Sheet feeding apparatus

Claim 1

An apparatus for feeding sheets comprising: a sheet table for receiving a stack of sheets to be fed, said sheet table having a slanting carrying surface for permitting stacked sheets to slide downward by the force of gravity; stop means selectively positionable in stop and release positions for retaining and aligning said stacked sheets on said carrying surface when selectively disposed in said stop position and for allowing said stacked and aligned sheets to slide downward along said carrying surface by the force of gravity when selectively disposed in said release position; first drive means for selectively moving said stop means between said stop position and said release position; guide means, having a static guide surface against which the sheets strike such that the forward edges of said sheets are aligned thereon, said guide means for guiding forward edges of said sheets as they slide down along said carrying surface in a predetermined direction when said stop means is moved to said release position by said first drive means, said carrying surface and said guide surface forming an obtuse angle; pick up means, disposed at the leading edge of said guide means in the feeding direction and contacting the forward edge of the uppermost sheet of the sheets aligned on said guide means, for picking up and delivering such uppermost sheets one by one; second drive means for driving said pick up means; and tapping means, disposed under a central portion of said sheet table, for causing said stop means to tap the sheets on said sheet table after the forward edges of the sheets strike against the guard face to forwardly feed the sheets aligned on the guard surface.

Claim 2

An apparatus for feeding sheets comprising: a sheet table for receiving a stack of sheets to be fed, said sheet table having a slanting carrying surface for permitting stacked sheets to slide downward by the force of gravity; stop means selectively positionable in stop and release positions for retaining and aligning said stacked sheets on said carrying surface when selectively disposed in said stop position and for allowing said stacked and aligned sheets to slide downward along said carrying surface by the force of gravity when selectively disposed in said release position; first drive means for selectively moving said stop means between said stop position and said release position; guide means, having a static guide surface against which the sheets strike such that the forward edges of said sheets are aligned thereon, said guide means for guiding forward edges of said sheets as they slide down along said carrying surface in a predetermined direction when said stop means is moved to said release position by said first drive means, said carrying surface and said guide surface forming an obtuse angle; pick up means, disposed at the leading edge of said guide means in the feeding direction and contacting the forward edge of the uppermost sheet of the sheets aligned on said guide means, for picking up and delivering such uppermost sheets one by one; second drive means for driving said pick up means; and tapping means, disposed under a central portion of said sheet table, for causing said stop means to tap the sheets on said sheet table after the forward edges of the sheets strike against the guard face to forwardly feed the sheets aligned on the guard surface.

Claim 20

An apparatus for feeding sheets comprising: a sheet table for receiving a stack of sheets to be fed, said sheet table having a slanting carrying surface for permitting stacked sheets to slide downward by the force of gravity; stop means for retaining and aligning said stacked sheets on said carrying surface when selectively disposed in a stop position and for allowing said stacked and aligned sheets to slide downward along said carrying surface by the force of gravity when selectively disposed in a release position; first drive means for selectively moving said stop means between said stop position and said release position; guide means, having a static guide surface against which the sheets strike such that the forward edges of said sheets are aligned thereon, said guide means for guiding forward edges of said sheets as they slide down along said carrying surface in a predetermined direction when said stop means is moved to said release position by said first drive means, said carrying surface and said guide surface forming an obtuse angle; pickup means, disposed close to said guide means and contacting the uppermost sheet of the sheets guided by said guide means, for picking up and delivering such uppermost sheets one by one, including: (a) an intake roller disposed to touch one side of a sheet guided by said guide means and rotatable in a direction to pick up said guided sheet; (b) a separating roller touching the other side of said guided sheet and rotatable in either direction to controllably perform pick up of said guided sheet and return of any other sheet, wherein said intake roller and said separating roller are arranged to face each other so that said separating roller contacts a portion of said other side of said guided sheet which corresponds to the contact portion of said one side of said guided sheet touched by said intake roller when said guided sheet is held between said intake roller and said separating roller; (c) torque transmission means for transmitting rotational force to said separating roller to return a sheet as said intake roller rotates in a direction to pick up said guided sheet, said torque transmission means including a rotation means for transmitting rotational force to said separating roller so that said separating roller is rotated at a peripheral speed approximately three times that of said intake roller; wherein said intake roller and said separating roller each have frictional members disposed thereon, whereby, when said guided sheet is held between said intake roller and said separating roller, rotational force is transmitted from the surface of said intake roller separating roller to rotate said separating roller in a direction to pickup said guided sheet if the frictional force applied to said frictional member of said separating roller is greater than said rotational force transmitted by said torque transmission means, and whereby said rotational force from the torque transmission means is transmitted to said separating roller to rotate said separating roller in a direction to return to said a sheet if the frictional force on said frictional member of said separating roller is smaller than said rotational force transmitted by said torque transmission means; wherein said torque transmission means includes a first shaft coupled to said separating roller, a second shaft for rotating said separating roller in a direction to return said a sheet, and a coil spring having one end fixed to said first shaft and the other end connected to said second shaft so as to be able to slide thereon under a given frictional force, whereby the rotatory force of said second shaft is transmitted through said coil spring to said first shaft by the given frictional force, and said separating roller is subjected to said rotatory force in said direction to return said a sheet.

Claim 21

An apparatus for feeding sheets comprising: a sheet table for receiving a stack of sheets to be fed, said sheet table having a slanting carrying surface for permitting stacked sheets to slide downward by the force of gravity; stop means for retaining and aligning said stacked sheets on said carrying surface when selectively disposed in a stop position and for allowing said stacked and aligned sheets to slide downward along said carrying surface by the force of gravity when selectively disposed in a release position; first drive means for selectively moving said stop means between said stop position and said release position; guide means, having a static guide surface against which the sheets strike such that the forward edges of said sheets are aligned thereon, said guide means for guiding forward edges of said sheets as they slide down along said carrying surface in a predetermined direction when said stop means is moved to said release position by said first drive means, said carrying surface and said guide surface forming an obtuse angle; pickup means, disposed close to said guide means and contacting the uppermost sheet of the sheets guided by said guide means, for picking up and delivering such uppermost sheets one by one, including: (a) an intake roller disposed to touch one side of a sheet guided by said guide means and rotatable in a direction to pick up said guided sheet; (b) a separating roller touching the other side of said guided sheet and rotatable in either direction to controllably perform pick up of said guided sheet and return of any other sheet, wherein said intake roller and said separating roller are arranged to face each other so that said separating roller contacts a portion of said other side of said guided sheet which corresponds to the contact portion of said one side of said guided sheet touched by said intake roller when said guided sheet is held between said intake roller and said separating roller; (c) torque transmission means for transmitting rotational force to said separating roller to return a sheet as said intake roller rotates in a direction to pick up said guided sheet, said torque transmission means including a rotation means for transmitting rotational force to said separating roller so that said separating roller is rotated at a peripheral speed approximately three times that of said intake roller; wherein said intake roller and said separating roller each have frictional members disposed thereon, whereby, when said guided sheet is held between said intake roller and said separating roller, rotational force is transmitted from the surface of said intake roller separating roller to rotate said separating roller in a direction to pickup said guided sheet if the frictional force applied to said frictional member of said separating roller is greater than said rotational force transmitted by said torque transmission means, and whereby said rotational force from the torque transmission means is transmitted to said separating roller to rotate said separating roller in a direction to return to said a sheet if the frictional force on said frictional member of said separating roller is smaller than said rotational force transmitted by said torque transmission means; wherein said torque transmission means includes a first shaft coupled to said separating roller, a second shaft for rotating said separating roller in a direction to return said a sheet, and a coil spring having one end fixed to said first shaft and the other end connected to said second shaft so as to be able to slide thereon under a given frictional force, whereby the rotatory force of said second shaft is transmitted through said coil spring to said first shaft by the given frictional force, and said separating roller is subjected to said rotatory force in said direction to return said a sheet.

Claim 22

An apparatus for feeding sheets comprising: a sheet table for receiving a stack of sheets to be fed, said sheet table having a slanting carrying surface for permitting stacked sheets to slide downward by the force of gravity, said carrying surface of said sheet table having a groove extending at right angles to the sheet downward sliding direction, and one end of said stop means forming a projected member to project above said sheet table through said groove when said stop means is in said stop position and to be be located below said sheet table when said stop means is in the release position; stop means for retaining and aligning said stacked sheets on said carrying surface when selectively disposed in a stop position and for allowing said stacked and aligned sheets to slide downward along said carrying surface by the force of gravity when selectively disposed in a release position, wherein said stop means includes a spring disposed at the other end portion of said stop means to urge the same in one direction, and includes cam means, adjoining said other end portion, for pressing said other end portion against an inherent urging force of said spring, and for pressing said other end portion of said stop means against said urging force of said spring so that said one end of said stop means is projected above said sheet table through said groove when said cam means abuts against said other end portion of said stop means; first drive means for selectively moving said stop means between said stop position and said release oosition, including a drive mechanism for rotating said cam means in one direction, so that said cam means periodically presses said stop means against said urging force of said spring, thereby continuously reciprocating said stop means so that said stop means periodically abuts against the underside of a guided sheet to vibrate the same; guide means, having a static guide surface against which the sheets strike such that the forward edges of said sheets are aligned thereon, said guide means for guiding forward edges of said sheets as they slide down along said carrying surface in a predetermined direction when said stop means is moved to said release position by said first drive means, said carrying surface and said guide surface forming an obtuse angle; pick up means, disposed close to said guide means and contacting the uppermost sheets guided by said guide means, for picking up and delivering such uppermost sheets one by one; and second drive means for driving said pick up means.

Claim 23

An apparatus for feeding sheets comprising: a sheet table for receiving a stack of sheets to be fed, said sheet table having a slanting carrying surface for permitting stacked sheets to slide downward by the force of gravity, said carrying surface of said sheet table having a groove extending at right angles to the sheet downward sliding direction, and one end of said stop means forming a projected member to project above said sheet table through said groove when said stop means is in said stop position and to be be located below said sheet table when said stop means is in the release position; stop means for retaining and aligning said stacked sheets on said carrying surface when selectively disposed in a stop position and for allowing said stacked and aligned sheets to slide downward along said carrying surface by the force of gravity when selectively disposed in a release position, wherein said stop means includes a spring disposed at the other end portion of said stop means to urge the same in one direction, and includes cam means, adjoining said other end portion, for pressing said other end portion against an inherent urging force of said spring, and for pressing said other end portion of said stop means against said urging force of said spring so that said one end of said stop means is projected above said sheet table through said groove when said cam means abuts against said other end portion of said stop means; first drive means for selectively moving said stop means between said stop position and said release oosition, including a drive mechanism for rotating said cam means in one direction, so that said cam means periodically presses said stop means against said urging force of said spring, thereby continuously reciprocating said stop means so that said stop means periodically abuts against the underside of a guided sheet to vibrate the same; guide means, having a static guide surface against which the sheets strike such that the forward edges of said sheets are aligned thereon, said guide means for guiding forward edges of said sheets as they slide down along said carrying surface in a predetermined direction when said stop means is moved to said release position by said first drive means, said carrying surface and said guide surface forming an obtuse angle; pick up means, disposed close to said guide means and contacting the uppermost sheets guided by said guide means, for picking up and delivering such uppermost sheets one by one; and second drive means for driving said pick up means.