Cannot print to HP OfficeJet K80

[Anonymous]

Hello all the good CUPS and eventually hplip people here,
I have a big problem using CUPS with my printer, HP OfficeJet K80. Formerly I was using hpoj+lprng which worked without a glitch, now I upgraded to hplip+cups+foomatic but I cannot print at all.
  The problem is that every job sent to the printer sits there ad infinitum and the syslog is receiving the following messages:
Dec 11 07:36:04 tangens hpiod: unable to read MlcReverseReply header: Success io/hpiod/mlc.cpp 230
Dec 11 07:36:06 tangens hpiod: unable to read MlcReverseReply header: Success io/hpiod/mlc.cpp 230
Dec 11 07:36:06 tangens hpiod: invalid MLCInitReply: cmd=0, result=3 , revision=70
Dec 11 07:36:07 tangens OfficeJet_K80?serial=MY236D61VMOH: INFO: open print channel failed; will retry in 30 seconds...
  USB communication with the printer is OK because the hp-toolbox utility can retrieve all the information (serial number, cartridge status...) from it.
  I've also tried to bypass hplip and use the /dev/usb/lp0 directly from cups, but the result is the same: jobs are sitting there forever and the printer doesn't blink its LED even once. Of course there aren't these messages in the syslog.
  Of course I've turned the log verbosity to debug and tried to explore error_log but I think it doesn't contain anything wrong. ps shows all the chain including gs, hpijs and hp: driver, all sleeping and waiting to be able to send the data.
  Any clue would be very appreciated; I really don't want to reinstall the old lprng and hpoj/ptal...
  With regards, Pavel Troller