Not sure about which Windows os's this is for but it's the only driver I could find for Mecer USB scanners. Specifically labeled as Mecer 600USB, it should work on any Mecer usb scanner. (don't flame me if it doesn't as I do not have a unit to test). The inf file mentions 1212U so it's possible it will work on other scanners models as well.
File is self extracting ... just change the default unzip folder if you not happy with the existing one... run SETUP.EXE to start installation.