CHAPTER 3 THEORY OF OPERATION
Confidential
3-30
3. The laser beams reflected by the reflection mirror go straight toward the exposure drum
below it, then expose the exposure drum.
The area exposed to the laser beam is the image to be printed. The surface potential of the
exposed area is reduced, forming the electrostatic image to be printed.
Fig. 3-35
2.5.3 Developing
Developing causes the toner to be attracted to the electrostatic image on the drum so as to
transform it into a visible image.
The developer consists of a non-magnetic toner. The developer roller is made of conductive
rubber and the supply roller (which is also made of conductive sponge) rotate against each
other. The toner is charged and carried from the supply roller to the developer roller. The
toner adheres to the developer roller and is conveyed to the exposure drum at an even
thickness controlled by the blade. The toner is nipped between the developer roller and the
drum and developed onto the latent image on the drum. The electrostatic field between the
drum and the developer roller, which is DC-biased from the high-voltage power supply, creates
the electrostatic potential to attract toner particles from the developer roller to the latent image
area on the drum surface.
Fig. 3-36
3
Primary charging
Laser beam exposure and developing
(a) Unexposed area
(Non image area)
(b) Exposed area
(Image area)
Transfer the image to paper
Drum
sleeve
0
2
1
1
2
3
(a)
(b)
+150
+400
+897
Surface
potential (V)
1 Cycle of drum
Supply roller
Blade
Developer roller
Exposure drum
Corona wire
Transfer roller
Time
