That would be fine, so long as it's not sold in stores alongside other items for purchase, and is explicitly and prominently communicated to the buyer. There's nothing wrong with renting, so long as everyone knows it's a rental.

Somehow, I think Lexmark might have a problem with this. They want the benefits of the rental model without the drawbacks.

There is nothing wrong with that. For the right price it could even be an net benefit the consumer. If PrintCo rents printers to customers for a fee and takes on the accompanying liability then consumers may have access to higher quality and more durable goods as it reduces PrintCo's maintenance cost.

However, using IP law to gain the rights of ownership without the responsibility is something entirely different.