Results of the 3 tests:
1. /usr/lib/cups/backend/hp
direct hp:/usb/photosmart_7550?serial=CN33I4116P7E "HP photosmart 7550" "HP photosmart 7550 USB CN33I4116P7E HPLIP" "MFG:HP;MDL:photosmart 7550;CLS:PRINTER;DES:photosmart 7550;SN:CN33I4116P7E;"
2. Results same as 1.
3. Printing still fails
Results of the 3 tests:
1. /usr/lib/ cups/backend/ hp
direct hp:/usb/ photosmart_ 7550?serial= CN33I4116P7E "HP photosmart 7550" "HP photosmart 7550 USB CN33I4116P7E HPLIP" "MFG:HP; MDL:photosmart 7550;CLS: PRINTER; DES:photosmart 7550;SN: CN33I4116P7E; "
2. Results same as 1.
3. Printing still fails