Ricoh K-C3.5L Service Training page 59

Development Bias
White areas: High negative charge (-950V)
Black areas: Discharged by the laser (about -150V)
Development bias (-650V): Forces the negatively-charged toner onto the
discharged areas of the drum.
Applied to development roller shaft through drive shaft.
Slide 59
More on Development Bias
This machine uses a negative-positive development system, in which black
areas of the latent image are at a low negative charge (about –154 ± 50 V) and
white areas are at a high negative charge (about –950 V).
To attract negatively charged toner to the black areas of the latent image on the
drum, the high voltage supply board applies a bias of –650 volts to the
development rollers throughout the image development process. The bias is
applied to the development roller shaft [A] through the drive shaft [B].
The development bias voltage (–650 V) can be adjusted with SP 2201 1.
Bias terminal
Development roller
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Model K-C3.5L