When the scan unit's lever that comes back to the sheet scan position pushes the system gear pin, the system gear starts rotating in clockwise direction.
Due to the system gear rotation, the pin B on the planet gear mounting arm is guided in the cam groove B, and the planet gear B is engaged with the system gear. Along with the system gear rotation, the scan unit locking lever moves toward the lock position.
Rotation of the system gear releases the pin A on the planet gear A mounting arm from the cam groove A. The planet gear A moves to the intermediate position between the scan unit drive side gear and the sheet scan drive side gear. At this time, the belt stops moving, and the scan unit stops accordingly just before the sheet scan position.
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Rotation of the system gear releases the pin B on the planet gear B mounting arm from the cam groove B, and the planet gear B is disengaged from the system gear. After the disengagement, the system gear is kept rotating in clockwise direction by the system gear biasing spring. The scan unit locking lever is moved by the system gear, and it stops after pushing the scan unit to the locking rib. Keep rotating the motor in the counter-clockwise direction for the sheet feeding operation.
Image forming operation details by next post: