Feeder apparatus for documents and the like

Abstract

The invention is a sheet feeder for engaging and removing a sheet of paper or other material from a stack and feeding it along a path. The sheet feeder can include a skimmer, a bumper, a separator, and a guide plate. The skimmer can include a timing belt or other positive drive, so the drive motor turns the drive roller to feed sheets in a uniform manner. The skimmer element can be laterally reciprocated to assist in separation of the top sheet from lower sheets in a stack. The bumper extends across the feed path and has a guide surface positioned to confront the leading edges of the sheets of the stack and direct the leading edge of an advancing engaged single sheet away from the remainder of the stack. The separator is designed for advancing the engaged sheet while retarding any adjacent sheets. In one embodiment, a friction roller rotates on one side of the feed path, advancing a single sheet forward along the feed path. A stationary friction element positioned on the other side of the feed path is axially offset from and interleaved radially with the friction roller. The engaged sheet is gripped between the interleaved friction roller and stationary friction element. In another embodiment, the separator has a driven advancing roller nipped with a driven retarding roller coupled to its drive by a friction clutch. The clutch normally slips and permits the retarding roller to be driven forward by the advancing roller when one or no sheets are engaged between the advancing and retarding rollers. The clutch engages and drives the retarding roller backward so long as a multifeed of two or more sheets is engaged between the advancing and retarding rollers. The guide plate extends between the skimmer and the separator, extending roughly parallel to the feed path. The guide plate guides the engaged single sheet substantially along the feed path, preventing the sheet from buckling.

Dependencies are inferred from the claim text.