Lexmark X7500 Service Manual - Page 20

4036-501 DADF Paper Path The DADF moves the paper along the paper path using a combination of rolls, solenoids, clutches and gears. The DADF adjusts the scanning timing to the specified paper movement speed and fixing the cartridges of the scanner at the DADF position. The DADF also allows the scanner to scan page 2 of the paper following page 1 using the gate change mechanism of the duplex function. 1. Simplex Paper Path • The rotation of the nudger roll, moves the paper on the DADF tray to the feed roll. • The paper moves to the registration roll by the rotation of the feed roll. • When the pre-registration sensor 1, located just in front of the registration roll, detects the passing of the top of the paper, the paper movement is interrupted for the specified time to synchronize with the paper feed timing. • The paper restarts toward the registration roll. • After passing on the DADF upper paper guide, the top of the paper reaches and actuates the paper present sensor of the pre-registration sensor. • At the position just in front of the large roll, the paper movement is interrupted again for the specified time to synchronize with the paper feed timing. • The paper is moved to the DADF platen glass by rotation of the large roll. • Along the way, the DADF registration sensor card interrupts the movement for the specified time to synchronize with the scanning timing of the scanner. • The sensor restarts to move the paper to the platen glass by the rotation of the large roll. • The image of the paper is scanned at the platen glass. • After scanning, the paper passes the gate through the lower path and is moved to the exit/reverse roll. • The rotation of the exit/reverse roll discharges the paper onto the DADF output tray. 1-10 Service Manual