Charging is affected by applying a DC voltage to the charge roller that is in contact with the EP (image) drum surface.
The charge roller is composed of two layers consisting of a conductive layer and a surface protective layer that has elasticity, in order to secure a good contact
with the EP (image) drum. When the DC voltage 1.30 KV KVDC) applied from the Power Supply Unit exceeds a threshold value, charging begins. The applied
voltage is proportional to charge potential with off set of approx. -550V.