Ricoh Di-C1.5a Manual page 144

The same motor drives the development unit for K.
The drum gear position sensor detects when the motor is not
working.
It also makes sure that the drum gear is at the correct angle when
printing starts.
This prevents variations in print quality caused by incorrect gear
meshing at the start of the job.
Slide 144
SC380 occurs if the sensors detect that the drums are not turning.
Drum Drive - K
144
Di-C1.5 Training
Drum Gear Position
Sensor - K
Drum/Development
Drive Motor - K