We recommend that you manually clean your Fargo printer every time you change your ribbon. Keeping your rollers clean will help prevent card jamming issues.
We recommend using Fargo 82133 cleaning cards
Insert an 82133 cleaning card onto the exit roller
Use the pause button (right button) to feed the card into the printer. Once it is inside the printer continue to advance the rollers while holding onto the cleaning card.
Example of a used cleaning card:
I have a DTC 1000 and have about 530 prints on it. I have been getting a black line on the leading edge of the cards lately. Would this be eliminated by using a cleaning card?
The cleaning cycle will probably not resolve this, but it is worth trying. I would also suggest updating the driver and firmware from fargosupport.com, then seeing if the problem occurs on a self test. If not, the software you use to print would be causing this.