Patent Publication Number: US-7717418-B2

Title: Envelope conveying and positioning apparatus and related methods

Description:
CROSS-REFERENCE 
     This application is generally related to the following co-pending U.S. patent applications: Ser. No. 12/231,739, entitled “Apparatus for Guiding and Cutting Web Products and Related Methods;” Ser. No. 12/231,753, entitled “Inserting Apparatus for Discrete Objects into Envelopes and Related Methods;” Ser. No. 12/231,754, entitled “Transporting Apparatus for Discrete Sheets into Envelopes and Related Methods;” Ser. No. 12/231,730, entitled “Conveying Apparatus for Envelopes and Related Methods;” and Ser. No. 12/231,749, entitled “Transporting Apparatus for Web Products and Related Methods”, all being filed on even date herewith and expressly incorporated herein by reference in their entirety. 
     TECHNICAL FIELD 
     The present invention generally relates to converting equipment and, more particularly, to apparatus for converting paper into sheets, collating and automatic envelope stuffing operations. 
     BACKGROUND 
     Converting equipment is known for automatically stuffing envelopes. Such equipment may include components for feeding a pre-printed web of paper, for cutting such web into one or more discrete sheets for collating sheets, and for feeding such discrete sheet collations into envelopes. Such equipment may further include components to convey the stuffed envelopes to a specified location. The industry has long known devices which accomplish these and other functions. However, improvements are needed where high volumes of paper piece count and high speeds are required without sacrificing reliability accuracy and quality of end product. 
     More particularly, a large roll of paper is typically printed in discrete areas with piece specific information. That is, the initial roll of paper comprises vast numbers of discrete areas of already-printed indicia-specific information with each discrete area defining what is to eventually comprise a single page or sheet of indicia specific information. To complicate the process, a variable number of sheets with related indicia must be placed into the envelopes so that the content of one envelope varies from the content of another by sheet count and, of course, by the specific indicia on the included sheets. As one example, financial reports of multiple customers or account specifics may require a varied number of customer or account specific sheets to be cut, respectively collated, stuffed and discharged for delivery. Thus, the contents of each envelope include either a single sheet or a “collation” of from two to many sheets, each “collation” being specific to a mailing to an addressee. 
     In such an exemplary operation, a financial institution might send billing or invoice information to each of its customers. The billing information or “indicia” for one customer may require anywhere from one final sheet to a number of sheets which must be collated, then placed in that customer&#39;s envelope. While all this information can be printed in sheet size discrete areas, on a single roll, these areas must be well defined, cut, merged or collated into sheets for the same addressee or destination, placed into envelopes, treated and discharged. Thus, a system for conducting this process has in the past included certain typical components, such as a paper roll stand, drive, sheet cutter, merge unit, accumulate or collate unit, folder, envelope feeder, envelope inserter, and finishing and discharge units. Electronic controls are used to operate the system to correlate the functions so correct sheets are collated and placed in correct destination envelopes. 
     In such multi-component systems, the pass-through rate from paper roll to finished envelope is dependent on the speed of each component, and overall production speed is a function of the slowest or weakest link component. Overall reliability is similarly limited. Moreover, the mean down time from any malfunction or failure to repair is limited by the most repair-prone, most maintenance consumptive component. Such systems are capital intensive, requiring significant floor plan or footprint, and require significant labor, materials and maintenance capabilities and facilities. 
     In some such systems, envelopes are fed from a magazine or conveying device that applies a constant pressure against a stack of envelopes, and with the force required to remove one of the envelopes from the stack being thus fixed. This may result in a force that is too high or too low for the operation. If the pressure is too high, for example, other components of the system may be unable to remove an envelope from the stack without damaging the envelope. 
     Other such systems may include motors that turn on and off or that reverse in order to adjust the pressure exerted upon the stack of envelopes. Such systems may present limitations as to the attainable speeds of operation. 
     Accordingly, it is desirable to provide improved envelope conveying and positioning apparatus for a subsequent insertion of discrete paper or film objects into the envelopes in a high speed handling machine. It is also desirable to provide a converting apparatus and related methods that address inherent problems observed with conventional converting apparatus. 
     SUMMARY 
     To these ends, a preferred embodiment of the invention includes managing the bias force exerted against a substantially horizontal stack of envelopes toward a feed position by biasing the stack against a feed pressure sensor apparatus proximate a feed position and controlling the bias force in response to the sensed feed pressure. 
     More particularly, an apparatus for processing envelopes includes a support plate and a pressure sensing lever for supporting a stack of envelopes in a generally upright orientation. The pressure sensing lever pivots in accordance with pressure exerted by the stack of envelopes. In some embodiments, a feeding apparatus is operatively controlled by a sensor monitoring the pivoting of the sensing lever such that pivotal movement of the pressure sensing lever is detected by the sensor and the feeding apparatus is controlled to change the pressure exerted against the stack of envelopes in response to sensed pressure changes. 
     In one embodiment, an apparatus is provided for processing envelopes in a generally upright orientation. The apparatus includes a frame structure and a support plate that is mounted on the frame structure and which is generally stationary relative to the support plate. The support plate has a generally flat surface for supporting a generally horizontal stack of the envelopes in a generally upright orientation. A pressure sensing lever of the apparatus is mounted on the frame structure and has a sensing surface oriented transverse to the support plate, with the pressure sensing lever being pivotally mountable and moveable in response to pressure exerted by the stack of the envelopes. The pressure sensing lever is positioned relative to the support plate to permit a leading portion of a first envelope of the stack to extend into a region downstream of the sensing surface. 
     The apparatus may include a feeding apparatus for moving the stack toward the pressure sensing lever. A sensor is operatively coupled to control the stack bias or feeding apparatus. The sensor is configured to detect pivotal movement of the pressure sensing lever, with the feeding apparatus being responsive to a signal received from the sensor corresponding to the pivotal movement of the pressure sensing lever. 
     Preferably the pressure sensing lever is biased so its upper end engaging the lead-most envelope is biased in an upstream direction toward the envelope stack. The pressure sensing lever may include first and second elongate portions that are respectively disposed on opposite sides of a pivot, with the first portion including the sensing surface and the second portion being operatively coupled to or otherwise associated with the sensor, with the second portion being longer than the first portion. The apparatus may include a stop member in fixed orientation relative to the support plate and configured to orient the stack of envelopes at an acute angle relative to the support plate. The stop member may be configured to support a front surface of the first envelope of the stack. The stop member is oriented transversely to the support plate for supporting the stack of envelopes, with the feeding apparatus being configured to adjust the bias or pressure exerted on the envelopes toward the stop member in response to the signal received from the sensor. 
     The sensor may, for example, be an infrared sensor. The support plate may include at least one ramp for receiving envelopes of the stack fed by the feeding apparatus. The apparatus may additionally include an envelope pick-up element movable to engage the leading portion of the first envelope to thereby remove the first envelope from the stack. The envelope pick-up element may be rotatable to engage at least two discrete portions of the first envelope. The stop member may be adjustable in accordance with a pre-determined length of the envelopes. 
     In another embodiment, an automatic envelope stuffing apparatus is provided having a first end associated with feeding of a roll of paper, a processing apparatus for converting the roll of paper into discrete sheets, and a stuffing apparatus for inserting the discrete sheets into envelopes. The apparatus includes a frame structure, and a support plate mounted on the frame structure and generally stationary relative to the frame structure, with the support plate having a generally flat surface for supporting a stack of the envelopes in a generally upright orientation. A pressure sensing lever is mounted on the frame structure and has a sensing surface oriented transverse to the support plate, with the pressure sensing lever being pivotally movable in response to pressure exerted by the stack, with the pressure sensing lever being positioned relative to the support plate to permit a leading portion of a first envelope of the stack to extend into a region downstream of the sensing surface. 
     In yet another embodiment, a method is provided for processing stack of envelopes. The method includes applying a first force against a stack of envelopes to move them in a travel direction, and engaging a first envelope of the stack with a pivotally movable surface. The movable surface is pivotally moved in response to the first feed force and a second feed force is applied against a stack of envelopes that is different from the first force. Applying a second feed force may, for example, include applying a feed force that is lower than the first feed force. The second feed force may be applied in response to pivotal movement of the movable surface. The method may additionally or alternatively include moving the stack of envelopes in a generally upright orientation. 
     In another embodiment, a method is provided for feeding single envelopes from a stack of envelopes. The method includes biasing the stack toward an envelope feed position and sensing pressure on a lead envelope at the feed position resulting from the biasing. The biasing is controlled in response to the sensing. 
     Such apparatus and methods are particularly useful in a paper converting and envelope stuffing system contemplating improved paper converting and sheet inserting apparatus and methods, modular based, and having improved paper handling apparatus, servo driven components, improved sensor density and improved control concepts controlling the system operation. One or more of the embodiments of the invention contemplate the provision of an improved transporting apparatus which can be used as a module of a modular paper converting and sheet insertion system where human capital, required space, required equipment, maintenance, labor and materials and facilities therefore are reduced compared to conventional systems of similar throughput. 
     More specifically, such improved apparatus and methods contemplate a plurality of functional modules providing the following functions in a series of modules of like or dissimilar modules where a specific module is multi-functional. The functions comprise:
         printed paper roll handling/unwinding;   paper slitting and cutting;   sheet collation and accumulation;   sheet folding;   transportation for interfacing with inserts;   envelope feeding;   collation interfacing and insertion; and   envelope treating and discharge.       

     More particularly, one or more aspects of the invention may contemplate, without limitation, new and unique apparatus and methods for:
         (a) guiding a web of the paper or film containing the printed indicia into a cutter apparatus;   (b) processing the web through slitting and transverse-cutting operation;   (c) transporting and merging discrete pieces of the insert;   (d) accumulating predefined stacks of discrete pieces of the insert;   (e) guiding and transporting a stack of discrete pieces of the insert toward an envelope-filling station;   (f) transporting individual envelopes toward the envelope-filling station;   (g) creating and processing a stack of the envelopes prior to the envelope-filling process; and   (h) processing an individual envelope from the stack of envelopes and through the envelope-filling station.       

     While the combination of the particular functions in the particular modules are unique combinations, the invention of this application lies primarily in the paper transporting apparatus and methods described herein. 
    
    
     
       BRIEF DESCRIPTION OF FIGURES 
         FIG. 1  is a perspective view illustrating a portion of a converter for stuffing envelopes with selected paper or film objects; 
         FIG. 2  is an elevation view of a portion of a stuffing or inserting apparatus of the converter of  FIG. 1 , more specifically associated with the encircled area  2  of  FIG. 1 ; 
         FIG. 3  is a perspective view of a vacuum drum and main roller of the inserting apparatus of  FIG. 2 ; 
         FIG. 4A  is a view similar to  FIG. 3 , additionally showing a sheet inserting assembly of the inserting apparatus of  FIG. 2 ; 
         FIG. 4B  is a view similar to  FIG. 4A  showing an envelope in a different position relative to that shown in  FIG. 4A ; 
         FIG. 4C  is a view similar to  FIGS. 4A-4B ; showing the envelope thereof in yet a different position; 
         FIG. 4D  is a view similar to  FIGS. 4A-4C , showing the envelope thereof in yet a different position relative to  FIGS. 4A-4C ; 
         FIG. 5  is a view similar to  FIG. 2  showing a stage of an inserting process; 
         FIG. 6  is a view similar to  FIGS. 2 and 5 , showing a portion of an envelope conveying apparatus; 
         FIG. 7  is a perspective view of a portion of the envelope conveying apparatus of  FIG. 6 ; 
         FIG. 8  is a view similar to  FIG. 6 , showing a stage in a process for conveying envelopes; 
         FIG. 8A  is a view similar to  FIG. 7  showing a portion of the envelope conveying apparatus at the stage illustrated in  FIG. 8 ; and 
         FIG. 9  is a view similar to  FIGS. 7 and 8A , showing a different stage in the processing for conveying envelopes. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to the figures and, more particularly to  FIG. 1 , a portion of an exemplary converter  10  is illustrated for processing a web  12  of paper or film. Although not shown, the web  12  processed by the converter  10  originates, for example, from a roll (not shown) of material containing such web. The roll is generally associated with a first end  14  of the converter  10  and is unwound in ways known in the art, for example, by driving a spindle receiving a core of the roll or by contacting a surface of the roll with a belt or similar device. Typically, the web  12  is pre-printed with indicia in discrete areas. 
     The web  12  thus travels in a machine direction, generally indicated by arrow  15 , through several modules that make up the converter  10 . In the exemplary embodiment of  FIG. 1 , converter  10  cuts the web material into discrete sheets (corresponding to the “areas”) of material (“inserts”) and feeds them into envelopes fed generally from an opposite end  16  of converter  10 . Converter  10  may further convey the envelopes containing the inserts away from the shown portion of the converter  10  for subsequent processing or disposition. The exemplary converter  10  includes, as noted above, several modules for effecting different steps in the processing of the web and the inserts resulting therefrom, as well as processing of the envelopes. Those of ordinary skill in the art will readily appreciate that converter  10  may include other modules in addition or instead of those shown herein. 
     A first of the shown modules, for example, is a cutting module  30  relatively proximate first end  14  of the converter  10  and which cuts the web  12  into discrete objects such as inserts (not shown) for subsequent processing. A conveying module  40  controls and transports the discrete inserts received from the cutting module and feeds them into a folding and buffering module  50 . Module  50  may, if necessary, form stacks of the discrete inserts for subsequent processing, for example, if the intended production requires stuffing the envelopes with inserts defined by more than one discrete sheet. Module  50  folds the discrete inserts, if required by the intended production, along a longitudinal axis of the discrete inserts disposed generally along the machine direction. Moreover, module  50  accumulates, collates or buffers sets of the discrete sheets into individually handled stacks, if the particular production so requires. 
     With continued reference to  FIG. 1 , an uptake module  60  takes the inserts from folding and buffering module  50  and cooperates with components of a stuffing module  70  to transport the inserts and feed them into envelopes. The envelopes, in turn, are handled and fed toward the stuffing module  70  by an envelope conveyor  80 . A conveying assembly  90  is operatively coupled to the stuffing module  70  and the envelope conveyor  80  for conveying the stuffed or filled envelopes away from the shown portion of converter  10  for subsequent processing or disposition. 
     With reference to  FIG. 2 , an exemplary stuffing module  70  is illustrated in greater detail. Module  70  includes a frame  72  that supports an inserting system or apparatus  100  that feeds the discrete sheets or inserts toward the envelopes, feeds the envelopes toward the discrete sheets, inserts the discrete sheets into the envelopes, and moves the stuffed envelopes toward the conveying assembly  90  ( FIG. 1 ). To these ends, apparatus  100  includes a feeding apparatus  110  in the form of a belt assembly  112  rotatable in a closed loop (only partially shown) and driven by a toothed wheel  114 . A plurality of fingers  116  extend from the belt assembly  112  and are spaced along the length of the belt assembly  112 . Fingers  116  engage the trailing edges of inserts  120  to thereby move them toward envelopes  130  in the general direction of arrow  134  while the envelopes  130  are moved toward the inserts  120  in the general direction of arrow  138 . A plurality of deflectable elements in the form, in this exemplary embodiment, of bristles  140 , form part of support elements  142  of the feeding apparatus  110 . The bristles  140  engage the inserts  120  as they move toward the envelopes  130 . 
     As noted above, the envelopes  130  first move in the general direction of arrow  138  toward the inserts  120 . This movement of the envelopes  130  is provided by cooperation between a rotating vacuum drum  150  and a rotating main roller  156  that nip each envelope  130 . Vacuum drum  150  and main roller  156  are supported from a frame  158  (shown in phantom in  FIG. 3 ) of stuffing module  70 . When the vacuum drum  150  and main roller  156  rotate in directions opposite one another, the engagement with an envelope  130  disposed between them results in the envelope  130  moving toward the inserts  120  at an insertion or stuffing station. More specifically, the vacuum drum  150  rotates in the direction indicated by arrow  160  (counterclockwise) while the main roller  156  rotates in the direction indicated by arrow  166  (clockwise). A distance between the vacuum drum  150  and main roller  156  is suitably chosen to effectively nip an envelope  130  therebetween. In this regard, therefore, this distance is chosen based on factors including but not limited to a predetermined thickness of the envelopes  130 . Although not shown, one or both of the vacuum drum  150  and main roller  156  may be adjustable to thereby permit adjustment of the distance between them. 
     The materials for vacuum drum  150  and main roller  156  are suitably chosen to permit engagement and movement of the envelopes in the direction of arrow  138 . For example, and without limitation, at least an outer surface if not a substantial portion of the main roller  156  may be made of rubber, urethane or other materials providing a predetermined level of friction against the envelopes  130 . Likewise, at least a surface  170  of vacuum drum  150  is made out of a metal such as stainless steel, which may further be coated with a release-type surface or texture to prevent, for example, build-up of adhesive or other materials on the surface  170 . 
     Vacuum drum  150  and main roller  156  receive each envelope from guides  180  (only one shown in the view of  FIG. 2 ) defined by oppositely disposed rails  182   a ,  182   b  that guide the envelopes  130 . More specifically, rails  182   a,    182   b  define a space between them that receives the lateral portions  130   a  ( FIG. 4 ) of each envelope  130 . Two pairs (only one shown) of driven secondary rollers  190   a ,  190   b  are positioned between the guides  180  to facilitate movement of the envelopes guided by guides  180 . More specifically, rollers  190   a ,  190   b  rotate in directions opposite one another (arrows  192   a ,  192   b ) and are positioned to nip a center portion of the envelopes  130  to thereby move the envelopes  130  toward the inserts  120 . 
     With continued reference to  FIG. 2  and with additional reference to  FIG. 3 , vacuum drum  150  includes a plurality of holes  200  on the surface  170  and configured to permit movement of the envelopes  130  with rotation of vacuum drum  150 . More particularly, holes  200  are in fluid communication with a schematically-depicted vacuum source  204  to generate a negative pressure at the surface  170  of the vacuum drum  150 . The negative pressure engages the envelopes  130  thereby retaining the envelopes  130  and preventing or minimizing movement of the envelopes  130  relative to vacuum drum  150  as vacuum drum  150  rotates. 
     In this exemplary embodiment, the vacuum source  204  is continuously operating i.e., it is continuously in an “ON” condition. Moreover, the vacuum drum  150  is electrically controlled, for example, servo-controlled to facilitate the selective application of negative pressure against selected groups of the holes  200  and thus, selected portions of the surface  170  of vacuum drum  150 . Selection of the holes  200  to which the vacuum source  204  directs the negative pressure is chosen, for example, based on a pitch or length  130 L of the envelopes  130 . In this regard, the vacuum drum  150  can be rotated relative to the vacuum source  204  to align vacuum source  204  with the desired group of holes  200  that enable engagement, by rotating surface  170 , of a particular type of envelope  130  and/or a selected portion of the envelope  130 . For example, vacuum drum  150  can be rotated relative to the vacuum source  204  such that negative pressure is not applied to the trailing portion of the envelope  130 , which may facilitate release of the envelope  130  from vacuum source  204 . 
     Vacuum drum  150  includes two lateral portions  150   a ,  150   b  having similar structures and rotatable from a common central core  150   c . The holes  200 , in this regard, are positioned on both of the lateral portions  150   a ,  150   b  to thereby permit even engagement of the envelopes  130 . Accordingly, the exemplary arrangement of holes  200  in this embodiment prevents or at least minimizes skewing of the envelopes  130  as they travel with rotation of the vacuum drum  150 . 
     With continued reference to  FIGS. 2-3 , a ramp element  210  is coupled to the vacuum drum  150  to permit release of the envelopes  130  from the surface  170  of vacuum drum  150 . More specifically, ramp element  210  is stationary relative to the vacuum drum  150  and is positioned between the two lateral portions  150   a ,  150   b  of vacuum drum  150 . Ramp element  210  is in the form of a solid block having a surface that is generally tangential to the surface  170  of vacuum drum  150 . In operation, as an envelope  130  moves with rotation of vacuum drum  150  (arrows  160 ), a leading portion  130   f  of the envelope  130  rides over the ramp element  210  to thereby disengage the leading portion  130   f  away from the surface  170  of vacuum drum  150 . 
     Those of ordinary skill in the art will appreciate that, alternatively, ramp element  210  could take other forms, so long as it is arranged to be generally tangential to the surface  170  of vacuum drum  150 . Likewise, it is contemplated that ramp element  210  could be alternatively a moving element, rather than completely stationary, so long as it is stationary relative to the vacuum drum  150 . For example, and without limitation, an alternative embodiment may include a ramp element that moves in the same or opposite direction relative to the vacuum drum so as to define a stationary ramp element relative to vacuum drum  150 . 
     With reference to  FIGS. 4A-4D , an exemplary inserting operation is illustrated.  FIG. 4A  depicts an envelope  130  moving with rotation (arrows  160 ) of the vacuum drum  150 . Holes  200  are in engagement with most of the length of envelope  130 . The orientation of envelope  130  is such that the leading portion  130   f  thereof is a flap of the envelope. Moreover, the orientation is such that the substrate of paper  130   g  defining the flap of the envelope  130  faces the surface  170  of vacuum drum  150 , while an opposite substrate  130   h  ( FIG. 4B ) faces the main roller  156 . Those of ordinary skill will appreciate that this orientation is merely exemplary and other alternative orientations may be substituted instead. 
       FIG. 4A  also shows the leading portion  130   f  of envelope  130  beginning to engage ramp element  210 . Envelope  130  is moreover shown moving toward a pair of outer extension elements  216  and a central extension element  218  of a transporting apparatus  220 . Transporting apparatus  220  conveys the inserts  120  ( FIG. 4B ) toward the envelope  130  and includes the feeding apparatus  110  and support elements  142  ( FIG. 2 ) described above. In this exemplary embodiment, moreover, transporting apparatus  220  includes a pair of clips  232  (only one shown) extending from a frame  236  (shown in phantom) of apparatus  220 . Transporting apparatus  220 , in this embodiment, also includes a pair of guide elements  242  that facilitate guidance of the inserts  120  into an envelope  130 . The positions of clips  232  are controlled by schematically-depicted motors  232   a  (only one shown) operatively coupled through jack screws (not shown) to the clips  232  and which permit automatic adjustment of the positions of clips  232  in response to the length  130 L of the envelopes  130 . More specifically, motors  232   a  facilitate adjusting a position of clips  232  toward and away from main roller  156 . Motors  232   a  may, for example, be stepper motors such as model HRA08C available from Sick Stegmann GmbH, a member of the Sick AG Group of Waldkirch, Germany. 
     With particular reference to  FIG. 4B , the envelope  130  is shown having partially engaged the extension elements  216 ,  218  in such a way that extension elements  216 ,  218  extend into an interior portion  130   n  of the envelope  130 . At this stage of the inserting process, and relative to the stage shown in  FIG. 4A , a greater portion of the length  130 L ( FIG. 2 ) of the envelope  130  has engaged the ramp element  210  and is accordingly disengaged from surface  170  of vacuum drum  150 .( FIG. 4A ). At this stage, likewise, insert  120  is shown moving, in the direction of arrow  250 , toward the interior portion  130   n  of envelope  130 . The insert  120  is shown with a leading edge  120 L thereof headed toward the interior portion  130   n.    
     With particular reference to  FIG. 4C , a stage of the inserting process is shown in which the envelope  130  is completely or at least mostly disengaged from the surface  170  of vacuum drum  150  ( FIG. 4A ). In this regard, rotation of vacuum drum  150  is such that envelope  130  slips relative to the rotational motion of vacuum drum  150 . Clips  232  (only one shown) is depicted engaging envelope  130  so as to provide a stopping or limiting surface in the movement (arrow  138 ) of envelope  130  toward insert  120 . Fingers  116  (shown in phantom) are depicted engaging a trailing edge  120   t  of insert  120  and thereby moving the insert  120  (arrow  250 ) toward the interior portion  130   n  of envelope  130 . Clips  232 , moreover, provide a lifting action for the envelope  130  such that, upon further movement of envelope  130  in the direction of arrow  138 , a trailing edge  130   t  of envelope  130  is forced upward (arrows  260 ) and above the main roller  156 , as shown in  FIG. 4D . As used herein, the terms “upward,” “upper,” “lower,” “above,” “forward,” “front,” “back,” and derivatives thereof are not intended as limiting but rather merely reflect the illustrative orientations shown in the figures. 
     With particular reference to  FIG. 4D , a stage of the inserting process is shown in which forward movement of the fingers  116  (arrow  250 ) results in movement of the envelope in a similar direction (arrow  264 ) generally away from the transporting apparatus  220  at the insertion or stuffing station and toward the conveying assembly  90  ( FIG. 1 ), for further disposition of the stuffed envelope  130 . More specifically, at the stage of the process depicted in  FIG. 4D , the leading edge  120 L of insert  120  has reached the trailing edge  130   t  of envelope  130 . Accordingly, forward movement of the fingers  116  exerts a force, through insert  120 , upon trailing edge  130   t  of envelope  130 , thereby resulting in movement of the stuffed envelope  130  in the direction of arrow  264 . 
     With continued reference to  FIG. 4D  and with further reference to  FIG. 5 , rotation of the main roller  156  (arrow  166 ) cooperates to move the stuffed envelope  130  in the direction of arrow  264 . More particularly, a rotating conveying roller  288  is disposed so as to define a small space between conveying roller  288  and main roller  156 . Conveying roller  288  may alternatively be in the form of any other rotating element such as, for example, an irregularly-shaped rotating element and thus not limited to circular rotating element as depicted in this embodiment. Conveying roller  288  rotates in a direction (arrow  290 ) opposite that of main roller  156 . The position of conveying roller  288  as well as its direction of rotation (arrow  290 ) relative to the direction of rotation (arrow  166 ) of main roller  156  permit nipping engagement of the stuffed envelope  130  and conveying thereof in the direction of arrow  264 . In this particular embodiment, conveying roller  288  rotates in a counterclockwise direction, although this is not intended to be limiting but rather exemplary. Accordingly, rotation of the main roller  156  in the direction of arrow  166  enables movement of the envelope  130  in a first direction (arrow  138 ) during a stage of the inserting process while enabling movement of the envelope  130  in a second direction (arrow  250 ) opposite the first direction (arrow  138 ) and in an opposite side of an axis  156   a  of rotation of main roller  156  during a different stage of the process. 
     With reference to  FIGS. 6-8 ,  8 A, and  9 , and as discussed above, the secondary rollers  190   a ,  190   b  engage a central portion of each envelope  130  to thereby move the envelopes  130  along the guides  180 . In this regard, the envelopes  130  enter the guides  180  by action of a rotating pick-up element  320  that engages the leading portion  130   f , of each of the envelopes  130 . More particularly, pick-up element  320  is an irregularly shaped rotating structure having a central portion  322  and outer portions  324 , both of which include respective circumferential surfaces  322   a ,  324   a  for engaging the envelopes  130 . 
     The central portion  322  is circumferentially positioned in front of the outer portions  324 , relative to the direction of rotation (arrow  352 ) thereof. Moreover, the central portion  322  of this exemplary embodiment is separately movable relative to the outer portions  324  such that the positions of these two portions  322 ,  324  of the pick-up element  320  can be adjusted relative to one another. Adjustment may be desirable, for example, to accommodate envelopes having different lengths  130 L. Pick-up element  320  is positioned adjacent an envelope stack supporting apparatus to jointly define an envelope conveying apparatus  350 , the details of which are discussed in further detail below. 
     Pick-up element  320  rotates, in this exemplary embodiment, and as noted above, in the direction of arrow  352 . In this regard, and with particular reference to the stage of the process shown in  FIG. 6 , a leading portion, in this embodiment, in the form of a flap  131   f  of a first envelope  131  of a stack of envelopes  130  is shown prior to engagement thereof by pick-up element  320 . Moreover, the first envelope  131  is shown oriented such that the flap  131   f  is hingedly movable generally in the direction of arrow  360 . 
     With particular reference to  FIG. 7 , the pick-up element  320  is shown having partially engaged envelope  131 . More particularly, the central portion  322  of pick-up element  320  is shown having rotated sufficiently to engage the flap  131   f  of the first envelope  131 , thereby causing flap  131   f  to hingedly rotate in the direction of arrow  360 . Moreover, outer portions  324  are shown prior to engaging the first envelope  131 . 
     With particular reference to  FIGS. 8-8A , pick-up element  320  is shown having rotated (arrows  376 ,  378 ) further in the direction of arrow  352  such that the central portion  322  and the outer portions  324  have engaged the flap  131   f  of the first envelope  131 . In this regard, rotation of the outer portions  324  results in engagement of outer portions  324  with a set of follower rollers  380  made, for example and without limitation, of rubber or urethane. The position of the follower rollers  380  relative to outer portions  324  is such that they jointly nip the flap  131   f , causing rotation of follower rollers  380  (arrow  388 ) and forward movement of the envelope  131  in the direction of arrow  382 .  FIGS. 8-8A  also show partial engagement, by pick-up element  320 , of discrete portions  131   m  of envelope  131 . Engagement of discrete portions  131   m  other than flap  131   f  facilitate a smooth conveyance of envelope  131  toward the guides  180 . 
     With particular reference to  FIG. 9 , pick-up element  320  is shown having rotated (arrows  390 ) further relative to the view of  FIGS. 8-8A . The envelope  131  is shown in a position such that the lateral portions  131   a  thereof have entered guides  180  (shown in phantom). In this regard, the rails  182   a,    182   b  of guides  180  are angled relative to one another in an entry portion  180   e  of guides  180  to facilitate movement of the lateral portions  131   a  into the space defined between rails  182   a ,  182   b . In the shown view, moreover, central portion  322  of pick-up element is no longer in engagement with envelope  131 , while outer portions  324  are rotating away from envelope  131  and thereby disengaging from envelope  131 . Although not shown, as pick-up element  320  continues to rotate (arrows  390 ), it engages a new first envelope  131  from the stack of envelopes  130 . 
     Referring again to  FIG. 6 , pick-up element  320  removes the first envelope  131  from a stack of envelopes supported by an envelope conveying system  420  that feeds envelopes  130  in a continuous fashion. Envelope conveying system  420  includes a support plate  422  mounted on and stationary relative to a frame structure  424 . Support plate includes a generally flat surface  422   a  that is adapted to support a generally horizontal stack of the envelopes  130 , each in a generally upright orientation. Moreover, in this exemplary embodiment, support plate  422  includes a ramp  423  to facilitate receiving envelopes  130 . As used herein, the terms “upright” and “generally horizontal” are not intended to be respectively restricted to perfectly vertical or horizontal orientations of the envelopes  130  or the stack thereof, but rather an orientation whereby they are supported edgewise. In this regard, therefore, and as shown in  FIG. 6 , the envelopes  130  are supported edgewise (along lower edges  130   e ) in a generally upright orientation though defining an acute angle relative to the support plate surface  422   a.    
     A stop member  428  of the envelope conveying system  420  is similarly supported from the frame structure  424  and is mounted in a fixed orientation relative to the support plate  422 . Stop member  428  includes a forward portion  428   a  that supports a front or forward facing face  131   w  of the first envelope  131  of the stack of envelopes  130 . A top portion  428   b  of the stop member  428  supports upper edges  130   u  of the envelopes  130 . In this regard, the stop member  428  is vertically adjustable (arrow  429 ) to accommodate envelopes  130  of different pitches or lengths  130 L. A schematically-depicted motor  430  is operatively coupled through a jack screw (not shown) to stop member  428  to facilitate automatic adjustment of the vertical position of stop member  428  in response to length  130 L. For example, and without limitation, motor  430  may be a stepper motor model HRA08C available from Sick Stegmann GmbH, a member of the Sick AG Group of Waldkirch, Germany. Jointly, the stop member  428  and the support plate  422  support the envelopes  130  in the generally upright orientation shown in  FIG. 6 . 
     With continued reference to  FIG. 6 , a pressure sensing lever  434  of the envelope conveying system  420  is oriented generally transversely to the support plate  422  and is pivotally movable about a pivot  440  fixedly coupled to the frame structure  424 . Pressure sensing lever  434  includes a sensing surface  434   a  that engages the first envelope  131  of the stack of envelopes  130 . Pressure sensing lever  434  has a first portion  436  that includes the sensing surface  434   a  and extending from the pivot  440 . A second portion  438  of the pressure sensing lever  434  also extends from the pivot  440  and away from the first portion  436 . In this embodiment, the first portion  436  is shorter than the second portion  438 . In operation, the first envelope  131  is in a feed position and oriented such that the flap  131  f of the first envelope  131  extends into a region downstream of (i.e., behind) the sensing surface  434   a.    
     A schematically-depicted sensor  450  is operatively coupled to, or in a position to sense, the second portion  438  for controlling a feeding apparatus  460  of the envelope conveying system  420 . Feeding apparatus  460  exerts a feed force upon the stack of envelopes  120  that biases the stack toward the envelope feed position shown in  FIG. 6 . The sensor  450  is in this embodiment an infrared-type sensor, positioned to aim at an extension  462  coupled to the second portion  438  of pressure sensing lever  434  and configured to detect movement of the extension  462 . In this exemplary embodiment, extension  462  is coupled to the frame structure  424  through a spring and hook assembly  463  (shown in phantom) to guide movement of extension  462  along the directions of arrow  470 , and with a predetermined spring bias to hold the pressure sensing lever  434  against the first (i.e., lead) envelope  131 . In this regard, movement of the extension  462  (arrow  470 ) results from a corresponding movement of the first portion  436  of pressure sensing lever  434  and which is caused by a feed force exerted by the stack of envelopes  130  against sensing surface  434   a.    
     More specifically, the force exerted by the stack of envelopes  130  upon sensing surface  434   a  results from a feed or bias force applied against the stack by the feeding apparatus  460 . This feed or bias force, in turn, determines the amount of pressure acting on the first envelope  131  held between the other envelopes  130  of the stack and the forward portion  428   a  of stop member  428 . The pressure acting on the first envelope  131 , in turn, determines the force necessary to remove the first envelope  131  from the stack of envelopes  130 . 
     In this embodiment, the feeding apparatus  460  is operatively coupled to the sensor  450 . In this regard, when sensor  450  detects movement of the extension  462  (arrow  470 ), sensor  450  sends a corresponding signal to feeding apparatus  460 . In response to this signal, feeding apparatus  460  decreases or increases the amount of feed force it applies against the stack of envelopes  130  and thus, the pressure acting on the pressure sensing lever  434  and stop member  428 . Accordingly, the feeding apparatus  460  is capable of controlling the pressure acting upon the first envelope  131  of the stack of envelopes  130  to thus maintain it at a predetermined desired level to facilitate removal of the first envelope  131  from the stack. For example, and without limitation, the feeding apparatus may, during operation, feed the envelopes  130  with a first feed force and a corresponding pressure exerted against the forward portion  428   a  of stop member  428 . This first force results in pivotal movement of the pressure sensing lever  434 . The sensor  450  detects the movement of extension  462  associated with the first force. Sensor  450 , in turn, sends a corresponding signal to the feeding apparatus  460  which, in response to the signal, adjusts the feed force with which it feeds the envelopes  130 , for example to a lower, second feed force. This lower second force results in a lower pressure exerted against forward portion  428   a  of stop member  428  which, in turn, results in a smaller deflection of pressure sensing lever  434 . 
     While the present invention has been illustrated by a description of various embodiments and while these embodiments have been described in considerable detail, it is not intended to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and method, and illustrative example shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of the general inventive concept.