HP LaserJet P2050 Service Manual - Page 102

Image-formation system Laser printing requires the interaction of several different technologies, including electronics, optics, and electrophotographics, to provide a printed page. Each process functions independently and must be coordinated with the other product processes. Image formation consists of the following five processes: ● electrostatic latent-image formation ● developing ● transfer ● fusing ● drum cleaning The five processes contain seven steps. Figure 5-8 Image-formation system Media path Direction of the drum rotation Block Step Latent image formation 2. Laser-beam exposure 1. Primary charging Drum cleaning 7. Drum cleaning Developing 3. Developing Delivery 6. Fusing Fusing 5. Separation 4. Transfer Transfer Pickup Step 1: Primary charging DC and AC biases are applied to the primary charging roller, which transfers a uniform negative potential to the photosensitive drum. Figure 5-9 Primary charging Primary charging roller Photosensitive drum Primary charging bias 90 Chapter 5 Theory of operation ENWW