Electrical structure Table 32. Sensors 240 Chapter 7 Troubleshooting C8523-90921 Sensor Location Type Qty ADF angle (detects when ADF is 30°) ADF optical/flag 1 ADF document length detection ADF optical/flag 2 ADF feeder switch ADF feeder optical/flag 1 ADF open/closed ADF optical/flag 1 Document detection flatbed optical/reflective 1 Document size flatbed optical/reflective 3 Document width ADF potentiometer 1 Flatbed carriage home position flatbed optical/flag 1 Paper loaded (empty) ADF feeder optical/flag 1 Pickup roller home position ADF feeder optical/flag 1 Registration detections ADF feeder optical flag 1 Skew detection ADF feeder optical flag 2 Timing ADF feeder optical/flag 1