Phaser 6300/6350/6360 Color Laser Printer Service Manual 2-3Theory of OperationSummary of the Printing ProcessThe printing process is summarized in the following steps. While reading thesummary, refer to the figures on pages 2-2, 2-5, and 2-6. These diagramsshow process flow and indicate the relative position of the componentsinvolved. The diagrams also include reference numbers that correspond toeach numbered step.1. Charging: The charge roller (RTC) is negatively charged by the HighVoltage Power Supply (HVPS) and is kept in contact with the drumsurface to provide a uniform negative charge on the drum as it rotates at aconstant speed. This occurs simultaneously for YMCK. The refresher is aconductive brush that is also negatively charged by the HVPS to pick offany toner particles left on the drum after image transfer to the IDT.2. Exposure: The Laser Unit uses a system of mirrors and lenses to scanthe drum surface in response to image data from the Image Processor.Where the laser exposes (writes) the drum surface it reduces the negativecharge to form an invisible latent image. This process is preformedsimultaneously for YMCK.3. Development: Toner is electrostatically attached to the invisible latentimage on the drum surface to form the visible image on the drum. Toner isfed into the developer using the agitator in the Toner Cartridge and augersystem in the Toner Cartridge Holder. The toner and the carrier in thedeveloper form a homogeneous layer on the magnet roller in theDeveloper Assembly. The magnet roller turns against the surface of thedrum and is kept at a constant negative potential. At areas on the drumsurface where the negative charge has not been reduced by the impact oflaser light, potential between the drum and the toner particles is lowerthan that between the magnet roller and the toner particles. At areaswhere the drum charge has been reduced, the potential between theparticles and drum is higher than between the magnet roller and tonerparticles are attracted to the drum. A thin semiconducting sleeve on themagnet roller is vibrated by an AC voltage to encourage migration of thetoner particles to the drum. When the toner particles attach to the drum,the negative charge of the particles reduces drum potential at that point,thus reducing the attraction of additional toner particles. This processoccurs simultaneously for YMCK.The electrostatic characteristics of the carrier deteriorate due to surfacecontamination by toner or scratches during agitation. In order to maintainelectrostatic characteristics, a slight amount of carrier is mixed with thetoner in the toner cartridge.The deteriorated carrier is collected in theImaging Unit.
