Material buildup on conveyor rollers, primarily on the return rollers which contact the dirty carrying side of the conveyor belt, account for an ever changing tracking problem. As the buildup changes on the rollers, the conveyor belt will also change to follow the buildup which is a false crown. Not only is the buildup a problem, but also the carry back which is deposited under the conveyors and ahs to be constantly shoveled and hosed down, requiring extensive labor cost.
The only answer is a conveyor belt scraper installed to operate on the face of the discharge pulley. There are as many different types and brands of belt scrapers as there are stars in the sky. They included rubber, urethane, ceramic, plastic, stainless steel, tungsten carbide, carbon steel, wood, air, water, etc. They are powered by air bags, car shock absorbers, torque arms, counterweights, hydraulics, air cylinders, and heaven only knows what else. There are many from which to choose.