SINGULATING SHEET FEEDER

Abstract

A singulating sheet feeder includes a deck for slidably supporting a plurality of sheets and a drive system for moving the sheets along the deck. The drive system includes a drive element for engaging a lowermost sheet to move the sheets into a shingled arrangement. The sheet feeder further includes a transport element for transporting the lowermost sheet away from the plurality of sheets and a separator element proximate to the transport element including a substantially planar surface for engaging leading edges of subsequent sheets to retard motion of the subsequent sheets as the lowermost sheet is transported, wherein the substantially planar surface is disposed at an acute angle to the deck.

Description

FIELD OF THE INVENTION

The present invention relates to a sheet feeder and, more particularly, to a sheet feeder for singulating sheets.

BACKGROUND OF THE INVENTION

Inserter systems are used to create mailpieces for a range of applications. Inserters receive paper in a feeder, then utilize a generally modular array of components to carry out the various processes associated with mailpiece creation. The processes include preparing documents, assembling the documents associated with a given mailpiece, adding any designated inserts, stuffing the assembly into an envelope, and printing information on the envelope.

Some inserter systems utilize web feeders, in which paper is provided from a roll or a fan-fold stack for processing to form documents. Such documents may comprise utility bills or financial statements, for example. Other systems utilize cut-sheet type feeders, in which a stack of individual sheets is provided to the system for processing.

A significant consideration for cut-sheet feeders is the ability to reliably deliver documents for processing, while protecting the preprinted information on the documents. Some conventional cut-sheet feeders have been found to damage documents during the feeding process. In some cases, documents printed on sensitive grades of paper have been scuffed or scratched. In other cases, documents printed using certain toners have had the printed content smudged or transferred to other documents.

SUMMARY OF EXEMPLARY ASPECTS

In the following description, certain aspects and embodiments of the present invention will become evident. It should be understood that the invention, in its broadest sense, could be practiced without having one or more features of these aspects and embodiments. It should also be understood that these aspects and embodiments are merely exemplary.

To overcome the drawbacks of the prior art and in accordance with the purpose of the invention, as embodied and broadly described herein, one aspect of the invention relates to a singulating sheet feeder comprising a deck for slidably supporting a plurality of sheets and a drive system for moving the sheets along the deck. The drive system may comprise a drive element for engaging a lowermost sheet to move the sheets into a shingled arrangement. The sheet feeder may further comprise a transport element for transporting the lowermost sheet away from the plurality of sheets and a separator element proximate to the transport element comprising a substantially planar surface for engaging leading edges of subsequent sheets to retard motion of the subsequent sheets as the lowermost sheet is transported, wherein the substantially planar surface is disposed at an acute angle to the deck.

In another aspect, the invention relates to a method of singulating sheets comprising slidably supporting a plurality of sheets on a deck and moving the sheets along the deck. In one embodiment, moving the sheets comprises engaging a lowermost sheet to move the sheets into a shingled arrangement. The method may further comprise transporting the lowermost sheet away from the plurality of sheets using a transport element, and engaging leading edges of subsequent sheets with a substantially planar surface of a separator element proximate to the transport element to retard motion of the subsequent sheets as the lowermost sheet is transported, wherein the substantially planar surface is disposed at an acute angle to the deck.

Aside from the structural and procedural arrangements set forth above, the invention could include a number of other arrangements, such as those explained hereinafter. It is to be understood that both the foregoing description and the following description are exemplary only.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings,

FIG. 1 is a schematic view of an inserter system utilizing an embodiment of the singulating sheet feeder of the present invention;

FIG. 2 is a side view of a portion of an embodiment of the singulating sheet feeder of the present invention; and

FIG. 3 is a detail view of the sheet feeder shown in FIG. 2.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Reference will now be made in detail to exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

Embodiments of the singulating sheet feeder according the invention will be described with reference to certain applications in mailpiece inserter systems. It should be understood, however, that the device of the invention may be used in association with other systems configured to handle and transport sheets.

A schematic view of an inserter system 10 incorporating the singulating sheet feeder 12 of the invention is shown in FIG. 1. The illustrated exemplary inserter system 10 comprises the sheet feeder 12, which provides preprinted documents for processing. The documents, which may comprise bills or financial statements, for example, are provided by the sheet feeder 12 as individual cut sheets.

The documents next move to an accumulator 14, where the documents for respective mailpieces are assembled and folded. The folded accumulations next move to a buffer 16, which holds the accumulations for sequential processing. The accumulations next move to a chassis 18. As each accumulation moves through the chassis 18, inserts from a plurality of feeder modules 20 are added to the accumulation.

The accumulations next enter an insertion area 22, where the finished accumulations are stuffed into envelopes provided by an envelope hopper 24, and the envelopes are sealed. The stuffed, sealed envelopes next pass through a transport system 26, which may invert the accumulations or maintain their orientation, depending on the application.

The envelopes then enter a printing area 28, where markings, such as a postage indicia and/or address information, for example, are applied using a printer 30. Finally, the completed mailpieces are deposited on a conveyor 32.

An embodiment of the singulating sheet feeder 12 will be described with reference to FIG. 2.

As discussed above, in some inserter systems the sheet feeder is arranged as the first module of a modular system. Accordingly, the sheet feeder 12 comprises a deck 34 for slidably supporting a plurality of sheets. The sheets comprise the preprinted documents that will form the mailpieces produced by the inserter system. Thus, the sheets may comprise statements, such as billing statements or banking statements, for example, or any other type of reports or information.

Inserter systems are capable of producing a large number of mailpieces in a given production run due to high processing speeds. Accordingly, a large group of sheets, which will form the mailpieces, may be placed on the deck at the beginning of a run.

The sheet feeder 12 further comprises a drive system 36 for moving the sheets along the deck 34. The drive system 36 may comprise multiple stages for moving the sheets in a controlled manner. For example, the drive system 36 may comprise an upstream portion, configured to move the bulk of the sheets in a continuous mode, and a downstream portion, configured to move a subset of the sheets sequentially.

In some embodiments, the drive system 36 comprises a drive element 38 for engaging a lowermost sheet to move the sheets into a shingled arrangement. In the embodiment shown in FIG. 2, the drive element 38 comprises a belt. In one example, the belt may comprise rubber or another material having a relatively high coefficient of friction for engaging the sheets for movement. Other types of drive elements may also be used. In addition, one or more drive elements may be used.

As the sheets are moved into the shingled arrangement, the sheets in the group begin to spread out in the direction of the transport path P, with the lower sheets in the group moving forward to be processed first. The lowermost sheet is the lead sheet and is processed first.

The sheet feeder 12 further comprises a transport element 40 for transporting the lowermost sheet away from the plurality of sheets. In the illustrated embodiment, the transport element 40 comprises a selectively rotatable roller. The roller in some embodiments is provided with a coating having relatively high coefficient of friction for engaging the sheets for movement. Other transport elements may also be used. In one embodiment, the drive element 38 and the transport element 40 are driven simultaneously to ensure precise transport of the lowermost sheet for downstream processing.

The sheet feeder 12 further comprises a separator element 42 proximate to the transport element 40. The separator element 42 comprises a substantially planar surface 44 for engaging leading edges of subsequent sheets to retard motion of the subsequent sheets as the lowermost sheet is transported. In the illustrated embodiment, the separator element 42 is stationary during the transport of sheets.

As shown in FIG. 2, the substantially planar surface 44 of the separator element 42 is disposed at an acute angle A to the deck 34. In one embodiment, the angle A ranges from approximately 50 degrees to approximately 70 degrees. In another embodiment, the angle A is approximately 60 degrees.

Unexpectedly, the separator element according to the invention does not utilize a surface having a high coefficient of friction, such as that provided by coatings or surface roughness, as in conventional devices. Rather, experimentation and testing have shown that superior results may be achieved in sheet singulation using a separator element having certain geometric features described herein. Due to the geometric features incorporated in the device of the invention, there is no need for the substantially planar surface 44 of the separator element to have a high coefficient of friction to assist in retarding the pieces to be held.

In one embodiment, the substantially planar surface 44 has an average surface roughness of approximately 10 microns or less. In one example, a separator element 42 was made from 2024 aluminum having a machined finish. In another example, the 2024 aluminum was coated with a nickel alloy to prevent premature wear due to the abrasive nature of particulate matter used in the paper-making process. Other alloys or other non-metallic compositions having a relatively low coefficient of friction may also be used.

In the illustrated embodiment, the planar surface 44 of the separator element 42 is disposed upstream of a contact point C between the transport element 40 and the lowermost sheet. In one example, the downstream edge 46 of the planar surface 44 is disposed 3 mm upstream of the contact point C. In other embodiments, the downstream edge 46 is located approximately at contact point C or downstream of contact point C.

In some embodiments, the separator element 42 according to the invention comprises a polygonal prism defining multiple substantially planar surfaces. In the embodiment shown in FIG. 2, the separator element 42 comprises a triangular prism mounted on a shaft 48. Other polygonal prisms may also be used.

In the illustrated embodiment, the separator element is selectively pivotable, as indicated by the curved arrow, to dispose a desired one of the multiple substantially planar surfaces at an acute angle to the deck 34. In such an arrangement, when a given surface has become worn or damaged, the separator element may be pivoted about its center 49 to present a new surface for subsequent use.

As shown in FIG. 2, the separator element 42 defines a gap G with respect to the transport element 40 in a direction perpendicular to the deck 34. In some embodiments, the gap has a height at least as large as a thickness of a sheet. In one example, the gap G is approximately equal to the thickness of a sheet. The gap G may also be greater than or less than the thickness of a sheet, depending on certain material properties of the sheets.

The shaft 48 illustrated in FIG. 2 forms a portion of an adjustment mechanism 50, supported by the device housing (not shown), for example, that allows a user to vary the size of the gap G, as well as the position of the separator element 42 along the transport path P.

In one embodiment, the sheet feeder 12 further comprises a take-away transport element 52 downstream of the transport element 40. The take-away transport element 52 comprises a driven roller 54 and an opposing follower roller 56 in the illustrated embodiment. In one embodiment, the take-away transport element 52 is driven simultaneously with the drive element 38 and the transport element 40 to ensure precise transport of the lowermost sheet for downstream processing.

In operation, a group of preprinted sheets are placed on the deck 34 of the sheet feeder 12. The drive system 36 is activated to move the sheets along the deck 34. The drive element 38 engages the lowermost sheet of the group and moves the sheets into a shingled arrangement.

In one example, the separator element 42 is adjusted so that the gap G with respect to the transport element 40 is slightly greater than the thickness of the sheets in the group being processed. In one example, the gap G is set to approximately 1.5 times the thickness of the sheets. As discussed above, other gap sizes may also be used.

As the sheets proceed along the deck 34, as shown in FIG. 3, the lowermost sheet 58 passes between the transport element 40 and the separator element 42 through the gap G, while the leading edges of the subsequent sheets 60-66 engage the substantially planar surface 44 of the separator element 42.

The action of the subsequent sheets 60-66 against the planar surface 44 creates a force on the lowermost sheet 58, which acts through the next subsequent sheet 60, i.e., the sheet adjacent to the lowermost sheet 58. That force creates a normal force between the transport element 40 and the lowermost sheet 58 that allows the transport element 40 to engage the lowermost sheet 58 and transport that sheet away from the group of sheets.

The angle of presentation of the planar surface 44 of the separator element 42, resulting from the acute angle A, the gap G, and the relative position along the transport path P, may mitigate the excessive forces generated by a wedging effect encountered in some conventional devices, where the subsequent sheets are compressed into a narrow space as the sheets are advanced.

The lowermost sheet 58 is then engaged by the take-away transport element 52, shown in FIG. 2, and transported for downstream processing.

The next subsequent sheet 60 then becomes the lowermost sheet and the process continues until all of the shingled sheets have been transported for downstream processing.

It will be apparent to those skilled in the art that various modifications and variations can be made to the structure and methodology described herein. Thus, it should be understood that the invention is not limited to the examples discussed in the specification. Rather, the present invention is intended to cover modifications and variations.

Claims

1. A singulating sheet feeder, comprising:

a deck for slidably supporting a plurality of sheets;

a drive system for moving the sheets along the deck, the drive system comprising a drive element for engaging a lowermost sheet to move the sheets into a shingled arrangement;

a transport element for transporting the lowermost sheet away from the plurality of sheets; and

a separator element proximate to the transport element comprising a substantially planar surface for engaging leading edges of subsequent sheets to retard motion of the subsequent sheets as the lowermost sheet is transported, wherein the substantially planar surface is disposed at an acute angle to the deck.

2. The sheet feeder of claim 1, wherein the transport element comprises a selectively rotatable roller.

3. The sheet feeder of claim 1, wherein the acute angle ranges from approximately 50 degrees to approximately 70 degrees.

4. The sheet feeder of claim 3, wherein the acute angle is approximately 60 degrees.

5. The sheet feeder of claim 1, wherein the substantially planar surface has an average surface roughness of approximately 10 microns or less.

6. The sheet feeder of claim 1, wherein the substantially planar surface is disposed proximate to a contact point between the feeding element and the lowermost sheet.

7. The sheet feeder of claim 1, wherein the separator element comprises a polygonal prism defining multiple substantially planar surfaces.

8. The sheet feeder of claim 7, wherein the separator element is selectively pivotable to dispose a desired one of the multiple substantially planar surfaces at an acute angle to the deck.

9. The sheet feeder of claim 1, wherein the separator element defines a gap with respect to the feeding element in a direction perpendicular to the deck.

10. The sheet feeder of claim 9, wherein the gap has a height approximately as large as a thickness of a sheet.

11. The sheet feeder of claim 9, wherein the separator element is adjustably mounted to allow the gap to be varied.

12. A method of singulating sheets, comprising:

slidably supporting a plurality of sheets on a deck;

moving the sheets along the deck, wherein moving comprises engaging a lowermost sheet to move the sheets into a shingled arrangement;

transporting the lowermost sheet away from the plurality of sheets using a transport element; and

engaging leading edges of subsequent sheets with a substantially planar surface of a separator element proximate to the transport element to retard motion of the subsequent sheets as the lowermost sheet is transported, wherein the substantially planar surface is disposed at an acute angle to the deck.

13. The method of claim 12, wherein the transport element comprises a selectively rotatable roller.

14. The method of claim 12, wherein the acute angle ranges from approximately 50 degrees to approximately 70 degrees.

15. The method of claim 14, wherein the acute angle is approximately 60 degrees.

16. The method of claim 12, wherein the substantially planar surface has an average surface roughness of approximately 10 microns or less.

17. The method of claim 12, wherein the substantially planar surface is disposed proximate to a contact point between the feeding element and the lowermost sheet.

18. The method of claim 12, wherein the separator element comprises a polygonal prism defining multiple substantially planar surfaces.

19. The method of claim 18, further comprising selectively pivoting the separator element to dispose a desired one of the multiple substantially planar surfaces at an acute angle to the deck.

20. The method of claim 12, wherein the separator element defines a gap with respect to the feeding element in a direction perpendicular to the deck.

21. The method of claim 20, wherein the gap has a height approximately as large as a thickness of a sheet.

22. The method of claim 20, further comprising adjusting a position of the separator element to vary the gap.