Canon MX700 printer shows error code 5100

The Canon MX700 5100 error indicates that there is something that might be causing obstruction between the rollers. Check for small paper shreds that might get stuck. If there are no obstruction, then this error can be caused of the white sliding thing where the printhead rests when the printer is not in use; it needs to be lubricated. Try to lubricate also the sliders with some grease so that the mechanism can now slide freely. You need to open the right panel of the printer by unscrewing the 2 screws to take it out.