Usage determination of multi-feed prevention roller

An image forming apparatus comprising:

• a main body including an image former;
• at least one sheet feeding apparatus to feed a sheet to the image former;
• and
• a controller to control the image former and the at least one sheet feeding apparatus to form an image on the sheet,
• wherein the at least one sheet feeding apparatus includes:
• a sheet stacker to stack at least one sheet;
• a sheet feed roller disposed at one side of the sheet stacker and to feed a sheet fed from the sheet stacker to the image former;
• a multi-feed prevention roller disposed to face the sheet feed roller and to prevent multi-feed of sheets fed from the sheet stacker;
• a magnetic torque limiter disposed coaxially with the multi-feed prevention roller;
• and
• a hall sensor disposed at one side of the magnetic torque limiter and to detect a rotation and a rotational direction of the magnetic torque limiter,
• wherein the controller is to,
• control to determine a value indicative of usage corresponding to the multi-feed prevention roller according to a signal indicative of the detected rotation and rotational direction of the magnetic torque limiter output from the hall sensor;
• and
• wherein the magnetic torque limiter includes,
• a plurality of permanent magnets provided circumferentially on a rotation shaft of the multi-feed prevention roller;
• a housing to surround the plurality of permanent magnets;
• and
• a magnetic member provided on an inner circumferential surface of the housing and facing the plurality of permanent magnets,
• wherein a portion of the housing facing the hall sensor is provided with a magnetic force emitting region through which a magnetic force of a permanent magnet among the plurality of permanent magnets is radiated to an outside of the housing over a circumferential region of the housing to cause the detection of the rotation and the rotational direction of the magnetic torque limiter by the hall sensor.