Canon iR4570 Series Service Manual page 312

Chapter 7
F-7-69
2) Shift the locking lever [1] to the left to release the
developing assembly.
F-7-70
3) Slide the developing assembly [1] slightly to the
front; then, disconnect the connector [2].
F-7-71
7-36
4) Remove the developing assembly [1].
F-7-72
Be sure to hold the developing assembly as shown.
F-7-73
When fitting the developing assembly, be sure to fit
the lower right segment [2] of the developing
assembly [1] in the rail [3] of the machine. Thereafter,
slide the developing assembly so that [A] of the
developing assembly matches [B] of the rail.