Transfer Block - Canon LBP5000 Series Service Manual

Developing blade
Toner feed roller
The toner (developer) used by the machine has insulating properties, and is charged to a negative potential as a result of friction against the surface of the developing
cylinder and the developing blade.
The area of the surface of the photosensitive drum exposed by the laser beam has a higher potential than the negatively charged toner on the cylinder. When such
an area moves close to the toner layer on the cylinder (possessing a negative potential), the difference in potential between the surface of the drum and that of the
cylinder (i.e., the drum has a higher potential) causes the toner to jump to the drum surface. This phenomenon is referred to as "toner projection," and is used to turn
the latent (static) image on the surface of the photosensitive drum into a visible image.
To facilitate the movement of toner to the surface of the photosensitive drum, and also to enhance the contrast of the output image, an AC bias is applied to the
developing cylinder.
The machine changes the developing bias according to the image density information signal from the video controller to vary the difference in potential of the sur-
face of the cylinder and that of the photosensitive drum, thus permitting the adjustment of the image density.
The development sheet is used to improve image quality while blocking stray toner.

2.4.1.5 Transfer block

LBP5000 / LBP5100
In this step, the toner image on the surface of the photosensitive drum is moved to print paper.
Step 4: Transfer
A positive charge is applied to the back of the print paper to attract the toner from the surface of the photosensitive drum to the paper. This process is repeated for
M, C, Y, and Bk in sequence, thus forming a toner image consisting of 4 colored layers on the paper.
Step 5: Separation
Developing sheet
Paper
Photosensitive
drum
Photosensitive drum
Developing cylinder
AC bias
DC bias
F-2-13
ETB belt
Transfer roller
DC bias
F-2-14
Chapter 2
0010-6059
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