I recently found that my printers were no longer working with one particular application (glabels).
The error message from CUPS was "/usr/lib/cups/filter/hpcups failed" and a bit of Googling suggested that changing the printer driver selected in CUPS might fix the error.... and it did. I'm using the hpijs driver now instead of the hpcups driver.
However it raises the question of how one decide which of many drivers available for a given printer one should select. For my HP1320 there's quite a lot to choose from:-
HP Laserjet 1320 - CUPS+Gutenprint v5.2.8-pre1 (en) HP Laserjet 1320 Foomatic/Postscript (en) HP Laserjet 1320 Foomatic/pxlmono (recommended) (en) HP Laserjet 1320 hpijs 3.12.12 (en) HP Laserjet 1320 Series hpijs 3.12.12 pcl3, (en) HP Laserjet 1320 Series pcl3, hpcups 3.12.12 (en) HP Laserjet 1320 Series Postscript (recommended) (en) HP Laserjet 1320 Series Postscript (recommended) (en) HP Laserjet 1320 Series Postscript (recommended) (en) HP Laserjet 1320 hpcups 3.12.12 (en)
..., and yes, the Postscript one is repeated three times with no visible differences.
So how is anyone supposed to decide which driver to use, I've not found any useful guidance anywhere.