Does anyone know what is wrong with my printer?

I bought a samsung CLP415 refurb off ebay a few months ago. I've been printing shipping labels and documents with no problem, or that I've noticed at least.

 

I started printing out images now, and the right side has magenta all over it. It tends to mainly happen during shadows and greys. I took out the magenta cartridge, and I cant see anything wrong with it from the outside. I think, and hope, the magenta cartridge is the only problem, but I don't want to buy a new cartridge, and then have it turn out that it was something else causing the issue.

 

Here is a few pics to show what is happening

probably just out of ink, if magenta is printing that would mean it's the other colour(s) that are low, I bet if you print a couple more pages and it will likely become more obvious

I have like 80% toner on all my cartridges. If I print out a bunch of copies, some have more magenta than others.