Canon W6400 Series Service Manual page 97

Front cover
g) Upper rear cover
When removing the upper rear cover, first remove the upper cover, the right rear cover, the left front cover, the left rear cover, and the paper release lever.
The hook located at the top end of the upper rear cover is engaged in the cover stay, so first rotate the top of the upper rear cover by 90 degrees in order to
remove the hook.
h) Rear cover
When removing the rear cover, remove 12 screws and remove the bottom end first.
2
1
Hook
F-4-12
F-4-13
1
Upper rear cover
Hook
Cover stay
Chapter 4
Hook
4-7