02/20006-68 DocuPrint N2025/N2825GP 5.14Initial IssueGeneral Procedures / InformationGP 5.14 Paper Transport AssemblyBTR Assembly – Figure 1The Bias Transfer Roll of the BTR Assembly is in contact with the drum in the Print Cartridge.The BTR is driven by the Drum Gear so that the BTR surface moves at the same speed as theDrum surface.The BTR applies a positive charge to the back side of the paper when the paper travelsbetween the BTR and the drum. The negatively charged toner image transfers from the drumsurface to the front side of the paper because it is attracted by the positive charge on the backside of the paper.Paper Transport Assembly (Includes the following components) –Metal Registration Roll and Rubber Registration Roll: The rotation of these Rolls is controlledby means of the Registration Clutch so as to register the paper with the image on the drum.Registration Sensor: Detects the arrival and departure of the paper at and from the registrationposition.BTR Bearing: Applies the toner image transferring voltage supplied from the HVPS to the BTRAssembly.Detack Saw: Imparts a negative charge to the back side of the paper to partially neutralize thepositive charge and let the paper peel off the drum.Zener Diode: Flows the electrostatic charge on the rolls and the paper guiding surfaces aroundthe BTR to the Frame Assembly, maintaining them at a constant voltage with respect to theFrame Assembly. By thus grounding through a Zener diode, the disturbance of the toner imageduring the transfer is better prevented.Figure 1 Bias Transfer Roll Assembly
