Sorry for the delay in replying to your request.
You may have already resolved your issue by now.
The advice below may help others with the same issue though.
In the case of a damaged (scratched) printhead, the lines always run along the cards longest length (landscape), and are always in exactly the same place.
They are normally White, and usually very thin (just a few pixels wide). You would also see the line on the used dye film too by unwinding some film from the take-up spool (at the front of the printer).
Sometimes in the case of older out-of warranty printers, it is easier / cheaper just to avoid that are of the card using the card design. The image can also be rotated 180 degrees in the driver's Printing Preferences. However, if the card design has a solid colour background, or the White line is in the centre of the card, printhead replacement may be the only option.
Depending on which Rio model you have (Rio, Rio 2, Rio2e, or Rio Pro), different printhead assemblies are available as a field replaceable unit. Part numbers are below;
Magicard Rio - FG/M9005-794
Magicard Rio 2 / Rio 2e - FG/M9006-630E
Magicard Rio Pro - FG/3652-0160
All are available from your local Magicard dealer / reseller.
Prevention is better than cure;
- Replace the sticky cleaning roller in the cleaning cassette as regular as possible.
- Only use good quality blank PVC card stock (no sharp edges, or burrs)
- Clean the printer regularly using the appropriate cleaning kit;
Rio, Rio 2, Rio 2e (Cleaning kit part number: M9005-761)
Rio Pro - (Cleaning kit part number 3633-0053) *
Rio Pro - (Sticky roller kit (5 rollers +metal shaft) - 3633-0054)*
* A sticky cleaning roller is supplied with every new dye film