printed pages are splotchy like there's a need for ink

My printer is printing very splotchy copies as if it needed ink. I changed the ink cartridges, and this problem persist. I performed the "clean heads" function, and didn't correct the problem. This is such a nice printer, and I hate to toss it. Please help if possible. Also, my printer was subjected to dust during a home renovation. I covered it and my computer as well as I could, but it did get dusty.