Hi, thank you for contacting JustAnswer.com. My name is Russell. I feel that your question deserves an answer, though you have evidently found a solution for yourself.
If the streaks are black, and go away for awhile with cleaning, then come back gradually, you probably have a leaking black toner cartridge.
But as I said, you have evidently found the solution. Thank you for bringing your question to us here at JustAnswer.com - you will be welcome to return another time to ask another question, in any category.