Kyocera KM-4230 Service Manual page 50

Formation of magnetic brush
The developing roller consists of a magnet roller with five poles and a sleeve roller.
Rotation of the sleeve roller around the magnet roller entrains developer, which in turn
forms a magnetic brush at pole N1 on the magnet roller. The height of the magnet brush
is regulated by the doctor blade; the developing result is affected by the position of the
poles on the magnet roller and the position of the doctor blade.
A developing bias voltage generated by the high-voltage transformer (HVTPCB) is
applied to the developing roller to provide image contrast.
4
A
2
5
A: Distances beteen the doctor blade and
developing roller: 0.53 ± 0.05 mm
1 Developing unit housing
2 Developing roller
3 Toner sensor (TNS)
4 Doctor blade
6
3
1
Figure 1-3-25 Forming a magnetic brush
7
Magnetic poles on the developing roller
85.5°
N1
59°
5 Developing spiral A
6 Developing spiral B
7 Developing spiral C
S2
74.5°
43.5°
S1
N2
×
–4
N1: 830 10 T
×
–4
N2: 630 10 T
×
–4
N3: 450 10 T
×
–4
S1: 860 10 T
×
–4
S2: 700 10 T
2A3/4
N3
1-3-27