Oki OKIPAGE 14i Service Manual page 50

2 The toner attracted to the developing roller is scraped off by the doctor blade, forming a thin coat of toner on the developing roller surface.
3 Toner is attracted to the exposed portion (low-potential part) of the image drum at the contact of the image drum and the developing roller, making the
electrostatic latent image visible.
An illustration of activities at the contact point of the image drum surface and the developing roller (arrow marks denote the direction of the electrical field).
Note:
The bias voltage required during the developing process is supplied to the toner supply roller and the developing roller, as shown below. -500 VDC is
supplied to the toner supply roller, -265 VDC to the developing roller.