Here are some useful links for downloading the latest drivers and software for you machines:
Official HP® Drivers and Software Download | HP® Customer Support
Konica Minolta Support & Downloads. Konica Minolta
Product Support and Drivers – Xerox
Support and Downloads (ricoh-usa.com)
Brother Drivers: Info & Downloads – Printer Drivers & More | Brother (brother-usa.com)
Canon U.S.A., Inc. | Drivers & Downloads
Drivers | Manuals | Software Downloads | Sharp for business (sharpusa.com)