There's no particular reason to make it a rental. They can still put whatever contractual restraints they want on a sale, they just have to enforce those under

There's no particular reason to make it a rental. They can still put whatever contractual restraints they want on a sale, they just have to enforce those under contract law, not via patent law. The entire reasoning for bringing a patent lawsuit is that it allows them to sue the refillers/resellers, instead of having to sue millions of individual customers who might have violated a shrink-wrap contract with Lexmark. Going into a cartridge rental business, besides adding a ton of overhead, wouldn't really change that -- they'd still need to go after the renters one at a time.