Development Block; Transfer Block - Canon Color imageCLASS MF9170c Service Manual

Chapter 7

7.1.4 Development Block

imageCLASS MF9170c / imageCLASS MF9150c / imageCLASS MF8450c
In this block, toner is adhered to the electrostatic latent image on the photosensitive drum to make it visible by the contact development method.
In the contact development method, the developing cylinder is closely engaged with the photosensitive drum. Development is performed when toner is transferred
from the developing cylinder to the photosensitive drum.
The toner (developer) used in the machine is a non-magnetic single-component toner, composed of resins, etc.
Step 4: Development
On the surface of the developing cylinder, toner is leveled by the developing blade to make an even layer of toner.
In this condition, the toner is charged negative due to the friction between the developing blade and the rotating developing cylinder, and the surface of the devel-
oping cylinder is charged negative.
Since the potential on the developing cylinder surface is lower than the light area on the photosensitive drum, the toner is separated from the developing cylinder
at the area where the photosensitive drum is engaged with the developing cylinder, and is adhered to the light area of the photosensitive drum. This makes the
electrostatic latent image on the photosensitive drum visible.
Since the potential in the dark area on the photosensitive drum is lower than the potential on the developing cylinder surface, the toner is not separated from the
developing cylinder.

7.1.5 Transfer Block

imageCLASS MF9170c / imageCLASS MF9150c / imageCLASS MF8450c
In this block, the toner on the photosensitive drum is transferred to paper, following four steps.
Step 5: Attraction
Paper is adhered to the ETB.
Since the machine transports paper upward, the paper is attracted to the ETB by electrostatic force so that it is not displaced from the feed path.
The fed paper is charged positive by the attraction roller, and is transported while being adhered to the ETB.
A positive DC bias is applied to the attraction roller.
7-4
Photosensitive drum
light area
dark area
Attraction roller
DC bias
Developing cylinder
F-7-6
ETB engaged roller
Paper
F-7-7
dark area
light area
ETB
0019-5015
0019-5016