Abstract:
A postal meter mail piece feeder comprising a hopper section, a singulating section and a mail piece turner. The hopper section comprises a bottom mail piece support deck for supporting mail pieces thereon, a rear wall having a mail piece drive for contacting and moving the mail pieces along the support deck, and a front stop for biasing the mail pieces towards the rear wall. The singulating section is downstream from the hopper section and comprises a retard drive and a sensor connected to the retard drive. The mail piece turner is downstream from the singulating section and comprises a turning surface for turning the mail pieces about 90° from the singulating section for entry into a postage applying section of a postage meter.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]    This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application No.: 60/190,433 filed Mar. 17, 2000, which is hereby incorporated by reference in its entirety. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention relates to postage meters and, more particularly, to a mail piece feeder.  
           [0004]    2. Prior Art  
           [0005]    Many different types of mail piece feeders for postage meters are well known in the art. Typically, these mail piece feeders can include a hopper in which mail pieces are stacked in a column; each mail piece being generally horizontally orientated, or at least feed away from the hopper in a horizontal orientation by a singulating or separating section. A problem with such feeders is that the vertical size of the stack of mail pieces in the hopper is usually limited. Too high a stack can cause feeding problems because of too much weight on the bottom mail piece. There is a desire to allow larger quantities of mail pieces to be located in a postage meter mail piece feeder hopper at any given time.  
         SUMMARY OF THE INVENTION  
         [0006]    In accordance with one embodiment of the present invention, a postal meter mail piece feeder is provided comprising a hopper section, a singulating section and a mail piece turner. The hopper section comprises a bottom mail piece support deck for supporting mail pieces thereon, a rear wall having a mail piece drive for contacting and moving the mail pieces along the support deck, and a front stop for biasing the mail pieces towards the rear wall. The singulating section is downstream from the hopper section and comprises a retard drive and a sensor connected to the retard drive. The mail piece turner is downstream from the singulating section and comprises a turning surface for turning the mail pieces about 90° from the singulating section for entry into a postage applying section of a postage meter.  
           [0007]    In accordance with one method of the present invention, a method of feeding mail pieces from a hopper comprising steps of feeding the mail pieces between a feed drive and a retard drive in a substantially vertical orientation; sensing presence of more than one mail piece between the feed drive and the retard drive at a same time; and when more than one mail piece is sensed between the feed drive and the retard drive at the same time, reversing direction of movement of the retard drive relative to the feed drive from a forward direction to a reverse direction.  
           [0008]    In accordance with another method of the present invention, a method of determining a presence of mail pieces in a mail piece singulator section of a mail piece feeder is provided comprising steps of determining a first value of a first characteristic of a retard drive for a first condition; determining a second value of the first characteristic of the retard drive for a second condition, the second condition comprising a single mail piece being located directly between the retard drive and a feeder drive; and comparing the first and second values to each other. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    The foregoing aspects and other features of the present invention are explained in the following description, taken in connection with the accompanying drawings, wherein:  
         [0010]    [0010]FIG. 1 is a schematic view of a postage meter apparatus incorporating features of the present invention;  
         [0011]    [0011]FIG. 2 is a schematic perspective view with a cut away section of the feeder section shown in FIG. 1;  
         [0012]    [0012]FIG. 2A is a partial perspective view of an alternate embodiment of the hopper section;  
         [0013]    [0013]FIG. 2B is a partial perspective view of an alternate embodiment of the turner of the feeder section shown in FIG. 2;  
         [0014]    [0014]FIG. 3 is a schematic view of the controller, feeder drive and retard drive of the feeder section shown in FIG. 2;  
         [0015]    FIGS.  4 A- 4 E are schematic views of the feed rollers and retard rollers with various different conditions of mail pieces between them;  
         [0016]    [0016]FIG. 5 is a chart of loads on the retard rollers at different times/conditions;  
         [0017]    [0017]FIG. 6 is a flow chart of one method of the present invention; and  
         [0018]    [0018]FIG. 7 is a flow chart of another method of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0019]    Referring to FIG. 1, there is shown a schematic view of a postage meter apparatus  10  incorporating features of the present invention. Although the present invention will be described with reference to the embodiments shown in the drawings, it should be understood that the present invention can be embodied in many alternate forms of embodiments. In addition, any suitable size, shape or type of elements or materials could be used.  
         [0020]    The apparatus  10  generally comprises a feeder section  12 , a scale and postage meter section  14  and an output section  16 . The three sections  12 ,  14 ,  16  could be provided as a single unit or could be modular units connected in series to each other. The output section  16  could be any suitable type of output section, such as a stacking bin for example. Many different types of output sections are known in the art. Many different types of scale and postage meter sections are also well known in the art. Any suitable type of scale and postage meter section  14  could be provided. The section  14  could also merely be a postage meter without a scale, or the scale could be provided as part of the feeder section  12  or between the two sections  12  and  14 .  
         [0021]    Referring also to FIG. 2, one embodiment of the feeder section  12  is shown. In the this embodiment the feeder  12  generally comprises a hopper section  18 , a singulating section  20 , and a mail piece turner section  22 . In alternate embodiments the turner section  22  might not be provided or could be provided with the section  14 . The hopper section  18  generally comprises a portion of the mail piece support deck  24 , a portion of the rear wall  26 , a portion of the feeder drive  28  and a front stop  30 . The support deck  24  extends the length of the feeder  12 , at least up until the turner section  22 . The rear wall  26  has a front facing mail piece contacting surface  32  which is preferably vertical, but may be inclined slightly forward or backward. The feeder drive  28  includes at least one drive motor  34  (see FIG. 3) connected between a controller  36  and high friction feed rollers  38 . The vertical series of feed rollers  38  are orientated in a substantially vertical plane and extend outward past the surface  32  through holes in the surface  32 . In an alternate embodiment the feed rollers  38  might not be connected to the controller. In another alternate embodiment the feed rollers  38  could be replaced by any suitable type of mechanical transport, such as belts for example. The front stop  30  is preferably spring biased towards the rear wall  26  to bias the mail pieces M towards the rear wall. However, any suitable type of system could be provided to move the mail pieces towards the feeder drive  28 . The feeder section  12  is adapted to have the mail pieces M loaded into the hopper section  18  in a substantially vertical orientation with the flap edge preferably located down against the deck  24  and the mail piece flap preferably facing forward. The motor  34  preferably rotates the feed rollers  38  at a constant velocity. However, in an alternate embodiment the velocity of the feed rollers  38  could be varied, such as by the controller  36  for example. The feed deck  24  could be flat or, as shown in FIG. 2A, an alternate embodiment could comprise light, low friction idler rollers  40  extending through holes  42  in a top surface of the deck  24 ′ on which the flap edges of the mail pieces move. The rollers  40  could project into the rear wall surface  32 ′ if desired. In alternate embodiments any suitable type of hopper section could be used including those well known in the art, such as a horizontally stacked or substantially horizontally reorientating feeding hopper for example.  
         [0022]    The singulating section  20  generally comprises a portion of the feeder drive  28 , a portion of the rear wall  26  and surface  32 , and a retard drive  44 . Referring also to FIG. 3, the retard drive  44  generally comprises a motor  46 , retard rollers  48  and at least one sensor  50 . The feed rollers and retard rollers might share the same motor with the retard rollers merely having a different variable and reversible transmission. The motor  46  could be a common motor with the motor  34 , the controller  36  controlling a reversible transmission between the common motor and the retard rollers  48 . In an alternate embodiment the retard rollers  48  could be replaced by drive belts or any other suitable mechanical drive. The sensor  50  is preferably a load or force sensor. However, in alternate embodiments any suitably type sensor(s) could be used, such as a speed sensor. The motor  46  is preferably a reversible motor and is connected to the controller  36 . The motor  46  drives the retard rollers  48 . The series of retard rollers  48  are orientated in a general vertical plane substantially parallel to the vertical plane of the series of feed rollers  38 . The retard rollers  48  are located opposite some of the feed rollers  38  and are preferably spring loaded in a direction towards the feed rollers  38  and contact the feed rollers  38  when no mail piece is located in the feed path between the two sets of rollers.  
         [0023]    In a preferred embodiment, the retard drive  44  is adapted to configure movement of the retard rollers in at least two movement configurations; both at least partially independent of movement of the opposing feed rollers  38 . In a first movement configuration the retard rollers  48  are rotated in a forward direction to move a mail piece between the sets of rollers  38 ,  48  in a forward lateral direction from the hopper section  18  towards the takeaway rollers  52 . The retard rollers  48  could be actively moved by the motor  46  at a speed slower than the feed rollers  38 , and/or be passively moved by direct contact with the feed rollers  38  or mail piece(s) driven by the feed rollers  38 . The sensor  50  can sense a predetermined characteristic of the retard rollers  48 , such as speed of the retard rollers or, preferably, a force different or load on the retard rollers  48  between the motor  46  and the feed rollers  38  or mail piece pushing against the retard roller. The sensor  50  sends this information to the controller  36 . In a second movement configuration, the retard rollers  48  are rotated in a reverse direction to move a mail piece located against the retard rollers  48  in a reverse lateral direction back towards the hopper section  18 . In a preferred method, during both the first and second movement configurations of the retard drive, the feeder drive  28  continues to move the feed rollers  38  in a forward direction. However, in alternate methods the feeder drive  28  could vary the speed of the feed rollers  38  or even stop rotation of the feed rollers  38  while the retard rollers experience the second movement configuration. In another alternate method, the second movement configuration could comprise the retard rollers being positively or actively stopped from rotation, such as by motor  46  or a brake, while the feed rollers  38  continue to rotate in the forward direction. As seen in FIG. 2, the retard rollers  48  are arranged in laterally offset sets along the mail piece feed path. The controller  36  and motor(s)  46  could be configured to rotate the offset sets of retard rollers at different speeds and/or directions relative to each other, or even allow the rollers to function as brakeable idler rollers. This could also be done for the horizontally spaced sets of feed rollers  38  in the singulating section  20 .  
         [0024]    Referring now also to FIGS.  4 A- 4 E,  5  and  6 , one method of operation of the singulating section  20  will be described. FIG. 6 corresponds to the embodiment wherein the sensor  50  is a load sensor and a signal of load  54  is sent to the controller  36 . At an initial time  4 A corresponding to FIG. 4A, the feed rollers  38  and retard rollers  48  are located against each other and are driven in a same feed direction; block  56  in FIG. 6. No mail pieces are located between the rollers  38 ,  48 . As indicated by block  58  in FIG. 6, the sensor  50  senses the load on the retard rollers  48 . This produces a signal corresponding to load  54   a  from the sensor  50 . At about time  4 B a mail piece M 1  is fed by the feed rollers  38  between the sets of rollers  38 ,  48  as seen in FIG. 4B. The load on the retard roller  48  will reduce because of slippage between the mail piece M 1  and the retard roller  48 ; the feed roller  38  having a higher coefficient of friction than the mail piece M 1 . This produces a signal corresponding to lower load  54   b  from the sensor  50 .  
         [0025]    In the event that more than one mail piece M 1 , M 2  are feed between the rollers  38 ,  48  at the same time, as shown in FIG. 4C, and time  4 C in FIG. 5, the output signal corresponding to load  54   c  from the sensor  50  will indicate a much lower load, such as 50% or less than the signals for loads  54   a  and  54   b . This is because the two mail pieces M 1 , M 2  can slide relative to each other; even though they are moving in the same forward direction. As indicated by block  60  in FIG. 6, the controller  36  is programmed or otherwise configured to determine if the load on the retard roller  48  has reduced past a first predetermined load sensor setting LS 1 . The setting LS 1  could be fixed, or manually adjustable and/or automatically adjustable. One example of an automatically adjustable system will be discussed further below with regard to FIG. 7, but any suitable adjustment system could be provided. If the information sent by the sensor to the controller matches or is reduced past setting LS 1  then, as indicated by block  62 , the controller  36  can change operation of the retard drive from the first movement configuration to the second movement configuration; in this case reversing direction of movement of the retard rollers as indicated by arrow B in FIG. 4C. Thus, at time  4 C′, when the roller  48  reverses direction, the load increases and then subsequently decreases to load  54   c ″ at time  4 C″ when the two mail pieces M 1 , M 2  slide in reverse directions relative to each other. The system can have suitable filters or otherwise be configured such that the load spike  54   c ′ does not cause the retard rollers  48  to return back to the forward direction of rotation A.  
         [0026]    The system continues to monitor the output from the sensor  50 . At time  4 D, when the second mail piece M 2  is no longer between the rollers  38 ,  48  but the first mail piece M 1  is between the rollers  38 ,  48  as shown in FIG. 4D, the load on the retard roller  38  increases to the load  54   d . However, this load  54   d  is below a second predetermined load sensor setting LS 2 . The second setting LS 2 i similar to the setting LS 1 , could be fixed or manually and/or automatically adjustable. At time  4 E, corresponding to FIG. 4E, the first mail piece M 1  exits from between the rollers  38 ,  48 . The two rollers  38 ,  48  then directly contact each other again. This causes the load on the retard roller  48  to spike to its highest level  54   e . Load level  54   e  is above the second setting LS 2 . As indicated by block  64  in FIG. 6, when the controller determines that the load on the retard roller has increased past the second predetermined load sensor setting, the controller can reverse the motor and reverse the direction of rotation of the retard roller back from direction B to a forward feed direction as indicated by block  66  in FIG. 6 and arrow A in FIG. 4E. Thus, the two mail pieces M 1  , M 2  have been separated and the second mail piece M 2  can now be feed forward. The load at the sensor, thus, returns to level  54   a  as indicated at time  4 E′ in FIG. 5. Of course, this is only an example of how features of the present invention can function. Variations will occur in timing, conditions (such as more than two mail pieces between the rollers  38 ,  48 ), and loads (due to such factors as coefficients of friction of the mail pieces, thickness of the mail pieces and rigidity of the mail pieces).  
         [0027]    The first setting LS 1  can be automatically adjustable based upon the mail pieces being fed. One example of automatically adjusting the system will now be described with reference to FIG. 7. This system adjusts the first setting LS 1  based upon frictional properties of the mail pieces being fed. As indicated by block  70  the system first determines the force or load on the retard roller during static feeding; time  4 A and force  54   a . As indicated by block  72 , then the system determines the force or load on the retard roller during dynamic sliding feeding of a single mail piece; time  4 B and force  54   b  . The controller  36  can then determine a ratio of the two forces/loads  54   a  and  54   b  as indicated by block  74 . Based upon information in the controller  36 , such as an algorithm or a chart or table of precollected imperical data for example, the controller  36  can vary the first setting LS 1  based upon this ratio as indicated by block  76 . This can prevent unnecessary triggering of reversal of the retard rollers for mail pieces having relatively low coefficients of friction, or prevent non-triggering of reversal of the retard rollers for mail pieces having relatively high coefficients of friction. Of course, this is only one example of adjustability. Other variations and alternate embodiments could be evident to those skilled in the art after reading the present description.  
         [0028]    Referring back to FIG. 2, once the mail pieces as separated by the singulating section  20 , the faster speed take away rollers  52  can move the mail pieces away from the singulating section and down the feed path. In this embodiment the feeder section  12  further comprises an angled flap roller  80 , a deflector  82  and a moistening brush  84 . The angled flap roller  80  can open the flap of the mail piece and drive the mail piece against the deck  24 . The deflector  82  can open the flap to allow the brush  84  to moisten the glue on the inside of the flap. In alternate embodiments the members  80 ,  82  and/or  84  might not be provided. The feeder section  12  can also comprise a sensor  51  which can be a mail piece sensor or sensing the leading edge or the trailing edge or presence of a mail piece. This could be used to determine when no mail pieces are in between the feeding wheels and for recording the static forces or loads on the wheels in this condition. The system could also be configured to turn the driving motion of the wheels ON and OFF based upon time and the input from the sensor  51 , or any other suitable input. In other words, the time chart shown in FIG. 5 does not need to be continuous, but may be intermittent or comprise periodic sampling of the loads (i.e.: by use of periodic clock signals). In alternate embodiments variations in timing of operations, and specific control operations (perhaps based upon inputs) could be varied.  
         [0029]    The turner section  22  generally comprises opposing belts  86  rotatably mounted on pulleys  88 ,  90 . The first pulleys  88  have rotation axes  92   a ,  92   b  parallel to each other in a substantially vertical orientation. The second pulleys  94 ,  96  have rotation axes  98   a ,  98   b  parallel to each other in a substantially horizontal orientation. The mail pieces M enter between the first pulleys  88  in a substantially vertical orientation and are moved by the belts  86  towards the opposite end at the pulleys  90 . As the belts  86  move the individual mail pieces, the orientation of the mail piece rotates about 90° to a substantially horizontal orientation. As the mail pieces exit the turner section  22  from between the pulleys  90 , they are propelled into the scale and postage meter section  14 . In alternate embodiments the turner section  22  might not be provided, such as when the postage meter applies postage to vertically orientated mail pieces.  
         [0030]    Referring also to FIG. 2B, an alternate embodiment of the turner section is shown. In this embodiment the surface  32 ′ of the rear wall  26 ′ has a deflector or pusher  33 . As the vertically orientated mail piece moves along the deck  24  and surface  32 ′, it contacts the projecting deflector  33 . This causes the top of the mail piece to tilt forward. Gravity then causes the top of the mail piece to rotate towards the deck  24 . Thus, a gravity system can be provided to reorientated the mail pieces to a substantially horizontal orientation.  
         [0031]    The present invention can provide a mixed mail feeder (which can feed different thickness mail pieces as well as different size mail and also handles sealed or unsealed mail) as well as nested and unnested mail. This invention utilizes a combination of paper handling technologies and a unique architecture to achieve desired features. The user preferably loads the mail into the hopper in the prescribed manner. In this case, an important aspect of this design is that the system will use gravity to advantage. The mail can be loaded into the system with the flap edge down and the flap facing the operator. In order to make loading more convenient, the loading deck is displaced up stream of the feed separation station, which allows additional mail to be loaded while the machine is running and not effect the machine operation. Since letters are on edge, the feeding forces are not effected by the size of the stack. The stack can be retained by a spring-loaded front stop, which can be opened with one hand while the mail is loaded with the other hand. The stack can lean approximately 10 degrees to the rear so that the stack will remain in place when the stop is pulled back for loading.  
         [0032]    Important features of the feeder are multiple (minimum two) separate high friction feed wheels along the rear wall and a similar number of separate retard feed rollers (independently spring loaded on a tapered input guide or throat leading to the takeaway rollers). The feed rollers and the retard rollers are located opposed to each other and are controlled/driven independently. The feeder deck can be provided with light, low friction idler rollers on which the incoming mail moves. An important feature of the invention is that the feed and retard opposing rollers can be driven by motors which can sense the force on the retard drive and determine whether the mail piece is being retarded; that is sliding on the adjacent mail piece closer to the feed deck, or whether it is being driven by the feeder with the high friction rollers.  
         [0033]    The detection system could also monitor and filter the instantaneous peaks in load caused by the breaking apart of two mail pieces caused by the force of static friction. Further capability of the system is selectable control for differences in friction between different mail; by monitoring the ratios of the static and sliding forces on the rollers. Typically the different between static and dynamic is between 20% and 50%. The difference between rubber to paper and paper to paper can be at least a factor of two, and can be easily detected to determine when one mail piece is in the roller nips. Since the mail pieces are moving slowly (during the period of static friction and sliding friction) the effect of their size and weight are minimized.  
         [0034]    If sliding (paper to paper) retard forces are detected, the retard system should continue to drive back the mail piece. If high feeding forces are detected than it can be assumed that the mail piece has been singulated and the retard system should reverse back to a forward direction and assist the feeding of the piece into the takeaway rollers. Once the mail piece is in the nip of the takeaway; the retard rollers could revert to the reverse action required for separation.  
         [0035]    The architecture and feeding logic provide very important features for the operator/customer. The input stack can be much larger than normally provided in a machine of this type (limited only by the size of the feed deck assembly), since the feeding forces are unaffected by a stack. The prior art stack height is normally limited to several inches (typically 5 inches). The feeding forces are primarily determined by the backstop pushing on the stack. The retard system is extremely robust, with three stages of retard or sets of retard rollers before the mail piece is taken away, providing additional capability to separate and feed mixed mail reliability. The lead edge alignment is optimally provided by gravity, which is more reliable than existing systems which attempt to drive a mail piece into alignment from the bottom of a stack. The feeder system can separate both sealed and unsealed mail over a range of sizes compatible with the size of the system.  
         [0036]    Once into the takeaway system, an angled driven friction roller can open the flap if it is not already sealed, and pass the flap through a moistening system while the mail piece is still vertical. After the piece has passed the sealing section, it could be passed through a set of turning belts which would turn the piece 90 degrees to present it to the horizontal dynamic scale transport deck. Optionally, a simpler less costly turning system could be provided by simply dropping the mail piece onto the dyna scale deck with appropriate guiding so that it would fall onto the deck aligned with the rear wall.  
         [0037]    It should be understood that the foregoing description is only illustrative of the invention. Various alternatives and modifications can be devised by those skilled in the art without departing from the invention. Accordingly, the present invention is intended to embrace all such alternatives, modifications and variances which fall within the scope of the appended claims.