Method and device for aligning a receiving envelope in a mail inserter

In a mail inserter having an envelope movement mechanism to move an envelope into an insertion station and a feeder to move a pack of insert material into an insertion position so that the insert material can be inserted into the envelope, a linear array of optical sensing elements is used to determine the position of one edge of the insert material and another linear array of optical sensing elements is used to determine the position of one edge of the receiving envelope in order to make sure that there is sufficient end clearance between the insert material and the receiving envelope. A stepper motor is used to adjust the envelope position, if the end clearance is outside a predetermined range.

TECHNICAL FIELD

The present invention relates generally to a mail inserter and, more particularly, to the adjustment of a receiving envelope in the insertion station relative to the insert material.

BACKGROUND OF THE INVENTION

A typical mailing machine has a mail inserter section where a pack of insert material is inserted into an envelope. The mailing machine may have an accumulation section where a plurality of insert documents are fed and accumulated into a stack. The accumulated documents may be folded. The mailing machine may also have a printing section for printing the insert documents or the envelopes. In order to ensure that a pack of insert material is properly inserted into a receiving envelope, the width of the envelope must be greater than the width of the pack by a certain amount. The minimum difference in width allowed on each side of the envelope is referred to as the required “end clearance”. The required end clearance depends on the thickness of the pack to be inserted into the receiving envelope. It may also depend on other factors such as the expected material tolerances, the accumulation system and the lateral offset when the accumulated documents are folded into a pack.

In general, when a pack of insert material and a receiving envelope are conveyed to the mail inserter section for mail insertion, they are separately aligned with the center line of the respective feeders. However, misalignment due to various factors may occur such that the required end clearance on one side of the receiving envelope may not be achievable.

It is thus desirable and advantageous to provide a method and system for aligning the pack of insert material relative to the receiving envelope before the insertion is carried out.

SUMMARY IF THE INVENTION

In a mail inserter having an envelope movement mechanism to move an envelope into an insertion station and a feeder to move a pack of insert material into an insertion position so that the insert material can be inserted into the envelope, a first linear array of optical sensing elements is used to determine the position of one edge of the insert material and a second linear array of optical sensing elements operated in a reflective mode is used to determine the position of one edge of the receiving envelope in order to make sure that there is sufficient end clearance between the insert material and the receiving envelope. Preferably, the first linear array is placed on the bottom of the insert material and a light source is placed on top of the insert material to cast a shadow of the insert material on the first linear array so that the edge position of the insert material can be determined from the shadow. As such, the thickness of the insert material can be taken into account when computing the error between the actual end clearance and the desired clearance. A stepper motor is used to move the envelope in a direction substantially perpendicular to the side edges of the envelope for adjusting the end clearance, if the error falls outside of a predetermined range.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1is a schematic representation of a mail inserter section in a mailing machine where a pack of insert material is inserted into an envelope. As shown inFIG. 1, the mail inserter section1has a feeder100for feeding a pack of insert material10from an upstream direction to an insertion station200. In the insertion station200, an envelope50is placed in an insertion area with the flap52of the envelope50opened to receive the insert material10. As shown, the insert10has a leading edge12and a trailing edge14defined by the feeding direction22. The insert material has a first side edge16and a second side edge18, defining the width of the insert material10. The envelope50has a first side edge56and a second side edge58, defining the width of the envelope. In order to ensure that the insert material10is properly inserted into the receiving envelope50, the width of the envelope must be greater than the width of the insert material by a certain amount so that each side of the envelope will have a sufficient end clearance. Furthermore, the envelope50must be placed at a designated location and the insert material10must be properly aligned with the width of the envelope50before the insert material10is inserted into the envelope10. While it is possible to align the insert material10against a reference, such as the center line of the feeder100, when the insert material10is moved to the mail inserter section100, mechanical tolerances and material tolerances may reduce the end clearance on one side of the envelope

In order to ensure that the required end clearance is met before the insert material10is inserted into the receiving envelope50, it is advantageous and desirable to use a sensing mechanism to sense the edge of the incoming insert material10and the edge of the receiving envelope50already placed at the insertion area. For example, an optical sensor30comprised of an array of sensing elements can be placed near the leading edge of the incoming insert material to measure the position of the first edge16with respect to a known datum. Likewise, an optical sensor70is used to measure the position of the first edge56of the receiving envelope50with respect to the same datum. The sensors30and70are operatively connected to a measurement or computation means37so that the end clearance available for the first edge56of the envelope50can be obtained. Based on technology development data, the minimum desired clearance is known and the error between the desired clearance and the measured end clearance can be computed. If the error exceeds a pre-determined amount, the envelope50is laterally shifted along direction80by a movement mechanism.

In one embodiment of the present invention, the receiving envelope50is held in a single nip formed by a roller222and one or more idlers224, as shown inFIGS. 2 and 3. The roller222is operatively connected to a motor220which is adapted to rotate along a rotation direction84along the rotational axis of the roller222in order to place the envelope50at a designated insertion area210. A linear drive230is used to move the envelope50laterally by an “error distance” so as to create at least on one side of the envelope50the minimum amount of end clearance required to successfully insert the insert material10. The linear drive230comprises a lead screw and a stepper motor, for example, can be used to move the roller222along the lateral direction80.

It is understood that when the required end clearance is achieved at the first edge56of the envelope50, the required end clearance is also available at the second edge58.

As shown inFIG. 3, the insert material10is supported by a supporting deck110and moved into the receiving envelope50by a conveyor120, for example. No lateral movement on the insert material is necessary to achieve the required end clearance.

A light source40is used to provide the light beam for optical sensing, as shown inFIG. 4. When the optical sensor30is partially covered by an incoming pack of insert material, a shadow is cast on the optical sensor30. The optical sensor30can be a CCD (Charge Coupled Device) linear sensor array, for example. Using such a light source to cast a shadow, a thickness of the pack can be taken into account when computing the error between the actual clearance and the desired clearance. It has been found that the edge position of a pack of insert material up to 6.0 mm thick can be accurately measured with regard to the required end clearance.

To measure the edge position of the envelope50, it is possible to use a CCD linear sensor array in reflective mode. As shown inFIG. 5, the position of the edge56of the envelope can be sensed by the reflection of light from the envelope. CCD linear arrays with an approximate linear resolution of 200 DPI (dot-per-inch) can be used for edge measurement, for example. The CCD linear sensor arrays30,70and the stepper motor in the movement mechanism230can be read and actuated by a dedicated microprocessor associated with the computing means, for example.

It would be appreciated by persons skilled in the art that there are other ways to achieve the required end clearance. For example, the measurement of the envelope edge can be carried out using an optical sensor in a through beam mode instead of the reflective mode as illustrated.

Thus, although the invention has been described with respect to one or more embodiments thereof, it will be understood by those skilled in the art that the foregoing and various other changes, omissions and deviations in the form and detail thereof may be made without departing from the scope of this invention.