Canon CLBR 460ps Service Manual page 127

4. ITB cleaning block
This block consists of two steps and moves the residual toner (note) on the intermediate trans-
fer belt to the photosensitive drum to clean the intermediate transfer belt.
Note: Residual toner
In the secondary transfer block, the toner on the intermediate transfer belt is transferred
to the paper, but some toner remains on the intermediate transfer belt. If a jam occurs,
the toner remains on the intermediate transfer belt. It is called the residual toner.
Step 7 ITB cleaning roller charging
In this step, the residual toner on the intermediate transfer belt is uniformly charged by apply-
ing a bias to the ITB cleaning roller when needed.
The ITB cleaning roller is usually detached from the intermediate transfer belt. The roller is
pressed against the intermediate transfer belt by the ITB cleaning roller contact cam during
charging for ITB cleaning.
The positive bias is applied to the ITB cleaning roller and the toner on the intermediate trans-
fer belt is uniformly charged.
After charging ends, the bias is turned OFF and the ITB cleaning roller is detached from the
intermediate transfer belt by moving the cleaning roller contact cam.
A negative charge is applied in the last rotation period to clean the residual toner attached to
the ITB cleaning roller.
ITB cleaning roller contact cam
ITB cleaning roller
Charged residual toner
Intermediate transfer belt
AC bias
DC
Figure 2-4-26
CHAPTER 2
Residual toner
2 - 69