I have an HP Laserjet Pro 200 M251nw. It's been very good for me until the past week. It's been printing reddish dots on covers lately. I did some research and tried cleaning the drum. I did that and it still keeps sprinkling the red dots on my covers. I just bought the red cartridge in December (for the low, low price of $85!), so I don't want to throw it out. Anybody have any suggestions?