2.5.2Electrophotographic Process
The electrophotographic processing is outlined below. The electrophotographic printing process is shown in Figure
1 Charging
The surface of the image drum is charged uniformly with a negative charge by applying the negative voltage to the charge roller.
2Exposure
Light emitted from the LED head irradiates the negatively charged surface of the image drum. The surface potential of the irradiated portion of the image drum surface becomes lower, forming the electrostatic latent image associated with the print image.
3Developing 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.
4Transfer
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.
5Temporary cleaning
Residual toner which remains on the image drum without being transferred is evened out by the cleaning roller and is temporarily attracted to the cleaning roller by static electricity.
6Fusing
The toner image transferred onto the paper is fused to the paper by heat and pressure.
An electrophotographic process timing chart is shown in Figure
2 - 13
