Dx4450.New ink put in but won't print

Question

Hi , The black ink ran out on my printer .I put a new one in ..followed all instructions ..shake ink etc etc ....it doesn't work ..it.reads as full but won't print . can't work out how to get it working .I thought about trying to replace one of the other colours to check if it is the inks but can't work out how to get it out . Hope someone can help me ? Thanks Mel