This is almost certainly a problem with the doctor blade on the black developer unit within the image unit. It can be repaired, and is a known issue with this image unit. Try and get it repaired under warranty, or it can be done if your competetant with a screwdriver and a soft cloth. This samsung printer is just a badged Xerox phaser 6110 try checking for solutions on that model too. Failing all those the only option is to replace the image unit.
Cleaning the drum for the black colour as peter625 suggested will make no difference as this machine uses only 1 drum for all 4 colours and has no seperate drum/developer technology.
Answers & Comments
This is almost certainly a problem with the doctor blade on the black developer unit within the image unit. It can be repaired, and is a known issue with this image unit. Try and get it repaired under warranty, or it can be done if your competetant with a screwdriver and a soft cloth. This samsung printer is just a badged Xerox phaser 6110 try checking for solutions on that model too.
Failing all those the only option is to replace the image unit.
Cleaning the drum for the black colour as peter625 suggested will make no difference as this machine uses only 1 drum for all 4 colours and has no seperate drum/developer technology.
Clean the drum for the black colour.