HP LaserJet 5000 Service Manual - Page 109

Image Formation System The image formation system is the main part of the printer, and consists of six stages: 1. Cleaning 2. Conditioning 3. Writing 4. Developing 5. Transferring 6. Fusing When the Formatter Board sends the print signal to the DC Controller Board, it drives the main motor to rotate the photosensitive drum, the developing cylinder, the primary charging roller, and the transfer charging roller. The primary charging roller places a uniform negative charge on the surface of the photosensitive drum. The laser beam modulated by the video signal is illuminated on the photosensitive drum surface to form the latent image on the drum with the laser diode. The latent image formed on the photosensitive drum is changed to a visual image by the toner on the developing cylinder, then transferred to the paper by the transfer charging roller. The residual toner on the photosensitive drum surface is scraped down with the cleaning blade. The potential on the drum is uniformed by the primary charging roller to prepare for a new latent image. The cartridge has a toner sensor that detects the remaining toner level and the presence of the cartridge. If the toner in the cartridge becomes lower than the specified level or if there is no cartridge in the printer, it is reported to the Formatter. 5-18 Functional Information EN