Canon imageRUNNER ADVANCE 4551i Service Manual page 67

■ Scanner Unit
● Configuration of the Scanner Unit
The Scanner Unit has the same mechanism as that of the reader. For details, refer to "Scanner Unit" in "Basic Configuration" in
the section "Reader Technology".
Note that there is a difference in their externals due to the shapes of the locations where the units are installed. For this reason,
the unit for the ADF and that for the reader cannot be exchanged.
Related Error Code
Light intensity error
• E301-0002: Light intensity is below the reference level at paper back shading.
Shading error
• E302-0101: Error in paper back white shading
• E302-0102: Error in paper back black shading
● Duplex Reading Control
2-sided originals are read using simultaneous duplex reading.
With one feed, the Scanner Unit of the Reader Unit reads the front side and the Scanner Unit of the ADF reads the back side
without reversing the paper.
Scanning position
for the front side
Service mode
• FEEDER > ADJUST > ADJMSCN1
: Zoom fine adjustment when reading 2-sided originals (horizontal scanning direction) [front side]
• FEEDER > ADJUST > ADJMSCN2
: Zoom fine adjustment when reading 2-sided originals (horizontal scanning direction) [back side]
• FEEDER > ADJUST > ADJSSCN1
: Zoom fine adjustment when reading 2-sided originals (vertical scanning direction) [front side]
• FEEDER > ADJUST > ADJSSCN2
: Zoom fine adjustment when reading 2-sided originals (vertical scanning direction) [back side]
● Glass shift control
This equipment has a Reading Glass on the bottom surface of the Scanner Unit.
This Reading Glass has a Standard White Plate used for shading correction and dust detection correction.
The Reader Controller drives the Read Motor (STM3) as needed to move the Reading Glass.
The Reader Controller performs the above-mentioned correction by comparing the position of the Standard White Plate and the
reflection data of the image scanning position.
Scanner Unit Scanning position
(ADF) for the rear side
Scanner Unit
(Reader)
54
2. Technology