02/20006-72 DocuPrint N2025/N2825GP 5.17Initial IssueGeneral Procedures / InformationGP 5.17 XerographicsInterlock Switch –When the Top Cover is open, the Interlock Switch is turned off, and thereby the power to theFuser Assembly is cut off. When the Top Cover is closed, the actuator of it presses down theInterlock Switch and then the power for the Fuser Assembly is recovered.Sensor Assembly Print Cartridge –Houses the Print Cartridge Sensor and the LD Switch. These switches are actuated by amolded tab on the Print Cartridge through an actuator inside the Print Cartridge SensorAssembly.Print Cartridge Sensor: The signal from this switch is used to stop the printer operation whenthe Print Cartridge is removed.LD Switch: Connected in series with the Laser Diode. This switch opens the 5 VDC circuit tothe Laser Diode when the Print Cartridge is removed. It functions as a safety switch to preventthe user or a service person from being exposed to the laser light.Print Cartridge –The Print Cartridge (Elector Photographic) (also called the Print Cartridge, for CustomerReplaceable Unit) consists of five major components.Drum: An aluminum cylinder with a coating of photoconductive material on the surface. Thephotoconductive coating (layer) holds an electrical charge placed on the surface while in dark-ness, and allows the charge to flow through the thickness when exposed to light.BCR (Bias Charge Roll): Places a uniform electrical charge on the drum surface, erasing anypatterns of decreased charge remaining from the previous cycle.Magnet Roll: Holds toner on its surface in a thin layer and transports it to the gap between thedrum and the Magnet Roll. Toner is supplied to the Magnet Roll by the two Agitators inside theToner Compartment.CM Blade (Charging and Metering Blade): Spreads toner on the Magnet Roll in a thin layer,and also gives toner a negative charge.Cleaning Blade: Scrapes the toner remaining after the Transfer step off the drum surface.Laser – Figure 1 & Figure 2The Laser (Raster Output Scanner) scans a laser light beam on the drum surface. The LaserAssembly consists of three major components: the Layer Diode Assembly, the ScannerAssembly, and the SOS PWB.LD Assembly: Generate laser light that is modulated on and off according to the print data sig-nal.Scanner Assembly - Consists of the Polygon Mirror with twelve sides (mirror facets) and theScanner Motor. The Polygon Mirror is secured to the shaft of the Scanner Motor,The Scanner Motor rotates the Polygon Mirror at a specified constant speed. The spinningPolygon Mirror reflects the beam through a lens and a mirror onto the rotating drum surface,scanning the beam from one side of the drum to the other, one scan per mirror facet.The scanning of the laser light beam on the drum surface from one side to the other switchingthe laser light on and off produces a latent image of one line. A two dimensional image is pro-duced by repeating the scanning of the laser light beam as the drum rotates. The resolution inthe scanning direction (right to left) is determined by the speed of the polygon motor and howquickly the laser can be modulated. The resolution in the process direction (top to bottom) isdetermined by the speed of the polygon motor (a faster scan allows the next line scanned tobegin more quickly).Figure 1 Laser
