Method and apparatus for feeding sheets

A method for controlling when each sheet in a stack of sheets is fed from the stack including:

• picking a sheet from a stack of sheets in response to a pick signal for movement along a predetermined feed path;
• measuring the feed time from when the pick signal is issued to cause picking of a sheet from a stack of sheets until the picked sheet reaches a predetermined position along the predetermined feed path;
• determining whether the measured feed time exceeds a predetermined maximum feed time;
• using the same time interval between the pick signal and the prior pick signal as the time interval between the prior pick signal and the preceding pick signal if the measured feed time exceeds the predetermined maximum feed time;
• determining whether the measured feed time is less than an expected feed time if the measured feed time did not exceed the predetermined maximum feed time;
• reducing the time interval between the pick signal and the prior pick signal if the measured feed time is not less than an expected feed time;
• and increasing the time interval between the pick signal and the prior pick signal if the measured feed time did not exceed the predetermined maximum feed time and was less than the expected feed time.

A sheet feeding apparatus for feeding each sheet from a stack of sheets including:

• picking means for picking a sheet from a stack of sheets for movement along a predetermined feed path;
• advancing means for advancing each picked sheet along the predetermined feed path;
• measuring means for measuring a feed measurement from when a pick signal is issued to said picking means until a picked sheet reaches a predetermined position along the predetermined feed path;
• first determining means for initially determining whether the magnitude of the measured feed measurement is greater than a predetermined maximum feed measurement for feeding a sheet from the stack of sheets to the predetermined position;
• first causing means for causing the pick signal to be sent to said picking means at the same measurement as for the prior picked sheet if said first determining means determines that the feed measurement is greater than the predetermined maximum feed measurement;
• second determining means for determining whether the magnitude of the measured feed measurement is less than an expected feed measurement for feeding a sheet from the stack of sheets to the predetermined position if the measured feed measurement is not greater than the predetermined maximum feed measurement;
• second causing means for causing the pick signal to be earlier to said picking means than for the prior picked sheet if said second determining means determines that the measured feed measurement is not less than the expected feed measurement;
• and third causing means for causing the pick signal to be issued later to said picking means than for the prior picked sheet if said second determining means determines that the feed measurement is less than the expected feed measurement.

A method for controlling when each sheet in a stack of sheets is fed from the stack including:

• picking a sheet from a stack of sheets in response to a pick signal for movement along a predetermined feed path;
• measuring the feed measurement from when the pick signal is issued to cause picking of a sheet from a stack of sheets until the picked sheet reaches a predetermined position along the predetermined feed path;
• determining whether the measured feed measurement exceeds a predetermined maximum feed measurement;
• using the same measurement interval between the pick signal and the prior pick signal as the measurement interval between the prior pick signal and the preceding pick signal if the measured feed measurement exceeds the predetermined maximum feed measurement;
• determining whether the measured feed measurement is less than an expected feed measurement if the measured feed measurement did not exceed the predetermined maximum feed measurement;
• reducing the measurement interval between the pick signal and the prior pick signal if the measured feed measurement is not less than an expected feed measurement;
• and increasing the measurement interval between the pick signal and the prior pick signal if the measured feed measurement did not exceed the predetermined maximum feed measurement and was less than the expected feed measurement.