Xerox ColorQube 9303 Series Service Manual page 1754

Figure 7 Registration/preheat assembly location
The registration / preheat assembly uses a single CIS scan bar to detect the rear lateral edge
of the sheet. Based on the location of this edge it can be determined if the sheet is wider or
narrower than expected by more than 10 mm. If the rear edge is within 10 mm of the expected
position, the lateral location of the sheet is corrected by the registration mechanism. If the rear
edge is more than 10 mm from the expected position a jam is declared by the machine. As the
CIS scan bar is mounted at an angle relative to the lateral direction, it can also detect sheet
skew.
The registration / preheat assembly reads the skew and position of the media and uses this
information to determine the amount of de-skew required to orient the media correctly from
inboard to outboard. De-skewing is accomplished by intentionally skewing the paper twice. The
sum of the two actions causes the media to be both aligned inboard to outboard and the lead
edge to be de-skewed. Due to these movements, the motion of the paper through the registra-
tion / preheat module is sometimes referred to as 'wag'.
Principles of Operation
Figure 8. The intentional skewing of the paper is accomplished by the steering rolls. The steer-
ing roll shafts align with one another but are separate and are driven by separate stepper
motors. Depending upon the width of the media, various idlers will be engaged to provide drive
to the paper. This is accomplished with the rear drive motor by running in reverse.
February 2013
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Figure 8 Skew correction drive
ColorQube® 9303 Family
Figure 9.