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Service Guide OKIPAGE 18/18n
Chapter 2 Operation Description
2.3.2 Electro-Photographic process
The electro-photographic processing is outlined below. Figure 2-5 shows the electro-photographic printing process.
1 Charging
The surface of the image drum is uniformly charged with negative charges by applying a negative voltage to the
charge roller.
2 Exposure
Light emitted from the LED head irradiates the negatively charged surface of the image drum. The surface potential
of the irradiated part of the image drum surface is lowered, so that an electrostatic latent image associated with the
print image is formed.
3 Developing and toner recovery
When the negatively charged toner is brought into contact with the image drum, it is attracted to the electrostatic
latent image by static electricity, making the image visible. At the same time, the residual toner on the image drum is
attracted to the developing roller by static electricity.
4 Transfer
When paper is placed over the image drum surface and a positive charge, opposite in polarity to the toner, is applied
to the reverse side of the paper from the transfer roller, the toner is attracted by the positive charge and is
transferred to the paper. As a result, the toner image formed on the image drum is transferred to the paper.
5 Temporary cleaning
Residual toner that remains on the image drum without being transferred is made uniform by the cleaning roller and
is temporarily attracted to the cleaning roller by static electricity.
6 Fusing
The toner image transferred to the paper is fused under heat and pressure. Figure 2-6 shows an
electro-photographic process timing chart.