Sheet feeding apparatus with pressure sensing vacuum assembly

Claim 1

A sheet feeding apparatus comprising: a bin for containing a stack of sheets to be fed; a movable carriage supporting at least one sucker member; a suction means for apply a vacuum to said sucker member; movement means for selectively moving said carriage in an engaging direction, by which said sucker member is brought into contact with a sheet on said stack of sheets to be fed, and in a retracting direction, by which said sucker member moves away from said stack of sheets to be fed; a control means coupled to said movement means for providing an electrical signal for selecting the direction of movement of said movement means; said control means including vacuum sensing transducer means communicating with said sucker member, said control means using said transducer means to detect when contact is made between said sucker member and said stack of sheets; said control means providing an electrical signal to initiate movement of said carriage in said engaging direction through a continuous motion and to initiate movement of said carriage in said retracting direction the instant contact is made and vacuum pressure at said sucker member attains a predetermined level adequate to hold a single sheet in contact with said sucker member during movement in the retracting direction.