Image Density Control - Ricoh FT7770 Service Manual

6. Image Density Control

Image density is controlled by changing the strength of the positive bias volt-
age that is applied to the development roller sleeve by the bias power pack.
Applying a bias voltage to the development sleeve reduces the potential be-
tween the development roller and the drum, thereby reducing the amount of
toner that is transferred to the drum. So, the stronger the bias voltage is,
the lighter the resulting copy image is.
The bias is controlled differently depending on whether the image density is
selected manually or the automatic ID system is used.
- Manual Image Density Control -
When image density is set manually, the development bias base level (VI)
shifts from +10 volts to +370 volts,
step changes the development bias +60 volts.
Moving the image density control one
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April, '89