Method and apparatus for controlling an auto compensation pick mechanism to reduce the occurence of multi-feeds

A method for controlling a sheet feeder assembly for an imaging apparatus, said sheet feeder assembly including a motor coupled to a gear train for applying a rotational force to a sheet picker roller, a media supply tray for holding a media stack having a plurality of media sheets, and a sheet separator for buckling a top sheet of print media to separate said top sheet from said media stack, said method comprising the steps of:

• providing a first drive profile for said sheet picker roller, wherein said first drive profile defines an initial velocity at which said sheet picker roller is driven until at least one of a backlash of said gear train is eliminated and said top sheet has been buckled, and defines an acceleration rate at which said sheet picker roller accelerates from said initial velocity directly to a target velocity;
• providing a second drive profile for said sheet picker roller, wherein said second drive profile defines said initial velocity at which said sheet picker roller is driven until at least one of a backlash of said gear train is eliminated and said top sheet has been buckled, and defining an acceleration rate at which said sheet picker roller accelerates from said initial velocity to an over-speed velocity higher than said target velocity, and defines a deceleration rate at which said picking roller decelerates to said target velocity;
• and
• selecting one of said first drive profile and said second drive profile.

A method for controlling an imaging apparatus, comprising the steps of:

• providing a print engine;
• providing a print media path leading to said print engine;
• providing a media supply tray for holding a media stack having a plurality of media sheets, said supply tray including a sheet separator for buckling a top sheet of print media to separate said top sheet from said media stack;
• providing a media sheet feeder assembly for supplying said media sheet to said print media path, said media sheet feeder assembly including a motor coupled to a gear train for applying a rotational force to a sheet picker roller;
• providing a first drive profile for said sheet picker roller, wherein said sheet picker roller is driven at an initial velocity until at least one of a backlash of said gear train is eliminated and said top sheet has been buckled, and thereafter, said sheet picker roller being accelerated from said initial velocity directly to a target velocity;
• providing a second drive profile for said sheet picker roller, wherein said sheet picker roller is driven at said initial velocity until at least one of a backlash of said gear train is eliminated and said top sheet has been buckled, and thereafter, said sheet picker roller being accelerated from said initial velocity to an over-speed velocity higher than said target velocity, and then decelerating said picking roller to said target velocity;
• establishing a desired rate of throughput of media through said media sheet path;
• determining an actual rate of throughput of media through said media sheet path;
• and
• if said actual rate of throughput is not less than said desired rate of throughput, said method further comprising the step of selecting said first drive profile for a subsequent operation of said sheet picker roller, and
• if said actual rate of throughput is less than said desired rate of throughput, said method further comprising the step of selecting said second drive profile for said subsequent operation of said sheet picker roller.

A sheet feeder assembly for an imaging apparatus, comprising:

• a media supply tray for holding a media stack having a plurality of media sheets, said media supply tray including a sheet separator for buckling a top sheet of print media to separate said top sheet from said media stack;
• a motor;
• a pick arm assembly having a gear train and a sheet picker roller, said gear train having a drive gear, at least one intermediate gear and a driven gear, said driven gear being rotatably coupled to said sheet picker roller and said drive gear being rotatably coupled to said motor for applying a rotational force to a sheet picker roller via said gear train;
• and
• a controller electrically coupled to said motor, said controller including control logic for controlling said motor to drive said sheet picker roller at a first velocity until at least one of a backlash of said gear train is eliminated and said top sheet has been buckled, and thereafter, controlling said motor to accelerate said sheet picker roller from said first velocity to a second velocity.

An imaging apparatus, comprising:

• a print engine;
• a print media path having an input port and an output port, said output port being in communication with said print engine;
• a media supply tray in communication with said input port of said print media path, said media supply tray holding a media stack having a plurality of media sheets, said supply tray including a sheet separator for buckling a top sheet of print media to separate said top sheet from said media stack;
• a media sheet feeder assembly in communication with said media supply tray and said print media path, said media sheet feeder supplying said media sheet to said print media path, said media sheet feeder assembly including a motor, a gear train, and a sheet picker roller, said gear train being coupled between said motor and said sheet feeder roller to transmit a rotational force from said motor to said sheet picker roller;
• means for providing a first drive profile for said sheet picker roller, wherein said sheet picker roller is driven at an initial velocity until at least one of a backlash of said gear train is eliminated and said top sheet has been buckled, and thereafter, said sheet picker roller being accelerated from said initial velocity directly to a target velocity;
• means for providing a second drive profile for said sheet picker roller, wherein said sheet picker roller is driven at said initial velocity until at least one of a backlash of said gear train is eliminated and said top sheet has been buckled, and thereafter, said sheet picker roller being accelerated from said initial velocity to an over-speed velocity higher than said target velocity, and then decelerating said picking roller to said target velocity;
• means for defining a desired rate of throughput of media through said media sheet path;
• means for determining an actual rate of throughput of media through said media sheet path;
• and
• decision means for determining if said actual rate of throughput is less than said desired rate of throughput, wherein if said actual rate of throughput is not less than said desired rate of throughput then said determining means further selecting said first drive profile for a subsequent operation of said sheet picker roller, and if said actual rate of throughput is less than said desired rate of throughput then said determining means further selecting said second drive profile for said subsequent operation of said sheet picker roller.