The scanner is designed to be used disconnected from the computer until it is time to upload the images stored in memory. That could be either the internal memory, either a SD card or a USB flash drive (Anywhere model). With these last two when you leave those plugged into the scanner and connect the scanner to the computer you will see two devices connected, one for the scanner and the other for the USB Flash/SD card (must be formatted in FAT32).
Think of this scanner as a USB storage device that can scan. It is not a TWAIN based scanner so you cannot use any program to access it. When you scan it stores the images in memory until you connect it to the computer where is shows up as another drive letter in My Computer (Windows) or on the desktop (Mac)