Oki 4M - Manual (Page 24)

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2.5 Electro-Photographic Process
(1) Electro-photographic process
The electro-photographic process is outlined below.
1 Charging
The surface of the OPC drum is charged negatively and uniformly by applying the DC
voltage to the CH roller.
2 Exposure
Light emitted from the LED head irradiates the negatively charged surface of the OPC
drum. The surface potential of the irradiated surface attenuates to form the electrostatic
latent image corresponding to the image signal.
3 Development and residual toner recovery
The negatively charged toner is brought into contact with the OPC drum, adhering to the
electrostatic latent image on the OPC drum by static electricity. This adhesion causes
the electrostatic latent image to change to a visible image.
At the same time, the residual toner on the OPC drum is attracted to the developing
rollerby static electricity.
4 Transfer
When paper is placed over the image drum surface, the positive charge which is
opposite in polarity to that of the toner, is applied to the reverse side by the transfer roller.
The toner is attracted by the positive charge and is transferred onto the paper. This
results in the transfer of the toner image formed on the image drum onto the paper.
5 Cleaning
The cleaning roller temporarily attracts the residual toner on the transferred OPC drum
with static electricity, then returns the toner to the OPC drum.
6 Fusing
The transferred unfused toner image is fused to a sheet of paper by applying heat and
pressure to the image.
Figure 2-5 is a flow for the electro-photographic process.