SERVICE MANUAL - O. Rensch OHG

2DC
(4) Development
The latent image constituted on the drum is developed into a visible image. The developing roller A contains a 3-pole
(S-N-S) magnet core B and an aluminum cylinder rotating around the magnet core B. Toner attracts to the developing
roller A since it is powdery ink made of black resin bound to iron particles. Doctor blade C, magnetized by magnet D,
is positioned approximately 0.3 mm above the developing roller A to constitute a smooth layer of toner in accordance
with the roller revolution.
C
Magnetism
0.1 mm
N
S
D
0.3 - 0.4 mm
E
S
F
N
S
Developing Bias
Engine board
bias output board
275±5 V DC
YC-B
A B + AC
YC302-10
HVCLK
YC7-7
Figure 2-1-14 Development
The developing roller A is applied with the AC-weighted, positive DC power source. Toner E on the developing roller A
is given a positive charge. The positively charged toner E is then attracted to the areas of the drum F which was
exposed to the laser light. (The gap between the drum F and the developing roller A is approximately 0.3 mm.) The
non-exposed areas of the drum F repel the positively charged toner as these areas maintain the positive charge.
The developing roller A is also AC-biased to ensure contrast in yielding by compensating the toner’s attraction and
repelling action during development.
2-1-14