Machines for inserting items such as sheets of paper into envelopes are known in the art. For example, Werner et al. (U.S. Pat. No. 6,164,046) discloses a mail inserter which has an envelope supply module and an insert material module disposed side-by-side from each other, mechanically linked by a table where a retrieved envelope is moved from the envelope supply module to the insertion station in a different direction. The mail inserter, as disclosed in Werner et al., is represented by a block diagram as shown in FIG. 1. As shown in FIG. 1, the mail inserter 1 has an insertion station 5 wherein insert material is inserted into a receiving envelope. The mail inserter 1 comprises an envelope supply module 10 to supply the envelopes and an insert material supply module 70 to supply the insert material. As disclosed in Werner et al., a typical insert material supply module has a plurality of feeders for separately releasing sheets of insert material onto a moving belt where the sheets of insert material are cumulated into stacks. The stacks of insert material are sequentially moved into the insertion station for insertion. From the envelope supply module 10, envelopes are retrieved one at a time by an envelope retrieval mechanism 20 and the retrieved envelope is moved toward the insertion station 5. Before reaching the insertion station 5, the flap of the retrieved envelope is opened by a flap opening mechanism 30. In the insertion station 5, the throat of the envelope is opened by a throat opening mechanism 40 so as to allow the insertion module 60 to move a pack of insert material into the receiving envelope. After the insertion is completed, the stuffed envelope is moved away from the insertion station 5. A flap closing section 50 is used to close the flap of the stuffed envelope. The closed envelope is then sealed and further processed.
As shown in FIG. 2, an envelope 90 has a flap 92. After the flap 92 is opened, a throat 98 is exposed. The throat 98 is formed by a front envelope panel 94 and a back envelope panel 96. After the flap is opened, the envelope 90 is moved to the insertion station along a direction 390. In the insertion station, the flap 92 of the envelope is typically held down by a mechanical means when the throat 98 is opened. The throat 98 can be opened by a number of different ways. For example, it can be opened by blowing a puff of air into the throat; or it can be opened by using one or more suction cups to pull up the back panel 96 of the envelope while holding down the front panel 94. Suction cups can be used to pull up the back panel 96 at two locations 42, for example. While the throat 98 of the envelope is opened, a pack of insert material 80 is moved along direction 380 into the envelope. Subsequently, the stuffed envelope 90′ is closed and sealed.
Jams may occur in a mail inserter in a number of places. For example, jams may occur in the insertion station when insert material crashes into the suction cups. If crush of the inserts happens late in the cycle, the envelope transport will try to move the envelope with inserts towards the flap closing section 50, pushing material against the suction cups in the direction of envelope motion. Jams may also occur in the insertion station when the just inserted envelope crushes against the previously inserted envelope jammed in the flap closing section 50. When the moving speed of the insert material is high a crash may damage the suction cups. The damage can be serious if the insert material is thick and heavy.
It is thus advantageous and desirable to provide a method and system to reduce the damages caused to the suction cups in a jam.