I'm currently playing with an old HP Designjet 755CM A0 plotter, and having a weird problem where I have no clue where to start researching. I'm using the printer via some noname USB to parallel adapter.
The printer always shows up as "Idle" in cups, even when printing. Now when the printer is printing something, and I start a new print job (which, I assume, should land in some spooler/queue), this happens:
It finishes the first print, then instead of the second print I get an empty A0 page, and (unlike normal jobs) pressing the Cancel button on the printer does not have any effect.
When I wait until the printer seems done and not moving anymore, then start the second job, everything works just fine.
Any ideas what could be going wrong?