Electrostatic Latent Image Formation Block; Developing Block - Canon MF8100 Series Service Manual

5) ITB cleaning block
Cleans residual toner on the photosensitive drum and ITB.
Step 9: Auxiliary ITB cleaning roller charging - Residual toner on the ITB is charged in order to be held on the ITB.
Step 10: ITB cleaning roller charging - Residual toner on the ITB is charged.
Step 11: ITB cleaning - Residual toner on the ITB is transferred onto the drum.
Step 12: Drum cleaning - Residual toner adhered to the drum is cleaned.

2.3.1.3 Electrostatic Latent Image Formation Block

This block comprises three steps, which forms an electrostatic latent image on the photosensitive drum.
After the completion of the last step in this block, negative charges remain in areas on the drum surface exposed to laser beams. Negative charges are removed from
areas exposed to the laser beams.
An image with negative charges on the drum is called an "electrostatic latent image" since it is invisible to the eye.
Step 1: Primary charging
A uniform negative potential is applied to the drum surface in preparation for latent image formation, in this step.
The primary charging roller is made with conductive rubber. A DC bias is applied to the primary charging roller to keep the potential on the drum surface uniformly.
Step 2: Laser beam exposure
An electrostatic latent image is formed on the photosensitive drum in this step.
When the laser beams scan a negatively charged drum surface, it causes the charges in areas struck by the laser beams to be neutralized. An electrostatic latent
image is formed in areas on the drum where the negative charges are eliminated.

2.3.1.4 Developing Block

This block is comprised of two steps (see Step 3 and Step 4). In this block, the image becomes visible by utilizing a developing method called contact development
method, where the toner is transferred onto the electrostatic latent image on the drum surface. In this method, developing cylinder adheres closely to the photosen-
sitive drum to push up the toner.
Toner (development agent) used in this printer is non-magnetic single-component toner, composed of resins, etc.
0
-100
Exposed
areas
-500
Primary Laser beam
charging exposure
(step 1) (step 2)
F-2-14
Photosensitive
drum
AC bias
DC bias
F-2-15
Laser beam
Unexposed
areas
F-2-16
Time (t)
Unexposed
areas
Primary Primary
transfer charging
(step 5) (step 1)
Primary charging roller
Exposed
areas
Chapter 2
0007-4978
0007-4979
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