Automatic sheet feeding apparatus

An automatic sheet feeding apparatus, comprising:

• a separation roller rotated in a sheet feeding direction;
• a reversible roller abutted against said separation roller and rotated in a direction opposite to the sheet feeding direction;
• first supporting means pivotally provided on a support shaft and adapted to support said reversible roller for movement toward and away from said separation roller;
• a feed roller disposed at a downstream side of said separation roller and rotated in the sheet feeding direction;
• a pinch roller abutted against said feed roller and rotated in the sheet feeding direction;
• second supporting means pivotally provided on the said support shaft and adapted to support said pinch roller for movement toward from away from said feed roller;
• driving force transmitting means for transmitting a driving force to said reversible roller and said pinch roller;
• and
• interruption means provided in said driving force transmitting means and adapted to interrupt the transmission of the driving force in response to a load;
• wherein said driving force transmitting means generates a force acting in a direction that said reversible roller is separated from said separation roller and a force acting in a direction that said pinch roller is urged against said feed roller by the transmitting driving force, and said support shaft is so positioned as to generate a force acting in a direction that said reversible roller is urged against said separation roller by a friction force that said reversible roller is received from said separation roller.

An image reading system, comprising:

• a separation roller rotated in a sheet feeding direction;
• a reversible roller abutted against said separation roller and rotated in a direction opposite to the sheet feeding direction;
• a feed roller disposed at a downstream side of said separation roller and rotated in the sheet feeding direction;
• a pinch roller supporting means for shifting said pinch roller in a direction toward and away from said feed roller, said pinch roller abutted against said feed roller and rotated in the sheet feeding direction;
• driving force transmitting means for transmitting a driving force to said pinch roller and then to said reversible roller;
• a torque limiter provided on said driving force transmitting means for interrupting the transmission of the driving torque from said pinch roller to said reversible roller when transmitting torque goes over a predetermined torque value;
• and
• reading means for reading an image on a sheet separated and fed one by one by means of said separation roller and said reversible roller;
• wherein the pressure of said pinch roller against said feed roller is adjusted in conformity with a variation in said predetermined torque value in said torque limiter.

An image reading system, comprising:

• a separation roller rotated in a sheet feeding direction;
• a reversible roller abutted against said separation roller and rotated in a direction opposite to the sheet feeding direction;
• first supporting means pivotally provided on a support shaft and adapted to support said reversible roller for movement toward and away from said separation roller;
• a feed roller disposed at a downstream side of said separation roller and rotated in the sheet feeding direction;
• a pinch roller abutted against said feed roller and rotated in the sheet feeding direction;
• second supporting means pivotally provided on the said support shaft and adapted to support said pinch roller for movement toward and away from said feed roller;
• driving force transmitting means for transmitting a driving force to said reversible roller and said pinch roller;
• interruption means provided in said driving force transmitting means and adapted to interrupt the transmission of the driving force in response to a load;
• and
• reading means for reading an image on a sheet separated one by one by means of said separation roller and said reversible roller and fed by said pinch roller and said feed roller;
• wherein said driving force transmitting means generates a force acting in a direction that said reversible roller is separated from said separation roller and a force acting in a direction that said pinch roller is urged against said feed roller by the transmitting driving force, and said support shaft is so positioned as to generate a force acting in a direction that said reversible roller is urged against said separation roller by a friction force that said reversible roller is received from said separation roller.

An automatic sheet feeding apparatus, comprising:

• a separation roller rotated in a sheet feeding direction;
• a reversible roller abutted against said separation roller and rotated in a direction opposite to the sheet feeding direction;
• a feed roller disposed at a downstream side of said separation roller and rotated in the sheet feeding direction;
• a pinch roller abutted against said feed roller and rotated in the sheet feeding direction;
• supporting means pivotally provided on a support shaft and adapted to support said pinch roller for movement toward and away from said feed roller;
• driving force transmitting means for transmitting a driving force to said reversible roller through said support shaft;
• and
• a torque limiter provided on said drive force transmitting means for interrupting the transmission of a driving torque of a predetermined torque value or greater to said reversible roller;
• wherein the torque applied around said supporting shaft to urge said pinch roller against said feed roller is adjusted in conformity with a variation in said predetermined torque value in said torque limiter.

An image reading apparatus, comprising:

• a separation roller rotated in a sheet feeding direction;
• a reversible roller abutted against said separation roller and rotated in a direction opposite to the sheet feeding direction;
• a feed roller disposed at a downstream side of said separation roller and rotated in the sheet feeding direction;
• a pinch roller abutted against said feed roller and rotated in the sheet feeding direction;
• supporting means pivotally provided on a support shaft and adapted to support said pinch roller for movement toward and away from said feed roller;
• driving force transmitting means for transmitting a driving force to said reversible roller through said support shaft;
• a torque limiter provided on said drive force transmitting means for interrupting the transmission of a driving torque of a predetermined torque value or greater to said reversible roller;
• and
• reading means for reading an image on a sheet separated one by one by means of said separation roller and said reversible roller and fed by said pinch roller and said feed roller;
• wherein the torque applied around said supporting shaft to urge said pinch roller against said feed roller is adjusted in conformity with a variation in said predetermined torque value in said torque limiter.