156 Theory of operation ENWW
Developing cylinder engaging/disengaging control
This controls the disengagement of the developing cylinder from the photosensitive drum to
prevent toner from being developed on the drum during non-transferring time.
The developing cylinder is engaged/disengaged when the DC controller drives the developing
engaging clutch (CL3) under a specified condition such as when one print is completed. (See
Figure 5-38.)
The following is the disengaging sequence.
1 The DC controller turns ON the developing engaging clutch (CL3).
2 When the CL3 stays engaged for specified time, the drive of delivery motor (M2) raises the
developing engaging lever up.
3 The developing engaging lever then raises the bottom of the cartridge in the back and
disengages the developing cylinder from the photosensitive drum.
The developing cylinder will engage back with the drum when the DC controller turns ON the CL3
for a specified time to put the developing engaging lever back to its original position.
The developing cylinder disengages under the following conditions.
• Power is turned ON
• Print operation is complete
• During cartridge cleaning (described on the following page)
• During ITB cleaning
Developing cylinder engaging/disengaging detection
It is detected whether or not the developing cylinder is engaged with the photosensitive drum. The
DC controller monitors the developing engaging sensor (PS14) during the developing cylinder
engagement/disengagement operation. (See Developing engaging/disengaging unit.) The
developing engaging lever has a projection on the top that pushes the developing engaging flag up
and shields the PS14 when the developing engaging lever stays lifted up. When the developing
cylinders are engaged, the PS14 is not shielded by the flag, so it does not output DEVELOPING
ENGAGING DETECTION signal (DEVHPSNS) (Condition “L”). When the lever is lifted up, the
PS14 is shielded by the flag and outputs DEVELOPING ENGAGING DETECTION signal
(DEVHPSNS) (Condition “H”).
The DC controller judges the “disengagement mechanism faulty” and sends the error message to
the formatter when the DEVHPSNS signal is not input/output within a specified time during
engagement/disengagement operation.
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