use. The only difference between an A4 scanner being used for a small business and personal use is that the former would probably be equipped with an automated sheet feeder to speed up the process of operation.