Paper jam on HP 4050N

[TAD45]

When I power up the printer, it displays,
" Paper Jam"

Any suggestions. Cannot use the printer.
I checked and could not locate any jam. Even took out the Fusing unit from the back to check.

Nothing obvious.
Cleaned the rollers. Could it be the Clutch device?

 

[DrB0b]

I would blow out with compressed air to make sure there isnt a small piece blocking a sensor that you may have missed. When powered on, does it run through the normal movements or is there no mechanical movement and it immediately throws the error?