Oki OKIPAGE 10e Service Manual page 38

The charge roller is composed of two layers, a conductive layer and a surface protective layer, both having elasticity to
secure good contact with the image drum. When the DC voltage applied by the power supply exceeds the threshold
value, charging begins. The applied voltage is proportional to the charge potential, with offset of approximately -550V.
(3) Exposure
Light emitted by the LED head irradiates the image drum surface with a negative charge. The surface potential of the
irradiated portion of the image drum drops, forming an electrostatic latent image associated with the image signal.