There are a few possible reasons why your scanner is not detecting documents when placed on the scanning tray.
1. The scanner is not correctly connected to the computer. Make sure that the USB cord is securely plugged into both the scanner and the computer, and that the computer is turned on. Sometimes it helps to unplug the scanner and then plug it back in or switch ports.
2. The scanning software may not be installed correctly or updated. If the software is out of date, you may need to download the latest version and install it properly.
3. There may be dust or smudges on the scanning bed which can cause problems with the sensor. Check the bed and make sure it’s clean and free of any dirt or debris.
4. The scanning settings may not be configured properly. Make sure the correct settings are selected for the paper size and type being scanned, as well as the color mode, dpi, etc.
5. The document may be too thick. Try using thinner paper or removing staples from the document before scanning.
If all else fails, try restarting the scanner, computer, or both. If none of these options solves the problem, contact the manufacturer for advice.