Lexmark W820 Service Manual - Page 51

4025-Finisher Paper Stack Sections From the Finisher Exit section, the paper or a bundle of paper is delivered on the Stacker Tray. The Stacker Height Sensor detects the stack amount of bundles of paper, and moves up or down the Stacker Tray according to the stack amount. At the initialization, the absolute position of the Stacker Tray is recognized by the rotation of the Liner Encoder. The Stacker Tray absolute position is defined to three positions, 25%, 50%, and 100%, according to the stack amount. The slits differently spaced on the Liner Encoder correspond to respective positions. The absolute position is recognized when the Stacker Tray Position Sensor detects a slit on the Liner Encoder for the first time. The Stacker Tray moves up to the position where the Sensor B of the Stacker Height Sensor turns off. Introduction 1-39