Mechanism for avoiding multiple sheet misfeeds in sheet media feed systems

A clearing mechanism for avoiding multiple sheet misfeeds in stacked sheet media feeding systems, the clearing mechanism comprising:

• a. a rotatable sheet pick/feed mechanism defining adjacent thereto a single sheet media feed zone;
• b. first and second cams operatively coupled to the pick/feed mechanism for rotation therewith;
• c. first and second cam followers that are selectively engaged by the first and second cams, respectively, at various predefined rotational orientations of the cams;
• d. a pivotal lever operatively coupled to the first and second cam followers and extending into the feed zone in a position obstructing the leading edges of the sheets in the media stack;
• e. the first cam temporarily engaging the first cam follower, upon rotation of the pick/feed mechanism into a sheet feeding orientation, to move the lever into a non-obstructing position that permits feeding the top sheet of the media stack through the feed zone;
• f. a return mechanism operatively coupled to the lever for continuously urging the lever toward the obstructing position;
• and
• g. the second cam operable, upon rotation of the drive mechanism into a pre-sheet feeding orientation, to temporarily engage the second cam follower to move the lever into the obstructing position.

A clearing mechanism for avoiding multiple sheet misfeeds in a stacked sheet media printer of the type having a single sheet pick/feed mechanism for feeding a single sheet from the top of a sheet media stack through a feed zone by rotation of one or more rollers defining a cylinder and selectively engaging the top sheet, the clearing mechanism comprising:

• a. radially extending first and second cams rotatably disposed along a central axis of the cylinder;
• b. first and second cam followers laterally aligned with the first and second cams, respectively, for selective engagement with the cams at various predefined rotational orientations of the cams;
• c. a lever pivotally coupled to the printer's chassis and fixedly connected to the cam followers, the lever having a distal end extending into the feed zone in a position obstructing the leading edges of the sheets in the media stack, the lever being moved by the first cam follower, upon rotation of the pick/feed mechanism into a first sheet feeding orientation wherein the first cam temporarily engages the first cam follower, through the feed zone into a non-obstructing position that permits feeding the top sheet;
• d. a return mechanism active when the rollers are in a second predefined rotational orientation to continuously urge the distal end of the lever toward the obstructing position after the leading edge of the top sheet has been fed downstream past the distal end of the lever;
• and
• e. the second cam operable, upon rotation of the drive mechanism into a pre-sheet feeding orientation, to temporarily engage the second cam follower to move the lever into the obstructing position.