Abstract:
A high speed, high volume mailing machine which utilizes ink jet technology for the printing of postage indicia on envelopes being fed through the mailing machine and on discrete portions of tape fed past the printing device of the mailing machine includes a tape storing and feeding mechanism which stores a roll of tape in the form of a web of indefinite length for feeding a discrete portion of the tape past the feeding device for each printing operation of the mailing machine, and feeds the tape forward to bring the printed portion thereof past and then reverses the movement of the tape to bring the new leading edge thereof to the beginning of the printing area. The tape storing and feeding mechanism provides a fixed support for the portion of the tape being printed on so as to maintain a critical gap between the surface of the tape and the plane of the jet nozzles to achieve a high printing quality. The tape storing and feeding mechanism also provides a feeding device which maintains effective control over the movement of the tape without contacting any part of the printed portion thereof, and further provides ample shock absorbing for the roll of tape so that sudden acceleration of the tape strip does not tear the tape in the printing area.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates generally to the field of ink jet printing, and more particularly to mailing machines which incorporate ink jet technology and have the capability of printing postage indicia either on envelopes fed successively through the mailing machine or on discrete lengths of tape that is stored in and dispensed from the mailing machine and then manually affixed to bulky mail pieces or packages. 
     Automatic high speed mailing machines of the type with which the present invention is utilized have long been well known and have achieved a high degree of commercial success. Mailing machines of this type typically include an elongated feed deck, an envelope conveyor mechanism extending along the feed deck, a hopper for holding a stack of envelopes with the flaps still open, a flap closing and sealing device located just downstream from the hopper, and a postage meter mounted over the feed deck just downstream from the flap closing and sealing device. The postage meter typically includes an accounting device for monitoring the amount of postage dispensed and a printing device for printing a postage indicia on the envelopes as they are fed along the feed deck. The postage meter further includes a postage amount setting mechanism by which the postage meter is manually set to print an appropriate amount of postage as required by the weight of the envelopes being fed through the mailing machine. Some of the more sophisticated mailing machines include an envelope weighing device interposed between the flap closing and sealing device for weighing each envelope as it passes over the weighing device and the postage meter for automatically setting the postage to print an appropriate amount of postage in the postage indicia. 
     Traditionally, from the earliest development of postage meters, the printing devices therein have utilized ink transfer technology, in which ink is transferred from a storage device to a rotary or flat bed printing die of the printing device, and the ink then being transferred from the printing die to the envelope, either by rotation of a curved printing die while the envelope is in motion, or by suitably pressing the envelope against the flat bed printing die. However, recent technological advances in the field of ink jet technology have resulted in this form of printing technology being adopted for use in postage meters, with the result that the printing devices in postage meters can now provide the same technical and operator advantages as are offered by ink jet technology in other types of printing applications. 
     One of the most significant problems that had to be overcome in adapting postage meters for use with ink jet technology was that of establishing and maintaining a proper physical orientation between the surface of an envelope traveling through the mailing machine on which the postage indicia was to be printed or between the surface of a piece of tape stored in the mailing machine on which the postage indicia was to be printed. In all prior mailing machines which utilized ink transfer technology, both the envelopes and the tape on which the postage indicia was printed were supported by a fixed surface against which the rotary or flat bed printing die pressed the envelope or piece of tape in order to effectively transfer the ink from the die to the surface of the envelope or tape. It must be remembered that a postage meter, in effect, is printing an indicia that is the equivalent of money, and therefore the print quality of the indicia must meet certain minimum standards for this type of printing established by the local Postal Authority. It was therefore critical that an effective and reliable die to envelope or tape surface pressure contact be obtained for each printing operation to ensure that the required printing quality was obtained. This presented little problem with the prior arrangement of providing a printing die which pressed against a printing surface which in turn was rigidly supported by a fixed surface during the printing operation. 
     All of this changed with the advent of ink jet technology in the postage meter field. In order for the ink jet nozzles of any ink jet printer to deposit ink on the surface of a receiving medium, it is critical that a small predetermined gap be maintained between the exit plane of the nozzles and the surface of the receiving medium, typically in the order of one sixteenth to one thirty-second of an inch. This gap is necessary to achieve proper and acceptable image quality, since too small a gap causes excessive ink to be deposited in the actual image area, resulting in a poor image quality, and too large a gap results in an image that appears fuzzy or out of focus. In heretofore conventional printing devices utilizing ink jet technology, such as computer printers, maintaining this gap was not a problem because the sheet of paper on which printing was taking place was always supported on a rigid, stationary surface while printing is taking place. For example, in a typical printer, the sheet of paper is typically wrapped partly around a roller and the ink jet print head moves laterally across the sheet to produce a line of print. When a full line has been printed, the sheet is indexed to the next line, and the print head moves across the sheet to print a second line, and so on until the printing operation is complete. In addition, in conventional ink jet printers, the item being printed upon does not vary in thickness so that, as long as the sheet remains flat on the supporting surface, there will be no variation in the gap between the printing surface and the plane of the ink jet nozzles. Also, conventional printers utilize a motor to drive the roll and then feed the tape web across the print means. The orientation of the motor connected to the roll employs a larger motor such that the inertia of the roll can be overcome. However, these large motors are expensive and, due to the large force, may tear or inconsistently feed the tape web. 
     The problem of maintaining the critical gap between the surface of an envelope and the plane of the ink jet nozzles was effectively solved with the invention disclosed and claimed in U.S. patent application Ser. No. 08/951,073 filed on Oct. 15, 1997 now U.S. Pat. No. 5,923,343 entitled MAILING MACHINE HAVING REGISTRATION SHIELD FOR INK JET PRINTING ON ENVELOPES and assigned to the assignee of this application. However, the invention disclosed and claimed in that application did not solve the problems inherent in utilizing ink jet technology in a postage meter to print a postage indicia on a discrete length of tape stored in the mailing machine. Since the thickness of the tape does not vary as it does with envelopes, the top registration invention of the prior application was not applicable to printing on tape. Also, once printing occurs on the envelope, it is ejected from the mailing machine and the next envelope is immediately presented to the printing device. With tape, on the other hand, when printing takes place on a discrete portion of the tape, which is typically stored in roll form and fed as a web, the tape must be advanced to a position where the printed portion can be severed from the web and ejected from the mailing machine, after which the tape must be fed in a reverse direction to bring the new leading edge of the web to the printing position, thereby avoiding what would otherwise be an unacceptable degree of waste of tape each time an indicia is printed. Still further, since the printed postage indicia is relatively small in relation to the surface area of an envelope, there is ample surface area available for engagement with the envelope of various types of feeding mechanisms to move the envelope through the mailing machine after printing occurs without running the risk of smearing the ink within the postage indicia area by contact with any part of the feeding mechanisms. With the tape, on the other hand, the size of the postage indicia is such that it occupies a major portion of the height of the strip of tape, thereby leaving very little marginal portion of the tape for contact with any portion of a tape feeding mechanism for moving the tape forwardly for printing and severing and then backwards to realign the new leading edge of the tape with the beginning of a printing location. Finally, it has been found that mailing machines of the type with which ink jet technology is utilized for printing postage indicia on envelopes can operate at such a high rate of speed that typical tape storing and feeding mechanisms cannot operate successfully to commence feeding of the tape without running a high risk of tearing it, simply because the stored roll of tape cannot be accelerated fast enough to reduce the shock of the sudden acceleration on the tape, with the result that the tape frequently tears, and the mailing machine must be shut down to rethread the tape through the feeding mechanism. 
     Thus, despite the successful solutions to the problems of printing postage indicia on envelopes using ink jet technology, several significant problems remain in printing postage indicia on tape for later affixation to bulky envelopes and packages. And since this capability is an important contribution to the commercial acceptance of large, high volume mailing machine, there remains a critical need for the development of an effective mechanism for storing and feeding tape in a mailing machine on which postage indicia can be printed with the same degree of speed and acceptable print quality that has been achieved in connection with printing of envelopes. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention substantially obviates, if not entirely eliminates, the problems associated with the feeding of tape within a mailing machine, or other ink jet printer, for the purpose of printing a postage indicia, or other indicia, thereon utilizing ink jet technology. The present invention addresses each of the problems mentioned above in connection with the design of an effective tape storing and feeding mechanism for use in a mailing machine utilizing ink jet technology for printing a postage indicia on the tape. Thus, the present invention provides a tape storing and feeding device which effectively maintains the proper critical gap between the surface of the tape being printed upon and the plane of the ink jet nozzles in order to achieve the necessary degree of print quality, which provides a tape feeding mechanism that effectively moves the tape in both forward and reverse directions without contacting any portion of the printed postage indicia and smearing the ink thereon, and provides an effective solution to the problem of tearing the tape due to sudden acceleration of the tape in order to maintain a high speed of operation of the mailing machine. 
     In its broader aspects, the present invention is a tape storing and feeding mechanism for an ink jet printer which has at least one ink jet print head for printing at least a portion of an indicia on a portion of a tape stored in the printer, where the storing and feeding mechanism includes a storage mechanism mounted in the printer for storing a roll of tape, and an elongated tape feeding and supporting structure having an essentially flat upper surface mounted in the printer in axial juxtaposition with the tape storing mechanism and in vertical juxtaposition with the print head for feeding the web along the upper surface so that the web is disposed beneath and moves past the print head, and also includes upstream and downstream tape feeding mechanisms mounted at opposite ends of the tape supporting structure for feeding discrete portions along the tape supporting structure, so that the tape supporting structure supports the tape with a uniform separation from the print head to assure good print quality. 
     In accordance with one aspect of the subject invention, the tape supporting structure has a plurality of ribs projecting upwards and downwards from upper and lower surfaces of the supporting structure and extending substantially from one end of the supporting structure to the other, the upper edge portions of the upwardly projecting ribs defining the upper surface of the tape supporting structure. The ribs further provide a reservoir for collecting excess or waste ink which may result during printing. 
     In accordance with another aspect of the subject invention, the tape storing and feeding mechanism includes a cover having an upper element spaced from and substantially parallel to the upper surface of the tape supporting structure, the cover engaging latches on the side of the tape supporting structure, and having an opening approximate to the print head for printing the indicia on the tape. 
     In accordance with still another aspect of the subject invention, the upwardly projecting ribs are cut away adjacent to the print head so that the upper surface is not contaminated by ink discharged from the print head in the absence of tape and such ink can accumulate in the space between the ribs without interfering with the operation of the printer. 
     In accordance with still another aspect of the subject invention, the tape storage mechanism includes a first well for storing the roll of tape, the tape being fed from a bottom portion of the roll, upwards along a front wall of the well to the tape supporting and feeding mechanism, where the front wall includes an extended, resilient portion for absorbing a portion of the force applied to the web by the tape feeding and supporting means to accelerate the tape. 
     In accordance with still another aspect of the subject invention, the tape storage mechanism includes a second well located downstream of the first well for receiving a loop of the tape formed when the tape is advanced after printing to a position where the printed portion can be severed, and the tape is then returned to a position upstream from the print head. 
     In accordance with yet another aspect of the subject invention, the tape feeding means is driven by a motor operatively coupled to a first set of rollers, rather than at the tape roll, thus a smaller, less expensive motor can be used to drive the tape web. 
     Having briefly described the general nature of the present invention, it is a principal object thereof to provide an improved tape feeding mechanism which reliably and accurately maintains a proper spacing between an ink jet print head and the upper surface of a tape upon which an indicia is printed by the print head. 
     Other objects and advantages of the subject invention will be apparent to those skilled in the art from consideration of the detailed description set forth below and the attached drawings. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a representative automatic high speed mailing machine which includes the tape feeding mechanism of the present invention. 
     FIG. 2 is a perspective view of an interior portion of the mailing machine shown in FIG. 1 showing the location of the tape feeding mechanism of the present invention. 
     FIG. 3 is a perspective view of the tape feeding mechanism of the present invention shown in exploded orientation to the printing device of the mailing machine. 
     FIG. 4 is a plan view of the tape feeding and supporting means with the cover member in place and showing a discrete length of tape in the position it would occupy just after a printing operation has taken place. 
     FIG. 5 is side view of the tape feeding and supporting means shown in FIG.  4 . 
     FIG. 6 is a sectional view taken on the line  6 — 6  of Fig. showing the details of the rib construction of the tape supporting means. 
     FIG. 7 is a side view of the tape feeding and supporting means shown in FIG.  6 . 
     FIG. 8 is a sectional view taken on the line  8 — 8  in Fig. showing details of construction of the upstream feeding mechanism. 
     FIG. 9 is a sectional view taken on the line  9 — 9  of Fig. showing details of the upper and lower rib construction of the tape supporting bridge. 
     FIG. 10 is a sectional view taken on the line  10 — 10  in FIG. 5 showing details of construction of the downstream feeding mechanism. 
     FIG. 11 is a side sectional view of the tape storage device shown in FIG. 3 but drawn to an enlarged scale. 
     FIG. 12 is plan view of the tape storage device shown in FIGS. 3 and 11 but with the roll of tape removed. 
     FIGS. 13-17 are diagramatic views of the tape feeding and supporting means showing the position of various portions of the tape during a complete cycle of operation of the mailing machine in printing a postage indicia on a discrete section of the tape. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings and particularly to FIGS. 1 and 2 thereof, the reference numeral  10  designates generally an automatic high speed mailing machine of the type in which the present invention is utilized, and comprises an elongate base, designated generally by the reference numeral  12 , which supports a feed deck  14  that extends substantially the length of the base  12 . A user interface having a control panel and a information display unit, designated generally by the reference numeral  20 , is suitably mounted on the mailing machine base  12  in the vicinity of a cover  18  so as to be conveniently accessible to an operator. The cover  18  encloses a suitable separating mechanism for withdrawing the bottom envelope of a stack and feeding it into the feeding mechanism that conveys it past the ink jet printing device further described below and provides jam access. Another cover, designated generally by the reference numeral  22 , encloses most of the operating components of the mailing machine  10 , including the tape storing and feeding mechanism described below, and can be raised to the dotted line position to afford an operator full access to the interior of the mailing machine  10 . In the mailing machine  10  for which the tape storing and feeding mechanism of the present invention was designed, a weighing scale (not shown) is suitably integrated into the feed deck  14  for weighing mail pieces as they move along the feed deck so as to automatically set the postage meter to cause the printing device further described below to print an appropriate amount of postage. A postage meter (not shown) is detachably mounted to a meter pocket  15  located underneath the cover  22 . The pocket  15  is suitable mounted to the base  12  to be repositionable so as to allow access to the meter. 
     A plurality of nudger rollers  24  are mounted beneath the infeed end of the feed deck  14  and project upwardly through suitable openings in the feed deck  14  for the purpose of separating the bottom envelope from a stack of envelopes placed on top of the nudger rollers  24 , the stack being confined by suitable rear and end walls  26  and  28  respectively. The nudger rollers  24  feed the bottom most envelope to a separating device (not shown) located beneath the cover  18 , which ensures that only one envelope at a time is fed into the mailing machine  10 . From the separating device, the envelopes are fed through a flap closing and sealing device (not shown) which is also located beneath the cover  18  which closes and seals the flaps to the rear panels of the envelopes. From there, the envelopes are fed into an elongate conveyor assembly, designated generally by the reference numeral  30  in FIG. 2, which conveys envelopes past an ink jet printing device, designated generally by the reference numeral  32 , for printing the postage indicia on the upper right hand corner of the envelopes. The envelope conveyor  30  includes an endless belt  34  which extends around suitable drive rollers  36  suitably mounted on the mailing machine base  12 , and a tensioning roller  38  to maintain proper tension on the belt  34 . The belt  34  includes a lower run  40 , and a plurality of back up pressure roller assemblies, designated generally by the reference numeral  42 , are suitably mounted on the base unit  12  beneath the lower run  40  of the belt  34 , each roller assembly  42  having a spring loaded arm  44  pivotally mounted on the base unit  12  and carrying a back up pressure roller  46  adjacent the free end of the arm  44 . With this arrangement, the plurality of back up rollers  46  maintain an envelope in firm driving engagement with the lower surface of the lower run  40  of the belt  34 . Since the conveyor assembly  30  forms no part of the present invention, further description thereof is not deemed necessary for a full understanding of the present invention. 
     With particular reference to FIGS. 2 and 3, it will be seen that the ink jet printing assembly  32  is mounted in the mailing machine base  12  generally in a location toward the downstream end of the envelope conveyor  30  and spaced therefrom toward the rear portion of the mailing machine  10 . The printing assembly  32  includes at least one but preferably a pair of digital ink jet print heads  48  and  50 , which are suitably mounted on a housing  52 . The housing  52  is suitably mounted on a frame  54  which in turn is mounted for lateral movement within the mailing machine base  12  between an intermediate position and two extreme positions, the printing assembly  32  being shown in FIG. 2 in the intermediate position. The frame is moved between the three positions by a threaded rod  56  suitably mounted on a standing portion  57  of the mailing machine base  12 . The rod  56 , when rotated in the opposite direction, cause the frame  54 , housing  52  and print heads  48  and  50  to move forwardly or rearwardly within the frame  12  from the intermediate position shown in FIG.  2 . The intermediate position is a stand-by or maintenance position in which the print head(s) of any ink jet printer is maintained when the printer is not in operation. When the printing assembly  32  is moved forwardly so that the frame  54  is contiguous with the forward portion of the rod(s)  56 , the print heads  48  and  50  are moved to a position overlying a guide plate  58  having a pair of apertures  60  through which the print heads  48  and  50  direct the ink from the nozzles on the lower end of the print heads  48  and  50  onto the surface of an envelope being conveyed past the location of the guide plate  58  by the conveyor assembly  30 . 
     With the foregoing description as background, the following description of the construction, orientation within the mailing machine  10  and operation of the tape storing and feeding mechanism of the present invention will be better understood. With particular reference to FIGS. 2,  3 ,  11  and  12 , the tape storing and feeding mechanism comprises an elongated tape storing means, designated generally by the reference numeral  62 , which, as best seen in FIG.  2 , is located generally rearwardly of the upstream end of the envelope conveyor  30 . The tape storing means  62  is preferably formed as a one-piece, molded plastic receptacle having a rear supporting section  64 , and a pair of upstanding side walls  66  and  68  which define an upper open trough  70  which extends the full length of the tape storing means  62 . The storing means  62  is suitably removably secured to a plate  71  which is part of the base  12  of the mailing machine  10 . As best seen in FIG. 11, the storing means  62  includes an upstream well, designated generally by the reference numeral  72 , which is defined by an upstream end wall  74 , upstream portions of the side walls  66  and  68 , an upstream bottom wall  76  which slants downwardly at a shallow angle from left to right as viewed in FIGS. 3 and 11, and a first intermediate wall  78  which slants sharply upwardly in the same direction. The upstream well  72  is adapted to hold a roll  80  of tape of indefinite length which is wound on a suitable spindle  82  which is easily manually accessible through the slots  84  in the upstream portions of the side walls  66  and  68  formed in the central portion of the upstream well  72 . The first intermediate wall  78  is integrally connected to the bottom wall  76 , but is free standing from that point on, in that the forward wall  78 , as best seen in FIG. 12, is formed as a pair of wall portions  86  forming an elongate aperture  88  therebetween, and which join together adjacent the upper end of the first intermediate wall  78  in a solid portion  90  which has a curved upper edge  92 . As best seen in FIG. 12, the upper edge  92  of the first intermediate wall  78  is not connected to the side walls  66  and  68 , as is the bottom portion, with the result that the upper edge  92  is free to move back and forth a limited distance due solely to the resilience of the plastic material from which the tape storing device  66  is formed. Wall  78  thus forms an elongated resilient element which absorbs the initial shock as the tape is accelerated, reducing the possibility that the tape might break. The tape storing device  62  further includes a downstream well, designated generally by the reference numeral  94 , which is defined by a second intermediate wall  96 , a bottom wall  98  and a downstream end wall  100  which terminates upwardly in a forwardly curved lip  102 , which constitutes a forward supporting means device  62 , again, all for a purpose to be made clear hereinbelow. 
     Still referring to FIGS. 3 and 11, it will be seen that, in the normal, unstressed condition of the tape from the roll  80  when the mailing machine  10  is not in operation, the roll  80  rests against the forward wall  78  by gravity due to the downward slant of the bottom wall  76 , and a portion  104  of tape from the roll  80  projects upwardly along the first intermediate wall  78  to form an upwardly projecting reverse loop portion  106  which joins with a downwardly extending portion  108  which extends downwardly into the well  94  for a major portion of the depth of the well  94 , as shown by the dotted lines in FIG.  3 . The portion  108  then joins with a downwardly projecting reverse loop portion  110  which joins with an upwardly extending portion  112 , the upper end of which is closely adjacent to the upper lip  102  of the downstream end wall  100  of the well  94 . A further portion of the tape, as well as the functions of the previously described portions, will be further described hereinbelow. 
     As best seen in FIG. 3, an elongated tape feeding and supporting means, designated generally by the reference number  114 , extends from the upper forwardly curved lip  102  of the tape storage device  62  to the forward wall  57  of the mailing machine base  12  for the purpose of feeding a discrete length of tape from the roll  80  thereof and supporting it beneath the print heads  48  and  50  of the printing device  32  in a manner now to be described. With reference to FIGS. 3 through 11, it will be seen that the tape feeding and supporting means  114  comprises essentially three major parts, a tape supporting bridge, designated generally by the reference numeral  116 , an upstream and downstream tape feeding mechanism, designated generally  118  and  120  respectively, and a cover device, designated generally by the reference numeral  122 , for supporting the bridge  116 . As previously mentioned, it is important in a ink jet printer to maintain the proper gap between the surface upon which printing takes place and the plane of the print head nozzles, and this is particularly difficult to maintain in a paper handling situation where the paper must be registered against the top surface rather than the bottom, as is the case in more customary ink jet printing applications. In the present invention, the supporting bridge  116  is the structure by which the tape is supported during the printing operation and therefore which must maintain the proper gap between the upper surface of the tape and the ink jet nozzles. This is accomplished by molding the supporting bridge  116  from a plastic composition that is essentially a glass and carbon filled nylon material which provides a high degree of rigidity, dimensional control, static dissipation, resistance to warping and a smooth, virtually friction free surface on which the tape moves, and is also resistant to inks. 
     As best seen in FIGS. 4,  7  and  11 , the supporting bridge  116  has a lip  124  which is upwardly curved in the direction of feed of the tape and which is adapted to fit over the upper forwardly curved lip  102  of the downstream wall  100  of the tape storage means  62 , the lip  124  also having a lateral dimension that is slightly less than that of the side walls  66  and  68  so as to fit therebetween and rest on the upper lip  102 . Thus, as best seen in FIG. 11, the tape will slide very easily over the transition from the lip  102  on the wall  100  to the lip  124  on the bridge  116 . The bridge  116  then has a relatively short infeed ramp portion  126  that is slightly inclined in the direction of feed, and a pair of side walls  128  and  130  which are spaced apart a distance substantially equal to the width of the tape, leaving just enough clearance so that the tape can pass freely between the walls  128  and  130 . The walls  128  and  130  assist with aligning the tape when tape reloading is necessary The ramp portion  126  merges adjacent the upstream feeding mechanism  118  with a relatively long tape supporting portion  132  which extends from the location of merger to the upstanding wall  57  of the mailing machine base  12 , to which the downstream end of the supporting portion  132  adjacent the downstream feeding mechanism  120 , is suitably secured as by the locating pin  134 . The bridge  116  is also provided with a pair of apertures  136  (FIG. 7) on a depending portion of the bridge  112  beneath the ramp  126  through which pins pass to connect the upstream end of the bridge  116  to a portion of the mailing machine base  112 . 
     Due to the criticality of maintaining the proper gap between the plane of the ink jet nozzles and the printing surface of the tape, the bridge  116 , including both the ramp portion  126  and the tape supporting portion  132 , is formed as a continuous flat strip  136  which has integrally molded downwardly and upwardly projecting side edges  137  and  138  respectively (FIG.  9 ), thereby forming in cross section a laterally elongated “H” configuration. The bridge  116  also has a plurality of depending and upstanding ribs  140  and  142  respectively molded integrally with the upper and lower surfaces of the strip  136  (FIGS.  7  and  9 ). The depending ribs  137  and  138  extend substantially the full length of the bridge  116 , while the upstanding ribs  142  are discontinuous and have a unique configuration as further described below. One function of the ribs  140  and  142  is to prevent warping during the molding process, since it is known that when molding a flat piece with ribs formed on one side, the flat piece tends to warp slightly and bow due to unsymmetrical cooling which occurs during the molding process, which, in the case of the bridge  116 , would cause the gap between the printing surface of the tape and the plane of the jet nozzles to vary across the printing area, resulting in an indicia of unacceptable print quality. The other function is to lend sufficient strength and rigidity to the bridge  116  to prevent any possibility that it can warp or otherwise change shape through prolonged use or damage from mishandling during the life of the mailing machine  10 . 
     With particular reference to FIGS. 6 and 7, it will be seen that the upstanding ribs  142  are of different lengths and are positioned in different locations on the upper surface of the flat strip  136 . A first group of ribs, labeled  142   a,    142   b,    142   c  and  142   d  commence substantially at the juncture of the infeed ramp  126  and the flat strip  136 , just on the downstream side of the feeding mechanism  118 . As best seen in FIG. 7, the upstream ends of these ribs are depressed below the nip of the feed rollers  152  and  162  of the upstream feed mechanism  118  to ensure that the lead edge of the tape will feed smoothly onto the ribs. The rib  142   a  extends in the downstream direction of tape feed for a major portion of the length of the tape supporting portion  136 , the rib  142   b  extends in the same direction for only a minor portion of the length of the supporting portion  136 , the rib  142   c  extends for a slightly less distance than the rib  142   b,  and the rib  142   d  is a very short rib disposed adjacent the lower feed roller  162  and terminates at an aperture  232  formed in the bottom wall of the tape supporting portion, below which a suitable tape edge detection device, designated generally by the reference numeral  234  which detects the arrival of the leading edge of the tape at the location of the aperture  232  for a purpose to be fully explained below. 
     By cutting away upper rib  142  in the regions P 1  and P 2  (FIG. 6) directly below print heads  48  and  50 , ink discharged from print heads  48  and  50  (either accidentally or to purge the print heads) does not contaminate the upper surface along which the tape moves. Other portions of ribs  142  are cut away to allow ink to accumulate in the entire volume defined by ribs  142 , which it is estimated to be sufficient to contain any amount of ink likely to accumulate in the life of a machine. Dams D are provided to prevent ink from flowing from this volume and contaminating the printer. 
     With particular reference now to FIGS. 4 through 8, the upstream tape feeding mechanism  118  is seen to comprise an upper roller assembly designated generally by the reference numeral  150  which comprises a roller having a plurality of large diameter segments  152  separated by smaller diameter segments  154 , the roller being mounted on an upper shaft  156 . The feeding mechanism  118  also includes a lower roller assembly designated generally by the reference numeral  160 , which also comprises a roller having a plurality of large diameter segments  162  separated by smaller diameter segments  164  which are located in a complimentary manner to the large and small diameter segments  152  and  154  of the upper roller assembly  118 . The lower roller is mounted on a lower shaft  166 , on one end of which is mounted a pulley  167 . As best seen in FIG. 8, the upper shaft  156  is journaled for rotation in the upper ends of a pair of elongated bearing blocks  168  which are mounted for limited vertical movement in a pair of suitable bearing housings  170  formed integrally with the upstream end of the tape support bridge  116  on both sides thereof. The lower shaft  166  is journaled for rotation in a pair of bearing plates  172  (FIG. 5) which are suitably secured to the bearing housings  170  as by the screws  174 . 
     Each of the bearing blocks  168  project downwardly sufficiently far to terminate in bifurcated projections  176  which extend beyond the bottom surface  179  of a portion of the support bridge  116  which extends between the bearing housings  170 , and an elongated plate  180  extends across the width of the bearing housings  170  and is mounted on the bifurcated projections  176  of the bearing blocks  168  by means of apertures  182  formed adjacent each end of the elongated plate  180  and which are of smaller diameter than the projections  176 , but which engage with an annular slot  184  formed in each projection  176  by compressing the legs of the bifurcated projections when the plate  180  is pressed over the projections  176 . A downwardly extending center stud  188  is formed integrally with the bottom surface  178  and is received in a center aperture  190  formed in the elongated plate  180 . A compression spring  192  is captured around the stud  188  between the upper surface of the elongated plate  180  and the bottom surface  178  of the portion of the support bridge  116  that extends between the bearing housings  170  so as to exert a downward force on the upper shaft  156 , thereby pressing the large diameter segments  152  of the upper roller into firm engagement with the corresponding segments  162  of the lower rollers so as to exert a firm driving engagement with the tape therebetween, as best seen in FIG.  8 . The bearing blocks  168  are provided with elongated slots  194  to provide for the limited movement thereof. 
     So far as described, the downstream roller assembly  120  is identical to that of the upstream roller assembly with the exceptions now described. With reference to FIG. 10, it will be seen that the upper roller assembly designated generally by the reference numeral  196  still comprises an upper shaft  198 , but in this assembly the upper roller has only two large diameter segments  200  with an elongated smaller diameter segment  202  extending therebetween, with the result that the tape is engaged only between the large diameter segments  200  of the upper roller and the corresponding outermost larger diameter segments  204  of the lower roller. It should also be noted that the lower shaft  206  for the lower roller has a pulley  208  mounted on the end thereof that corresponds to the end of the lower shaft  176  which carries the pulley  167 , and a timing belt  210  extends between the pulleys  176  and  208  so that the shafts  166  and  206  are driven in synchronism at the same velocity. As best seen in FIG. 3, a second pulley  212  is mounted on the lower shaft  166  of the lower roller assembly  160 , and a drive belt  214  is connected between this pulley and a suitable motor mounted in the base  12  of the mailing machine, with the result that the shaft  166  is the main drive shaft for both the upstream and downstream tape feeding mechanisms  118  and  120 . 
     In a preferred embodiment of the invention, a knife edge roller (not shown) having a narrow contact surface is positioned between rollers  200  so as to bear upon an unprinted portion of the tape in order to prevent the tape from bowing upwards and coming into contact with cover  220  after the indicia is printed and while the ink is still wet, as well as to guide entrance into downstream paths (not shown). 
     Referring now particularly to FIGS. 4,  5  and  9 , the cover device  122  which extends over the top of the tape supporting bridge  116  is seen to comprise an elongated strip of sheet metal  220  which extends substantially from the nip of the rollers in the upstream and downstream tape feeding mechanisms  118  and  120 , and is adapted to lie on the upper surface of the upwardly projecting side edges  138 . A pair of side edges  222  extend downwardly and terminate in short laterally outwardly angled flanges  224 . The cover device  122  is removably retained in place on the supporting bridge  116  by means of a plurality of projections (not shown) which are engaged by the detents  226  formed on the side edges  222  of the cover device  122 . 
     The cover device  122  is provided with an elongated aperture designated generally by the reference number  230  in FIGS. 4 and 6. 
     FIGS. 13 through 17 show a schematic representation of the operation of the tape feeding and supporting mechanism of the subject invention. Initially, tape from roll  80  is held substantially tautly above well  94  by upstream feeding mechanism  118 . Detector  252  and light source  254  detect the leading edge of the tape to synchronize operation of the tape storing and feeding mechanism of the invention with operation of print heads  48  and  50 . 
     In FIG. 14, feeding mechanism  118  advances the tape past print heads  48  and  50 , which print an indicia, until the tape is engaged by downstream feeding mechanism  120  which continues to advance the tape until it is severed by conventional severing mechanism  250 . 
     Then, in FIG. 15, the tape storing and feeding mechanism reverses and withdraws the tape to the initial position, forming a loop in well  94 . By reversing the tape, wastage of the portion of the tape drawn past print heads  48  and  50  before the printed indicia is severed is avoided. 
     In FIG. 16, feeder mechanism  118  again advances the tape for printing, and in FIG. 17 the indicia is printed and the tape advanced by feeder mechanism  120  and the cycle repeats.