Having trouble with a USB-connected Brother HL L2321D laser printer (this is not a network printer... has neither LAN nor WiFi support) to my Ubuntu MATE 20.04 PC where by prints are erratically or partly successful. I can never print more than 1 or max 2 pages at a time. The manufacturer provided drivers are installed. The printer works flawlessly when connected to a Windows 10 PC.
Someone on another forum suggested trying Driverless printing, since Debian 10 added support for those. Brother website says that this printer model supports IPP protocol (though no claim of IPP-Everywhere that apprently includes IPP-over-USB support). If IPP-over-USB works, then hopefully the Driverless printing facility should work (assuming the issue to be an imperfect driver).
For the moment, I am struggling to troubleshoot because I'm not quiet sure how CUPS works ? The spool log shows all the c* and d* (control & data) files for all print jobs, each of them reporting "success", even if not a page of print came out. When such failed print jobs are fired, I see the printer "incoming command/data" LED (Ready LED) flash, but the drum/roller don't spin up, nor does a page come out. There is no jam, nothing.