%2.4.2 Electrophotographic Process
2.4.2 Electrophotographic Process
The electrophotographic processing is outlined below. Figure 2-7 shows the electrophotographic printing
process.
1 Charging
The surface of the image drum is given a uniform negative charge by applying the 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 portion becomes lower, forming the electrostatic latent image
associated with the print image.
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, 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 transfers the toner image formed on the image drum onto
the paper.
5 Temporary cleaning
Residual toner, which remains on the image drum without being transferred, is evened out by the
cleaning roller and is attracted to the cleaning roller by static electricity.
6 Fusing
The transferred toner image is fused to the paper by heat and pressure.
Figure 2-8 shows an electrophotographic process timing chart.
OKI OL600/610ex (96-01-18