Apparatus for detecting media edges in a media input tray

A media picking device for a media input tray of an image forming apparatus, the media picking device comprising:

• an arm engaging a stack of media sheets in the media input tray by being rotatable into the media tray;
• a pick shaft rotatably connected to one end of the arm;
• a first pick tire rotatably disposed at a first end of the pick shaft and a second pick tire rotatably disposed at a second end of the pick shaft, the first and second pick tires contacting and picking a topmost media sheet in the media input tray;
• and
• a sensing mechanism comprising:
• a photointerrupter disposed at one end of the arm, the photointerrupter including a pair of opposed arms and a light beam passing between the opposed arms;
• and
• a flag pivotable about the pick shaft, the flag moving from a first position to a second position when the leading edge of the media sheet being picked passes by and moving from the second position to the first position when the trailing edge of the media sheet being picked passes by, the flag having a first end for contacting the media sheet being picked and a blocking member at a second end, the blocking member of the flag entering and exiting the opposed arms as the flag moves between the first and second positions, wherein the sensing mechanism provides an output signal representative of the leading and trailing edges of the media sheet being picked as the flag moves from the first position to the second position and from the second position to the first position.

A device to move media sheets within an image forming apparatus, the device comprising:

• an arm rotatably driven from the image forming apparatus and positioned to engage a stack of media sheets in a media input tray;
• a pick shaft rotatably connected to one end of the arm;
• at least one pick tire mounted on the pick shaft for engaging a topmost media sheet in a stack of media sheets in a media input tray;
• a sensing mechanism comprising a photointerrupter disposed on the arm, the photointerrupter having a light emitting element and a light receiving element and actuated by a light beam traveling from the light emitting element to the light receiving element;
• and
• a member mounted on the arm and pivotable about the pick shaft and interrupting the light beam when the member is not in contact with a media sheet being picked.