Canon iR C6800 Series Service Manual page 321

Chapter 7
DC CON: DC controller
What follows below is an additional explanation of the individual biases used in the transfer assemblies:
1. Primary Transfer Bias (application bias: DC)
The primary transfer bias is used to transfer the toner image on the photosensitive drum to the ITB, and is applied
to the primary transfer roller.
2.Primary Transfer Reverse Bias (application bias: DC)
This bias is used to clean (remove) the patch pattern formed on the ITB for image stabilization control (Dmax, Dhalf,
ATR).
In the course of image stabilization control, this bias is applied so that the patch pattern (toner) is retuned from the
ITB to the photosensitive drum for collection by the photosensitive drum cleaner.
3. Primary Transfer Static Eliminator Bias (application bias: DC)
The primary transfer static eliminator is arranged to the side of the primary transfer roller, serving to prevent the
toner image from flying astray as the result of discharge between the ITB and the primary transfer downstream roller.
4. Secondary Transfer Bias (application bias: DC, DC)
The secondary transfer bias is used to transfer the toner image from the ITB to paper. There are 2 types of secondary
transfer biases, and they are applied to the secondary transfer outside roller.
At time of printing, a DC bias is applied to the secondary transfer outside roller. The DC reverse bias is used to
remove the residual toner from the secondary transfer roller; its application will cause the residual toner on the
secondary transfer roller to be attracted to the ITB for collection to the waste toner bottle by the work of the ITB
cleaner.
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