Gp 3.1 Print Process Overview - Xerox DocuPrint N2125 Service Manual

GP 3.1 Print Process Overview

Print Process Overview (Figure 1) (Figure 2)
There are seven steps in the N2125 print process. This seven step cycle is repeated for each
sheet of paper that is sent through the printer.
The seven steps in the print process are:
1. Charge
A bias charge roll places a uniform negative electric charge on the drum surface.
2. Exposure
The laser scanner scans the drum surface with a very thin beam of laser light modulated
according to the signal from the Print Engine Controller to form an invisible electrostatic
latent image on the drum surface.
3. Development
Attracts toner to the electrostatic latent image on the drum surface to form a visible toner
image.
4. Transfer
Transfers the toner image from the drum surface to the paper.
5. Discharge
Partially neutralizes the charge on the paper to allow the paper to peel off the drum sur-
face.
6. Fusing
Permanently fixes the toner image to the paper by heat and pressure.
7. Cleaning
Cleans the drum surface of the remaining toner.
Figure 1 Block Diagram of the Print Cycle
Figure 1 illustrates the N2125 print cycle. It shows the sequence of events for the xerographic
process 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 individual
components 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.
Initial Issue
DocuPrint N2125
Figure 2 Side View Block Diagram of the Print Cycle
Print Process Description
1. Charge (Figure 3)
The Bias Charge Roll (BCR) places a uniform negative electrostatic charge on the drum
surface. The drum surface is made of a photoconductive material that holds the electrical
charge as long as the drum remains in darkness. Light striking the drum discharges the
surface charge.
The BCR is a conductive roll that is positioned slightly above the surface of the drum. The
HVPS PWB supplies the BCR with two voltages; a negative DC charge voltage and an AC
discharge voltage The negative DC voltage creates a uniform negative charge across the
surface of the drum. The AC voltage removes any residual DC charge that was left from
the previous print cycle.
02/2000
6-25
General Procedures / Information
GP 3.1