The suit alleges HP paid Staples, the largest U.S. specialty retailer of office supplies, more than $100 million in MDF to stop selling lower-priced printer cartridges for HP printers, Reuters said.

Users plunge the device down to reload the toner cartridge, and the process of refilling the Neverstop takes just 15 seconds, HP said. The reload kits come with enough toner to print 2,500 pages ...