That looks like a dirty paper roller. I suggest either having it professionaly cleaned or attempt it yourself if you are confortable with it. There is toner sitting somewhere in the printer on the roller and it looks like it is piled up on the edge. If the printer in general is clean, I would suggest taking a can of compressed air to it, but with CAUTION. You do not want to inhale toner. Make sure you are in very open space or maybe outside. WARNING though, if it is a very dirty printer, you might just blow toner everywhere and make everything dirty. That is when you might want to consider professional cleaning.
Also, try not to use cheap remanufactored toner cartridges. They have a much higher chance of leaking toner and can make a big mess.
Also, if you have already gone through and cleaned what you could see, try these laser printer cleaning sheets. They are worth a shot before you attempt anything more expensive. And whatever you buy, make sure it is made to work with a laser printer. They can get very hot and need to be used with the proper cleaning sheets.
Alternatively, you also might want to invest in the toner approved vacuum. These are designed to deal with toner and fine particles. I have personaly used this one at an old job. You do not want to use a standard vacuum. These come with a toner specific bag/filter.