02/20006-25DocuPrint N2125 GP 3.1General Procedures / InformationInitial IssueGP 3.1 Print Process OverviewPrint Process Overview (Figure 1) (Figure 2)There are seven steps in the N2125 print process. This seven step cycle is repeated for eachsheet of paper that is sent through the printer.The seven steps in the print process are:1. ChargeA bias charge roll places a uniform negative electric charge on the drum surface.2. ExposureThe laser scanner scans the drum surface with a very thin beam of laser light modulatedaccording to the signal from the Print Engine Controller to form an invisible electrostaticlatent image on the drum surface.3. DevelopmentAttracts toner to the electrostatic latent image on the drum surface to form a visible tonerimage.4. TransferTransfers the toner image from the drum surface to the paper.5. DischargePartially neutralizes the charge on the paper to allow the paper to peel off the drum sur-face.6. FusingPermanently fixes the toner image to the paper by heat and pressure.7. CleaningCleans the drum surface of the remaining toner.Figure 1 Block Diagram of the Print CycleFigure 1 illustrates the N2125 print cycle. It shows the sequence of events for the xerographicprocess and the paper flow into and out of the printer.Figure 2 is both a cut-away side view of the N2125 printer that shows the location of individualcomponents within the printer, and a side view block diagram that shows the major compo-nents that are directly related to the print cycle and to the paper path.The pages following Figure 2 describe in detail each step of the print cycle.Figure 2 Side View Block Diagram of the Print CyclePrint Process Description1. Charge (Figure 3)The Bias Charge Roll (BCR) places a uniform negative electrostatic charge on the drumsurface. The drum surface is made of a photoconductive material that holds the electricalcharge as long as the drum remains in darkness. Light striking the drum discharges thesurface charge.The BCR is a conductive roll that is positioned slightly above the surface of the drum. TheHVPS PWB supplies the BCR with two voltages; a negative DC charge voltage and an ACdischarge voltage The negative DC voltage creates a uniform negative charge across thesurface of the drum. The AC voltage removes any residual DC charge that was left fromthe previous print cycle.
