The primary charge roller is a cylinder composed of a metal core and conductive rubber. Its main function is to bring a uniform charge to the drum core to absorb toner, and to eliminate the residual potential on the drum core.

The primary charge roller is a new environmentally friendly charging method that reduces the generation of ozone, charges evenly, and is noise-free. It is widely used in laser printers and is also used in low-speed copiers. The voltage of the laser printer charging roller is -600V to -700V, and there are also positive charging ones. Charging electrode wires can charge at a higher level, generally between 6000V and 8000V.