Development - Kyocera KM-1820 Service Manual

2GM

(4) Development

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