DesignJet, Large Format Printers & Digital Press

My normally reliable Designjet 510 has suddenly started having printing problems: it will start printing my drawings, no problem, but it will suddenly stop and the printhead just 'hangs' and won't print anymore.  It sometimes starts right at the beginning of a print, sometimes it gets nearly to the end of the drawing before it stops, but it just can't seem to finish the print job.  The printer doesn't show an error message, it still shows that it's printing, but no matter how long I leave it, it won't get to the end of a drawing.   I'm on Microsoft Windows 10 - there was a hiccup when I upgraded Windows, but after reinstalling the printer driver, it seemed to work again no problem.  I'm tearing my hair out (and wasting vast amounts of paper) trying to get anything to print!  Any pointers would be gratefully received.

Thanks.

P.S. I posted this problem before, then thought I had sorted it by tweaking the printer settings, but it has started again and I'm not closer to finding out why!!!!