HP LaserJet P2050 Service Manual - Page 103

Step 2: Laser beam exposure The laser beam scans the photosensitive drum to neutralize negative charges on parts of the drum. An electrostatic latent image is formed on the drum where negative charges were neutralized. Laser beam Unexposed area Exposed area Step 3: Developing The developing cylinder comes in contact with the photosensitive drum to deposit toner onto the electrostatic latent image. NOTE: The charges on the exposed area of the drum are shown as positive in Figure 5-10 Developing on page 91. The charges are actually negative, but they are more positive than the charges on the developing cylinder. Figure 5-10 Developing Blade Developing roller Exposed area Unexposed area Unexposed area Exposed area Developing bias Photosensitive drum Toner acquires a negative charge through friction from the developing cylinder and the blade. When the negatively charged toner comes in contact with the drum, the toner adheres to the electrostatic latent image. The image on the drum becomes visible because of the toner. Step 4: Transfer The transfer charging roller, to which a dc positive bias is applied, imparts a positive charge on the print media. When the print media comes in contact with the photosensitive drum, the toner is transferred to the print media. ENWW Image-formation system 91