Sheet feeder

Claim 2

A sheet feeder, comprising: a sheet supply support bed; a sheet separating belt means comprised of two spaced drums and at least one endless belt of high friction characteristics reeved about the drums; first power means to drive said drums and belt in a direction to move a bottom run of said belt the direction of feed; a document support bed extending adjacent said bottom run in an angular relationship normally out of document feed contact with said belt; a retard roller having a one-way clutch, said roller mounted in contact with said belt between said drums, said clutch permitting rotation only in a counter-feed direction; a pressure foot positioned within the loop of the belt between the drums with a second power means to press the belt into contact with said bed by distending the belt; and control means for distending the belt prior to full drive of the belt by said first power means to thereby stretch the belt in a reverse drive direction by a small increment prior to the belt drive and thereby increment the retard roller, whereby a fresh retard surface is brought into service with each sheet feed cycle.

Claim 3

In combination, a sheet feeder and utilization device, comprising: a sheet supply support bed defining a lead edge sheet stack position; a frictional retard surface fixed against motion in a sheet feed direction; spaced first and second belt support pulleys; power drive means for one of said pulleys; an endless sheet separation belt reeved around said pulleys, one of said pulleys being just forward of the lead edge stack position and at a location to hold the belt in cooperative relation with said retard surface, said belt having a run normally extending at an angle from said one pulley upwardly over said stack position and out of conveying contact with sheets of a stack, and being forcibly deflectable into contact therewith; a belt distending means positioned between said first and second pulleys at a location adjacent said deflectable belt run and opposite said supply support bed for distending said belt toward said bed upon command into a substantially parallel and congruent relationship with the orientation of said sheet supply bed; means for moving said support bed towards said belt as a sheet stack thereon is depleted; a feed control system having feed cycle initiating means for controlling the starting of the drive for said belt in said direction of feed and commanding operation of said belt distending means; a sheet utilization means including a sheet forwarding means independent of said sheet separation belt for accepting and processing a delivered sheet; a cycle terminating means responsive to a sheet delivered to a position wherein a sheet lead edge lies beyond said sheet feeder and is within the active ambit of said sheet forwarding means for stopping said power drive means and restoring the belt distending means to inactive position, whereby the fed document will advance under the influence of the sheet utilization forwarding means without causing the belt to drive a next document in the stack due to belt motion induced by friction between the fed document and the belt; and said terminating means initiating utilization means into action.

Claim 4

In combination, a sheet feeder and utilization device, comprising: a sheet supply support bed defining a lead edge sheet stack position; a frictional retard surface fixed against motion in a sheet feed direction; spaced first and second belt support pulleys; power drive means for one of said pulleys; an endless sheet separation belt reeved around said pulleys, one of said pulleys being just forward of the lead edge stack position and at a location to hold the belt in cooperative relation with said retard surface, said belt having a run normally extending at an angle from said one pulley upwardly over said stack position and out of conveying contact with sheets of a stack, and being forcibly deflectable into contact therewith; a belt distending means positioned between said first and second pulleys at a location adjacent said deflectable belt run and opposite said supply support bed for distending said belt toward said bed upon command into a substantially parallel and congruent relationship with the orientation of said sheet supply bed; means for moving said support bed towards said belt as a sheet stack thereon is depleted; a feed control system having feed cycle initiating means for controlling the starting of the drive for said belt in said direction of feed and commanding operation of said belt distending means; a sheet utilization means including a sheet forwarding means independent of said sheet separation belt for accepting and processing a delivered sheet; a cycle terminating means responsive to a sheet delivered to a position wherein a sheet lead edge lies beyond said sheet feeder and is within the active ambit of said sheet forwarding means for stopping said power drive means and restoring the belt distending means to inactive position, whereby the fed document will advance under the influence of the sheet utilization forwarding means without causing the belt to drive a next document in the stack due to belt motion induced by friction between the fed document and the belt; and said terminating means initiating utilization means into action.