Tape storing and feeding mechanism for mailing machines

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.

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.

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 142a, 142b, 142c and 142d 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 142a
 extends in the downstream direction of tape feed for a major portion of
 the length of the tape supporting portion 136, the rib 142b extends in the
 same direction for only a minor portion of the length of the supporting
 portion 136, the rib 142c extends for a slightly less distance than the
 rib 142b, and the rib 142d 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 P1 and P2 (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.