Integrated chassis for automatic document feeder in a scanning unit

Abstract

In a scanning unit such as a facsimile machine, an automatic document feeder transports individual sheets from a stack of documents along a document path over a scanning window to an output tray. An upper guide member includes an integrated chassis which provides most of the functional features required for picking individual sheets from a stack of documents in an input tray and transporting the sheet past a scanning window. The various components incorporated in the integrated chassis include a document separation mechanism, pre-scanning pinch rollers, post-scanning pinch rollers, a spring-loaded limiter with minimal paper path obstruction, a hinging mechanism to facilitate manual access to the document path, a latching mechanism, referencing datums, and ESD grounding including ESD brushes adjacent the document path and an ESD shield for a circuit board housed in the upper guide member. In the preferred form, the integrated chassis is formed from an enlarged sheet metal plate which attaches to the underside of a manual control/display panel with the circuit board sandwiched therebetween.