Abstract:
A document feeder employs a lifting lever to lift stacked documents away from a feed roller each time a document is being fed away from the stack. In this way the separation of documents is enhanced, providing a mechanism that more readily accommodates documents of varying shapes, thicknesses, and materials. The feeder uses a motor linked by one-way clutches to feed mechanisms for documents and for labels, stacked separately. The motor is driven in one direction to feed documents and in the other direction to feed labels. A moistener is provided below the paper path, and the moistener is mounted so that it can be slidably removed. When it is removed, feed rollers are permitted to relax and move apart which helps in the clearing of jams.

Description:
BACKGROUND 
     The invention relates generally to a feeder for documents which are to be franked in a postage meter, and relates particularly to an improved feeder which accomplishes reliable separation for individual feeding of documents from a stack even if they are of varying thicknesses and varying materials. The feeder is able to accommodate batches of documents, each batch being of documents of a particular size, but the feeder is readily adjustable to a different size of batch. Stated differently, the stack may be adjusted to one document size per batch. 
     A particularly difficult part of the design of any stacked document feeder is the separation of documents. It is critical that documents be passed one by one from the feeder to later equipment in the paper path, such as a postage meter. The passage of documents one by one permits the postage meter to frank each of them in a reliable way. It is important that misfeeds such as duplicate feeding of two or more documents be minimized or eliminated. It is desirable that the feeder be capable of feeding not only documents but also labels, which are used for applying postage to mail pieces that are unable to pass through the feeder and through the postage meter. It is also preferable that the feeder have a moistener with which envelopes may be moistened and sealed. With the moistener a typical problem is the need to replace parts of the moistener that age and need to be replaced, such as a sponge or brush. It is also desirable that any document jams in the feeder be easy to clear. 
     The many design goals just described must, of necessity, be fulfilled (if at all) within constraints of cost and size (form factor). It is thus particularly desirable to accomplish these many design goals at reasonable cost and while minimizing parts count and assembly steps. 
     SUMMARY 
     A document feeder employs a lifting lever to lift stacked documents away from a feed roller each time a document is being fed away from the stack. In this way the separation of documents is enhanced, providing a mechanism that more readily accommodates documents of varying shapes, thicknesses, and materials. The feeder uses a motor linked by one-way clutches to feed mechanisms for documents and for labels, stacked separately. The motor is driven in one direction to feed documents and in the other direction to feed labels. A moistener is provided below the paper path, and the moistener is mounted so that it can be slidably removed. When it is removed, feed rollers are permitted to relax and move apart which helps in the clearing of jams. 
    
    
     DESCRIPTION OF THE DRAWING 
     The invention will be described with respect to a drawing in several figures, of which: 
     FIG. 1 is a cross section showing feeder elements such as rollers which interact directly with mail pieces and labels; 
     FIG. 2 is a side view showing the driving interactions among the feeder elements of FIG. 1; 
     FIGS. 3 and 4 are cross sections showing a feeder lever in first and second positions; 
     FIG. 5 shows in exploded and perspective view some of the feeder elements of FIG. 1 along with a moistener and a water bottle; and 
     FIGS. 6A,  6 B, and  6 C show the feeder lever of FIGS. 3 and 4 in greater detail in side, top, and perspective views respectively. 
    
    
     Where possible, like elements in figures are shown with like reference designations. 
     DETAILED DESCRIPTION 
     FIG. 1 is a cross section showing feeder elements such as rollers which interact directly with mail pieces and labels. Mail pieces  28 , typically documents such as cards or envelopes, may be stacked by a user in a stacking area above roller  20 . Guides, omitted for clarity in FIG. 1, define the stacking area and are adjustable for various sizes of envelopes and cards. A mail piece may proceed along a paper path beginning at arrow  29  and may eventually reach a later (downstream) portion of the paper path as shown by arrow  30 . Later the mail piece desirably enters a postage meter (franking machine) most of which is omitted for clarity from FIG.  1 . 
     The movement of a mail piece from the stacking area to the postage meter is as follows. First, a mail piece triggers the sensor  71 . This may be because a stack of documents is in the stacking area, in which case the bottom piece reaches the sensor  71 . Alternatively, instead of a stack of documents, it may happen that a single document is hand-fed into the feeder, thus triggering the sensor  71 . 
     Next the mail piece (for example, the bottom piece of the stack  28 , or an individually hand-fed mail piece) is driven along the paper path (rightwards in FIG. 1) to roller  21 . A counter-rotating roller  22  rotates (clockwise in FIG.  1 ). The roller  22  has a rubber ring as described further below, which tends to repel mail pieces other than the bottom mail piece, forcing them backwards in the paper path (leftwards in FIG.  1 ). This prevents or at least minimizes double feeding. Separation of stacked pieces is always difficult, but this separator roller  22  helps in the process of separation. 
     The mail piece that is being fed (that is, the bottom piece of the stack  28  or an individually hand-fed mail piece) is gripped roller  21  and a rib on roller  22 . Roller  21  carries the mail piece further along the paper path until it is gripped by rollers  23 ,  24 . One of these rollers is a driver roller, while the other is an idler roller, driven by contact with the driver roller or by contact with a mail piece that moves because of contact with the driver roller. In an exemplary embodiment, roller  24  is a driver roller and roller  23  is the idler roller. Roller  23  is spring-loaded and is able to move downward to accommodate thicker mail pieces. 
     Rollers  23 ,  24  carry the mail piece further along the paper path until it is gripped by rollers  25 ,  26 . One of these rollers is a driver roller, while the other is an idler roller, driven by contact with the driver roller or by contact with a mail piece that moves because of contact with the driver roller. In an exemplary embodiment, roller  26  is a driver roller and roller  25  is the idler roller. Roller  25  is spring-loaded and is able to move downward to accommodate thicker mail pieces. 
     As will be described below in connection with the moistener  65 , it is desirable that the spring loading of rollers  23 ,  25  be linked (for example by camming surfaces) with the position of the moistener  65 . 
     As will be appreciated, all of the rollers which are below the paper path (that is, rollers  20 ,  21 ,  23 , and  25 ) rotate clockwise in FIG. 1, thereby urging any mail piece in the direction of the paper path toward the postage meter (to the right in FIG.  1 ). It will also be appreciated that all of the rollers that are above the paper path (except the separator roller  22 ) rotate counter-clockwise in FIG. 1, likewise urging any mail piece in the direction of the paper path toward the postage meter. Those skilled in the art will appreciate that rollers  20 ,  21 ,  23 , and  25  are preferably set up so that the each roller that is further long in the paper path has a tangential velocity no less than, and preferably greater than, the tangential velocity of the roller preceding it in the paper path. 
     FIG. 1 also shows the moving elements associated with the printing of labels. When a label is to be printed, roller  27  rotates counterclockwise in FIG. 1, drawing a label downward along label path  31 . The label proceeds past but preferably does not touch roller  26  (which rolls clockwise during label feeding) and along path  32 , into the postage meter. 
     Roller  20  contacts mail pieces with a relatively “live” surface such as neoprene black, rubber 35° shore. Roller  21  is likewise a relatively “live” surface such as neoprene black, rubber 45° shore. 
     Roller  22  has a rubber ring (mentioned above) which may be PU UK2 55° shore, green. The main body of roller  22  may be POM. Roller  27  may be neoprene black, rubber 35° shore. (“Shore” is an industry-standardized measure of hardness for flexible materials.) 
     A sensor  71  senses presence of at least one mail piece in the stacker area. Sensors  72 ,  73  are located in a post meter (franking machine), most of which is omitted for clarity in FIG.  1 . In an exemplary embodiment, these sensors are LED-phototransistors operating in an infrared wavelength. 
     The sequence of steps for franking an envelope or other mail piece are as follows. A mail piece or a stack of mail pieces are placed in the stacking area, an event sensed by sensor  71 . This information is made available by the feeder to the postage meter via a communications channel. At some point, the postage meter becomes ready to frank, learns of the presence of a mail piece at sensor  71 , and communicates with the feeder. The result of this communication is that the feeder begins feeding. Rollers  20 ,  21 ,  22 ,  23 ,  24 ,  25 , and  26  rotate as described above, and one or more mail pieces are passed singly along the paper path  29 ,  30  to the postage meter, past sensors  72 ,  73 . The mail pieces are franked. 
     The sequence of steps for franking a label are as follows. One or more labels are stacked in a label stacking area, omitted for clarity in FIG.  1 . At some point, the user communicates to the postage meter that it is desired to frank a label, and the meter communicates with the feeder. The result of this communication is that the feeder begins feeding a label. Rollers  26  and  27  rotate as described above, and one label is passed singly along the paper path  32  to the postage meter, past sensors  72 ,  73 . The label is franked. The motor is operated for a period of time selected to be sufficient to pass one label through the feeder. 
     It will be appreciate that one skilled in the art may devise obvious variations on this arrangement, deviating in no way from the invention. For example, the manner in which the user communicates that a label is to be franked need not be by means of a communication to the postage meter, but may as well be a communication to the feeder or to some other communicatively coupled equipment. 
     FIG. 2 is a side view showing the driving interactions among the feeder elements of FIG. 1. A motor  41  has a worm gear  42  engaging a corresponding gear on the shaft of roller  24 . Roller  24  is belted to roller  26 . Thus when motor  41  rotates in one direction (the direction for envelope feeding), rollers  24  and  26  rotate counterclockwise in FIG. 1, and idler rollers  23 ,  25  rotate clockwise. On the other hand, when motor  41  rotates in its other direction (the direction for label feeding), rollers  24  and  26  rotate clockwise in FIG. 1, and idler rollers  23 ,  25  rotate counterclockwise. 
     Importantly, one-way clutches  90 ,  91  are provided. When roller  26  rotates in the direction for label feeding (clockwise in FIG.  1 ), then clutch  91  grips and causes roller  27  to rotate (counterclockwise in FIG. 1) to feed a label. When roller  26  rotates the other direction, clutch  91  relaxes and roller  27  does not rotate. The clutches  90 ,  91  may be spring-type clutches or roller clutches. 
     In either direction of rotation, rollers  23  and  25  are idlers, simply following the motion of their respective rollers  24 ,  26 . 
     In a similar way, roller  24  drives gear  44  but only through clutch  90 . This, when roller  24  rotates in the direction for envelope feeding (counterclockwise in FIG.  1 ), clutch  90  grips and causes gear driving of gear  44 , clockwise. When roller  24  rotates the other direction, clutch  90  relaxes and gear  44  does not rotate. 
     Gear  44  engages further with gears  43  and  45 , and through them to rollers  21  and  22 . In this way, rotation of roller  24  in the direction for envelope feeding (counterclockwise in FIG. 1) causes rotation of rollers  21  and  22 , both clockwise in FIG.  1 . Belt  46  links rollers  21  and  20  so that roller  20  also rotates clockwise in FIG.  1 . 
     It will thus be appreciated that the use of the clutches  90 ,  91  permits many benefits for the feeder. It becomes necessary to provide only one motor, rather than more than one, to permit feeding mail pieces and labels. The motor is heavy, and reducing the number of motors saves weight and bulk. The overall complexity of the apparatus is reduced, since there need not be levers, solenoids, electrically operated clutches, or other break-prone moving parts to shift the feeder from mail piece mode to label mode and back again. The wire count and connector pin count is reduced because of the reduction in the number of motors. 
     FIGS. 3 and 4 are cross sections showing a feeder lever  51  in first and second positions. In FIG. 3, there is no mail piece between rollers  21  and  22 . There may well have been a previous mail piece  55  which would have previously passed through and beyond rollers  21 ,  22  in which case it may have reached rollers  23 ,  24 . Feeder lever  51  importantly pivots at pivot point  53  which is between roller  20  and roller  21  and in this embodiment is located below the paper path. Although not shown in FIG. 3 for clarity, rollers  21  and  22  are each bipartate, each having an axial spacing between its two parts. The two axial spacings are one above the other, positioned to allow end  54  of lever  51  to move up and downward above and below the paper path. In FIG. 3 the end  54  has moved upward to a position above the paper path, surrounded by the two parts of the roller  22 . 
     Turning briefly now to FIGS. 6A,  6 B, and  6 C, what is shown is the feeder lever  51  in more detail. Side view FIG. 6A shows the pivot point  53 , the end  54 , and end  52 . FIG. 6B is a top view revealing that end  52  is desirably bipartate with the two parts of end  52  straddling roller  20 . FIG. 6C shows these details in a perspective view. 
     Returning now to FIG. 3 it may be seen why the end  54  moved upward, namely that the mail pieces  57  press downward on end  52 . As mentioned above, lever end  52  is preferably bipartate, with portions located axially at either end of the roller  20 . 
     Now consider the sequence of events in FIG. 3 when the feeder operates. The bottom mail piece  56  (in the stack  57 ) is in frictional contact with roller  20 . When roller  20  rotates, the mail piece  56  is urged along the paper path (rightward in FIG. 3) toward roller  21 . 
     Turning now to FIG. 4, we see the consequences of a mail piece (now shown with reference numeral  60 ) having reached the roller  21 . The mail piece  60 , being stiff, presses the lever end  54  downwards into the space between the two parts of roller  21 . The geometry of the lever  51  and the nearby structure is such that downward motion of end  54 , given fixed pivot point  53 , results in upward motion of end  52 . This lifts the bottom mail piece  58  (if present) and any other mail pieces in the stack  59  (if present) upwards, and none of the mail pieces in the stack  59  is in contact with roller  20 . 
     Stated differently, what is shown is a feeding method including the steps of: 
     allowing documents  57  in the stack area to come in contact with a first roller  20  (FIG.  3 ), 
     passing a lowermost document  56  in the stack area in the exit direction, 
     lifting the documents  59  in the stack area above the first roller  20  when the lowermost document  56 ,  60  reaches a second roller  21  (FIG.  4 ), and 
     allowing documents  57  in the stack area to come in contact with the first roller  20  after the lowermost document  55  has passed the second roller  21  (FIG.  3 ). 
     Those with experience in the separation of pieces will appreciate that separating uniform pieces (such as separating sheets for printing in a printer) is difficult, but that separating non-uniform pieces (such as separating a stack of non-identical envelopes) is even more difficult. The task is even more difficult if the envelopes are of differing thicknesses or contain other matter such as staples and paper clips. It will thus be appreciated by those skilled in the art of feeding envelopes and other mail pieces that the lever  51  contributes substantially to the successful separation of envelopes and other mail pieces. This lever  51 , especially when combined with the counter-rotating roller  22 , achieves very successful separation, even with envelopes and other potentially non-uniform mail pieces. 
     One skilled in the art will of course appreciate that obvious variations may be devised which permit the great benefits of the lever  51  while departing from the precise configuration just described. For example, while it is considered desirable that the rollers  21  and  22  are each bipartate with portions to one side of the lever end  54  and to its other side, unitary rollers  21  and  22  could likely be used with the lever end axially disposed to one end or the other of the rollers  21 ,  22 . 
     In an exemplary embodiment the motor  41  is a DC motor, but could as well be a stepper motor or any other reversible motor. Those skilled in the art will appreciate that while it is most desirable to use a single motor and two clutches to accomplish the separate mail piece and label feeding functions, it would be possible to forgo those savings by using two distinct motors, one for each feeding function, still obtaining the desirable paper separation functions described in connection with lever  51 . In such a case the motors could be AC motors. Likewise it will be appreciated that while it is most desirable to use the lever  51 , the lever  51  could be omitted and the benefits of the use of a single motor and two clutches would be retained. 
     FIG. 5 shows in exploded and perspective view some of the feeder elements of FIG. 1 along with a moistener assembly  65  and a water bottle  63 . Plate  95  defines the paper path previously described, and protruding upwards through plate  95  are roller  20 , bipartate roller  21 , rollers  23 , and roller  25 . Lever end  54  is visible between portions of roller  21 . Lever ends  52  are visible astride roller  20 . In the exploded view of FIG. 5, roller  22  is visible above roller  21 , and rollers  24  and  26  are visible above rollers  23  and  25 . A tape or label feeder housing  60  permits stacking labels nearby to roller  27  for label feeding, and the housing is accessible to the user through opening  62  in housing  61 . In normal operation, housing  61  is attached to plate  95  and most of the moving parts of the feeder are protected by housing  61  and by other housings omitted for clarity in FIG.  5 . 
     Moistener  65  is slidable into a corresponding recess in the plate  95 . While it is considered preferable that this motion be linear and at right angles to the paper path direction, those skilled in the art will appreciate that this motion could be at some other angle or could be rotary motion about a pivot axis such as a vertical axis, all without departing from the invention. A sponge or brush assembly  66  is positioned so as to seal envelope flaps as envelopes pass along the paper path. 
     Insertion of the moistener  65  into the plate  95  accomplishes at least two important results. First, a receptacle  67  is thereby positioned to receive a valve  64  of a water bottle  63 . In this way, water is dispensed into the moistener as needed to make up for water used in sealing, and water lost to evaporation. Second, one or more cam surfaces on moistener  65  cause rollers  23 ,  25  to be urged upwards in a spring-loaded way. 
     Thus, the removable feeder permits easy cleaning, replacement of wear parts such as sponges and brushes, and the clearing of jams. 
     A lever, omitted for clarity in the figures, permits the user to select whether the moistener will or will not moisten and seal envelopes. This raises or lowers the sponge or brush assembly  66  relative to the paper path. Preferably the linkage between this lever and the moistener is such that the moistener may be removed regardless of the position of this lever. 
     It will thus be appreciated by those skilled in the art that the removable moistener  65  is of great help in the clearing of document jams. When a jam occurs, the user removes the bottle  63  and gently pulls out the moistener  65  outward. If the jam was connected with the sponge or brush assembly  66 , then it may be readily cleared because the assembly  66  is in plain view and is fully accessible. Furthermore, removal of the moistener  65  relaxes the usual upward spring loading of the rollers  23 ,  25  and allows them to move downward. This helps in removing any jammed mail piece or foreign matter that was previously difficult to remove due to the rollers  23 ,  25 . 
     The separation concept used herein offers many improvements over earlier feeders. The system requires no active server elements, and carries out its task with steady rotation of the intake rollers. There is no need for stopping and starting as with some feeders and separation rollers. The rollers are radially symmetric, as distinguished from some more trouble-prone rollers that have a bump in one area to assist in separation. The separation system avoids the use of cams and cam followers which bring about cyclic, trouble-prone movements of active elements. 
     Those skilled in the art will have no difficulty devising myriad obvious variations on the invention, all of which are intended to be encompassed by the claims which follow.