HP LaserJet M9040/M9050 Service Manual - Page 155

Table 5-12 Image formation process (continued) Step process laser discharged areas of the latent image on the photosensitive drum and is repelled from the negatively charged (unexposed) areas. Pre-transfer The pre-transfer upper guide receives bias to prevent toner from adhering to it from the photosensitive drum. Transfer The transfer charging roller applies a positive charge to the paper causing the negatively charged toner image to be attracted to the paper from the photosensitive drum. Separation As the paper is separated from the photosensitive drum, the static charge eliminator reduces the charge on the paper. This stabilizes the feed system and prevents loss of the toner image in temperature and humidity. Fusing The paper with the toner image on it passes between the heated fuser roller and the pressure roller. This melts the toner and presses it into the paper. Drum cleaning After the separation process, the drum is cleaned and conditioned for the next image. The cleaning blade, which is always in contact with the surface of the drum, scrapes off excess toner. The excess toner is stored in the waste toner receptacle. Print cartridge Figure 5-32 Layout of the print cartridge 5 12 4 3 13 12 8 11 10 9 6 7 Table 5-13 Print cartridge components Number Description 1 Primary charging roller 2 Laser beams 3 Blade 4 Developing cylinder 5 Toner reservoirs 6 Cartridge memory ENWW Image formation system 137