brother 930 fax machine ?

You're right. A new ribbon won't help. The ribbon is not used when sending faxes.
Only the scanner is used.

I'd say if you get these lines either when making a copy of sending faxes, it means there is some dust/dirt on the glass covering the scanner.
Likely dried correction fluid. LOL!

Some just can't wait for it to dry properly before trying to send the fax.
These little spots accumulate over time and create these lines.

There could be lots of dust under the glass as well.

It is strange however the same pattern of lines show when RECEIVING faxes as well.

faxmando@yahoo.com
December 2008