Method and apparatus for stacking mixed mail

A method of stacking a plurality of mailpieces sequentially incoming from an upstream direction so as to form a mail stack on a stacking deck, wherein each mailpiece has a leading edge and a trailing edge and the mailpieces in the mail stack are registered against a registration wall, said method comprising the steps of:

• 1) sensing the leading edge of a mailpiece as the mailpiece is incoming from the upstream direction;
• 2) moving the mailpiece toward the registration wall in response to sensing its leading edge;
• 3) continuing the movement of the mailpiece toward the registration wall until the trailing edge of the mailpiece is sensed, at which time said movement of the mailpiece is paused;
• 4) sensing the leading edge of a next following mailpiece incoming from the upstream direction;
• 5) moving the next following mailpiece and the previous mailpiece toward the registration wall so as to cause the leading edge of the next following mailpiece to overlap with the trailing edge of the previous mailpiece and so that the next following mailpiece is further away from the resulting mail stack than the previous mailpiece;
• 6) continuing the movement of the next following and previous mailpiece toward the registration wall so that each previous mailpiece is moved into contact with the registration wall and to then form part of the mail stack as it is urged onto the stacking deck by the next following mailpiece, said movement of the next following mailpiece continuing until the trailing edge of the next following mailpiece is sensed, at which time said movement of the next following mailpiece is paused;
• and
• 7) repeating steps 4 through 6 for the remaining mailpieces of said plurality of mailpieces.