Document separation apparatus

Apparatus for processing sheets by moving the sheets from sheet-inject means for injecting said sheets along a given path via advance means to a destination at a controlled rate, the apparatus comprising:

• control means for setting a prescribed nominal minimum inter-document gap value g.sub.n ;
• and for controlling said sheet-inject means to pick successive sheets from said inject means and advance them via said advance means along said given path at an adjustable time period after a previous sheet had been so picked, to thus aim for said "nominal" minimum inter, document gap value g.sub.n ;
• sensor means for sensing the distance d between each so-picked sheet and the following sheet and inputting distance d to said control means which is adapted to responsively compare said distance d with said nominal minimum interdocument gap value g.sub.n and thereby establish the variance-distance .gradient.d from said nominal minimum interdocument gap value g.sub.n by causing said advance means to accelerate or decelerate the succeeding sheet to thereby decrease the sensed variation .gradient.d from said nominal, minimum interdocument gap value g.sub.n ;
• said control means being arranged to set the next pick time automatically by deriving and storing a value g representing the instantaneous associated gap-distance;
• and,
• comparing said stored distanced with stored values representing the desired nominal minimum interdocument gap value, to responsively control said advance means to
• adjust the acceleration or deceleration to drive said instantaneous gap value g toward said nominal minimum interdocument gap value, whereby the number of sheets passing through the system per unit time may be controlled and maximized;
• and
• gap control means arranged to detect when a "variant-gap" g.sub.vv that is less than, or more than, nominal gap g.sub.n, occurs, and to responsively accelerate/decelerate the sheet following to reduce gap variance from said nominal gap g.sub.n ;
• and also to detect and register a repeated occurrence of said variant-gap condition for N successive sheets, and when such is detected, to responsively stop the input means for a suitable delay time.