HP M5025 Service Manual - Page 180

ADF Input tray Sensor-wide media (S1) and sensor long media (S2) is positioned at the input tray assembly. These sensors allow firmware to detect if A4 and Letter media sizes are positioned in portrait or landscape mode. Deskew Separation Roller Pick Roller Input Tray S1 S4 S3 S2 S5 S6 Exit Prescan Diverter Drive Roller Duplex Path Postscan Part Drive Roller Figure 4-37 ADF operation ADF simplex printing operation sequence 1. The sensor jam cover (S3) is interrupted when the jam cover is closed, and sensor media presence (S4) is interrupted when media is loaded on the input tray. 2. The feed motor rotates clockwise to lower the pick roller. A cutout on the gears on the side of the lid ensures the proper rotation distance. 3. The pick motor rotates counterclockwise to drive the pick roller to pick media. 4. Deskew sensor (S5) is interrupted when the leading edge of the media is driven past it, and the firmware registers the position of the leading edge of the media. 5. The leading edge of the media is driven into the nip point of the deskew drive roller and deskew pinch rollers. A preset amount of overdrive of media into this nip point is carried to create a buckle of media for pick skew correction. 6. The pick motor rotates clockwise to rotate the deskew drive roller to pull media into the prescan drive roller. 7. Following this, transmission gears for the pick and separator rollers disengage from the gear train. This allows the pick and separator rollers to free-wheel while media is pulled in by the deskew drive roller. 8. The feed motor rotates counterclockwise to drive the media into the prescan sensor (S6). 9. The firmware registers the position of the leading edge of the media while prescan sensor (S6) is activated. 10. The feed motor continues rotating counterclockwise to drive the leading edge of the media through the preset distance from sensor prescan (S6) to the scan zone. 11. When the media arrives, the scanner scans and retrieves data. 12. Sensor prescan (S6) is not interrupted when the trailing edge of the media passes it. 13. The firmware sequence registers the trailing edge of the media position. 14. The feed motor continues rotating counterclockwise to drive the media trailing edge through the preset distance from prescan sensor (S6) to the scan zone. 15. After this, the scanner finishes scanning and retrieving data. 16. The feed motor continues rotating counterclockwise to drive the trailing edge of the media past the scan zone. 17. The solenoid clamps the exit pinch rollers 150 Chapter 4 Theory of operation ENWW