I have a 4-5 year old HP Color LaserJet 2600N that has been serving me well. Recently, it suddenly began producing prints with 2 vertical blue streaks, along the plane of the paper - one on left, one on right side of the paper. I tried to print a blank page of document, and it still produces the same blue streaks. What does this mean? Is my fuser at fault? Any advice is greatly appreciated. Thanks!