Static Latent Image Formation Block; Development Block - Canon L100 Service Manual

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Technical Overview > Image Formation System > Overview/Configuration > Development Block

■ Static Latent Image Formation Block

This block is comprised of two steps and forms static latent images on the photosensitive
drum.
When the final step of this block completes, negative charge remains at dark areas on the
drum surface where laser beam has not been exposed, and negative charge is eliminated
from bright areas on the drum surface with laser beam exposed. The images on the drum
with negative charge are called static latent images because human eyes cannot detect them.
0
Surface
potential
(V)
Primary
charging
(step 1)
Step 1: Primary charging
For preparation of latent image formation, the surface of photosensitive drum is charged
with even negative potential. In this primary charging, the charge is applied from the primary
charging roller directly to the photosensitive drum.
DC bias is applied to the primary charging roller to maintain an even potential on the surface
of the photosensitive drum.
Primary charging roller
Photosensitive drum
2 Technical Overview > Image Formation System > Overview/Configuration > Development Block
Time (t)
Exposed area
Unexposed area
Laser Transfer Primary
beam (step 4) charging
exposure (step 1)
(step 2)
F-2-13
DC bias
F-2-14
Step 2: Laser beam exposure
In this step, static latent images are formed on the photosensitive drum with laser beam.
When laser beams are scanned on the photosensitive drum negatively charged, bright areas
lose their charges, eliminating negative potential on the surface of the photosensitive drum;
on those portions, static latent images are formed.
Unexposed
area

■ Development Block

This block is comprised of one step; it puts toners to the static latent images on the surface of
the photosensitive drum and visualizes the images using toner projection development. The
toner projection development makes the toner jump on the surface of the photosensitive drum
and develops the images.
The toner (developer) used for this equipment is a one-component toner that comprises
magnetic body and resin, etc.
Step 3: Development
Toner is affixed to static latent images on the surface of the photosensitive drum.
The toner is charged negatively by friction between the developing cylinder and the surface of
the developing blade.
An area on the photosensitive drum exposed with laser beam has higher potential than the
developing cylinder; the potential difference between the drum surface and the cylinder
enables the toner to jump on the drum surface and makes them visible images.
AC bias superimposed with the development DC negative bias is applied to the developing
cylinder.
Blade
Developing cylinder
Exposed area
Unexposed
area
Photosensitive drum
Laser beam
Exposed
area
F-2-15
AC bias
Unexposed area
Exposed area
DC bias
F-2-16
2-15
2-15