Datasheet

Installation and Configuration of Printers 79
FIGURE 1.35 The fusing step of the EP process
Fusing roller
Pressure roller
Putting It All Together Figure 1.36 summarizes all the EP process printing steps. First,
the printer uses a rubber scraper to clean the photosensitive drum. Then the printer places
a uniform, negative, –600VDC charge on the photosensitive drum by means of a charge
corona. The laser paints an image onto the photosensitive drum, discharging the image
areas to a much lower voltage (–100VDC). The developing roller in the toner cartridge has
charged (–600VDC) toner stuck to it. As it rolls the toner toward the photosensitive drum,
the toner is attracted to (and sticks to) the areas of the photosensitive drum that the laser has
discharged. The image is then transferred from the drum to the paper at its line of contact by
means of the corona wire (or corona roller) with a +600VDC charge. The static-eliminator
strip removes the high, positive charge from the paper, and the paper, now holding the image,
moves on. The paper then enters the fuser, where the fuser roller and the pressure roller make
the image permanent. The paper exits the printer, and the printer starts printing the next
page or returns to its ready state.
FIGURE 1.36 The EP print process
Laser
Mirror
Charge corona
Toner cartridge
Toner
Developer roller
Transfer
corona wire
Static-
eliminator strip
Fuser unit
Paper
EP drum
Waste toner
receptacle
Fusing roller
Pressure roller
LED Printers
An LED printer uses a light-emitting diode instead of a laser. The LED isn’t built into the
toner cartridge; it’s separate, so that when you replace the toner cartridge, all you get is
new toner.
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