Ricoh FT4460, Service Manual, Page: 106 / 413

7. ID SENSOR
7.1 ID SENSOR IMAGE CORRECTION (Vr Pattern)
The ID sensor image correction system, detects residual voltage on the OPC
drum, and corrects the image by changing the grid bias, development bias,
and lamp voltage.
The residual voltage is detected by comparing the Vsg and the Vrp.
The Vrp pattern is created by applying a 0 voltage bias. Toner particles are at-
tracted to the drum surface by the residual voltage.
The Vrp pattern is checked for the first five copies after initialization. There-
after, the pattern is checked for the first five copies of each 1,000 copy cycles.
NOTE: Color copies and Toner Density Detection cycles will interrupt the Vr
detection cycle.
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