We originally set out to do this because we were having problems getting an older model laser printer, specifically a Konica Minolta PP1350W, to work with MacOS High Sierra (10.13). With previous versions of MacOS we’d been able to connect the printer directly to the computer, and with some fiddling with drivers and other software, get it to work. But newer versions of MacOS seem to be far less tolerant of this, and we had a spare Raspberry Pi, so the idea came to us to use the Raspberry Pi as a bridge between the printer and any computers on the local network from which we wanted to be able to print. The bonus is that the printer is no longer tethered to a single machine, but instead can potentially be used by any computer on the local network.
You do not need to have a Raspberry Pi to make this work – any computer that can run Linux will do. And of course the Raspberry Pi or other Linux computer can be used for other purposes besides this. We do not guarantee that this technique will work for every older printer out there, but this will work with a surprising number of them.
Source: Convert an older model USB printer to a networked printer using a Raspberry Pi or other Linux-based computer — also works well for making an older printer compatible with a newer version of MacOS – Two “Sort Of” Tech Guys