Lexmark W820 Service Manual - Page 53

4025-Finisher Paper Stack Components • The Stack Tray Paper Sensor detects the presence of paper on the Stacker Tray. • The Stacker Tray Position Sensor detects the current position of the Stacker Tray from the Liner Encoder. The Liner Encoder has three slits differently spaced along the edge, and according to these differently spaced slits, the Stacker Tray positions on the Finisher are classified into 25%, 50% and 100% positions. • The two sensors on the side of the Stacker Height Sensor detect the top surface of the bundle of paper on the Stacker Tray. • Once the Stacker Tray moves down where the top surface of paper is below the Sensor B, it moves up again. After the Sensor B detects that the top surface of paper passed the Sensor B, the Stacker Tray moves up further by the specified level, and then stops. This position is the Home Position (HP). • When the Sensor A detects the bundle of paper stacked on the Stacker Tray, the Stacker Tray moves down where the top surface of paper is below the Sensor B, and then moves up again to the home position. • When the bundle of paper on the Stacker Tray is removed and the Sensor B detects no paper, the Stacker Tray moves up and down to the home position. Introduction 1-41