41154001TH Rev.2 24 /2.3.2 Electrophotographic ProcessThe electrophotographic processing is outlined below. The electrophotographic printing processis shown in Figure 2-4.1 ChargingThe surface of the image drum is charged uniformly with a negative charge by applying thenegative voltage to the charge roller.2 ExposureLight 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.3 Developing and toner recoveryWhen the negatively charged toner is brought into contact with the image drum, it is attractedto 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 rollerby static electricity.4 TransferWhen paper is placed over the image drum surface, the positive charge which is opposite inpolarity to that of the toner, is applied to the reverse side of the paper by the transfer roller.The toner is attracted by the positive charge and is transferred onto the paper. This resultsin the transfer of the toner image formed on the image drum onto the paper.5 Temporary cleaningResidual toner which remains on the image drum without being transferred is evened out bythe cleaning roller and is temporarily attracted to the cleaning roller by static electricity.6 FusingThe toner image transferred onto the paper is fused to the paper by heat and pressure.An electrophotographic process timing chart is shown in Figure 2-5.
