Datasheet

76 Chapter 1
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Hardware
FIGURE 1.30 The cleaning step of the EP process
Cleaning blade
Used toner
Used toner
hopper
Print drum
The actual amount of toner removed in the cleaning process is quite
small. The cartridge will run out of toner before the used toner recep-
tacle fills up.
Step 2: Conditioning In the conditioning step (Figure 1.31), a special wire (called a primary
corona or charge corona) within the EP toner cartridge (above the photosensitive drum) gets
a high voltage from the HVPS. It uses this high voltage to apply a strong, uniform negative
charge (around –600VDC) to the surface of the photosensitive drum.
FIGURE 1.31 The conditioning step of the EP process
Charge corona wire
EP drum
Step 3: Writing In the writing step of the EP process, the laser is turned on and scans
the drum from side to side, flashing on and off according to the bits of information the
printer controller sends it as it communicates the individual bits of the image. In each
area where the laser touches the photosensitive drum, the drum’s charge is severely
reduced from –600VDC to a slight negative charge (around –100VDC). As the drum
rotates, a pattern of exposed areas is formed, representing the images to be printed.
Figure 1.32 shows this process.
At this point, the controller sends a signal to the pickup roller to feed a piece of paper into
the printer, where it stops at the registration rollers.
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